Directory of Researchers

KONDO Narihiko
Graduate School of Human Development and Environment / Department of Human Development
Professor
Physical Education, Health and Sport Sciences
Last Updated :2022/05/11

Researcher Profile and Settings

Affiliation

  • <Faculty / Graduate School / Others>

    Graduate School of Human Development and Environment / Department of Human Development
  • <Related Faculty / Graduate School / Others>

    Faculty of Global Human Sciences / Department of Human Development and Community, Faculty of Human Development / Department of Human Behavior, Organization for Advanced and Integrated Research

Teaching

  • Faculty of Global Human Sciences, 2021, Adaptation of Physical Function 1
  • Faculty of Global Human Sciences, 2021, Graduation Thesis
  • Faculty of Global Human Sciences, 2021, Adaptation of Physical Function 2
  • Office for the Promotion of International Exchange, 2021, Introductory Practice of Health and Sport Sciences
  • Office for the Promotion of International Exchange, 2021, Introductory Practice of Health and Sport Sciences
  • Office for the Promotion of International Exchange, 2021, Practice of Health and Sport Sciences 1
  • Office for the Promotion of International Exchange, 2021, Practice of Health and Sport Sciences 2
  • Graduate School of Human Development and Environment / Department of Human Development, 2021, Topic in Applied Human Physiology and Adaptation I-1
  • Graduate School of Human Development and Environment / Department of Human Development, 2021, Independent Studies Ⅰ
  • Graduate School of Human Development and Environment / Department of Human Development, 2021, Independent Studies Ⅱ
  • Graduate School of Human Development and Environment / Department of Human Development, 2021, Topic in Applied Human Physiology and Adaptation I-2
  • Graduate School of Human Development and Environment / Department of Human Development, 2021, Seminar on Applied Human Physiology and Adaptation 1
  • Graduate School of Human Development and Environment / Department of Human Development, 2021, Seminar on Applied Human Physiology and Adaptation 2
  • Graduate School of Human Development and Environment / Department of Human Development, 2021, Independent Studies Ⅲ
  • Graduate School of Human Development and Environment / Department of Human Development, 2021, Independent Studies Ⅳ
  • Graduate School of Human Development and Environment / Department of Human Development, 2021, Topics in Applied Human Physiology and Adaptation II-1
  • Graduate School of Human Development and Environment / Department of Human Development, 2021, Topics in Applied Human Physiology and Adaptation II-2
  • Faculty of Human Development, 2021, Physical Adaptation to Environment and Exercise

Research Activities

Research Areas

  • Life sciences / Sports science

Awards

  • Oct. 2005 日本体力医学会, 第60回日本体力医学会優秀発表賞, 「非温熱性要因が長時間運動時の熱放散反応に及ぼす影響」の研究発表

    近藤 徳彦

Published Papers

  • Tatsuro Amano, Takako Asami, Tomoko Ichinose-Kuwahara, Dai Okushima, Hiroyuki Ueda, Narihiko Kondo, Yoshimitsu Inoue

    We investigated the influence of exercise intensities and regional differences in the sudomotor recruitment pattern in boys. Six prepubertal boys (age 11 ± 1 yr) cycled at light, moderate, and high exercise intensity (35%, 50%, and 65% VO2max) for 30 min in a temperate condition (28 °C, 40% relative humidity). Local sweat rate (ventilated capsule) and number of activated sweat glands (starch-iodine technique) at five body sites were assessed and sweat gland output was calculated. Responses in boys were compared with those in nine young men (23 ± 1 yr) tested under identical conditions. The forehead, chest, back, and forearm, but not thigh, sweat rate increased from light to moderate and at high intensities in boys (all p ≤ 0.005) but not from moderate to high (all p ≥ 0.071). The sweat rate on the forehead was relatively higher (p ≤ 0.045) and thigh was lower (p ≤ 0.050) than other sites in boys at moderate and high intensities. Exercise intensity-dependent sweating was associated with activating more sweat glands but not increasing glandular output in boys. The sweat rate in boys was attenuated versus men heterogeneously across body sites concurrent to low glandular outputs (all p ≤ 0.027). We conclude that exercise intensity modulates the sweat rate in boys by changing the number of activated sweat glands heterogeneously among skin sites. Age-related differences in the sudomotor pattern are evident at higher exercise intensities. Development of glandular output per gland occurring from boys to young men may play a key role in modulating sweat rate with respect to exercise intensity and regional differences.

    01 Jan. 2022, Physiology & behavior, 243, 113642 - 113642, English, International magazine

    Scientific journal

  • Kazuhiro Harada, Kouhei Masumoto, Keiko Katagiri, Ai Fukuzawa, Michiko Touyama, Daichi Sonoda, Makoto Chogahara, Narihiko Kondo, Shuichi Okada

    OBJECTIVES: Although neighborhood is considered to be a crucial source of social network to promote health among older adults, current findings are mostly derived from observational study designs. This study examined whether participations in event-based community programs could increase neighborhood social network and whether such increase could lead to desirable changes in mental and physical health among older adults. METHOD: This study employed quasi-experimental design. A baseline questionnaire survey was sent to residents of Tsurukabuto community aged 60 years or more (n = 1769); 1,068 responded. Community events were implemented approximately once a month for three years. Then, a three-year follow-up survey questionnaire was sent to the respondents of the baseline survey. The total number of respondents in the latter survey was 662; of the total, 173 participated in the intervention. Strong and weak ties with neighbors, mental well-being (Ikigai-9), health-related quality of life (HRQOL), and instrumental activity of daily living (IADL) were measured in the surveys. RESULTS: The path analysis revealed that intervention participation was significantly associated with changes in strong ties (standardized path coefficient = 0.12) and changes in strong ties were associated with those in Ikigai-9 scores (standardized path coefficient = 0.15). The total and indirect effects of intervention participation on Ikigai-9 scores were significant. Significant intervention effects were not observed for HRQOL and IADL scores. CONCLUSION: This study found that participation in our event-based intervention could indirectly and positively influence older adults' mental well-being through their strong ties with their neighbors.

    Dec. 2021, Aging & mental health, 25 (12), 2235 - 2245, English, International magazine

    Scientific journal

  • Richie P Goulding, Simon Marwood, Tze-Huan Lei, Dai Okushima, David C Poole, Thomas J Barstow, Narihiko Kondo, Shunsaku Koga

    This study tested the hypothesis that the respiratory compensation point (RCP) and breakpoint in deoxygenated [heme] [deoxy[heme]BP, assessed via near-infrared spectroscopy (NIRS)] during ramp incremental exercise would occur at the same metabolic rate in the upright (U) and supine (S) body positions. Eleven healthy men completed ramp incremental exercise tests in U and S. Gas exchange was measured breath-by-breath and time-resolved-NIRS was used to measure deoxy[heme] in the vastus lateralis (VL) and rectus femoris (RF). RCP (S: 2.56 ± 0.39, U: 2.86 ± 0.40 L·min-1, P = 0.02) differed from deoxy[heme]BP in the VL in U (3.10 ± 0.44 L·min-1, P = 0.002), but was not different in S in the VL (2.70 ± 0.50 L·min-1, P = 0.15). RCP was not different from the deoxy[heme]BP in the RF for either position (S: 2.34 ± 0.48 L·min-1, U: 2.76 ± 0.53 L·min-1, P > 0.05). However, the deoxy[heme]BP differed between muscles in both positions (P < 0.05), and changes in deoxy[heme]BP did not relate to ΔRCP between positions (VL: r = 0.55, P = 0.080, RF: r = 0.26, P = 0.44). The deoxy[heme]BP was consistently preceded by a breakpoint in total[heme], and was, in turn, itself preceded by a breakpoint in muscle surface electromyography (EMG). RCP and the deoxy[heme]BP can be dissociated across muscles and different body positions and, therefore, do not represent the same underlying physiological phenomenon. The deoxy[heme]BP may, however, be mechanistically related to breakpoints in total[heme] and muscle activity.

    01 Nov. 2021, American journal of physiology. Regulatory, integrative and comparative physiology, 321 (5), R712-R722, English, International magazine

    Scientific journal

  • Naoto Fujii, Glen P Kenny, Tatsuro Amano, Yasushi Honda, Narihiko Kondo, Takeshi Nishiyasu

    Na+-K+-ATPase is integrally involved in mediating cutaneous vasodilation during an exercise-heat stress, which includes an interactive role with nitric oxide synthase (NOS). Here, we assessed if Na+-K+-ATPase also contributes to cutaneous thermal hyperemia induced by local skin heating, which is commonly used to assess cutaneous endothelium-dependent vasodilation. Furthermore, we assessed the extent to which NOS contributes to this response. Cutaneous vascular conductance (CVC) was measured continuously at four forearm skin sites in 11 young adults (4 women). After baseline measurement, local skin temperature was increased from 33°C to 39°C to induce cutaneous thermal hyperemia. Once a plateau in CVC was achieved, each skin site was continuously perfused via intradermal microdialysis with either: 1) lactated Ringer solution (control), 2) 6 mM ouabain, a Na+-K+-ATPase inhibitor, 3) 20 mM l-NAME, a NOS inhibitor, or 4) a combination of both. Relative to the control site, CVC during the plateau phase of cutaneous thermal hyperemia (∼50% max) was reduced by the lone inhibition of Na+-K+-ATPase (-19 ± 8% max, P = 0.038) and NOS (-32 ± 4% max, P < 0.001), as well as the combined inhibition of both (-37 ± 9% max, P < 0.001). The magnitude of reduction was similar between NOS inhibition alone and combined inhibition (P = 1.000). The administration of both Na+-K+-ATPase and NOS inhibitors fully abolished the plateau of CVC with values returning to preheating baseline values (P = 0.439). We show that Na+-K+-ATPase contributes to cutaneous thermal hyperemia during local skin heating to 39°C, and this response is partially mediated by NOS.NEW & NOTEWORTHY Cutaneous thermal hyperemia during local skin heating to 39°C, which is highly dependent on nitric oxide synthase (NOS), is frequently used to assess endothelium-dependent cutaneous vasodilation. We showed that Na+-K+-ATPase mediates the regulation of cutaneous thermal hyperemia partly via NOS-dependent mechanisms although a component of the Na+-K+-ATPase modulation of cutaneous thermal hyperemia is NOS independent. Thus, as with NOS, Na+-K+-ATPase may be important in the regulation of cutaneous endothelial vascular function.

    01 Nov. 2021, Journal of applied physiology (Bethesda, Md. : 1985), 131 (5), 1408 - 1416, English, International magazine

    Scientific journal

  • Huixin Zheng, Claire E Badenhorst, Tze-Huan Lei, Ahmad Munir Che Muhamed, Yi-Hung Liao, Tatsuro Amano, Naoto Fujii, Takeshi Nishiyasu, Narihiko Kondo, Toby Mündel

    Measurement error(s) of exercise tests for women are severely lacking in the literature. The purpose of this investigation was to 1) determine whether ovulatory status or ambient environment were moderating variables when completing a 30-min self-paced work trial and 2) provide test-retest norms specific to athletic women. A retrospective analysis of three heat stress studies was completed using 33 female participants (31 ± 9 yr, 54 ± 10 mL·min-1·kg-1) that yielded 130 separate trials. Participants were classified as ovulatory (n = 19), anovulatory (n = 4), and oral contraceptive pill users (n = 10). Participants completed trials ∼2 wk apart in their (quasi-) early follicular and midluteal phases in two of moderate (1.3 ± 0.1 kPa, 20.5 ± 0.5°C, 18 trials), warm-dry (2.2 ± 0.2 kPa, 34.1 ± 0.2°C, 46 trials), or warm-humid (3.4 ± 0.1 kPa, 30.2 ± 1.1°C, 66 trials) environments. We quantified reliability using limits of agreement, intraclass correlation coefficient (ICC), standard error of measurement (SEM), and coefficient of variation (CV). Test-retest reliability was high, clinically valid (ICC = 0.90, P < 0.01), and acceptable with a mean CV of 4.7%, SEM of 3.8 kJ (2.1 W), and reliable bias of -2.1 kJ (-1.2 W). The various ovulatory status and contrasting ambient conditions had no appreciable effect on reliability. These results indicate that athletic women can perform 30-min self-paced work trials ∼2 wk apart with an acceptable and low variability irrespective of their hormonal status or heat-stressful environments.NEW & NOTEWORTHY This study highlights that aerobically trained women perform 30-min self-paced work trials ∼2 wk apart with acceptably low variability and their hormonal/ovulatory status and the introduction of greater ambient heat and humidity do not moderate this measurement error.

    01 Nov. 2021, Journal of applied physiology (Bethesda, Md. : 1985), 131 (5), 1496 - 1504, English, International magazine

    Scientific journal

  • N Gerrett, T Amano, Y Inoue, Narihiko Kondo

    PURPOSE: We examined whether eccrine sweat glands ion reabsorption rate declined with age in 35 adults aged 50-84 years. Aerobic fitness (VO2max) and salivary aldosterone were measured to see if they modulated ion reabsorption rates. METHODS: During a passive heating protocol (lower leg 42 °C water submersion) the maximum ion reabsorption rates from the chest, forearm and thigh were measured, alongside other thermophysiological responses. The maximum ion reabsorption rate was defined as the inflection point in the slope of the relation between galvanic skin conductance and sweat rate. RESULTS: The maximum ion reabsorption rate at the forearm, chest and thigh (0.29 ± 0.16, 0.33 ± 0.15, 0.18 ± 0.16 mg/cm2/min, respectively) were weakly correlated with age (r ≤  - 0.232, P ≥ 0.05) and salivary aldosterone concentrations (r ≤  - 0.180, P ≥ 0.179). A moderate positive correlation was observed between maximum ion reabsorption rate at the thigh and VO2max (r = 0.384, P = 0.015). Salivary aldosterone concentration moderately declined with age (r =  - 0.342, P = 0.021). Whole body sweat rate and pilocarpine-induced sudomotor responses to iontophoresis increased with VO2max (r ≥ 0.323, P ≤ 0.027) but only moderate (r =  - 0.326, P = 0.032) or no relations (r ≤  - 0.113, P ≥ 0.256) were observed with age. CONCLUSION: The eccrine sweat glands' maximum ion reabsorption rate is not affected by age, spanning 50-84 years. Aldosterone concentration in an aged cohort does not appear to modulate the ion reabsorption rate. We provide further support for maintaining cardiorespiratory fitness to attenuate any decline in sudomotor function.

    Nov. 2021, European journal of applied physiology, 121 (11), 3145 - 3159, English, International magazine

    Scientific journal

  • Tomomi Fujimoto, Naoto Fujii, Kohei Dobashi, Yinhang Cao, Ryoko Matsutake, Masataka Takayanagi, Narihiko Kondo, Takeshi Nishiyasu

    Thermal sensation, a key component of behavioral thermoregulation, is modulated by the changes in both skin and core temperatures. Although cutaneous thermal sensation to local cold is blunted during exercise as compared to rest in normothermic humans, it remains to be determined whether this holds true during core cooling. Furthermore, when local skin thermal sensation is diminished during exercise, it remains unclear whether whole-body thermal sensation is also attenuated. We therefore tested whether low-intensity exercise (VO2: ~1300 ml min-1) attenuates local skin and/or whole-body thermal sensation in hypothermic young males. Eleven healthy young males (24 ± 2 years) were cooled through cold water immersion (18 °C) up to their lower abdomen while resting (rest trial) and during low-intensity cycling (30-60 W, 30 rpm) (exercise trial). Body temperature, cardiorespiratory variables, and whole-body (9-point scale: 0, unbearably cold; 4, neutral; 8, unbearably hot) and local skin thermal sensation were measured at baseline on land and before the esophageal temperature (Tes) began to decrease (defined as -0.0 Tes) and after 0.5 and 1.0 °C decrements in Tes from baseline during the immersion period. Local skin thermal sensation was measured using a thermostimulator with Peltier element that was attached to the chest. The temperature of the probe was initially equilibrated to the chest skin temperature, then gradually decreased at a constant rate (0.1 °C s -1) until the participants felt coolness. The difference between the initial skin temperature and the local skin temperature that felt cool was assessed as an index of local skin thermal sensation. Throughout the immersions, esophageal and mean skin temperatures did not differ between the rest and exercise trials. Local skin thermal sensation also did not differ between the two trials or at any core temperature level. By contrast, the whole-body thermal sensation score was higher (participants felt less cold) in the exercise than in the rest trial at esophageal temperature of -1.0 °C (1.25 ± 0.46 vs. 0.63 ± 0.35 units, P = 0.035). These results suggest that local skin thermal sensation during low-intensity exercise is not affected by a decrease in core temperature. However, whole-body thermal sensation mediated by a decrease in core temperature (-1.0 °C) is blunted by low-intensity exercise during cold water immersion.

    15 Oct. 2021, Physiology & behavior, 240, 113531 - 113531, English, International magazine

    Scientific journal

  • Tze-Huan Lei, Masashi Fujiwara, Nicola Gerrett, Tatsuro Amano, Toby Mündel, Yoshimitsu Inoue, Dai Okushima, Takeshi Nishiyasu, Narihiko Kondo

    Seasonal acclimatization from winter to summer is known to enhance thermoeffector responses in hot-dry environments during exercise whereas its impact on sweat evaporation and core temperature (Tcore) responses in hot-humid environments remains unknown. We, therefore, sought to determine whether seasonal acclimatization is able to modulate whole body sweat rate (WBSR), evaporated sweat rate, sweating efficiency, and thermoregulatory function during cycling exercise in a hot-humid environment (32°C, 75% RH). We also determined whether the increase in air velocity could enhance evaporated sweat rate and sweating efficiency before and after seasonal acclimatization. Twelve males cycled for 1 h at 40% V̇o2max in winter (preacclimatization) and repeated the trial again in summer (after acclimatization). For the last 20 min of cycling at a steady-state of Tcore, air velocity increased from 0.2 (0.04) m/s to 1.1 (0.02) m/s by using an electric fan located in front of the participant. Seasonal acclimatization enhanced WBSR, unevaporated sweat rate, local sweat rate and mean skin temperature compared with preacclimatization state (all P < 0.05) whereas sweating efficiency was lower (P < 0.01) until 55 min of exercise. Tcore and evaporated sweat rate were unaltered by acclimatization status (all P > 0.70). In conclusion, seasonal acclimatization enhances thermoeffector responses but does not attenuate Tcore during exercise in a hot-humid environment. Furthermore, increasing air velocity enhances evaporated sweat rate and sweating efficiency irrespective of acclimated state. NEW & NOTEWORTHY Seasonal acclimatization to humid heat enhances eccrine sweat gland function and thus results in a higher local and whole body sweat rate but does not attenuate Tcore during exercise in a hot-humid environment. Sweating efficiency is lower after seasonal acclimatization to humid heat compared with preacclimatization with and without the increase of air velocity. However, having a lower sweating efficiency does not mitigate the Tcore response during exercise in a hot-humid environment.

    01 Aug. 2021, Journal of applied physiology (Bethesda, Md. : 1985), 131 (2), 520 - 531, English, International magazine

    Scientific journal

  • Huixin Zheng, Claire E Badenhorst, Tze-Huan Lei, Yi-Hung Liao, Ahmad Munir Che Muhamed, Naoto Fujii, Narihiko Kondo, Toby Mündel

    The current study investigated whether ambient heat augments the inflammatory and postexercise hepcidin response in women and if menstrual phase and/or self-pacing modulate these physiological effects. Eight trained females (age: 37 ± 7 yr; V̇o2max: 46 ± 7 mL·kg-1·min-1; peak power output: 4.5 ± 0.8 W·kg-1) underwent 20 min of fixed-intensity cycling (100 W and 125 W) followed by a 30-min work trial (∼75% V̇o2max) in a moderate (MOD: 20 ± 1°C, 53 ± 8% relative humidity) and warm-humid (WARM: 32 ± 0°C, 75 ± 3% relative humidity) environment in both their early follicular (days 5 ± 2) and midluteal (days 21 ± 3) phases. Mean power output was 5 ± 4 W higher in MOD than in WARM (P = 0.02) such that the difference in core temperature rise was limited between environments (-0.29 ± 0.18°C in MOD, P < 0.01). IL-6 and hepcidin both increased postexercise (198% and 38%, respectively); however, neither was affected by ambient temperature or menstrual phase (all P > 0.15). Multiple regression analysis demonstrated that the IL-6 response to exercise was explained by leukocyte and platelet count (r2 = 0.72, P < 0.01), and the hepcidin response to exercise was explained by serum iron and ferritin (r2 = 0.62, P < 0.01). During exercise, participants almost matched their fluid loss (0.48 ± 0.18 kg·h-1) with water intake (0.35 ± 0.15 L·h-1) such that changes in body mass (-0.3 ± 0.3%) and serum osmolality (0.5 ± 2.0 osmol·kgH2O-1) were minimal or negligible, indicating a behavioral fluid-regulatory response. These results indicate that trained, iron-sufficient women suffer no detriment to their iron regulation in response to exercise with acute ambient heat stress or between menstrual phases on account of a performance-physiological trade-off.

    01 Jun. 2021, American journal of physiology. Regulatory, integrative and comparative physiology, 320 (6), R780-R790, English, International magazine

    Scientific journal

  • Tze-Huan Lei, Masashi Fujiwara, Nicola Gerrett, Tatsuro Amano, Toby Mundel, Yoshimitsu Inouc, Dai Okushima, Takeshi Nishiyasu, Narihiko Kondo

    Seasonal acclimatization from winter to summer is known to enhance thermoeffector responses in hot-dry environments during exercise whilst its impact on sweat evaporation and core temperature (Tcore) responses in hot-humid environments remains unknown. We therefore sought to determine whether seasonal acclimatization is able to modulate whole-body sweat rate (WBSR), evaporated sweat rate, sweating efficiency and thermoregulatory function during cycling exercise in a hot-humid environment (32∘C, 75% RH). We also determined whether the increase in air-velocity, could enhance evaporated sweat rate and sweating efficiency before and after seasonal acclimatization. Twelve males cycled for 1-hour at 40% VO2max in winter (pre-acclimatization) and repeated the trial again in summer (after-acclimatization). For the last 20-min of cycling at a steady-state of Tcore, air-velocity increased from 0.2 (0.04) m/s to 1.1 (0.02) m/s by using an electric fan located in front of the participant. Seasonal acclimatization enhanced WBSR, unevaporated sweat rate, local sweat rate and mean skin temperature compared to pre-acclimatization state (all P<0.05) whilst sweating efficiency was lower (P<0.01) until the 55-min of exercise. Tcore and evaporated sweat rate were unaltered by acclimatization status (all P>0.70). In conclusion, seasonal acclimatization enhances thermoeffector responses but does not attenuate Tcore during exercise in a hot-humid environment. Furthermore, increasing air-velocity enhances evaporated sweat rate and sweating efficiency irrespective of acclimated state.

    27 May 2021, Journal of applied physiology (Bethesda, Md. : 1985), English, International magazine

    Scientific journal

  • Richie P Goulding, Dai Okushima, Yoshiyuki Fukuoka, Simon Marwood, Narihiko Kondo, David C Poole, Thomas J Barstow, Shunsaku Koga

    PURPOSE: We tested the hypothesis that incremental ramp cycling exercise performed in the supine position (S) would be associated with an increased reliance on muscle deoxygenation (deoxy[heme]) in the deep and superficial vastus lateralis (VLd and VLs, respectively) and the superficial rectus femoris (RFs) when compared to the upright position (U). METHODS: 11 healthy men completed ramp incremental exercise tests in S and U. Pulmonary [Formula: see text]O2 was measured breath-by-breath; deoxy[heme] was determined via time-resolved near-infrared spectroscopy in the VLd, VLs and RFs. RESULTS: Supine exercise increased the overall change in deoxy[heme] from baseline to maximal exercise in the VLs (S: 38 ± 23 vs. U: 26 ± 15 μM, P < 0.001) and RFs (S: 36 ± 21 vs. U: 25 ± 15 μM, P < 0.001), but not in the VLd (S: 32 ± 23 vs. U: 29 ± 26 μM, P > 0.05). CONCLUSIONS: The present study supports that the impaired balance between O2 delivery and O2 utilization observed during supine exercise is a regional phenomenon within superficial muscles. Thus, deep muscle defended its O2 delivery/utilization balance against the supine-induced reductions in perfusion pressure. The differential responses of these muscle regions may be explained by a regional heterogeneity of vascular and metabolic control properties, perhaps related to fiber type composition.

    May 2021, European journal of applied physiology, 121 (5), 1283 - 1296, English, International magazine

    Scientific journal

  • Naoto Fujii, Glen P Kenny, Gregory W McGarr, Tatsuro Amano, Yasushi Honda, Narihiko Kondo, Takeshi Nishiyasu

    Transient receptor potential vanilloid 4 (TRPV4) channels exist on vascular endothelial cells and eccrine sweat gland secretory cells in human skin. Here, we assessed whether TRPV4 channels contribute to cutaneous vasodilation and sweating during whole body passive heat stress (protocol 1) and to cutaneous vasodilation during postocclusive reactive hyperemia and local thermal hyperemia (protocol 2). Intradermal microdialysis was employed to locally deliver pharmacological agents to forearm skin sites, where cutaneous vascular conductance (CVC) and sweat rate were assessed. In protocol 1 (12 young adults), CVC and sweat rate were increased by passive whole body heating, resulting in a body core temperature elevation of 1.2 ± 0.1°C. The elevated CVC and sweat rate assessed at sites treated with TRPV4 channel antagonist (either 200 µM HC-067047 or 125 µM GSK2193874) were not different from the vehicle control site (5% dimethyl sulfoxide). After whole body heating, the TRPV4 channel agonist (100 µM GSK1016790A) was administered to each skin site, eliciting elevations in CVC. Relative to control, this response was partly attenuated by both TRPV4 channel antagonists, confirming drug efficacy. In protocol 2 (10 young adults), CVC was increased following a 5-min arterial occlusion and during local heating from 33 to 42°C. These responses did not differ between the control and the TRPV4 channel antagonist sites (200 µM HC-067047). We show that TRPV4 channels are not required for regulating cutaneous vasodilation or sweating during a whole body passive heat stress. Furthermore, they are not required for regulating cutaneous vasodilation during postocclusive reactive hyperemia and local thermal hyperemia.

    01 Apr. 2021, American journal of physiology. Regulatory, integrative and comparative physiology, 320 (4), R563-R573, English, International magazine

    Scientific journal

  • Nicola Gerrett, Tatsuro Amano, Yoshimitsu Inoue, Narihiko Kondo

    NEW FINDINGS: What is the central question to this study? Do the sweat glands' maximum ion reabsorption rates increase following heat acclimation in healthy older individuals and is this associated with elevated aldosterone concentrations? What is the main finding and its importance? Sweat gland maximum ion reabsorption rates improved heterogeneously across body sites, which occurred without any changes in aldosterone concentration following a controlled hyperthermic heat acclimation protocol in healthy older individuals. ABSTRACT: We examined whether the eccrine sweat glands' ion reabsorption rates improved following heat acclimation (HA) in older individuals. Ten healthy older adults (>65 years) completed a controlled hyperthermic (+0.9°C rectal temperature, Tre ) HA protocol for nine non-consecutive days. Participants completed a passive heat stress test (lower leg 42°C water submersion) pre-HA and post-HA to assess physiological regulation of sweat gland ion reabsorption at the chest, forearm and thigh. The maximum ion reabsorption rate was defined as the inflection point in the slope of the relation between galvanic skin conductance and sweat rate (SR). We explored the responses again after a 7-day decay. During passive heating, the Tb thresholds for sweat onset on the chest and forearm were lowered after HA (P < 0.05). However, sweat sensitivity (i.e. the slope), the SR at a given Tre and gross sweat loss did not improve after HA (P > 0.05). Any changes observed were lost during the decay. Pilocarpine-induced sudomotor responses to iontophoresis did not change after HA (P ≥ 0.801). Maximum ion reabsorption rate was only enhanced at the chest (P = 0.001) despite unaltered aldosterone concentration after HA. The data suggest that this adaptation is lost after 7 days' decay. The HA protocol employed in the present study induced partial adaptive sudomotor responses. Eccrine sweat gland ion reabsorption rates improved heterogeneously across the skin sites. It is likely that aldosterone secretion did not alter the chest sweat ion reabsorption rates observed in the older adults.

    Jan. 2021, Experimental physiology, 106 (1), 302 - 315, English, International magazine

    Scientific journal

  • Tomoaki Ohashi, Nicola Gerrett, Satoru Shinkawa, Tomomi Sato, Ryo Miyake, Narihiko Kondo, Shigenobu Mitsuzawa

    Sweat sensors that can continuously sample sweat are critical for determining the time-dependent physiological responses occurring in normal daily life. Here, a new device, termed fluidic patch, for collecting human sweat samples at defined time intervals is developed, and the proof-of-concept is demonstrated. The device comprises micropumps and a disposable microfluidic patch attached to the human skin. The fluidic patch continuously collects aliquots of freshly secreted sweat accumulated in the fluidic pathway at accurately defined time windows (typically 5 min). By measuring the weight of the collected samples, the local sweat rate is calculated. The sweat sample collected can be directly subjected to a wide range of chemical analyses. For the proof-of-concept, we compared the sweat rates during passive heating in human trials using the fluidic patch and the conventional ventilated sweat capsule system. Although the sweat rate obtained using the fluidic patch highly correlated with that of the ventilated sweat capsule (R2 = 0.96, y = 1.4x - 0.05), the fluidic patch overestimated the sweat rate compared with the ventilated capsule system when the sweat rate exceeded 0.5 mg/(cm2·min). The sampled sweat was analyzed for sodium, potassium, chloride, lactate, pyruvate, and cortisol. The device could obtain the time courses of the concentrations of the abovementioned three ions; the concentrations of sodium and chloride increased linearly with the sweat rate during passive heating (R2 = 0.76 and 0.66, respectively). The device can reliably measure the sweat rate and collect sweat samples for chemical analysis. It can be utilized for real-time physiological investigations toward wider applications.

    01 Dec. 2020, Analytical chemistry, 92 (23), 15534 - 15541, English, International magazine

    Scientific journal

  • Tatsuro Amano, Naoto Fujii, Glen P Kenny, Takeshi Nishiyasu, Yoshimitsu Inoue, Narihiko Kondo

    While human eccrine sweat glands respond to adrenergic agonists, there remains a paucity of information on the factors modulating this response. Thus, we assessed the relative contribution of α- and β-adrenergic sweating during a heat exposure and as a function of individual factors of sex and training status. α- and β-adrenergic sweating was assessed in forty-eight healthy young men (n = 35) and women (n = 13) including endurance-trained (n = 12) and untrained men (n = 12) under non-heat exposure (temperate, 25°C; n = 17) and heat exposure (hot, 35°C; n = 48) conditions using transdermal iontophoresis of phenylephrine (α-adrenergic agonist) and salbutamol (β-adrenergic agonist) on the ventral forearm, respectively. Adrenergic sweating was also measured after iontophoretic administration of atropine (muscarinic receptor antagonist) or saline (control) to evaluate how changes in muscarinic receptor activity modulate the adrenergic response to a heat exposure (n = 12). α- and β-adrenergic sweating was augmented in hot compared with temperate conditions (both P ≤ .014), albeit the relative increase was greater in β (~5.4-fold)- as compared to α (~1.5-fold)-adrenergic-mediated sweating response. However, both α- and β-adrenergic sweating was abolished by atropinization (P = .001). Endurance-trained men showed an augmentation in α- (P = .043) but not β (P = .960)-adrenergic sweating as compared to untrained men. Finally, a greater α- and β-adrenergic sweating response (both P ≤ .001) was measured in habitually active men than in women. We show that heat exposure augments α-and β-adrenergic sweating differently via mechanisms associated with altered muscarinic receptor activity. Sex and training status modulate this response.

    Dec. 2020, Experimental dermatology, 29 (12), 1216 - 1224, English, International magazine

    Scientific journal

  • Tatsuro Amano, Naoto Fujii, Glen P Kenny, Yumi Okamoto, Yoshimitsu Inoue, Narihiko Kondo

    We evaluated the hypothesis that the activation of L-type voltage-gated Ca2+ channels contributes to exercise training-induced augmentation in cholinergic sweating. On separate days, 10 habitually trained and 10 untrained men participated in two experimental protocols. Prior to each protocol, we administered 1% verapamil (Verapamil, L-type voltage-gated Ca2+ channel blocker) and saline (Control) at forearm skin sites on both arms via transdermal iontophoresis. In protocol 1, we administered low (0.001%) and high (1%) doses of pilocarpine at both the verapamil-treated and verapamil-untreated forearm sites. In protocol 2, participants were passively heated by immersing their limbs in hot water (43°C) until rectal temperature increased by 1.0°C above baseline resting levels. Sweat rate at all forearm sites was continuously measured throughout both protocols. Pilocarpine-induced sweating in Control was higher in trained than in untrained men for both the concentrations of pilocarpine (both P ≤ 0.001). Pilocarpine-induced sweating at the low-dose site was attenuated at the Verapamil versus the Control site in both the groups (both P ≤ 0.004), albeit the reduction was greater in trained as compared with in untrained men (P = 0.005). The verapamil-mediated reduction in sweating remained intact at the high-dose pilocarpine site in the untrained men (P = 0.004) but not the trained men (P = 0.180). Sweating did not differ between Control and Verapamil sites with increases in rectal temperature in both groups (interaction, P = 0.571). We show that activation of L-type voltage-gated Ca2+ channels modulates sweat production in habitually trained men induced by a low dose of pilocarpine. However, no effect on sweating was observed during passive heating in either group.

    01 Nov. 2020, American journal of physiology. Regulatory, integrative and comparative physiology, 319 (5), R584-R591, English, International magazine

    Scientific journal

  • Kazuhiro Harada, Kouhei Masumoto, Keiko Katagiri, Ai Fukuzawa, Michiko Touyama, Daichi Sonoda, Makoto Chogahara, Narihiko Kondo, Shuichi Okada

    OBJECTIVES: Although neighborhood is considered to be a crucial source of social network to promote health among older adults, current findings are mostly derived from observational study designs. This study examined whether participations in event-based community programs could increase neighborhood social network and whether such increase could lead to desirable changes in mental and physical health among older adults. METHOD: This study employed quasi-experimental design. A baseline questionnaire survey was sent to residents of Tsurukabuto community aged 60 years or more (n = 1769); 1,068 responded. Community events were implemented approximately once a month for three years. Then, a three-year follow-up survey questionnaire was sent to the respondents of the baseline survey. The total number of respondents in the latter survey was 662; of the total, 173 participated in the intervention. Strong and weak ties with neighbors, mental well-being (Ikigai-9), health-related quality of life (HRQOL), and instrumental activity of daily living (IADL) were measured in the surveys. RESULTS: The path analysis revealed that intervention participation was significantly associated with changes in strong ties (standardized path coefficient = 0.12) and changes in strong ties were associated with those in Ikigai-9 scores (standardized path coefficient = 0.15). The total and indirect effects of intervention participation on Ikigai-9 scores were significant. Significant intervention effects were not observed for HRQOL and IADL scores. CONCLUSION: This study found that participation in our event-based intervention could indirectly and positively influence older adults' mental well-being through their strong ties with their neighbors.

    29 Oct. 2020, Aging & mental health, 1 - 11, English, International magazine

    Scientific journal

  • Richie P Goulding, Simon Marwood, Dai Okushima, David C Poole, Thomas J Barstow, Tze-Huan Lei, Narihiko Kondo, Shunsaku Koga

    We hypothesized that the performance of prior heavy exercise would speed pulmonary oxygen uptake (V̇o2) kinetics (i.e., as described by the time constant, [Formula: see text]) and reduce the amplitude of muscle deoxygenation (deoxy[heme]) kinetics in the supine (S) but not upright (U) body position. Seventeen healthy men completed heavy-intensity constant-work rate exercise tests in S and U consisting of two bouts of 6-min cycling separated by 6-min cycling at 20 W. Pulmonary V̇o2 was measured breath by breath; total and deoxy[heme] were determined via time-resolved near-infrared spectroscopy (NIRS) at three muscle sites. Priming exercise reduced [Formula: see text] in S (bout 1: 36 ± 10 vs. bout 2: 28 ± 10 s, P < 0.05) but not U (bout 1: 27 ± 8 s vs. bout 2: 25 ± 7 s, P > 0.05). Deoxy[heme] amplitude was increased after priming in S (bout 1: 25-28 μM vs. bout 2: 30-35 μM, P < 0.05) and U (bout 1: 13-18 μM vs. bout 2: 17-25 μM, P > 0.05), whereas baseline total[heme] was enhanced in S (bout 1: 110-179 μM vs. bout 2: 121-193 μM, P < 0.05) and U (bout 1: 123-186 μM vs. bout 2: 137-197 μM, P < 0.05). Priming exercise increased total[heme] in both S and U, likely indicating enhanced diffusive O2 delivery. However, the observation that after priming the amplitude of the deoxy[heme] response was increased in S suggests that the reduction in [Formula: see text] subsequent to priming was related to a combination of both enhanced intracellular O2 utilization and increased O2 delivery.NEW & NOTEWORTHY Here we show that oxygen uptake (V̇o2) kinetics are slower in the supine compared with upright body position, an effect that is associated with an increased amplitude of skeletal muscle deoxygenation in the supine position. After priming in the supine position, the amplitude of muscle deoxygenation remained markedly elevated above that observed during upright exercise. Hence, the priming effect cannot be solely attributed to enhanced O2 delivery, and enhancements to intracellular O2 utilization must also be contributory.

    01 Oct. 2020, Journal of applied physiology (Bethesda, Md. : 1985), 129 (4), 810 - 822, English, International magazine

    Scientific journal

  • Tatsuro Amano, Shin Sekihara, Naoto Fujii, Glen P Kenny, Yoshimitsu Inoue, Narihiko Kondo

    NEW FINDINGS: What is the central question of this study? Does the administration of the adrenergic presynaptic release inhibitor bretylium tosylate modulate sweating during exercise in the heat, and does this response differ between habitually trained and untrained men? What is the main finding and its importance? Iontophoretic administration of bretylium tosylate attenuates sweating during exercise in the heat in habitually trained and untrained men. However, a greater reduction occurred in trained men. The findings demonstrate a role for cutaneous adrenergic nerves in the regulation of eccrine sweating during exercise in the heat and highlight a need to advance our understanding of neural control of human eccrine sweat gland activity. ABSTRACT: We recently reported an influence of cutaneous adrenergic nerves on eccrine sweat production in habitually trained men performing an incremental exercise bout in non-heat stress conditions. Based on an assumption that increasing heat stress induces cholinergic modulation of sweating, we evaluated the hypothesis that the contribution of cutaneous adrenergic nerves on sweating would be attenuated during exercise in the heat. Twenty young habitually trained and untrained men (n = 10/group) underwent three successive bouts of 15 min of light-, moderate- and vigorous-intensity cycling (equivalent to 30, 50, and 70% of peak oxygen uptake ( V ̇ O 2 peak ) respectively), each separated by a 15 min recovery while wearing a perfusion suit perfused with warm water (43°C). Sweat rate (ventilated capsule) was measured continuously at two bilateral forearm skin sites treated with 10 mm bretylium tosylate (an inhibitor of neurotransmitter release from adrenergic nerve terminals) and saline (control) via transdermal iontophoresis. A greater sweat rate was measured during vigorous exercise only in trained as compared to untrained men (P = 0.014). In both groups, sweating was reduced at the bretylium tosylate versus control sites, albeit the magnitude of reduction was greater in the trained men (P ≤ 0.024). These results suggest that cutaneous adrenergic nerves modulate sweating during exercise performed under a whole-body heat stress, albeit a more robust response occurs in trained men. While it is accepted that a cholinergic mechanism plays a primary role in the regulation of sweating during an exercise-heat stress, our findings highlight the need for additional studies aimed at understanding the neural control of human eccrine sweating.

    Oct. 2020, Experimental physiology, 105 (10), 1692 - 1699, English, International magazine

    Scientific journal

  • Richie P Goulding, Dai Okushima, Simon Marwood, David C Poole, Thomas J Barstow, Tze-Huan Lei, Narihiko Kondo, Shunsaku Koga

    Oxygen uptake (V̇o2) kinetics are slowed in the supine (S) position purportedly due to impaired muscle O2 delivery ([Formula: see text]); however, these conclusions are predicated on single-site measurements in superficial muscle using continuous-wave near-infrared spectroscopy (NIRS). This study aimed to determine the impact of body position [i.e., upright (U) versus S] on deep and superficial muscle deoxygenation (deoxy[heme]) using time-resolved (TR-) NIRS, and how these relate to slowed pulmonary V̇o2 kinetics. Seventeen healthy men completed constant power tests during 1) S heavy-intensity exercise and 2) U exercise at the same absolute work rate, with a subset of 10 completing additional tests at the same relative work rate as S. Pulmonary V̇o2 was measured breath-by-breath and, deoxy- and total[heme] were resolved via TR-NIRS in the superficial and deep vastus lateralis and superficial rectus femoris. The fundamental phase V̇o2 time constant was increased during S compared with U (S: 36 ± 10 vs. U: 27 ± 8 s; P < 0.001). The deoxy[heme] amplitude (S: 25-28 vs. U: 13-18 µM; P < 0.05) and total[heme] amplitude (S: 17-20 vs. U: 9-16 µM; P < 0.05) were greater in S compared with U and were consistent for the same absolute (above data) and relative work rates (n = 10, all P < 0.05). The greater deoxy- and total[heme] amplitudes in S vs. U supports that reduced perfusive [Formula: see text] in S, even within deep muscle, necessitated a greater reliance on fractional O2 extraction and diffusive [Formula: see text]. The slower V̇o2 kinetics in S versus U demonstrates that, ultimately, these adjustments were insufficient to prevent impairments in whole body oxidative metabolism.NEW & NOTEWORTHY We show that supine exercise causes a greater degree of muscle deoxygenation in both deep and superficial muscle and increases the spatial heterogeneity of muscle deoxygenation. Therefore, this study suggests that any O2 delivery gradient toward deep versus superficial muscle is insufficient to mitigate impairments in oxidative function in response to reduced whole muscle O2 delivery. More heterogeneous muscle deoxygenation is associated with slower V̇o2 kinetics.

    01 Sep. 2020, Journal of applied physiology (Bethesda, Md. : 1985), 129 (3), 535 - 546, English, International magazine

    Scientific journal

  • Tatsuro Amano, Naoto Fujii, Glen P Kenny, Yoshimitsu Inoue, Narihiko Kondo

    PURPOSE: Human eccrine sweat glands respond to α1-adrenergic receptor agonists. We recently reported that adrenergic mechanisms contribute to sweating in endurance-trained men during an incremental exercise to volitional fatigue. However, it remains unclear if this response is mediated by α1-adrenergic receptor activation. METHODS: Twelve endurance-trained men performed an incremental cycling bout until exhaustion while wearing a water-perfused suit to clamp skin temperature at ~ 34 °C. Bilateral forearm sweat rates were measured wherein the distal area was treated with either 1% terazosin (α1-adrenergic receptor antagonist) or saline solution on the opposite limb (Control) via transdermal iontophoresis. We also measured proximal bilateral forearm sweat rate in untreated sites to confirm that no between-limb differences in forearm sweat rate occurred. Once sweat rate returned to pre-exercise resting levels at ~ 20 min postexercise, 0.25% phenylephrine (α1-adrenergic receptor agonist) was iontophoretically administered to skin to verify α1-adrenergic receptor blockade. RESULTS: Sweat rates at the proximal untreated right and left forearm sites were similar during exercise (interaction, P = 0.581). Similarly, no effect of terazosin on sweat rate was measured relative to control site (interaction, P = 0.848). Postexercise administration of phenylephrine increased sweat rate at the control site (0.08 ± 0.09 mg cm-2 min-1), which was suppressed by ~ 90% at the terazosin-treated site (0.01 ± 0.02 mg cm-2 min-1) (P = 0.026), confirming that α1-adrenergic receptor blockade was intact. CONCLUSION: Our findings demonstrate that α1-adrenergic receptors located at eccrine sweat glands do not contribute to eccrine sweating during incremental exercise in young endurance-trained men.

    May 2020, European journal of applied physiology, 120 (5), 1123 - 1129, English, International magazine

    Scientific journal

  • Kazuhiro Harada, Kouhei Masumoto, Ai Fukuzawa, Michiko Touyama, Koji Sato, Narihiko Kondo, Shuichi Okada

    This study examined whether satisfaction with social interactions and the number of people interacted with during walking groups is associated with affective responses among older adults. Twenty-six older adults were asked to participate in five walking group sessions. The participants walked together for 40-50 min. In every session, the participants reported their affective responses to walking (positive engagement, tranquility, and negative affect), their level of satisfaction with the social interactions experienced, and the number of people interacted with during the walk. The available data were from 107 person-sessions. Multilevel models revealed that, although a higher number of people interacted with was not significantly associated with improvements in any affective responses, higher satisfaction with the interactions was significantly associated with improvements in positive engagement at both the within- and between-person levels. This study found that higher satisfaction with the interactions was associated with desirable affective responses among older adults.

    24 Apr. 2020, Journal of aging and physical activity, 28 (2), 287 - 293, English, International magazine

    Scientific journal

  • Tze-Huan Lei, Zachary J Schlader, Ahmad Munir Che Muhamed, Huixin Zheng, Stephen R Stannard, Narihiko Kondo, James D Cotter, Toby Mündel

    PURPOSE: Recent studies have determined that ambient humidity plays a more important role in aerobic performance than dry-bulb temperature does in warm environments; however, no studies have kept humidity constant and independently manipulated temperature. Therefore, the purpose of this study was to determine the contribution of dry-bulb temperature, when vapor pressure was matched, on the thermoregulatory, perceptual and performance responses to a 30-min cycling work trial. METHODS: Fourteen trained male cyclists (age: 32 ± 12 year; height: 178 ± 6 cm; mass: 76 ± 9 kg; [Formula: see text]: 59 ± 9 mL kg-1 min-1; body surface area: 1.93 ± 0.12 m2; peak power output: 393 ± 53 W) volunteered, and underwent 1 exercise bout in moderate heat (MOD: 34.9 ± 0.2 °C, 50.1 ± 1.1% relative humidity) and 1 in mild heat (MILD: 29.2 ± 0.2 °C, 69.4 ± 0.9% relative humidity) matched for vapor pressure (2.8 ± 0.1 kPa), with trials counterbalanced. RESULTS: Despite a higher weighted mean skin temperature during MOD (36.3 ± 0.5 vs. 34.5 ± 0.6 °C, p < 0.01), none of rectal temperature (38.0 ± 0.3 vs. 37.9 ± 0.4 °C, p = 0.30), local sweat rate (1.0 ± 0.3 vs. 0.9 ± 0.4 mg cm-2 min-1, p = 0.28), cutaneous blood flow (283 ± 116 vs. 287 ± 105 PU, p = 0.90), mean power output (206 ± 37 vs. 205 ± 41 W, p = 0.87) or total work completed (371 ± 64 vs. 369 ± 70 kJ, p = 0.77) showed any difference between environments during the work trial. However, all perceptual measures (perceived exertion, thermal discomfort, thermal sensation, skin wettedness, pleasantness, all p < 0.05) were affected detrimentally during MOD compared to MILD. CONCLUSION: In a warm and compensable environment, dry-bulb temperature did not influence high-intensity cycling performance when vapor pressure was maintained, whilst the perceptual responses were affected.

    Apr. 2020, European journal of applied physiology, 120 (4), 841 - 852, English, International magazine

    Scientific journal

  • Tze-Huan Lei, Hiroki Matsukawa, Dai Okushima, Nicola Gerrett, Zachary J Schlader, Toby Mündel, Masashi Fujiwara, Narihiko Kondo

    We examined whether partial clothing removal is an effective thermoregulatory behaviour to attenuate both thermoregulatory and perceptual strain in a moderate environment (23 °C, 65% RH) during and after exercise. Ten healthy males (age: 21.9 (0.9) years; height: 173.9 (6.2) cm; mass: 62.3 (8.2) kg; body surface area: 1.8 (0.1) m2; VO2max: 51.8 (13.3) mL.kg-1.min-1) wore a long sleeve polyester shirt and performed two randomized cycling trials for 40 min at 40% VO2max followed by 20 min recovery. In one trial, they were permitted to roll up their sleeves at any time they wanted (Roll) whereas in the other trial, they were instructed to remain with long sleeves (No Roll) until the end of the recovery. Thermoregulatory variables were measured continuously whilst thermal perceptions (forearm wettedness perception (WPForearm), forearm and whole-body thermal discomfort (TDForearm, TDWhole), local and whole-body thermal sensation (TSForearm, TSWhole) and whole-body wettedness perception (WPwhole)) were measured every 10 min. All subjects behaved by rolling up their sleeves at 21.6 (4.7) minutes. Tskin (32.3 (0.2) °C, vs 32.0 (0.1) °C, p = 0.03), local sweat rate on the forearm (0.24 (0.08) mg.cm-2.min-1 vs 0.2 (0.04) mg.cm-2.min-1, p = 0.05), WPForearm, TDForearm, TSForearm and WPWhole were all lower in Roll than No Roll (all p < 0.05) whilst Tcore and cutaneous vascular conductance (CVC) on the forearm were not different (all p > 0.7) throughout the entire trial. We conclude that this behavioural response is an effective thermoregulatory behaviour to modulate local sudomotor function and thermal perceptions, WPWhole during exercise but only Tsk, TDForearm WPForearm and WPWhole persisted throughout the recovery in a moderate environment.

    01 Mar. 2020, Physiology & behavior, 215, 112768 - 112768, English, International magazine

    Scientific journal

  • Dai Okushima, David C Poole, Thomas J Barstow, Narihiko Kondo, Lisa M K Chin, Shunsaku Koga

    NEW FINDINGS: What is the central question of this study? Does the presence and extent of heterogeneity in the ratio of O2 delivery to uptake across human muscles relate specifically to different muscle activation patterns? What is the main finding and its importance? During ramp incremental knee-extension and cycling exercise, the profiles of muscle deoxygenation (deoxy[haemoglobin + myoglobin]) and diffusive O2 potential (total[haemoglobin + myoglobin]) in the vastus lateralis corresponded to different muscle activation strategies. However, this was not the case for the rectus femoris, where muscle activation and deoxygenation profiles were dissociated and might therefore be determined by other structural and/or functional attributes (e.g. arteriolar vascular regulation and control of red blood cell flux). ABSTRACT: Near-infrared spectroscopy has revealed considerable heterogeneity in the ratio of O2 delivery to uptake as identified by disparate deoxygenation {deoxy[haemoglobin + myoglobin] (deoxy[Hb + Mb])} values in the exercising quadriceps. However, whether this represents a recruitment phenomenon or contrasting vascular and metabolic control, as seen among fibre types, has not been established. We used knee-extension (KE) and cycling (CE) incremental exercise protocols to examine whether differential muscle activation profiles could account for the heterogeneity of deoxy[Hb + Mb] and microvascular haemoconcentration (i.e. total[Hb + Mb]). Using time-resolved near-infrared spectroscopy for the quadriceps femoris (vastus lateralis and rectus femoris) during exhaustive ramp exercise in eight participants, we tested the following hypotheses: (i) the deoxy[Hb + Mb] (i.e. fractional O2 extraction) would relate to muscle activation levels across exercise protocols; and (ii) KE would induce greater total[Hb + Mb] (i.e. diffusive O2 potential) at task failure (i.e. peak O2 uptake) than CE irrespective of muscle site. At a given level of muscle activation, as assessed by the relative integrated EMG normalized to maximal voluntary contraction (%iEMGmax ), the vastus lateralis deoxy[Hb + Mb] profile was not different between exercise protocols. However, at peak O2 uptake and until 20% iEMGmax for CE, rectus femoris exhibited a lower deoxy[Hb + Mb] (83.2 ± 15.5 versus 98.2 ± 19.4 μm) for KE than for CE (P < 0.05). The total[Hb + Mb] at peak O2 uptake was not different between exercise protocols for either muscle site. These data support the hypothesis that the contrasting patterns of convective and diffusive O2 transport correspond to different muscle activation patterns in vastus lateralis but not rectus femoris. Thus, the differential deoxygenation profiles for rectus femoris across exercise protocols might be dependent upon specific facets of muscle architecture and functional haemodynamic events.

    Mar. 2020, Experimental physiology, 105 (3), 531 - 541, English, International magazine

    Scientific journal

  • Naoto Fujii, Gregory W McGarr, Glen P Kenny, Tatsuro Amano, Yasushi Honda, Narihiko Kondo, Takeshi Nishiyasu

    Local skin heating to 42°C causes cutaneous thermal hyperemia largely via nitric oxide (NO) synthase (NOS)-related mechanisms. We assessed the hypothesis that ATP-sensitive K+ (KATP) channels interact with NOS to mediate cutaneous thermal hyperemia. In 13 young adults (6 women, 7 men), cutaneous vascular conductance (CVC) was measured at four intradermal microdialysis sites that were continuously perfused with 1) lactated Ringer solution (control), 2) 5 mM glibenclamide (KATP channel blocker), 3) 20 mM NG-nitro-l-arginine methyl ester (NOS inhibitor), or 4) a combination of KATP channel blocker and NOS inhibitor. Local skin heating to 42°C was administered at all four treatment sites to elicit cutaneous thermal hyperemia. Thirty minutes after the local heating, 1.25 mM pinacidil (KATP channel opener) and subsequently 25 mM sodium nitroprusside (NO donor) were administered to three of the four sites (each 25-30 min). The local heating-induced prolonged elevation in CVC was attenuated by glibenclamide (19%), but the transient initial peak was not. However, glibenclamide had no effect on the prolonged elevation in CVC in the presence of NOS inhibition. Pinacidil caused an elevation in CVC, but this response was abolished at the glibenclamide-treated skin site, demonstrating its effectiveness as a KATP channel blocker. The pinacidil-induced increase in CVC was unaffected by NOS inhibition, whereas the increase in CVC elicited by sodium nitroprusside was partly (15%) inhibited by glibenclamide. In summary, we showed an interactive effect of KATP channels and NOS for the plateau of cutaneous thermal hyperemia. This interplay may reflect a vascular smooth muscle cell KATP channel activation by NO.

    01 Feb. 2020, American journal of physiology. Regulatory, integrative and comparative physiology, 318 (2), R390-R398, English, International magazine

    Scientific journal

  • Kazuhiro Harada, Kouhei Masumoto, Narihiko Kondo

    This study examined whether routine work time was associated with exercise time, moderate-to-vigorous physical activity (MVPA), and step counts (SC) among middle-aged and older adults. A 7-day diary survey was conducted with 158 adults, and 138 participated in the 1-year follow-up survey for measuring routine work time and exercise time. An accelerometer was used to measure MVPA and SC, and a questionnaire assessed perceived barriers and self-efficacy. Daily analyses revealed that while longer routine work time was associated with shorter exercise time after adjusting for perceived exercise barriers and exercise self-efficacy, it was associated with higher amounts of MVPA and SC. Longitudinal analysis showed that increased routine work time was associated with decreased exercise time and increased MVPA and SC. Changes in perceived barriers and self-efficacy did not mediate these associations. Actual lack of time would inhibit exercise behavior independently of perceived barriers and self-efficacy but elevates MVPA and SC.

    Feb. 2020, Journal of behavioral medicine, 43 (1), 44 - 56, English, International magazine

    Scientific journal

  • Kazuhiro Harada, Kouhei Masumoto, Narihiko Kondo

    This study examined whether routine work time was associated with exercise time, moderate-to-vigorous physical activity (MVPA), and step counts (SC) among middle-aged and older adults. A 7-day diary survey was conducted with 158 adults, and 138 participated in the 1-year follow-up survey for measuring routine work time and exercise time. An accelerometer was used to measure MVPA and SC, and a questionnaire assessed perceived barriers and self-efficacy. Daily analyses revealed that while longer routine work time was associated with shorter exercise time after adjusting for perceived exercise barriers and exercise self-efficacy, it was associated with higher amounts of MVPA and SC. Longitudinal analysis showed that increased routine work time was associated with decreased exercise time and increased MVPA and SC. Changes in perceived barriers and self-efficacy did not mediate these associations. Actual lack of time would inhibit exercise behavior independently of perceived barriers and self-efficacy but elevates MVPA and SC.

    SPRINGER/PLENUM PUBLISHERS, Feb. 2020, JOURNAL OF BEHAVIORAL MEDICINE, 43 (1), 44 - 56, English

    [Refereed]

    Scientific journal

  • Naoto Fujii, Tatsuro Amano, Glen P Kenny, Yasushi Honda, Narihiko Kondo, Takeshi Nishiyasu

    NEW FINDINGS: What is the central question of this study? What is the role of nicotinic receptors in the regulation of normothermic cutaneous blood flow and cutaneous vasodilatation and sweating during whole-body heating induced following resting in a non-heat-stress condition? What is the main finding and its importance? Nicotinic receptors modulated cutaneous vascular tone during rest in a non-heat-stress condition and in the early stage of heating, but they had a limited role in mediating cutaneous vasodilatation when core temperature increased >0.4°C. Further, the contribution of nicotinic receptors to sweating was negligible during whole-body heating. Our findings provide new insights into the role of nicotinic receptors in end-organ function of skin vasculature and sweat glands in humans. ABSTRACT: Nicotinic receptors are present in human skin including cutaneous vessels and eccrine sweat glands as well as peripheral nerves. We tested the hypothesis that nicotinic receptors do not contribute to the control of cutaneous vascular tone in the normothermic state, but are involved in mediating cutaneous vasodilatation and sweating during a whole-body passive heat stress in humans. We first performed a nicotinic receptor blocker verification protocol in six young adults (one female) wherein increases in cutaneous vascular conductance and sweating elicited by 10 mm nicotine were blocked by administration of 500 µm hexamethonium to confirm effective blockade. Thereafter, 12 young males participated in a passive heating protocol. After an instrumentation period in a non-heat-stress condition, participants rested for a 10 min baseline period. Thereafter, oesophageal temperature was increased by 1.0°C using water-perfusion suits. Cutaneous vascular conductance, sweat rate, active sweat gland density and sweat output per individual gland were assessed with and without 500 µm hexamethonium administered via intradermal microdialysis. Hexamethonium reduced cutaneous vascular conductance by 22-34% during normothermia and the early stage of heating. However, this effect was diminished as oesophageal temperature increased >0.4°C. Active sweat gland density was reduced by hexamethonium when oesophageal temperature was elevated by 0.4-0.6°C above baseline resting. However, this was paralleled by a marginal increase in sweat gland output. Consequently, sweat rate remained unchanged. We showed that nicotinic receptors modulate cutaneous perfusion during normothermia and the early stage of heating, but not when core temperature increases >0.4°C. Additionally, they play a limited role in mediating sweating during heating.

    Dec. 2019, Experimental physiology, 104 (12), 1808 - 1818, English, International magazine

    Scientific journal

  • Kazuhiro Harada, Kouhei Masumoto, Ai Fukuzawa, Michiko Touyama, Koji Sato, Narihiko Kondo, Shuichi Okada

    This study examined whether satisfaction with social interactions and the number of people interacted with during walking groups is associated with affective responses among older adults. Twenty-six older adults were asked to participate in five walking group sessions. The participants walked together for 40-50 min. In every session, the participants reported their affective responses to walking (positive engagement, tranquility, and negative affect), their level of satisfaction with the social interactions experienced, and the number of people interacted with during the walk. The available data were from 107 person-sessions. Multilevel models revealed that, although a higher number of people interacted with was not significantly associated with improvements in any affective responses, higher satisfaction with the interactions was significantly associated with improvements in positive engagement at both the within- and between-person levels. This study found that higher satisfaction with the interactions was associated with desirable affective responses among older adults.

    17 Nov. 2019, Journal of aging and physical activity, 1 - 7, English, International magazine

    [Refereed]

  • 朝食をモデルとした食事摂取が若年女性の体温調節反応に及ぼす影響

    米浪 直子, 池田 麻友美, 一之瀬 智子, 大上 安奈, 天野 達郎, 上田 博之, 近藤 徳彦, 井上 芳光

    日本生理人類学会, Nov. 2019, 日本生理人類学会誌, 24 (4), 131 - 138, Japanese

    [Refereed]

  • Tatsuro Amano, Yuki Sugiyama, Junya Okumura, Naoto Fujii, Glen P Kenny, Takeshi Nishiyasu, Yoshimitsu Inoue, Narihiko Kondo, Katsumi Sasagawa, Yasuaki Enoki, Daisuke Maejima

    NEW FINDINGS: What is the central question of this study? What are the effects of isomaltulose, an ingredient in carbohydrate-electrolyte beverages to maintain glycaemia and attenuate the risk of dehydration during exercise heat stress, on postexercise rehydration and physiological heat loss responses? What is the main finding and its importance? Consumption of a 6.5% isomaltulose-electrolyte beverage following exercise heat stress restored hydration following a 2 h recovery as compared to a 2% solution or water only. While the 6.5% isomaltulose-electrolytes increased plasma volume and plasma osmolality, which are known to modulate postexercise heat loss, sweating and cutaneous vascular responses did not differ between conditions. Consequently, ingestion beverages containing 6.5% isomaltulose-electrolytes enhanced postexercise rehydration without affecting heat loss responses. ABSTRACT: Isomaltulose is a disaccharide carbohydrate widely used during exercise to maintain glycaemia and hydration. We investigated the effects of ingesting a beverage containing isomaltulose and electrolytes on postexercise hydration state and physiological heat loss responses. In a randomized, single-blind cross-over design, 10 young healthy men were hypohydrated by performing up to three 30 min successive moderate-intensity (50% heart rate reserve) bouts of cycling, each separated by 10 min, while wearing a water-perfusion suit heated to 45°C. The protocol continued until a 2% reduction in body mass was achieved. Thereafter, participants performed a final 15 min moderate-intensity exercise bout followed by a 2 h recovery. Following cessation of exercise, participants ingested a beverage consisting of (i) water only (Water), (ii) 2% isomaltulose (CHO-2%), or (iii) 6.5% isomaltulose (CHO-6.5%) equal to the volume of 2% body mass loss within the first 30 min of the recovery. Changes in plasma volume (ΔPV) after fluid ingestion were greater for CHO-6.5% compared with CHO-2% (120 min postexercise) and Water (90 and 120 min) (all P ≤ 0.040). Plasma osmolality remained elevated with CHO-6.5% compared with consumption of the other beverages at 30 and 90 min postexercise (all P ≤ 0.050). Urine output tended to be reduced with CHO-6.5% compared to other fluid conditions (main effect, P = 0.069). Rectal and mean skin temperatures, chest sweat rate and cutaneous perfusion did not differ between conditions (all P > 0.05). In conclusion, compared with CHO-2% and Water, consuming a beverage consisting of CHO-6.5% and electrolytes during recovery under heat stress enhances PV recovery without modulating physiological heat loss responses.

    Oct. 2019, Experimental physiology, 104 (10), 1494 - 1504, English, International magazine

    Scientific journal

  • Naoto Fujii, Glen P Kenny, Tatsuro Amano, Yasushi Honda, Narihiko Kondo, Takeshi Nishiyasu

    Transient receptor potential vanilloid 4 (TRPV4) channels exist in the endothelial cells of cutaneous blood vessels and the secretory cells of eccrine sweat glands. We assessed if exogenous TRPV4 channel activation elicits cutaneous vasodilatation and sweating in humans in vivo, and if so, whether this response is mediated by nitric oxide synthase (NOS)- cyclooxygenase (COX)- and/or Ca2+-sensitive K+ (KCa) channel-related mechanisms. In ten healthy young adults (24±2 years, 5 women), cutaneous vascular conductance and sweat rate were assessed at four dorsal forearm skin sites continuously treated with either: 1) lactated Ringer's solution (Control), 2) 20 mM L-NAME, a non-selective NOS inhibitor, 3) 10 mM ketorolac, a non-selective COX inhibitor, or 4) 50 mM TEA, a non-selective KCa channel blocker. A potent and selective TRPV4 channel agonist, GSK1016790 A (GSK101), was administered to each skin site in a dose-dependent manner (1, 10, 100, 1000 μM each for ≥30min) via intradermal microdialysis. Administration of 100 and 1000 μM GSK101 increased cutaneous vascular conductance from pre-infusion level at the Control site (48±12 and 57±9%max, respectively, P≤0.004). This response was markedly (53-83%) attenuated by NOS inhibition, COX inhibition, or KCa channel blockade (all P≤0.037), except KCa channel blockade had no effect during 1000 μM GSK101 administration. GSK101 did not influence sweat rate regardless of skin site. We showed that in human skin in vivo, exogenous activation of TRPV4 channels mediates cutaneous vasodilatation, but not sweating through NOS, COX, and KCa channel mechanisms.

    05 Sep. 2019, European journal of pharmacology, 858, 172462 - 172462, English, International magazine

    Scientific journal

  • Shunsaku Koga, Dai Okushima, David C Poole, Harry B Rossiter, Narihiko Kondo, Thomas J Barstow

    Relative perfusion of active muscles is greater during knee extension ergometry (KE) than cycle ergometry (CE). This provides the opportunity to investigate the effects of increased O2 delivery (Q̇o2) on deoxygenation heterogeneity among quadriceps muscles and pulmonary oxygen uptake (V̇o2) kinetics. Using time-resolved near-infrared spectroscopy, we hypothesized that compared with CE the superficial vastus lateralis (VL), superficial rectus femoris, and deep VL in KE would have 1) a smaller amplitude of the exercise-induced increase in deoxy[Hb + Mb] (related to the balance between V̇o2 and Q̇o2); 2) a greater amplitude of total[Hb + Mb] (related to the diffusive O2 conductance); 3) a greater homogeneity of regional muscle deoxy[Hb + Mb]; and 4) no difference in pulmonary V̇o2 kinetics. Eight participants performed square-wave KE and CE exercise from 20 W to heavy work rates. Deoxy[Hb + Mb] amplitude was less for all muscle regions in KE (P < 0.05: superficial, KE 17-24 vs. CE 19-40; deep, KE 19 vs. CE 26 μM). Furthermore, the amplitude of total[Hb + Mb] was greater for KE than CE at all muscle sites (P < 0.05: superficial, KE, 7-21 vs. CE, 1-16; deep, KE, 11 vs. CE, -3 μM). Although the amplitude and heterogeneity of deoxy[Hb + Mb] were significantly lower in KE than CE during the first minute of exercise, the pulmonary V̇o2 kinetics was not different for KE and CE. These data show that the microvascular Q̇o2 to V̇o2 ratio, and thus tissue oxygenation, was greater in KE than CE. This suggests that pulmonary and muscle V̇o2 kinetics in young healthy humans are not limited by Q̇o2 during heavy-intensity cycling.

    01 Jul. 2019, American journal of physiology. Regulatory, integrative and comparative physiology, 317 (1), R203-R213, English, International magazine

    Scientific journal

  • HARADA KAZUHIRO, Masumoto Kouhei, Kondo Narihiko

    Jul. 2019, Journal of Physical Activity and Health, 16, 556 - 564, English

    [Refereed]

    Scientific journal

  • 【筋肉・エクササイズとミネラル代謝】エクササイズ時の発汗と汗電解質の調節

    天野 達郎, 藤井 直人, Gerrett Nicola, 西保 岳, 近藤 徳彦

    <文献概要>運動時における発汗と汗電解質の調節に関して最近の研究をもとに概説した.運動時の発汗は体温などの温熱性要因と温度に依存しないセントラルコマンドや活動筋からの求心性入力などの非温熱性要因により統合的に調節されている.発汗調節の経路は視床下部からの遠心性交感神経信号が主となるが,それ以外にも末梢でさまざまな要因に影響される.汗の前駆物質には血漿と同じレベルの塩分が含まれるが,汗腺の導管部で多くの塩分が再吸収される.皮膚コンダクタンス-発汗量の関係から間接的にこの再吸収能が評価できると考えられ,汗腺での再吸収能が暑熱順化,身体部位差,性差などに修飾されることがこの手法により明らかとなった.このように運動時には発汗量と汗電解質はさまざまな要因により調節されている.

    (株)日本メディカルセンター, Jul. 2019, 腎と骨代謝, 32 (3), 233 - 239, Japanese

  • Kazuhiro Harada, Kouhei Masumoto, Narihiko Kondo

    BACKGROUND: Although the beneficial effects of physical activity and exercise on mental health are well known, the optimal conditions for them for benefitting mental health are still unclear. Engaging in exercise with others might have more desirable effects on mental health than engaging in exercise alone. This study examined the associations between exercising alone, exercising with others, and mental health among middle-aged and older adults. METHODS: Baseline and 1-year follow-up surveys were conducted with 129 individuals. Time spent exercising alone or with others was measured using a 7-day diary survey. Total physical activity was objectively measured using an accelerometer. Mental well-being was assessed using the simplified Japanese version of the World Health Organization Five Well-Being Index, and mental distress was assessed using the Japanese version of the Kessler Distress Scale (K6). RESULTS: Cross-lagged and simultaneous effects models revealed that exercising with others positively influenced mental well-being. Exercising alone and total physical activity did not significantly influence mental well-being. Neither total physical activity, exercising alone, nor exercising with others was significantly associated with mental distress. CONCLUSION: Engaging in exercise with others could be effective in improving mental well-being relative to engaging in exercise alone.

    27 Jun. 2019, Journal of physical activity & health, 16 (7), 556 - 564, English, International magazine

    Scientific journal

  • Ai Fukuzawa, Keiko Katagiri, Kazuhiro Harada, Kouhei Masumoto, Makoto Chogahara, Narihiko Kondo, Shuichi Okada

    Ikigai, one of the indices of well-being, tends to decline with age because resources relating to ikigai decline. However, there are individual differences in this decline. This study tested for maintenance of ikigai among Japanese elderly, using a longitudinal study investigating the moderating role of social capital on the effects of changes in human capital on ikigai. We conducted a panel survey targeting 1,068 people (M age = 73.01 years) in 2013, and 686 people in 2017. The variables were ikigai, changes in human capital (self-rated financial status, physical health) and social capital (social networks, trust in others), educational level, and control variables. Multiple regression analyses revealed the interaction effects of changes in physical health and changes in social networks (strong ties, weak ties) on follow-up ikigai. Post hoc analyses indicated that declines in physical health predicted declines in ikigai among those whose social networks (strong ties and weak ties) had declined in the 4-year study, but these relationships were not significant among those whose social networks had increased. The results suggest that older adults can weaken the adverse effect of a decline in human capital on ikigai by maintaining or increasing social networks.

    WILEY, Jun. 2019, ASIAN JOURNAL OF SOCIAL PSYCHOLOGY, 22 (2), 172 - 182, English

    [Refereed]

    Scientific journal

  • HARADA KAZUHIRO, 村上 晴香, 宮地 元彦, KONDO NARIHIKO

    Apr. 2019, 体力科学, 68, 105 - 116, Japanese

    [Refereed]

    Scientific journal

  • HARADA KAZUHIRO, Masumoto Kouhei, Kondo Narihiko

    Apr. 2019, Journal of Behavioral Medicine, 42, 315 - 329, English

    [Refereed]

    Scientific journal

  • Kazuhiro Harada, Kouhei Masumoto, Narihiko Kondo

    This study examined the associations of time spent out of home with physical activity and sedentary behavior among middle-aged and older adults. A diary survey was conducted for 7 days with 157 adults to measure out-of-home time and working status. Time spent in sedentary behavior and levels of physical activity were measured using an accelerometer. After a year, 137 individuals from the original sample participated in a follow-up survey. From the daily analyses of 535 non-working days and 347 working days, multilevel models revealed that on non-working days, more out-of-home time was associated with less sedentary time and higher levels of physical activity at both within- and between-person levels. Longitudinal analyses of non-working days supported these results. However, on working days, similar associations were not revealed by daily or longitudinal analyses. These results suggest that increasing out-of-home time could contribute to increased physical activity and reduced sedentary behavior on non-working days.

    Apr. 2019, Journal of behavioral medicine, 42 (2), 315 - 329, English, International magazine

    Scientific journal

  • Gerrett N, Amano T, Havenith G, Inoue Y, KONDO NARIHIKO

    PurposeChanges in mean skin temperature (T-sk) have been shown to modify the maximum rate of sweat ion reabsorption. This study aims to extend this knowledge by investigating if modifications could also be caused by local T-sk.MethodsThe influence of local T-sk on the sweat gland maximum ion reabsorption rates was investigated in ten healthy volunteers (three female and seven male; 20.81.2years, 60.47.7kg, 169.4 +/- 10.4cm) during passive heating (water-perfused suit and lower leg water immersion). In two separate trials, in a randomized order, one forearm was always manipulated to 33 degrees C (Neutral), whilst the other was manipulated to either 30 degrees C (Cool) or 36 degrees C (Warm) using water-perfused patches. Oesophageal temperature (T-es), forearm T-sk, sweat rate (SR), galvanic skin conductance (GSC) and salivary aldosterone concentrations were measured. The sweat gland maximum ion reabsorption rates were identified using the SR threshold for an increasing GSC.ResultsThermal [T-es and body temperature (T-b)] and non-thermal responses (aldosterone) were similar across all conditions (p>0.05). A temperature-dependent response for the sweat gland maximum ion reabsorption rates was evident between 30 degrees C (0.18 +/- 0.10mg/cm(2)/min) and 36 degrees C (0.28 +/- 0.14mg/cm(2)/min, d=0.88, p<0.05), but not for 33 degrees C (0.22 +/- 0.12mg/cm(2)/min), d=0.44 and d=0.36, p>0.05.Conclusion The data indicate that small variations in local T-sk may not affect the sweat gland maximum ion reabsorption rates but when the local T-sk increases by >6 degrees C, ion reabsorption rates also increase.

    SPRINGER, Mar. 2019, Eur J Appl Physiol, 119 (3), 685 - 695, English

    [Refereed]

    Scientific journal

  • N Gerrett, T Amano, G Havenith, Y Inoue, Narihiko Kondo

    PURPOSE: Changes in mean skin temperature (Tsk) have been shown to modify the maximum rate of sweat ion reabsorption. This study aims to extend this knowledge by investigating if modifications could also be caused by local Tsk. METHODS: The influence of local Tsk on the sweat gland maximum ion reabsorption rates was investigated in ten healthy volunteers (three female and seven male; 20.8 ± 1.2 years, 60.4 ± 7.7 kg, 169.4 ± 10.4 cm) during passive heating (water-perfused suit and lower leg water immersion). In two separate trials, in a randomized order, one forearm was always manipulated to 33 °C (Neutral), whilst the other was manipulated to either 30 °C (Cool) or 36 °C (Warm) using water-perfused patches. Oesophageal temperature (Tes), forearm Tsk, sweat rate (SR), galvanic skin conductance (GSC) and salivary aldosterone concentrations were measured. The sweat gland maximum ion reabsorption rates were identified using the ∆SR threshold for an increasing ∆GSC. RESULTS: Thermal [Tes and body temperature (Tb)] and non-thermal responses (aldosterone) were similar across all conditions (p > 0.05). A temperature-dependent response for the sweat gland maximum ion reabsorption rates was evident between 30 °C (0.18 ± 0.10 mg/cm2/min) and 36 °C (0.28 ± 0.14 mg/cm2/min, d = 0.88, p < 0.05), but not for 33 °C (0.22 ± 0.12 mg/cm2/min), d = 0.44 and d = 0.36, p > 0.05. CONCLUSION: The data indicate that small variations in local Tsk may not affect the sweat gland maximum ion reabsorption rates but when the local Tsk increases by > 6 °C, ion reabsorption rates also increase.

    Mar. 2019, European journal of applied physiology, 119 (3), 685 - 695, English, International magazine

    Scientific journal

  • Choo HC, Peiffer JJ, Lopes-Silva JP, Mesquita RNO, Amano T, KONDO NARIHIKO, Abbiss CR

    Two studies were conducted to examine the effects of ice slushy ingestion (ICE) and cold water immersion (CWI) on thermoregulatory and sweat responses during constant (study 1) and self-paced (study 2) exercise. In study 1, 11 men cycled at 40-50% of peak aerobic power for 60 min (33.2 ± 0.3°C, 45.9 ± 0.5% relative humidity, RH). In study 2, 11 men cycled for 60 min at perceived exertion (RPE) equivalent to 15 (33.9 ± 0.2°C and 42.5 ± 3.9%RH). In both studies, each trial was preceded by 30 min of CWI (~22°C), ICE or no cooling (CON). Rectal temperature (Tre), skin temperature (Tsk), thermal sensation, and sweat responses were measured. In study 1, ICE decreased Tre-Tsk gradient versus CON (p = 0.005) during first 5 min of exercise, while CWI increased Tre-Tsk gradient versus CON and ICE for up to 20 min during the exercise (p<0.05). In study 2, thermal sensation was lower in CWI versus CON and ICE for up to 35-40 min during the exercise (p<0.05). ICE reduced thermal sensation versus CON during the first 20 min of exercise (p<0.05). In study 2, CWI improved mean power output (MPO) by ~8 W, compared with CON only (p = 0.024). In both studies, CWI (p<0.001) and ICE (p = 0.019) delayed sweating by 1-5 min but did not change the body temperature sweating threshold, compared with CON (both p>0.05). Increased Tre-Tsk gradient by CWI improved MPO while ICE reduced Tre but did not confer any ergogenic effect. Both precooling treatments attenuated the thermal efferent signals until a specific body temperature threshold was reached.

    Feb. 2019, PLoS One, 14 (2), e0212966, English, International magazine

    [Refereed]

    Scientific journal

  • Respiratory mechanics and cerebral blood flow during heat-induced hyperventilation and its voluntary suppression in passively heated humans

    Tsuji B, Hoshi Y, Honda Y, Fujii N, Sasaki Y, Cheung SS, KONDO NARIHIKO, Nishiyasu T

    Jan. 2019, Physiol Rep, 7 (1), e13967, English

    [Refereed]

    Scientific journal

  • Bun Tsuji, Yuta Hoshi, Yasushi Honda, Naoto Fujii, Yosuke Sasaki, Stephen S Cheung, Narihiko Kondo, Takeshi Nishiyasu

    We investigated whether heat-induced hyperventilation can be voluntarily prevented, and, if so, how this modulates respiratory mechanics and cerebral blood flow in resting heated humans. In two separate trials, 10 healthy men were passively heated using lower body hot-water immersion and a water-perfused garment covering their upper body (both 41°C) until esophageal temperature (Tes ) reached 39°C or volitional termination. In each trial, participants breathed normally (normal-breathing) or voluntarily controlled minute ventilation (VE ) at a level equivalent to that observed after 5 min of heating (controlled-breathing). Respiratory gases, middle cerebral artery blood velocity (MCAV), work of breathing, and end-expiratory and inspiratory lung volumes were measured. During normal-breathing, VE increased as Tes rose above 38.0 ± 0.3°C, whereas controlled-breathing diminished the increase in VE (VE at Tes  = 38.6°C: 25.6 ± 5.9 and 11.9 ± 1.3 L min-1 during normal- and controlled-breathing, respectively, P < 0.001). During normal-breathing, end-tidal CO2 pressure and MCAV decreased with rising Tes , but controlled-breathing diminished these reductions (at Tes  = 38.6°C, 24.7 ± 5.0 vs. 39.5 ± 2.8 mmHg; 44.9 ± 5.9 vs. 60.2 ± 6.3 cm sec-1 , both P < 0.001). The work of breathing correlated positively with changes in VE (P < 0.001) and was lower during controlled- than normal-breathing (16.1 ± 12.6 and 59.4 ± 49.5 J min-1 , respectively, at heating termination, P = 0.013). End-expiratory and inspiratory lung volumes did not differ between trials (P = 0.25 and 0.71, respectively). These results suggest that during passive heating at rest, heat-induced hyperventilation increases the work of breathing without affecting end-expiratory lung volume, and that voluntary control of breathing can nearly abolish this hyperventilation, thereby diminishing hypocapnia, cerebral hypoperfusion, and increased work of breathing.

    Jan. 2019, Physiological reports, 7 (1), e13967, English, International magazine

    Scientific journal

  • Hui C Choo, Jeremiah J Peiffer, João P Lopes-Silva, Ricardo N O Mesquita, Tatsuro Amano, Narihiko Kondo, Chris R Abbiss

    Two studies were conducted to examine the effects of ice slushy ingestion (ICE) and cold water immersion (CWI) on thermoregulatory and sweat responses during constant (study 1) and self-paced (study 2) exercise. In study 1, 11 men cycled at 40-50% of peak aerobic power for 60 min (33.2 ± 0.3°C, 45.9 ± 0.5% relative humidity, RH). In study 2, 11 men cycled for 60 min at perceived exertion (RPE) equivalent to 15 (33.9 ± 0.2°C and 42.5 ± 3.9%RH). In both studies, each trial was preceded by 30 min of CWI (~22°C), ICE or no cooling (CON). Rectal temperature (Tre), skin temperature (Tsk), thermal sensation, and sweat responses were measured. In study 1, ICE decreased Tre-Tsk gradient versus CON (p = 0.005) during first 5 min of exercise, while CWI increased Tre-Tsk gradient versus CON and ICE for up to 20 min during the exercise (p<0.05). In study 2, thermal sensation was lower in CWI versus CON and ICE for up to 35-40 min during the exercise (p<0.05). ICE reduced thermal sensation versus CON during the first 20 min of exercise (p<0.05). In study 2, CWI improved mean power output (MPO) by ~8 W, compared with CON only (p = 0.024). In both studies, CWI (p<0.001) and ICE (p = 0.019) delayed sweating by 1-5 min but did not change the body temperature sweating threshold, compared with CON (both p>0.05). Increased Tre-Tsk gradient by CWI improved MPO while ICE reduced Tre but did not confer any ergogenic effect. Both precooling treatments attenuated the thermal efferent signals until a specific body temperature threshold was reached.

    2019, PloS one, 14 (2), e0212966, English, International magazine

    Scientific journal

  • FEMORAL ARTERIAL BLOOD FLOW RESPONSE DURING THE KNEE EXTENSION EXERCISE IN OLDER MEN

    OUE Anna, SAKOTA Tae, ICHINOSE-KUWAHARA Tomoko, KOGA Shunsaku, KONDO Narihiko, INOUE Yoshimitsu

    To clarify whether the increase in the conduit artery blood flow during dynamic exercise with a small skeletalmuscle groups was inhibited by aging, we compared femoral artery blood flow at rest and during the submaximal kneeextension exercise (0 W, 10 W, 20 W and 30 W) between older (O group) and young (Y group) males. Absolute bloodflow of femoral artery at rest and during exercise at low intensity was smaller in O than Y groups. However, femoralartery blood flow corrected by skeletal muscle mass during exercise at 10~30 W was not attenuated by aging. Theseresults suggested that, during the knee extension exercise within the range of the load intensity that we used in thisstudy, even the older males can maintain the femoral artery blood flow that is equal to young males, in other words,the aging does not inhibit increase of the femoral artery blood flow.

    日本生理人類学会, 2019, Japanese Journal of Physiological Anthropology, 24 (1), 19 - 26, Japanese

    [Refereed]

  • HARADA KAZUHIRO, Masumoto Kouhei, Kondo Narihiko

    Dec. 2018, Research Quarterly for Exercise and Sport, 89, 440 - 449, English

    [Refereed]

    Scientific journal

  • Kazuhiro Harada, Kouhei Masumoto, Narihiko Kondo

    PURPOSE: Although it has been proposed that 1 spouse's health behaviors might correlate with the other spouse's health behavior among married couples, few studies have focused on sedentary behavior. This study examined whether objectively measured sedentary behavior and physical activity are correlated with each other and whether attachment to one's spouse moderates such correlations among middle-aged and older married couples. METHODS: Seventy-two couples participated in the survey. This study measured time engaged in sedentary behavior and moderate-to-vigorous physical activity (MVPA), step counts by an accelerometer for 7 days, and attachment to one's spouse, age, education, and frailty by questionnaires. RESULTS: Multiple regression analyses showed that the sedentary behaviors of 1 spouse statistically significantly regressed on those of the other spouse (β = .30-.47). The regressions of husbands' MVPA and step counts on those of their wives were statistically marginally significant (β = .22-.25), while the regressions of wives' MVPA and step counts on those of their husbands were not statistically significant (β = .15-.18). The interaction terms of the attachment with one's spousal accelerometer variables on those of the other spouse were not statistically significant (β = -.02 to .16). CONCLUSIONS: This study revealed that sedentary behaviors were correlated with each other among couples and attachment to one's spouse did not moderate these correlations. Sedentary behaviors of 1 spouse might influence the other, regardless of attachment to one's spouse. The concordance for physical activity was weaker than that for sedentary behavior.

    Dec. 2018, Research quarterly for exercise and sport, 89 (4), 440 - 449, English, International magazine

    Scientific journal

  • Tatsuro Amano, Anna Igarashi, Naoto Fujii, Daichi Hiramatsu, Yoshimitsu Inoue, Narihiko Kondo

    PURPOSE: This study investigated the influence of β-adrenergic receptor blockade on sweating during bilateral static knee extension (KE) and lateral isometric handgrip (IH) exercises followed by post-exercise muscle ischemia (PEMI) in habitually trained individuals. METHOD: Ten habitually trained men (maximum oxygen uptake, 57.1 ± 3.4 ml kg-1 min-1) were mildly heated by increasing their skin temperature, and bilateral KE or lateral IH exercises at an intensity of 60% maximum voluntary contraction were subsequently performed for 1 min, followed by PEMI to stimulate muscle metaboreceptors for 2 min. Sweat rates were measured on the bilateral forearms (KE) or thighs (IH) transdermally administered with 1% propranolol (propranolol, a non-selective β-adrenergic receptor inhibitor) or saline (control) via iontophoresis. RESULTS: Relative to the pre-exercise baseline values, IH exercise (P = 0.038) followed by PEMI (P = 0.041) similarly increased sweat rates on the thighs at both control and propranolol sites (baseline, 0.05 ± 0.04 vs. 0.05 ± 0.04; IH, 0.14 ± 0.12 vs. 0.15 ± 0.14; PEMI, 0.14 ± 0.16 vs. 0.14 ± 0.16 mg cm-2 min-1). KE increased sweat rates on the forearms (P = 0.001) at both control and propranolol sites similarly (baseline, 0.02 ± 0.03 vs. 0.02 ± 0.03; KE, 0.21 ± 0.19 vs. 0.20 ± 0.18), whereas PEMI did not significantly induce sweating at these sites (P = 0.260) (0.09 ± 0.12 and 0.10 ± 0.12 mg cm-2 min-1, respectively). CONCLUSION: These results suggest that non-thermal drives induced by static exercise and PEMI do not elicit β-adrenergic sweating in habitually trained individuals even when the non-thermal drives are originated from leg(s) under the conditions in the present study.

    Dec. 2018, European journal of applied physiology, 118 (12), 2669 - 2677, English, International magazine

    Scientific journal

  • β-Adrenergic receptor blockade does not modify non-thermal sweating during static exercise and following muscle ischemia in habitually trained individuals

    Amano T, Igarashi A, Fujii N, Hiramatsu D, Inoue Y, KONDO NARIHIKO

    Nov. 2018, Eur J Appl Physiol, 118 (12), 2669 - 2677., English

    [Refereed]

    Scientific journal

  • Age-related attenuation of conduit artery blood flow response to passive heating differs between the arm and leg

    Oue A, Asashima C, Oizumi R, Ichinose-Kuwahara T, KONDO NARIHIKO, Inoue Y

    Nov. 2018, Eur J Appl Physiol, 118 (11), 2307 - 2318, English

    [Refereed]

    Scientific journal

  • Anna Oue, Chie Asashima, Risa Oizumi, Tomoko Ichinose-Kuwahara, Narihiko Kondo, Yoshimitsu Inoue

    PURPOSE: Little is known about why the attenuation of heat loss responses with aging begins in the lower limbs. This study sought to determine whether passive heating causes the age-related decrease and limb-specific difference of blood flow (BF) responses between conduit brachial and femoral arteries, which are related to differences of cutaneous vascular conductance (CVC) between the upper and lower limbs. METHOD: In 15 older and 12 younger males, BF in the brachial and femoral arteries was ultrasonically measured and CVC in the forearm and thigh was assessed during lower leg immersion in hot water at 42 °C (ambient temperature: 30 °C, relative humidity: 45%) for 40 min. RESULTS: The increased BF of brachial artery at the end of passive heating was similar between both age groups (older: 140 ± 4%; younger: 146 ± 11%), while that of femoral artery was smaller in older than younger group (119 ± 4% vs. 166 ± 11%, P < 0.01). Moreover, the increased CVC in the forearm was similar between the age groups (older: 356 ± 50%; younger: 308 ± 46%), although CVC in the thigh was significantly lower in older than younger group (303 ± 33% vs. 427 ± 51%, P < 0.05). These results corresponded to the BF responses of the brachial and femoral arteries, respectively. CONCLUSION: These results indicate that age-related decrease and limb-specific difference occur also in conduit arteries of arm and leg, which might be related to the different reduction in CVC between forearm and thigh.

    Nov. 2018, European journal of applied physiology, 118 (11), 2307 - 2318, English, International magazine

    Scientific journal

  • Tatsuro Amano, Naoto Fujii, Yoshimitsu Inoue, Narihiko Kondo

    It remains unknown whether cutaneous adrenergic nerves functionally contribute to sweat production during exercise. This study examined whether cutaneous adrenergic nerve blockade attenuates sweating during incremental exercise, specifically in habitually trained individuals. Accordingly, 10 habitually trained and 10 untrained males (V̇o2max: 56.7 ± 5.4 and 38.9 ± 6.7 ml·kg-1·min-1, respectively; P < 0.001) performed incremental semirecumbent cycling (20 W/min) until exhaustion. Sweat rates (ventilated capsule) were measured at two bilateral forearm skin sites on which either 10 mM bretylium tosylate (BT) (an inhibitor of neurotransmitter release from sympathetic adrenergic nerve terminals) or saline (Control) was transdermally administered via iontophoresis. BT treatment delayed sweating onset in both groups (∼0.66 min; P = 0.001) and suppressed the sweat rate relative to the Control treatment at ≥70% relative total exercise time in trained individuals (each 10% increment; all P ≤ 0.009) but not in untrained counterparts ( P = 0.122, interaction between relative time × treatment). Changes in total sweat production at the BT site relative to the Control site were greater in trained individuals than in untrained counterparts (area under the curve, -0.86 ± 0.67 and -0.22 ± 0.39 mg/cm2, respectively; P = 0.023). In conclusion, we demonstrated that cutaneous adrenergic nerves do modulate sweating during incremental exercise, which appeared to be more apparent in habitually trained men (e.g., ≥70% maximum workload). Although our results indicated that habitual exercise training may augment neural adrenergic sweat production during incremental exercise, additional studies are required to confirm this possibility. NEW & NOTEWORTHY We demonstrated for the first time that cutaneous adrenergic nerves do modulate sweating during high-intensity exercise in humans (≥70% maximum workload). In addition, neural adrenergic sweating appeared to be greater in habitually trained individuals than in untrained counterparts, although further studies are necessary to confirm such a possibility. Nonetheless, the observations presented herein advance our understanding on human thermoregulation while providing new evidence for the neutral mediation of adrenergic sweating during exercise.

    01 Oct. 2018, Journal of applied physiology (Bethesda, Md. : 1985), 125 (4), 1041 - 1050, English, International magazine

    Scientific journal

  • Amano T, Fujii N, Inoue Y, KONDO NARIHIKO

    It remains unknown whether cutaneous adrenergic nerves functionally contribute to sweat production during exercise. This study examined whether cutaneous adrenergic nerve blockade attenuates sweating during incremental exercise, specifically in habitually trained individuals. Accordingly, 10 habitually trained and 10 untrained males (V̇o2max: 56.7 ± 5.4 and 38.9 ± 6.7 ml·kg-1·min-1, respectively; P < 0.001) performed incremental semirecumbent cycling (20 W/min) until exhaustion. Sweat rates (ventilated capsule) were measured at two bilateral forearm skin sites on which either 10 mM bretylium tosylate (BT) (an inhibitor of neurotransmitter release from sympathetic adrenergic nerve terminals) or saline (Control) was transdermally administered via iontophoresis. BT treatment delayed sweating onset in both groups (∼0.66 min; P = 0.001) and suppressed the sweat rate relative to the Control treatment at ≥70% relative total exercise time in trained individuals (each 10% increment; all P ≤ 0.009) but not in untrained counterparts ( P = 0.122, interaction between relative time × treatment). Changes in total sweat production at the BT site relative to the Control site were greater in trained individuals than in untrained counterparts (area under the curve, -0.86 ± 0.67 and -0.22 ± 0.39 mg/cm2, respectively; P = 0.023). In conclusion, we demonstrated that cutaneous adrenergic nerves do modulate sweating during incremental exercise, which appeared to be more apparent in habitually trained men (e.g., ≥70% maximum workload). Although our results indicated that habitual exercise training may augment neural adrenergic sweat production during incremental exercise, additional studies are required to confirm this possibility. NEW & NOTEWORTHY We demonstrated for the first time that cutaneous adrenergic nerves do modulate sweating during high-intensity exercise in humans (≥70% maximum workload). In addition, neural adrenergic sweating appeared to be greater in habitually trained individuals than in untrained counterparts, although further studies are necessary to confirm such a possibility. Nonetheless, the observations presented herein advance our understanding on human thermoregulation while providing new evidence for the neutral mediation of adrenergic sweating during exercise.

    Oct. 2018, J Appl Physiol, 125 (4), 1041 - 1050, English, International magazine

    [Refereed]

    Scientific journal

  • Danilo Iannetta, Dai Okushima, Erin Calaine Inglis, Narihiko Kondo, Juan M Murias, Shunsaku Koga

    It was recently demonstrated that an O2 extraction reserve, as assessed by the near-infrared spectroscopy (NIRS)-derived deoxygenation signal ([HHb]), exists in the superficial region of vastus lateralis (VL) muscle during an occlusion performed at the end of a ramp-incremental test. However, it is unknown whether this reserve is present and/or different in magnitude in other portions and depths of the quadriceps muscles. We tested the hypothesis that an O2 extraction reserve would exist in other regions of this muscle but is greater in deep compared with more superficial portions. Superficial (VL-s) and deep VL (VL-d) as well as superficial rectus femoris (RF-s) were monitored by a combination of low- and high-power time-resolved (TRS) NIRS. During the occlusion immediately post-ramp-incremental test there was a significant overshoot in the [HHb] signal ( P < 0.05). However, the magnitude of this increase was greater in VL-d (93.2 ± 42.9%) compared with VL-s (55.0 ± 19.6%) and RF-s (47.8 ± 14.0%) ( P < 0.05). The present study demonstrated that an O2 extraction reserve exists in different pools of active muscle fibers of the quadriceps at the end of a ramp exercise to exhaustion. The greater magnitude in the reserve observed in the deeper portion of VL, however, suggests that this portion of muscle may present a greater surplus of oxygenated blood, which is likely due to a greater population of slow-twitch fibers. These findings add to the notion that the plateau in the [HHb] signal toward the end of a ramp-incremental exercise does not indicate the upper limit of O2 extraction. NEW & NOTEWORTHY Different portions of the quadriceps muscles exhibited an untapped O2 extraction reserve during a blood flow occlusion performed at the end of a ramp-incremental exercise. In the deeper portion of the vastus lateralis muscle, this reserve was greater compared with superficial vastus lateralis and rectus femoris. These data suggest that the O2 extraction reserve may be dependent on the vascular and/or oxidative capacities of the muscles.

    01 Aug. 2018, Journal of applied physiology (Bethesda, Md. : 1985), 125 (2), 313 - 319, English, International magazine

    Scientific journal

  • Nicola Gerrett, Katy Griggs, Bernard Redortier, Thomas Voelcker, Narihiko Kondo, George Havenith

    By combining galvanic skin conductance (GSC), stratum corneum hydration (HYD) and regional surface sweat rate (RSR) measurements at the arm, thigh, back and chest, we closely monitored the passage of sweat from gland to skin surface. Through a varied exercise-rest protocol, sweating was increased slowly and decreased in 16 male and female human participants (25.3 ± 4.7 yr, 174.6 ± 10.1 cm, 71.3 ± 12.0 kg, 53.0 ± 6.8 ml·kg-1·min-1). ∆GSC and HYD increased before RSR, indicating pre-secretory sweat gland activity and skin hydration. ∆GSC and HYD typically increased concomitantly during rest in a warm environment (30.1 ± 1.0°C, 30.0 ± 4.7% relative humidity) and only at the arm did ∆GSC increase before an increase in HYD. HYD increased before RSR, before sweat was visible on the skin, but not to full saturation, contradicting earlier hypotheses. Maximal skin hydration did occur, as demonstrated by a plateau in all regions. Post exercise rest resulted in a rapid decrease in HYD and RSR but a delayed decline in ∆GSC. Evidence for reabsorption of surface sweat into the skin following a decline in sweating, as hypothesized in the literature, was not found. This suggests that skin surface sweat, after sweating is decreased, may not diffuse back into the dermis, but is only evaporated. These data, showing distinctly different responses for the three measured variables, provide useful information about the fate of sweat from gland to surface that is relevant across numerous research fields (e.g., thermoregulation, dermatology, ergonomics and material design). NEW & NOTEWORTHY After sweat gland stimulation, sweat travels through the duct, penetrating the epidermis before appearing on the skin surface. We found that only submaximal stratum corneum hydration was required before surface sweating occurred. However, full hydration occurred only once sweat was on the surface. Once sweating reduces, surface sweat evaporation continues, but there is a delayed drying of the skin. This information is relevant across various research fields, including environmental ergonomics, dermatology, thermoregulation, and skin-interface interactions.

    01 Aug. 2018, Journal of applied physiology (Bethesda, Md. : 1985), 125 (2), 459 - 469, English, International magazine

    Scientific journal

  • 暑熱環境における身体能力のリミットコントロール

    KONDO NARIHIKO, Zachary Schlander, Toby Mundel, Nicola Gerrett

    Aug. 2018, 体育の科学, 68 (8), 561-565, Japanese

    Scientific journal

  • Sweat from gland to skin surface: production, transport, and skin absorption

    Gerrett N, Griggs K, Redortier B, Voelcker T, KONDO NARIHIKO, Havenith G

    Aug. 2018, J Appl Physiol, 125 (2), 459 - 469, English

    [Refereed]

    Scientific journal

  • Amano T, Okushima D, Breese BC, Bailey SJ, Koga S, KONDO NARIHIKO

    PURPOSE: We investigated the influence of inorganic nitrate ([Formula: see text]) supplementation on local sweating and cutaneous vascular responses during exercise in hot conditions. METHOD: Eight healthy, young subjects were assigned in a randomized, double-blind, crossover design to receive [Formula: see text]-rich beetroot (BR) juice (140 mL/day, containing ~ 8 mmol of [Formula: see text]) and [Formula: see text]-depleted placebo (PL) juice (140 mL/day, containing ~ 0.003 mmol of [Formula: see text]) for 3 days. On day 3 of supplementation, subjects cycled at an intensity corresponding to 55% of [Formula: see text]O2max for 30 min in hot conditions (30 °C, 50% relative humidity). Chest and forearm sweat rate (SR) and skin blood flow (SkBF), were measured continuously. Cutaneous vascular conductance (CVC) was calculated by SkBF/mean arterial pressure (MAP). RESULTS: Prior to exercise, plasma [Formula: see text] (21 ± 6 and 581 ± 161 µM) and nitrite ([Formula: see text], 87 ± 28 and 336 ± 156 nM) concentrations were higher after BR compared to PL supplementation (P ≤ 0.011, n = 6). Oesophageal, mean skin, and mean body temperatures during exercise were not different between conditions. In addition, BR supplementation did not affect SR, SkBF, and CVC during exercise. A lower MAP was found after 30 min of exercise following BR supplementation (112 ± 6 and 103 ± 6 mmHg for PL and BR, respectively, P = 0.021). CONCLUSION: These results suggest that inorganic [Formula: see text] supplementation, which increases the potential for O2-independent NO production, does not affect local sweating and cutaneous vascular responses, but attenuates blood pressure in young healthy subjects exercising in a hot environment.

    Aug. 2018, Eur J Appl Physiol, 118 (8), 1579 - 1588, English, International magazine

    [Refereed]

    Scientific journal

  • Blood flow occlusion-related O2 extraction "reserve" is present in different muscles of the quadriceps but greater in deeper regions after ramp-incremental test

    Iannetta D, Okushima D, Inglis EC, KONDO NARIHIKO, Murias JM, Koga S

    Aug. 2018, J Appl Physiol, 125 (2), 313 - 319, English

    [Refereed]

    Scientific journal

  • Tatsuro Amano, Dai Okushima, Brynmor C Breese, Stephen J Bailey, Shunsaku Koga, Narihiko Kondo

    PURPOSE: We investigated the influence of inorganic nitrate ([Formula: see text]) supplementation on local sweating and cutaneous vascular responses during exercise in hot conditions. METHOD: Eight healthy, young subjects were assigned in a randomized, double-blind, crossover design to receive [Formula: see text]-rich beetroot (BR) juice (140 mL/day, containing ~ 8 mmol of [Formula: see text]) and [Formula: see text]-depleted placebo (PL) juice (140 mL/day, containing ~ 0.003 mmol of [Formula: see text]) for 3 days. On day 3 of supplementation, subjects cycled at an intensity corresponding to 55% of [Formula: see text]O2max for 30 min in hot conditions (30 °C, 50% relative humidity). Chest and forearm sweat rate (SR) and skin blood flow (SkBF), were measured continuously. Cutaneous vascular conductance (CVC) was calculated by SkBF/mean arterial pressure (MAP). RESULTS: Prior to exercise, plasma [Formula: see text] (21 ± 6 and 581 ± 161 µM) and nitrite ([Formula: see text], 87 ± 28 and 336 ± 156 nM) concentrations were higher after BR compared to PL supplementation (P ≤ 0.011, n = 6). Oesophageal, mean skin, and mean body temperatures during exercise were not different between conditions. In addition, BR supplementation did not affect SR, SkBF, and CVC during exercise. A lower MAP was found after 30 min of exercise following BR supplementation (112 ± 6 and 103 ± 6 mmHg for PL and BR, respectively, P = 0.021). CONCLUSION: These results suggest that inorganic [Formula: see text] supplementation, which increases the potential for O2-independent NO production, does not affect local sweating and cutaneous vascular responses, but attenuates blood pressure in young healthy subjects exercising in a hot environment.

    Aug. 2018, European journal of applied physiology, 118 (8), 1579 - 1588, English, International magazine

    Scientific journal

  • 運動時の体温調節

    天野達郎, Nicola Gerrett, KONDO NARIHIKO

    Jul. 2018, 臨床スポーツ医学, 35 (7), 660-663, Japanese

    Scientific journal

  • 【暑さと熱中症対策-スポーツの安全とパフォーマンスのために-】対策に必要な基礎知識 運動時の体温調節

    天野 達郎, Gerrett Nicola, 近藤 徳彦

    (株)文光堂, Jul. 2018, 臨床スポーツ医学, 35 (7), 660 - 663, Japanese

  • Bun Tsuji, Davide Filingeri, Yasushi Honda, Tsubasa Eguchi, Naoto Fujii, Narihiko Kondo, Takeshi Nishiyasu

    01 May 2018, Journal of applied physiology (Bethesda, Md. : 1985), 124 (5), 1213 - 1213, English, International magazine

  • 高齢者における近隣の坂道に対する認識と活動的な移動習慣との関連-斜面市街地を対象とした検討

    HARADA KAZUHIRO, MASUMOTO Kouhei, KATAGIRI KEIKO, FUKUZAWA AI, CHOGAHARA MAKOTO, KONDO NARIHIKO, OKADA SHUICHI

    日本運動疫学会, May 2018, 運動疫学研究, 20 (1), 16 - 25, Japanese

    [Refereed]

    Scientific journal

  • Kazuhiro Harada, Kouhei Masumoto, Keiko Katagiri, Ai Fukuzawa, Makoto Chogahara, Narihiko Kondo, Shuichi Okada

    AimGoing outdoors more frequently is beneficial for maintaining and improving health-related quality of life (HRQOL) among older adults. However, individual differences can alter the effects of going outdoors. The present study aimed to examine whether relationships between going outdoors and HRQOL were moderated by living alone and employment status.MethodsThe present study was a secondary analysis of 14-month prospective data (n = 613). Variables used in this study were baseline data on the frequency of going outdoors, HRQOL (physical and mental component summary scores assessed using the Japanese version of the Medical Outcomes study Short Form 8-Item Health Survey), living alone, employment status, potential confounders (sex, age, educational level and instrumental activities of daily living) and follow-up data on HRQOL.ResultsMixed models showed that the interaction term of going outdoors and currently living alone on both the physical and mental component summary and that of going outdoors and current employment status on the mental component were significant. Stratified analyses showed that going outdoors more frequently predicted the physical and mental component summary among those who lived with others, and the mental component summary among those who were unemployed.ConclusionsThese results show that the influence of going outdoors on HRQOL was moderated by living alone and employment status. Going outdoors more frequently might be important for the maintenance of HRQOL, especially among unemployed older adults living with others. Geriatr Gerontol Int 2018; 18: 640-647.

    WILEY, Apr. 2018, GERIATRICS & GERONTOLOGY INTERNATIONAL, 18 (4), 640 - 647, English

    [Refereed]

    Scientific journal

  • Kazuhiro Harada, Kouhei Masumoto, Keiko Katagiri, Ai Fukuzawa, Makoto Chogahara, Narihiko Kondo, Shuichi Okada

    AIM: Going outdoors more frequently is beneficial for maintaining and improving health-related quality of life (HRQOL) among older adults. However, individual differences can alter the effects of going outdoors. The present study aimed to examine whether relationships between going outdoors and HRQOL were moderated by living alone and employment status. METHODS: The present study was a secondary analysis of 14-month prospective data (n = 613). Variables used in this study were baseline data on the frequency of going outdoors, HRQOL (physical and mental component summary scores assessed using the Japanese version of the Medical Outcomes study Short Form 8-Item Health Survey), living alone, employment status, potential confounders (sex, age, educational level and instrumental activities of daily living) and follow-up data on HRQOL. RESULTS: Mixed models showed that the interaction term of going outdoors and currently living alone on both the physical and mental component summary and that of going outdoors and current employment status on the mental component were significant. Stratified analyses showed that going outdoors more frequently predicted the physical and mental component summary among those who lived with others, and the mental component summary among those who were unemployed. CONCLUSIONS: These results show that the influence of going outdoors on HRQOL was moderated by living alone and employment status. Going outdoors more frequently might be important for the maintenance of HRQOL, especially among unemployed older adults living with others. Geriatr Gerontol Int 2018; 18: 640-647.

    Apr. 2018, Geriatrics & gerontology international, 18 (4), 640 - 647, English, Domestic magazine

    Scientific journal

  • Kazuhiro Harada, Kouhei Masumoto, Keiko Katagiri, Ai Fukuzawa, Makoto Chogahara, Narihiko Kondo, Shuichi Okada

    AimStrengthening neighborhood social networks is important for promoting health among older adults. However, effective intervention strategies aimed at increasing older adults' social networks have not yet been established. The present study examined whether a university-led community intervention that provided communication opportunities could increase older Japanese adults' neighborhood social networks.MethodsThe present study used a quasi-experimental design. Before the intervention, using postal mail, we carried out a baseline questionnaire survey that was sent to all people living in the Tsurukabuto community aged 60 years (n = 1769), of whom 1068 responded. For the community intervention, 18 event-based programs were provided over the course of 1 year at Kobe University. Academic staff at Kobe University organized all the programs. During the program, social interactions among participants were promoted. A follow-up survey was distributed to those who responded to the baseline survey, and 710 individuals answered the question about their participation in the intervention programs (138 respondents were participants, 572 were non-participants). The neighborhood social network was measured in both the baseline and follow-up surveys.ResultsAnalysis of covariance showed that the changes in neighborhood social network among participants in the program was significantly higher than the changes among non-participants (P = 0.046) after adjusting for the baseline score of social network.ConclusionsThe present study found that participants of the intervention expanded their neighborhood social network, but non-participants did not. This finding shows that community interventions using university resources could increase older adults' neighborhood social networks. Geriatr Gerontol Int 2018; 18: 462-469.

    WILEY, Mar. 2018, GERIATRICS & GERONTOLOGY INTERNATIONAL, 18 (3), 462 - 469, English

    [Refereed]

    Scientific journal

  • Kazuhiro Harada, Kouhei Masumoto, Keiko Katagiri, Ai Fukuzawa, Makoto Chogahara, Narihiko Kondo, Shuichi Okada

    AIM: Strengthening neighborhood social networks is important for promoting health among older adults. However, effective intervention strategies aimed at increasing older adults' social networks have not yet been established. The present study examined whether a university-led community intervention that provided communication opportunities could increase older Japanese adults' neighborhood social networks. METHODS: The present study used a quasi-experimental design. Before the intervention, using postal mail, we carried out a baseline questionnaire survey that was sent to all people living in the Tsurukabuto community aged ≥60 years (n = 1769), of whom 1068 responded. For the community intervention, 18 event-based programs were provided over the course of 1 year at Kobe University. Academic staff at Kobe University organized all the programs. During the program, social interactions among participants were promoted. A follow-up survey was distributed to those who responded to the baseline survey, and 710 individuals answered the question about their participation in the intervention programs (138 respondents were participants, 572 were non-participants). The neighborhood social network was measured in both the baseline and follow-up surveys. RESULTS: Analysis of covariance showed that the changes in neighborhood social network among participants in the program was significantly higher than the changes among non-participants (P = 0.046) after adjusting for the baseline score of social network. CONCLUSIONS: The present study found that participants of the intervention expanded their neighborhood social network, but non-participants did not. This finding shows that community interventions using university resources could increase older adults' neighborhood social networks. Geriatr Gerontol Int 2018; 18: 462-469.

    Mar. 2018, Geriatrics & gerontology international, 18 (3), 462 - 469, English, Domestic magazine

    Scientific journal

  • Nicola Gerrett, Tatsuro Amano, Yoshimitsu Inoue, George Havenith, Narihiko Kondo

    The sweat glands maximum ion reabsorption rates were investigated (n = 12, 21.7 ± 3.0 years, 59.4 ± 9.8 kg, 166.9 ± 10.4 cm and 47.1 ± 7.5 mL/kg/min) during two separate endogenous protocols; cycling at 30% (LEX) and 60% VO2max (MEX) and one exogenous trial; passive heating (PH) (43°C water lower leg immersion) in 27°C, 50%RH. Oesophageal temperature (Tes ), skin temperature (Tsk ), and forearm, chest and lower back sweat rate (SR) and galvanic skin conductance (GSC) were measured. Salivary aldosterone was measured pre-and postheating (n = 3). Using the ∆SR threshold for an increasing ∆GSC to identify maximum sweat ion reabsorption rate revealed higher reabsorption rates during MEX compared to PH (mean of all regions: 0.63 ± 0.28 vs. 0.44 ± 0.3 mg/cm2 /min, P < 0.05). It was not possible to identify the ion reabsorption rate during LEX for some participants. Tes and mean Tsk were different between conditions but mean body temperature (Tb ) and local Tsk (forearm, chest and back) were similar (P > 0.05). Aldosterone increased more during MEX (72.8 ± 36.6 pg/mL) compared to PH (39.2 ± 17.5 pg/mL) and LEX (1.8 ± 9.7 pg/mL). The back had a higher threshold than the forearm (P < 0.05) but it was similar to the chest (P > 0.05) (mean of all conditions; 0.64 ± 0.33, 0.42 ± 0.25, 0.54 ± 0.3 mg/cm2 /min, respectively). Although the differences between conditions may be influenced by thermal or nonthermal mechanism, our results indicate a possibility that the sweat glands maximum ion reabsorption rates may be different between exercise and passive heating without mediating skin regional differences.

    Mar. 2018, Physiological reports, 6 (5), English, International magazine

    Scientific journal

  • Bun Tsuji, Davide Filingeri, Yasushi Honda, Tsubasa Eguchi, Naoto Fujii, Narihiko Kondo, Takeshi Nishiyasu

    Elevating core temperature at rest causes increases in minute ventilation (V̇e), which lead to reductions in both arterial CO2 partial pressure (hypocapnia) and cerebral blood flow. We tested the hypothesis that in resting heated humans this hypocapnia diminishes the ventilatory sensitivity to rising core temperature but does not explain a large portion of the decrease in cerebral blood flow. Fourteen healthy men were passively heated using hot-water immersion (41°C) combined with a water-perfused suit, which caused esophageal temperature (Tes) to reach 39°C. During heating in two separate trials, end-tidal CO2 partial pressure decreased from the level before heating (39.4 ± 2.0 mmHg) to the end of heating (30.5 ± 6.3 mmHg) ( P = 0.005) in the Control trial. This decrease was prevented by breathing CO2-enriched air throughout the heating such that end-tidal CO2 partial pressure did not differ between the beginning (39.8 ± 1.5 mmHg) and end (40.9 ± 2.7 mmHg) of heating ( P = 1.00). The sensitivity to rising Tes (i.e., slope of the Tes - V̇E relation) did not differ between the Control and CO2-breathing trials (37.1 ± 43.1 vs. 16.5 ± 11.1 l·min-1·°C-1, P = 0.31). In both trials, middle cerebral artery blood velocity (MCAV) decreased early during heating (all P < 0.01), despite the absence of hyperventilation-induced hypocapnia. CO2 breathing increased MCAV relative to Control at the end of heating ( P = 0.005) and explained 36.6% of the heat-induced reduction in MCAV. These results indicate that during passive heating at rest ventilatory sensitivity to rising core temperature is not suppressed by hypocapnia and that most of the decrease in cerebral blood flow occurs independently of hypocapnia. NEW & NOTEWORTHY Hyperthermia causes hyperventilation and concomitant hypocapnia and cerebral hypoperfusion. The last may underlie central fatigue. We are the first to demonstrate that hyperthermia-induced hyperventilation is not suppressed by the resultant hypocapnia and that hypocapnia explains only 36% of cerebral hypoperfusion elicited by hyperthermia. These new findings advance our understanding of the mechanisms controlling ventilation and cerebral blood flow during heat stress, which may be useful for developing interventions aimed at preventing central fatigue during hyperthermia.

    01 Jan. 2018, Journal of applied physiology (Bethesda, Md. : 1985), 124 (1), 225 - 233, English, International magazine

    Scientific journal

  • Social Networks as a Factor in Volunteering among Elderly Japanese with Lower Socioeconomic Status

    Fukuzawa Ai, Keiko Katagiri, Kazuhiro Harada, Kouhei Masumoto, Makoto Chogahara, Narihiko Kondo, Shuichi Okada

    2018, Japanese Psychological Research, English

    [Refereed]

    Scientific journal

  • Harada Kazuhiro, Masumoto Kouhei, Katagiri Keiko, Fukuzawa Ai, Chogahara Makoto, Kondo Narihiko, Okada Shuichi

    Objective: This study examined the association between the perception of hilly environment and active transportation among older adults living in sloping land.

    Methods: This study was cross-sectional. A questionnaire survey was conducted with older adults (n = 1021) residing in Tsurukabuto area in Nada-ward, Kobe-city. Among the respondents, 693 individuals (67.9%) answered the survey. In this study, data from 337 individuals aged 65 or more without serious mobility limitations and missing data were analyzed. Active transportation was measured as "transportation outside Tsurukabuto area by walking or cycling at least once a week." To evaluate participants' perception of the hilly environment, they were asked whether transportation was difficult due to the hilly neighborhood. Gender, age group, living arrangement, perceived economic status, driving status, exercise activity at least twice a week, being overweight, knee pain, and psychological distress were also examined in the questionnaire. A poisson regression analysis was performed, with active transportation as the dependent variable, and the perception of the hilly environment and other factors as the independent variables.

    Results: Among the respondents, 21.2% engaged in active transportation. The poisson regression analysis revealed that those who negatively perceived the hilly environment (adjusted prevalence ratio = 0.64, 95% confidence interval = 0.42-0.96) were less likely to engage in active transportation than those who did not negatively perceived it.

    Conclusion: The present study found that the those without negative perception of the hilly environment tended to engage in active transportation among the respondents. This finding indicates that reducing negative perception of the hilly environment might influence active transportation among older adults living in sloping land.

    Japanese Association of Exercise Epidemiology, 2018, Research in Exercise Epidemiology, 20 (1), 16 - 25, Japanese

    [Refereed]

    Scientific journal

  • Harada Kazuhiro, MASUMOTO Kouhei, KONDO NARIHIKO

    Nov. 2017, 日本健康教育学会誌, 25, 258 - 268, Japanese

    [Refereed]

    Scientific journal

  • Naoto Fujii, Erii Aoki-Murakami, Bun Tsuji, Glen P Kenny, Kei Nagashima, Narihiko Kondo, Takeshi Nishiyasu

    We evaluated cold sensation at rest and in response to exercise-induced changes in core and skin temperatures in cold-sensitive exercise trained females. Fifty-eight trained young females were screened by a questionnaire, selecting cold-sensitive (Cold-sensitive, n = 7) and non-cold-sensitive (Control, n = 7) individuals. Participants rested in a room at 29.5°C for ~100 min after which ambient temperature was reduced to 23.5°C where they remained resting for 60 min. Participants then performed 30-min of moderate intensity cycling (50% peak oxygen uptake) followed by a 60-min recovery. Core and mean skin temperatures and cold sensation over the whole-body and extremities (fingers and toes) were assessed throughout. Resting core temperature was lower in the Cold-sensitive relative to Control group (36.4 ± 0.3 vs. 36.7 ± 0.2°C). Core temperature increased to similar levels at end-exercise (~37.2°C) and gradually returned to near preexercise rest levels at the end of recovery (>36.6°C). Whole-body cold sensation was greater in the Cold-sensitive relative to Control group during resting at a room temperature of 23.5°C only without a difference in mean skin temperature between groups. In contrast, cold sensation of the extremities was greater in the Cold-sensitive group prior to, during and following exercise albeit this was not paralleled by differences in mean extremity skin temperature. We show that young trained females who are sensitive to cold exhibit augmented whole-body cold sensation during rest under temperate ambient conditions. However, this response is diminished during and following exercise. In contrast, cold sensation of extremities is augmented during resting that persists during and following exercise.

    Nov. 2017, Physiological reports, 5 (20), English, International magazine

    Scientific journal

  • Fujii N, Aoki-Murakami E, Tsuji B, Kenny GP, Nagashima K, Kondo N, Nishiyasu T

    Nov. 2017, Physiological reports, 5 (20)

    [Refereed]

  • Kouhei Masumoto, Takaharu Yaguchi, Hiroshi Matsuda, Hideaki Tani, Keisuke Tozuka, Narihiko Kondo, Shuichi Okada

    Aim: A number of interventions have been undertaken to develop and promote social networks among community dwelling older adults. However it has been difficult to examine the effects of these interventions, because of problems in assessing interactions. The present study was designed to quantitatively measure and visualize face-to-face interactions among elderly participants in an exercise program. We also examined relationships among interactional variables, personality and interest in community involvement, including interactions with the local community. Methods: Older adults living in the same community were recruited to participate in an exercise program that consisted of tour sessions. We collected data on face-to-face interactions of the participants by using a wearable sensor technology device. Results: Network analysis identified the communication networks of participants in the exercise program, as well as changes in these networks. Additionally, there were significant correlations between the number of people involved in face-to-face interactions and changes in both interest in community involvement and interactions with local community residents, as well as personality traits, including agreeableness. Conclusions: Social networks in the community are essential for solving problems caused by the aging society. We showed the possible applications of face-to-face interactional data for identifying core participants having many interactions, and isolated participants having only a few interactions within the community. Such data would be useful for carrying out efficient interventions for increasing participants' involvement with their community.

    WILEY, Oct. 2017, GERIATRICS & GERONTOLOGY INTERNATIONAL, 17 (10), 1752 - 1758, English

    [Refereed]

    Scientific journal

  • Kouhei Masumoto, Takaharu Yaguchi, Hiroshi Matsuda, Hideaki Tani, Keisuke Tozuka, Narihiko Kondo, Shuichi Okada

    AIM: A number of interventions have been undertaken to develop and promote social networks among community-dwelling older adults. However, it has been difficult to examine the effects of these interventions, because of problems in assessing interactions. The present study was designed to quantitatively measure and visualize face-to-face interactions among elderly participants in an exercise program. We also examined relationships among interactional variables, personality and interest in community involvement, including interactions with the local community. METHODS: Older adults living in the same community were recruited to participate in an exercise program that consisted of four sessions. We collected data on face-to-face interactions of the participants by using a wearable sensor technology device. RESULTS: Network analysis identified the communication networks of participants in the exercise program, as well as changes in these networks. Additionally, there were significant correlations between the number of people involved in face-to-face interactions and changes in both interest in community involvement and interactions with local community residents, as well as personality traits, including agreeableness. CONCLUSIONS: Social networks in the community are essential for solving problems caused by the aging society. We showed the possible applications of face-to-face interactional data for identifying core participants having many interactions, and isolated participants having only a few interactions within the community. Such data would be useful for carrying out efficient interventions for increasing participants' involvement with their community. Geriatr Gerontol Int 2017; 17: 1752-1758.

    Oct. 2017, Geriatrics & gerontology international, 17 (10), 1752 - 1758, English, Domestic magazine

    Scientific journal

  • Masashi Ichinose, Tomoko Ichinose-Kuwahara, Kazuhito Watanabe, Narihiko Kondo, Takeshi Nishiyasu

    The purpose of the present study was to test our hypothesis that unloading the carotid baroreceptors alters the threshold and gain of the muscle metaboreflex in humans. Ten healthy subjects performed a static handgrip exercise at 50% of maximum voluntary contraction. Contraction was sustained for 15, 30, 45, and 60 s and was followed by 3 min of forearm circulatory arrest, during which forearm muscular pH is known to decrease linearly with increasing contraction time. The carotid baroreceptors were unloaded by applying 0.1-Hz sinusoidal neck pressure (oscillating from +15 to +50 mmHg) during ischemia. We estimated the threshold and gain of the muscle metaboreflex by analyzing the relationship between the cardiovascular responses during ischemia and the amount of work done during the exercise. In the condition with unloading of the carotid baroreceptors, the muscle metaboreflex thresholds for mean arterial blood pressure (MAP) and total vascular resistance (TVR) corresponded to significantly lower work levels than the control condition (threshold for MAP: 795 ± 102 vs. 662 ± 208 mmHg and threshold for TVR: 818 ± 213 vs. 572 ± 292 kg·s, P < 0.05), but the gains did not differ between the two conditions (gain for MAP: 4.9 ± 1.7 vs. 4.4 ± 1.6 mmHg·kg·s-1·100 and gain for TVR: 1.3 ± 0.8 vs. 1.3 ± 0.7 mmHg·l-1·min-1·kg·s-1·100). We conclude that the carotid baroreflex modifies the muscle metaboreflex threshold in humans. Our results suggest the carotid baroreflex brakes the muscle metaboreflex, thereby inhibiting muscle metaboreflex-mediated pressor and vasoconstriction responses.NEW & NOTEWORTHY We found that unloading the carotid baroreceptors shifts the pressor threshold of the muscle metaboreflex toward lower metabolic stimulation levels in humans. This finding indicates that, in the normal loading state, the carotid baroreflex inhibits the muscle metaboreflex pressor response by shifting the reflex threshold to higher metabolic stimulation levels.

    01 Sep. 2017, American journal of physiology. Heart and circulatory physiology, 313 (3), H650-H657, English, International magazine

    Scientific journal

  • Tatsuro Amano, Naoto Fujii, Glen P Kenny, Yoshimitsu Inoue, Narihiko Kondo

    The aim of our study was to determine if habitual endurance training can influence the relative contribution of nitric oxide synthase (NOS) and cyclooxygenase (COX) in the regulation of sweating during a passive heat stress in young adults. Ten trained athletes and nine untrained counterparts were passively heated until oral temperature (as estimated by sublingual temperature, Tor) increased by 1.5°C above baseline resting. Forearm sweat rate (ventilated capsule) was measured at three skin sites continuously perfused with either lactated Ringer's solution (Control), 10 mmol/L NG -nitro-L-arginine methyl ester (L-NAME, non-selective NOS inhibitor), or 10 mmol/L ketorolac (Ketorolac, non-selective COX inhibitor) via intradermal microdialysis. Sweat rate was averaged for each 0.3°C increase in Tor Sweat rate at the L-NAME site was lower than Control following a 0.9 and 1.2°C increase in Tor in both groups (all P ≤ 0.05). Relative to the Control site, NOS-inhibition reduced sweating similarly between the groups (P = 0.51). Sweat rate at the Ketorolac site was not different from the Control at any levels of Tor in both groups (P > 0.05). Nevertheless, a greater sweat rate was measured at the end of heating in the trained as compared to the untrained individuals (P ≤ 0.05). We show that NOS contributes similarly to sweating in both trained and untrained individuals during a passive heat stress. Further, no effect of COX on sweating was measured for either group. The greater sweat production observed in endurance-trained athletes is likely mediated by factors other than NOS- and COX-dependent mechanisms.

    Sep. 2017, Physiological reports, 5 (17), English, International magazine

    Scientific journal

  • Shunsaku Koga, Dai Okushima, Thomas J Barstow, Harry B Rossiter, Narihiko Kondo, David C Poole

    To date our knowledge of skeletal muscle deoxygenation as measured by near-infrared spectroscopy (NIRS) is predicated almost exclusively on sampling of superficial muscle(s), most commonly the vastus lateralis (VL-s). Recently developed high power NIRS facilitates simultaneous sampling of deep (i.e., rectus femoris, RF-d) and superficial muscles of RF (RF-s) and VL-s. Because deeper muscle is more oxidative with greater capillarity and sustains higher blood flows than superficial muscle, we used time-resolved NIRS to test the hypotheses that, following exercise onset, the RF-d has slower deoxy[Hb+Mb] kinetics with reduced amplitude than superficial muscles. Thirteen participants performed cycle exercise transitions from unloaded to heavy work rates. Within the same muscle (RF-s vs. RF-d) deoxy[Hb+Mb] kinetics (mean response time, MRT) and amplitudes were not different. However, compared with the kinetics of VL-s, deoxy[Hb+Mb] of RF-s and RF-d were slower (MRT: RF-s, 51 ± 23; RF-d, 55 ± 29; VL-s, 18 ± 6 s; P < 0.05). Moreover, the amplitude of total[Hb+Mb] was greater for VL-s than both RF-s and RF-d (P < 0.05). Whereas pulmonary V˙O2 kinetics (i.e., on vs. off) were symmetrical in heavy exercise, there was a marked on-off asymmetry of deoxy[Hb+Mb] for all three sites i.e., MRT-off > MRT-on (P < 0.05). Collectively these data reveal profoundly different O2 transport strategies, with the RF-s and RF-d relying proportionately more on elevated perfusive and the VL-s on diffusive O2 transport. These disparate O2 transport strategies and their temporal profiles across muscles have previously been concealed within the "global" pulmonary V˙O2 response.

    Sep. 2017, Physiological reports, 5 (17), English, International magazine

    Scientific journal

  • Tatsuro Amano, Yosuke Shitara, Naoto Fujii, Yoshimitsu Inoue, Narihiko Kondo

    The aim of the present study was to determine the β-adrenergic contribution to sweating during incremental exercise in habitually trained males. Nine habitually trained and 11 untrained males performed incremental cycling until exhaustion (20 W/min). Bilateral forearm sweat rates (ventilated capsule) were measured at two skin sites that were transdermally administered via iontophoresis with either 1% propranolol (Propranolol, a nonselective β-adrenergic receptor antagonist) or saline (Control). The sweat rate was evaluated as a function of both relative (percentage of maximum workload) and absolute exercise intensities. The sweat rate at the Propranolol site was lower than the control during exercise at 80 (0.57 ± 0.21 and 0.45 ± 0.19 mg·cm-2·min-1 for Control and Propranolol, respectively) and 90% (0.74 ± 0.22 and 0.65 ± 0.17 mg·cm-2·min-1, respectively) of maximum workload in trained males (all P < 0.05). By contrast, no between-site differences in sweat rates were observed in untrained counterparts (all P > 0.05). At the same absolute intensity, higher sweat rates on the control site were observed in trained males relative to the untrained during exercise at 160 (0.23 ± 0.20 and 0.04 ± 0.05 mg·cm-2·min-1 for trained and untrained, respectively) and 180 W (0.40 ± 0.20 and 0.13 ± 0.13 mg·cm-2·min-1, respectively) (all P < 0.05), whereas this between-group difference was not observed at the Propranolol site (all P > 0.05). We show that the β-adrenergic mechanism does modulate sweating during exercise at a submaximal high relative intensity in habitually trained males. The β-adrenergic mechanism may in part contribute to the greater sweat production in habitually trained males than in untrained counterparts during exercise.NEW & NOTEWORTHY We demonstrated for the first time that the β-adrenergic mechanism does modulate sweating (i.e., β-adrenergic sweating) during exercise using a localized β-adrenoceptor blockade in humans in vivo. β-Adrenergic sweating was evident in habitually trained individuals during exercise at a submaximal high relative intensity (80-90% maximal work). This observation advances our understanding of human thermoregulation during exercise and of the mechanism that underlies sweat gland adaptation to habitual exercise training.

    01 Jul. 2017, Journal of applied physiology (Bethesda, Md. : 1985), 123 (1), 182 - 189, English, International magazine

    Scientific journal

  • Tatsuro Amano, Megumi Hirose, Kana Konishi, Nicola Gerrett, Hiroyuki Ueda, Narihiko Kondo, Yoshimitsu Inoue

    PURPOSE: It is recently reported that determining sweat rate (SR) threshold for increasing galvanic skin conductance (GSC) would represent a maximum rate of sweat ion reabsorption in sweat glands. We evaluate the maximum rate of sweat ion reabsorption over skin regions, sex, and long-term exercise training by using the threshold analysis in the present study. METHODS: Ten males (2 untrained, 4 sprinters, and 4 distance runners) and 12 females (5 untrained, 4 sprinters, and 3 distance runners) conducted graded cycling exercise for 45 min at low, middle, and high exercise intensities (heart rate 100-110, 120-130, and 140-150 beats/min, respectively) for 10, 15, and 20 min, respectively, at 30 °C and 50% relative humidity. Comparisons were made between males and females and among untrained individuals, distance runners, and sprinters on the back and forearm. RESULTS: SR threshold for increasing GSC on back was significantly higher than that of forearm (P < 0.05) without any sex differences (back 0.70 ± 0.08 and 0.61 ± 0.04, forearm 0.40 ± 0.05 and 0.45 ± 0.06 mg/cm2/min for males and females, respectively). Distance runners and sprinters showed higher SR threshold for increasing GSC than that of untrained subjects on back (P < 0.05) but not on forearm (back 0.45 ± 0.06, 0.83 ± 0.06, and 0.70 ± 0.04, forearm 0.33 ± 0.04, 0.49 ± 0.02, and 0.39 ± 0.07 mg/cm2/min for untrained subjects, distance runners, and sprinters, respectively). CONCLUSION: These results suggest that the maximum sweat ion reabsorption rate on the back is higher than that of forearm without sex differences. Furthermore, exercise training in distance runners and sprinters improves the maximum sweat ion reabsorption rate on the back.

    Jul. 2017, European journal of applied physiology, 117 (7), 1317 - 1327, English, International magazine

    Scientific journal

  • Brynmor C Breese, David C Poole, Dai Okushima, Stephen J Bailey, Andrew M Jones, Narihiko Kondo, Tatsuro Amano, Shunsaku Koga

    This study investigated the influence of dietary inorganic nitrate (NO3-) supplementation on pulmonary O2 uptake (V˙O2) and muscle deoxyhemoglobin/myoglobin (i.e. deoxy [Hb + Mb]) kinetics during submaximal cycling exercise. In a randomized, placebo-controlled, cross-over study, eight healthy and physically active male subjects completed two step cycle tests at a work rate equivalent to 50% of the difference between the gas exchange threshold and peak V˙O2 over separate 4-day supplementation periods with NO3--rich (BR; providing 8.4 mmol NO3-∙day-1) and NO3--depleted (placebo; PLA) beetroot juice. Pulmonary V˙O2 was measured breath-by-breath and time-resolved near-infrared spectroscopy was utilized to quantify absolute deoxy [Hb + Mb] and total [Hb + Mb] within the rectus femoris, vastus lateralis, and vastus medialis There were no significant differences (P > 0.05) in the primary deoxy [Hb + Mb] mean response time or amplitude between the PLA and BR trials at each muscle site. BR significantly increased the mean (three-site) end-exercise deoxy [Hb + Mb] (PLA: 91 ± 9 vs. BR: 95 ± 12 μmol/L, P < 0.05), with a tendency to increase the mean (three-site) area under the curve for total [Hb + Mb] responses (PLA: 3650 ± 1188 vs. BR: 4467 ± 1315 μmol/L sec-1, P = 0.08). The V˙O2 slow component reduction after BR supplementation (PLA: 0.27 ± 0.07 vs. BR: 0.23 ± 0.08 L min-1, P = 0.07) correlated inversely with the mean increases in deoxy [Hb + Mb] and total [Hb + Mb] across the three muscle regions (r2 = 0.62 and 0.66, P < 0.05). Dietary NO3- supplementation increased O2 diffusive conductance across locomotor muscles in association with improved V˙O2 dynamics during heavy-intensity cycling transitions.

    Jul. 2017, Physiological reports, 5 (14), English, International magazine

    Scientific journal

  • Breese Brynmor C., Poole David C., Okushima Dai, Bailey Stephen J., Jones Andrew M., Kondo Narihiko, Amano Tatsuro, Koga Shunsaku

    This study investigated the influence of dietary inorganic nitrate (NO3(-)) supplementation on pulmonary O2 uptake (V˙O2) and muscle deoxyhemoglobin/myoglobin (i.e. deoxy [Hb+Mb]) kinetics during submaximal cycling exercise. In a randomized, placebo-controlled, cross-over study, eight healthy and physically active male subjects completed two step cycle tests at a work rate equivalent to 50% of the difference between the gas exchange threshold and peak (V˙O2) over separate 4-day supplementation periods with (NO3(-))‐rich (BR; providing 8.4mmol (NO3(-))−∙day−1) and (NO3(-)) ‐depleted (placebo; PLA) beetroot juice. Pulmonary (V˙O2) was measured breath-by-breath and time-resolved near-infrared spectroscopy was utilized to quantify absolute deoxy [Hb+Mb] and total [Hb+Mb] within the rectus femoris, vastus lateralis, and vastus medialis. There were no significant differences (P>0.05) in the primary deoxy [Hb+Mb] mean response time or amplitude between the PLA and BR trials at each muscle site. BR significantly increased the mean (three-site) end-exercise deoxy [Hb+Mb] (PLA: 91 ± 9 vs. BR: 95 ± 12 μmol/L, P < 0.05), with a tendency to increase the mean (three-site) area under the curve for total [Hb + Mb] responses (PLA: 3650 ± 1188 vs. BR: 4467 ± 1315 μmol/L sec−1, P = 0.08). The (V˙O2) slow component reduction after BR supplementation (PLA: 0.27 ± 0.07 vs. BR: 0.23 ± 0.08Lmin(-1), P=0.07) correlated inversely with the mean increases in deoxy [Hb+Mb] and total [Hb+Mb] across the three muscle regions (r(2)=0.62 and 0.66, P<0.05). Dietary (NO3(-))supplementation increased O2 diffusive conductance across locomotor muscles in association with improved (V˙O2) dynamics during heavy-intensity cycling transitions.

    Wiley, Jul. 2017, Physiological Reports, 5 (14), e13340, English

  • Tatsuro Amano, Megumi Hirose, Kana Konishi, Nicola Gerrett, Hiroyuki Ueda, Narihiko Kondo, Yoshimitsu Inoue

    Purpose It is recently reported that determining sweat rate (SR) threshold for increasing galvanic skin conductance (GSC) would represent a maximum rate of sweat ion reabsorption in sweat glands. We evaluate the maximum rate of sweat ion reabsorption over skin regions, sex, and longterm exercise training by using the threshold analysis in the present study. Methods Ten males (2 untrained, 4 sprinters, and 4 distance runners) and 12 females (5 untrained, 4 sprinters, and 3 distance runners) conducted graded cycling exercise for 45 min at low, middle, and high exercise intensities (heart rate 100-110, 120-130, and 140-150 beats/min, respectively) for 10, 15, and 20 min, respectively, at 30 degrees C and 50% relative humidity. Comparisons were made between males and females and among untrained individuals, distance runners, and sprinters on the back and forearm. Results SR threshold for increasing GSC on back was significantly higher than that of forearm (P < 0.05) without any sex differences (back 0.70 +/- 0.08 and 0.61 +/- 0.04, forearm 0.40 +/- 0.05 and 0.45 +/- 0.06 mg/cm(2)/min for males showed higher SR threshold for increasing GSC than that of untrained subjects on back (P < 0.05) but not on forearm (back 0.45 +/- 0.06, 0.83 +/- 0.06, and 0.70 +/- 0.04, forearm 0.33 +/- 0.04, 0.49 +/- 0.02, and 0.39 +/- 0.07 mg/cm(2)/min for untrained subjects, distance runners, and sprinters, respectively). Conclusion These results suggest that the maximum sweat ion reabsorption rate on the back is higher than that of forearm without sex differences. Furthermore, exercise training in distance runners and sprinters improves the maximum sweat ion reabsorption rate on the back.

    SPRINGER, Jul. 2017, EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY, 117 (7), 1317 - 1327, English

    [Refereed]

    Scientific journal

  • Tatsuro Amano, Yosuke Shitara, Naoto Fujii, Yoshimitsu Inoue, Narihiko Kondo

    The aim of the present study was to determine the beta-adrenergic contribution to sweating during incremental exercise in habitually trained males. Nine habitually trained and 11 untrained males performed incremental cycling until exhaustion (20 W/min). Bilateral forearm sweat rates (ventilated capsule) were measured at two skin sites that were transdermally administered via iontophoresis with either 1% propranolol (Propranolol, a nonselective beta-adrenergic receptor antagonist) or saline (Control). The sweat rate was evaluated as a function of both relative (percentage of maximum workload) and absolute exercise intensities. The sweat rate at the Propranolol site was lower than the control during exercise at 80 (0.57 +/- 0.21 and 0.45 +/- 0.19 mg .cm(-2) .min(-1) for Control and Propranolol, respectively) and 90% (0.74 +/- 0.22 and 0.65 +/- 0.17 mg u cm(-2).min(-1), respectively) of maximum workload in trained males (all P = 0.05). By contrast, no between-site differences in sweat rates were observed in untrained counterparts (all P = 0.05). At the same absolute intensity, higher sweat rates on the control site were observed in trained males relative to the untrained during exercise at 160 (0.23 +/- 0.20 and 0.04 +/- 0.05 mg.cm(-2).min(-1) for trained and untrained, respectively) and 180 W (0.40 +/- 0.20 and 0.13 +/- 0.13 mg.cm(-2).min(-1), respectively) (all P = 0.05), whereas this between-group difference was not observed at the Propranolol site (all P = 0.05). We show that the beta-adrenergic mechanism does modulate sweating during exercise at a submaximal high relative intensity in habitually trained males. The beta-adrenergic mechanism may in part contribute to the greater sweat production in habitually trained males than in untrained counterparts during exercise.

    AMER PHYSIOLOGICAL SOC, Jul. 2017, JOURNAL OF APPLIED PHYSIOLOGY, 123 (1), 182 - 189, English

    [Refereed]

    Scientific journal

  • Naoto Fujii, Toshiya Nikawa, Bun Tsuji, Glen P Kenny, Narihiko Kondo, Takeshi Nishiyasu

    The activation of cutaneous vasodilation and sweating are essential to the regulation of core temperature during exercise in the heat. We assessed the effect of graduated compression induced by wearing stockings on cutaneous vasodilation and sweating during exercise in the heat (30°C). On two separate occasions, nine young males exercised for 45 min or until core temperature reached ~1.5°C above baseline resting while wearing either (1) stockings causing graduated compression (graduate compression stockings, GCS), or (2) loose-fitting stockings without compression (Control). Forearm vascular conductance was evaluated by forearm blood flow (venous occlusion plethysmography) divided by mean arterial pressure to estimate cutaneous vasodilation. Sweat rate was estimated using the ventilated capsule technique. Core and skin temperatures were measured continuously. Exercise duration was similar between conditions (Control: 42.2 ± 3.6 min vs. GCS: 42.2 ± 3.6 min, P = 1.00). Relative to Control, GCS increased forearm vascular conductance during the late stages (≥30 min) of exercise (e.g., at 40 min, 15.6 ± 5.6 vs. 18.0 ± 6.0 units, P = 0.01). This was paralleled by a greater sensitivity (23.1 ± 9.1 vs. 32.1 ± 15.0 units°C-1, P = 0.043) and peak level (14.1 ± 5.1 vs. 16.3 ± 5.7 units, P = 0.048) of cutaneous vasodilation as evaluated from the relationship between forearm vascular conductance with core temperature. However, the core temperature threshold at which an increase in forearm vascular conductance occurred did not differ between conditions (Control: 36.9 ± 0.2 vs. GCS: 37.0 ± 0.3°C, P = 0.13). In contrast, no effect of GCS on sweating was measured (all P > 0.05). We show that the use of GCS during exercise in the heat enhances cutaneous vasodilation and not sweating.

    May 2017, Physiological reports, 5 (9), English, International magazine

    Scientific journal

  • Naoto Fujii, Toshiya Nikawa, Bun Tsuji, Narihiko Kondo, Glen P Kenny, Takeshi Nishiyasu

    PURPOSE: We investigated whether graduated compression induced by stockings enhances cutaneous vasodilation in passively heated resting humans. METHODS: Nine habitually active young men were heated at rest using water-perfusable suits, resulting in a 1.0 °C increase in body core temperature. Heating was repeated twice on separate occasions while wearing either (1) stockings that cause graduated compression (pressures of 26.4 ± 5.3, 17.5 ± 4.4, and 6.1 ± 2.0 mmHg at the ankle, calf, and thigh, respectively), or (2) loose-fitting stockings without causing compression (Control). Forearm vascular conductance during heating was evaluated by forearm blood flow (venous occlusion plethysmography) divided by mean arterial pressure to estimate heat-induced cutaneous vasodilation. Body core (esophageal), skin, and mean body temperatures were measured continuously. RESULTS: Compared to the Control, forearm vascular conductance during heating was higher with graduated compression stockings (e.g., 23.2 ± 5.5 vs. 28.6 ± 5.8 units at 45 min into heating, P = 0.001). In line with this, graduated compression stockings resulted in a greater sensitivity (27.5 ± 8.3 vs. 34.0 ± 9.4 units °C-1, P = 0.02) and peak level (25.5 ± 5.8 vs. 29.7 ± 5.8 units, P = 0.004) of cutaneous vasodilation as evaluated from the relationship between forearm vascular conductance with mean body temperature. In contrast, the mean body temperature threshold for increases in forearm vascular conductance did not differ between the Control and graduated compression stockings (36.5 ± 0.1 vs. 36.5 ± 0.2 °C, P = 0.85). CONCLUSIONS: Our results show that graduated compression associated with the use of stockings augments cutaneous vasodilation by modulating sensitivity and peak level of cutaneous vasodilation in relation to mean body temperature. However, the effect of these changes on whole-body heat loss remains unclear.

    May 2017, European journal of applied physiology, 117 (5), 921 - 929, English, International magazine

    Scientific journal

  • Fujii N, Nikawa T, Tsuji B, Kenny GP, Kondo N, Nishiyasu T

    May 2017, Physiological reports, 5 (9)

    [Refereed]

  • 運動時におけるヒトの発汗調節特性

    近藤 徳彦, 天野 達郎, Gerrett Nicola

    日本発汗学会, Apr. 2017, 発汗学, 24 (1), 2 - 5, Japanese

  • 河崎 素乃美, YAGUCHI TAKAHARU, MASUMOTO KOUHEI, KONDO NARIHIKO, OKADA SHUICHI

    Mar. 2017, 応用数理, 27, 13 - 20, Japanese

    [Refereed][Invited]

    Scientific journal

  • Tatsuro Amano, Seiko Kai, Michi Nakajima, Tomoko Ichinose-Kuwahara, Nicola Gerrett, Narihiko Kondo, Yoshimitsu Inoue

    NEW FINDINGS: What is the central question of this study? Non-thermal factors (e.g. muscle metaboreflex) contribute to the sweating response during exercise. Although it is well recognized that the sweating responses caused by core temperature elevation in prepubertal children and the elderly are attenuated compared with young adults, it is unknown whether non-thermal sweating is also attenuated in these populations. What is the main finding and its importance? The non-thermal sweating response during isometric hand-grip exercise and isolated muscle metaboreflex were attenuated in prepubertal children compared with young adults in a non-uniform manner over the body, but only during the muscle metaboreflex in the elderly. This may explain the maturation- and ageing-related decline of sweating during exercise. The purpose of the present study was to investigate sweating responses to isometric hand-grip (IH) exercise and muscle metaboreflex in prepubertal children and the elderly. In hot conditions (ambient temperature, 35°C; relative humidity, 45%), 13 healthy young adults, 10 prepubertal children and 10 elderly subjects (aged 20.4 ± 1.2, 11.4 ± 0.5 and 63.5 ± 3.1 years, respectively) repeated a three hand-grip exercise protocol that consisted of 1 min IH exercise at 15, 30 or 45% of maximal voluntary contraction (MVC) followed by 2 min postexercise forearm occlusion. Local sweat rates (SRs) on the forehead, chest, forearm, thigh and palm were continuously measured (ventilated capsule method). The forehead SR in prepubertal children during IH exercise at 45% MVC was significantly lower than that of young adults (0.26 ± 0.22 and 0.08 ± 0.15 mg cm-2  min-1 for young adults and children, respectively; P < 0.05) but not of the elderly at any exercise intensities. The SR on the chest (0.22 ± 0.22 and -0.01 ± 0.05 mg cm-2  min-1 for young adults and children, respectively), forearm (0.14 ± 0.12 and 0.03 ± 0.04 mg cm-2  min-1 ) and thigh (0.13 ± 0.10 and 0.02 ± 0.03 mg cm-2  min-1 ) during postexercise occlusion at 45% MVC was significantly lower in children than in young adults (P < 0.05). Elderly subjects showed a significantly lower SR on the forearm (0.04 ± 0.04 and 0.01 ± 0.02 mg cm-2  min-1 for young adults and elderly, respectively) and thigh (0.07 ± 0.07 and 0.01 ± 0.03 mg cm-2  min-1 ) at 15% MVC and on the thigh at 45% MVC (0.13 ± 0.10 and 0.04 ± 0.04 mg cm-2  min-1 ) during postexercise occlusion compared with young adults (P < 0.05). These results suggest that sweating responses to IH exercise and muscle metaboreflex were underdeveloped in prepubertal children and that ageing attenuates the response to the muscle metaboreflex in a way that is not consistent across the body.

    01 Feb. 2017, Experimental physiology, 102 (2), 214 - 227, English, International magazine

    Scientific journal

  • Baies Haqani, Naoto Fujii, Narihiko Kondo, Glen P Kenny

    Metaboreceptors can modulate cutaneous blood flow and sweating during heat stress but the mechanisms remain unknown. Fourteen participants (31 ± 13 years) performed 1-min bout of isometric handgrip (IHG) exercise at 60% of their maximal voluntary contraction followed by a 3-min occlusion (OCC), each separated by 10 min, initially under low (LHS, to activate sweating without changes in core temperature) and high (HHS, whole-body heating to a core temperature increase of 1.0°C) heat stress conditions. Cutaneous vascular conductance (CVC) and sweat rate were measured continuously at four forearm skin sites perfused with 1) lactated Ringer's solution (Control), 2) 10 mmol L-NAME [inhibits nitric oxide synthase (NOS)], 3) 10 mmol Ketorolac [inhibits cyclooxygenase (COX)], or 4) 4 mmol theophylline (THEO; inhibits adenosine receptors). Relative to pre-IHG levels with Control, NOS inhibition attenuated the metaboreceptor-mediated increase in sweating under LHS and HHS (P ≤ 0.05), albeit the attenuation was greater under LHS (P ≤ 0.05). In addition, a reduction from baseline was observed with THEO under LHS during OCC (P ≤ 0.05), but not HHS (both P > 0.05). In contrast, CVC was lower than Control with L-NAME during OCC in HHS (P ≤ 0.05), but not LHS (P > 0.05). We show that metaboreceptor activation modulates CVC via the stimulation of NOS and adenosine receptors, whereas NOS, but not COX or adenosine receptors, contributes to sweating at all levels of heating.

    Feb. 2017, Physiological reports, 5 (3), English, International magazine

    Scientific journal

  • Tatsuro Amano, Seiko Kai, Michi Nakajima, Tomoko Ichinose-Kuwahara, Nicola Gerrett, Narihiko Kondo, Yoshimitsu Inoue

    The purpose of the present study was to investigate sweating responses to isometric hand-grip (IH) exercise andmuscle metaboreflex in prepubertal children and the elderly. In hot conditions (ambient temperature, 35 degrees C; relative humidity, 45%), 13 healthy young adults, 10 prepubertal children and 10 elderly subjects (aged 20.4 +/- 1.2, 11.4 +/- 0.5 and 63.5 +/- 3.1 years, respectively) repeated a three hand-grip exercise protocol that consisted of 1 min IH exercise at 15, 30 or 45% of maximal voluntary contraction (MVC) followed by 2 min postexercise forearm occlusion. Local sweat rates (SRs) on the forehead, chest, forearm, thigh and palm were continuously measured (ventilated capsule method). The forehead SR in prepubertal children during IH exercise at 45% MVC was significantly lower than that of young adults (0.26 +/- 0.22 and 0.08 +/- 0.15 mg cm(-2) min(-1) for young adults and children, respectively; P < 0.05) but not of the elderly at any exercise intensities. The SR on the chest (0.22 +/- 0.22 and -0.01 +/- 0.05 mg cm(-2) min(-1) for young adults and children, respectively), forearm (0.14 +/- 0.12 and 0.03 +/- 0.04 mg cm(-2) min(-1)) and thigh (0.13 +/- 0.10 and 0.02 +/- 0.03 mg cm(-2) min(-1)) during postexercise occlusion at 45% MVC was significantly lower in children than in young adults (P < 0.05). Elderly subjects showed a significantly lower SR on the forearm (0.04 +/- 0.04 and 0.01 +/- 0.02 mg cm(-2) min(-1) for young adults and elderly, respectively) and thigh (0.07 +/- 0.07 and 0.01 +/- 0.03 mg cm(-2) min(-1)) at 15% MVC and on the thigh at 45% MVC (0.13 +/- 0.10 and 0.04 +/- 0.04 mg cm-2 min-1) during postexercise occlusion compared with young adults (P< 0.05). These results suggest that sweating responses to IH exercise and muscle metaboreflex were underdeveloped in prepubertal children and that ageing attenuates the response to the muscle metaboreflex in a way that is not consistent across the body.

    WILEY, Feb. 2017, EXPERIMENTAL PHYSIOLOGY, 102 (2), 214 - 227, English

    [Refereed]

    Scientific journal

  • KAWASAKI Sonomi, YAGUCHI Takaharu, MASUMOTO Kouhei, KONDO Narihiko, OKADA Shuichi

    2017, 日本応用数理学会論文誌, 27 (2), 112 - 146, Japanese

    [Refereed]

    Scientific journal

  • Greater V˙O2peak is correlated with greater skeletal muscle deoxygenation amplitude and hemoglobin concentration within individual muscles during ramp-incremental cycle exercise.

    Dai Okushima, David C Poole, Thomas J Barstow, Harry B Rossiter, Narihiko Kondo, T Scott Bowen, Tatsuro Amano, Shunsaku Koga

    It is axiomatic that greater aerobic fitness (V˙O2peak) derives from enhanced perfusive and diffusive O2 conductances across active muscles. However, it remains unknown how these conductances might be reflected by regional differences in fractional O2 extraction (i.e., deoxy [Hb+Mb] and tissue O2 saturation [StO2]) and diffusive O2 potential (i.e., total[Hb+Mb]) among muscles spatially heterogeneous in blood flow, fiber type, and recruitment (vastus lateralis, VL; rectus femoris, RF). Using quantitative time-resolved near-infrared spectroscopy during ramp cycling in 24 young participants (V˙O2peak range: ~37.4-66.4 mL kg-1 min-1), we tested the hypotheses that (1) deoxy[Hb+Mb] and total[Hb+Mb] at V˙O2peak would be positively correlated with V˙O2peak in both VL and RF muscles; (2) the pattern of deoxygenation (the deoxy[Hb+Mb] slopes) during submaximal exercise would not differ among subjects differing in V˙O2peak Peak deoxy [Hb+Mb] and StO2 correlated with V˙O2peak for both VL (r = 0.44 and -0.51) and RF (r = 0.49 and -0.49), whereas for total[Hb+Mb] this was true only for RF (r = 0.45). Baseline deoxy[Hb+Mb] and StO2 correlated with V˙O2peak only for RF (r = -0.50 and 0.54). In addition, the deoxy[Hb+Mb] slopes were not affected by aerobic fitness. In conclusion, while the pattern of deoxygenation (the deoxy[Hb+Mb] slopes) did not differ between fitness groups the capacity to deoxygenate [Hb+Mb] (index of maximal fractional O2 extraction) correlated significantly with V˙O2peak in both RF and VL muscles. However, only in the RF did total[Hb+Mb] (index of diffusive O2 potential) relate to fitness.

    Dec. 2016, Physiological reports, 4 (23), English, International magazine

    Scientific journal

  • Tatsuro Amano, Masaki Ishitobi, Yukio Ogura, Yoshimitsu Inoue, Shunsaku Koga, Takeshi Nishiyasu, Narihiko Kondo

    Changing stride frequency may influence oxygen uptake and heart rate during running as a function of running economy and central command. This study investigated the influence of stride frequency manipulation on thermoregulatory responses during endurance running. Seven healthy endurance runners ran on a treadmill at a velocity of 15km/h for 60min in a controlled environmental chamber (ambient temperature 27°C and relative humidity 50%), and stride frequency was manipulated. Stride frequency was intermittently manipulated by increasing and decreasing frequency by 10% from the pre-determined preferred frequency. These periods of increase or decrease were separated by free frequency running in the order of free stride frequency, stride frequency manipulation (increase or decrease), free stride frequency, and stride frequency manipulation (increase or decrease) for 15min each. The increased and decreased stride frequencies were 110% and 91% of the free running frequency, respectively (196±6, 162±5, and 178±5steps/min, respectively, P<0.01). Compared to the control, stride frequency manipulation did not affect rectal temperature, heart rate, or the rate of perceived exhaustion during running. Whole-body sweat loss increased significantly when stride frequency was manipulated (1.48±0.11 and 1.57±0.11kg for control and manipulated stride frequencies, respectively, P<0.05), but stride frequency had a small effect on sweat loss overall (Cohen's d=0.31). A higher mean skin temperature was also observed under mixed frequency conditions compared to that in the control (P<0.05). While the precise mechanisms underlying these changes remain unknown (e.g. running economy or central command), our results suggest that manipulation of stride frequency does not have a large effect on sweat loss or other physiological variables, but does increase mean skin temperature during endurance running.

    Oct. 2016, Journal of thermal biology, 61, 61 - 66, English, International magazine

    Scientific journal

  • Tatsuro Amano, Masaki Ishitobi, Yukio Ogura, Yoshimitsu Inoue, Shunsaku Koga, Takeshi Nishiyasu, Narihiko Kondo

    Changing stride frequency may influence oxygen uptake and heart rate during running as a function of running economy and central command. This study investigated the influence of stride frequency manipulation on thermoregulatory responses during endurance running. Seven healthy endurance runners ran on a treadmill at a velocity of 15 km/h for 60 min in a controlled environmental chamber (ambient temperature 27 degrees C and relative humidity 50%), and stride frequency was manipulated. Stride frequency was intermittently manipulated by increasing and decreasing frequency by 10% from the pre-determined preferred frequency. These periods of increase or decrease were separated by free frequency running in the order of free stride frequency, stride frequency manipulation (increase or decrease), free stride frequency, and stride frequency manipulation (increase or decrease) for 15 min each. The increased and decreased stride frequencies were 110% and 91% of the free running frequency, respectively (196 +/- 6, 162 +/- 5, and 178 +/- 5 steps/min, respectively, P < 0.01). Compared to the control, stride frequency manipulation did not affect rectal temperature, heart rate, or the rate of perceived exhaustion during running. Whole-body sweat loss increased significantly when stride frequency was manipulated (1.48 +/- 0.11 and 1.57 +/- 0.11 kg for control and manipulated stride frequencies, respectively, P < 0.05), but stride frequency had a small effect on sweat loss overall (Cohen's d=0.31). A higher mean skin temperature was also observed under mixed frequency conditions compared to that in the control (P < 0.05). While the precise mechanisms underlying these changes remain unknown (e.g. running economy or central command), our results suggest that manipulation of stride frequency does not have a large effect on sweat loss or other physiological variables, but does increase mean skin temperature during endurance running. (C) 2016 Published by Elsevier Ltd.

    PERGAMON-ELSEVIER SCIENCE LTD, Oct. 2016, JOURNAL OF THERMAL BIOLOGY, 61, 61 - 66, English

    [Refereed]

    Scientific journal

  • 地域ケアシステム導入に関する活動分析ーその5-

    城 仁士, 榎並 莉穂, 藤原 義章, OKADA SHUICHI, 近藤 徳彦, 井上 真理

    神戸大学大学院人間発達環境学研究科, Sep. 2016, 神戸大学大学院人間発達環境学研究科 研究紀要, 第10巻 (第1号), 77 - 85, Japanese

    [Refereed]

    Scientific journal

  • Bun Tsuji, Yasushi Honda, Narihiko Kondo, Takeshi Nishiyasu

    We investigated whether heat-induced hyperventilation during exercise is affected by time of day, as diurnal variation leads to higher core temperatures in the evening. Nineteen male subjects were divided into two experiments (protocol 1, n = 10 and protocol 2, n = 9). In protocol 1, subjects performed cycle exercise at 50% peak oxygen uptake in the heat (37 degrees C and 50% RH) in the morning (0600) and evening (1800). Results showed that baseline resting and exercising esophageal temperature (T-es) were significantly (0.5 degrees C) higher in the evening than morning. Minute ventilation ((V) over dot(E)) increased from 54.3 +/- 7.9 and 54.9 +/- 6.8 l/min at 10 min to 71.4 +/- 8.1 and 76.5 +/- 11.8 l/min at 48.5 min in the morning and evening, respectively (both P < 0.01). Time of day had no effect on (V) over dot(E) (P = 0.44). When (V) over dot(E) as the output response was plotted against Tes as thermal input, the Tes threshold for increases in (V) over dot(E) was higher in the evening than morning (37.2 +/- 0.7 vs. 36.6 +/- 0.6 degrees C, P = 0.009), indicating the ventilatory response to the same core temperature is smaller in the evening. In protocol 2, the circadian rhythm-related higher resting T-es seen in the evening was adjusted down to the same temperature seen in the morning by immersing the subject in cold water. Importantly, the time course of changes in (V) over dot(E) during exercise were smaller in the evening, but the threshold for (V) over dot(E) remained higher in the evening than morning (P < 0.001). Collectively, those results suggest that time of day has no effect on time course hyperventilation during exercise in the heat, despite the higher core temperatures in the evening. This is likely due to diurnal variation in the control of ventilation in response to rising core temperature.

    AMER PHYSIOLOGICAL SOC, Aug. 2016, AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY, 311 (2), R401 - R409, English

    [Refereed]

    Scientific journal

  • 高強度のウォームアップ運動が活動筋の酸素動態に及ぼす影響

    古賀 俊策, 近藤 徳彦, 福岡 義之, 天野 達郎, 奥島 大

    高強度のウォームアップ(W-up)運動を用いると,W-up運動後の主運動における活動筋の酸素消費量(VO2)の増加が速くなり,酸素不足が減少する.本研究では,表層筋に加えて深層筋も含めた活動筋の酸素動態を計測し,高強度のW-up運動が活動筋の酸素動態に及ぼす影響を明らかにした.時間分解・近赤外分光装置を用いて,活動筋における脱酸素化ヘモグロビン+ミオグロビン(HHb)を計測した.大腿直筋深層部のHHbは第1運動と第2運動の開始後の約5分目において定常状態を示し,VO2とQの増加速度のマッチングが生じたことが示唆された.さらに,第1運動と第2運動において大腿直筋深層部におけるHHbの時定数と平均応答時間は表層部に比べて有意に遅かった.HHbはVO2/Qを反映するので,表層筋に比べて遅筋線維が多く含まれ,運動中の筋温がより高い深層筋では,酸素供給が十分になって活動筋全体のVO2とQのバランスが改善され,酸素不足が減少したと推測される.(著者抄録)

    (公財)石本記念デサントスポーツ科学振興財団, Jun. 2016, デサントスポーツ科学, 37, 154 - 160, Japanese

  • Tatsuro Amano, Masashi Ichinose, Yoshimitsu Inoue, Takeshi Nishiyasu, Shunsaku Koga, Glen P. Kenny, Narihiko Kondo

    We examined whether the sustained activation of metaboreceptor in forearm during cycling exercise can modulate sweating and cutaneous vasodilation. On separate days, 12 young participants performed a 1.5-min isometric handgrip exercise at 40% maximal voluntary contraction followed by 1) 9-min forearm ischemia (Occlusion, to activate metaboreceptor) or 2) no ischemia (Control) in thermoneutral conditions (27(circle)C, 50%) with mean skin temperature clamped at 34(circle)C. Thirty seconds after the handgrip exercise, participants cycled for 13.5 min at 40% VO2 max. For Occlusion, forearm ischemia was maintained for 9 min followed by no ischemia thereafter. Local sweat rate (SR, ventilated capsule) and cutaneous vascular conductance (CVC, laser-Doppler perfusion units/ mean arterial pressure) on the contralateral nonischemic arm as well as esophageal and skin temperatures were measured continuously. The period of ischemia in the early stages of exercise increased SR (+ 0.03 mg(.)cm (-2) (.) min (-1), P < 0.05) but not CVC (P > 0.05) above Control levels. No differences were measured in the esophageal temperature at which onset of sweating (Control 37.19 +/- 0.09 vs. Occlusion 37.07 +/- 0.09(circle)C) or CVC (Control 37.21 +/- 0.08 vs. Occlusion 37.08 +/- 0.10(circle)C) as well as slopes for these responses (all P > 0.05). However, a greater elevation in SR occurred thereafter such that SR was significantly elevated at the end of the ischemic period relative to Control (0.37 +/- 0.05 vs. 0.23 +/- 0.05 mg(.)cm (-2.)min (- 1), respectively, P < 0.05) despite no differences in esophageal temperature. We conclude that the activation of forearm muscle metaboreceptor can modulate sweating, but not CVC, during cycling exercise without affecting the core temperature-SR relationship.

    AMER PHYSIOLOGICAL SOC, Jun. 2016, AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY, 310 (11), R1332 - R1339, English

    [Refereed]

    Scientific journal

  • ヒトの体温調節特性を生かしたスポーツウエアの開発

    天野 達郎, 島名 孝次, 堀川 直幹, Gerrett Nicola, 近藤 徳彦

    (株)文光堂, Mar. 2016, 臨床スポーツ医学, 33 (3), 313 - 315, Japanese

  • T. Scott Bowen, Shunsaku Koga, Tatsuro Amano, Narihiko Kondo, Harry B. Rossiter

    Time-resolved near-infrared spectroscopy (TRS-NIRS) allows absolute quantitation of deoxygenated haemoglobin and myoglobin concentration ([HHb]) in skeletal muscle. We recently showed that the spatial distribution of peak [HHb] within the quadriceps during moderate-intensity cycling is reduced with progressive hypoxia and this is associated with impaired aerobic energy provision. We therefore aimed to determine whether reduced spatial distribution of skeletal muscle [HHb] was associated with impaired aerobic energy transfer during exhaustive ramp-incremental exercise in hypoxia. Seven healthy men performed ramp-incremental cycle exercise (20 W/min) to exhaustion at 3 fractional inspired O-2 concentrations (FIO2): 0.21, 0.16, 0.12. Pulmonary O-2 uptake ((V) over dot O-2) was measured using a flow meter and gas analyser system. Lactate threshold (LT) was estimated non-invasively. Absolute muscle deoxygenation was quantified by multichannel TRS-NIRS from the rectus femoris and vastus lateralis (proximal and distal regions). (V) over dotO(2peak) and LT were progressively reduced (p< 0.05) with hypoxia. There was a significant effect (p< 0.05) of FIO2 on [HHb] at baseline, LT, and peak. However the spatial variance of [HHb] was not different between FIO2 conditions. Peak total Hb ([Hb(tot)]) was significantly reduced between FIO2 conditions (p< 0.001). There was no association between reductions in the spatial distribution of skeletal muscle [HHb] and indices of aerobic energy transfer during ramp-incremental exercise in hypoxia. While regional [HHb] quantified by TRS-NIRS at exhaustion was greater in hypoxia, the spatial distribution of [HHb] was unaffected. Interestingly, peak [Hb(tot)] was reduced at the tolerable limit in hypoxia implying a vasodilatory reserve may exist in conditions with reduced FIO2.

    SPRINGER, 2016, OXYGEN TRANSPORT TO TISSUE XXXVII, 876, 19 - 26, English

    [Refereed]

    Scientific journal

  • Tsuji B, Hayashi K, Kondo N, Nishiyasu T

    2016, Temperature, 3 (1), 146 - 160, English

    [Refereed]

    Scientific journal

  • 小倉幸雄, 井上芳光, 内之宮愛子, 北村優佳, 大森隆裕, 大上安奈, LEE Jason, Kai Wei, 近藤徳彦

    2016, 体育学研究, 61 (2), 607‐619(J‐STAGE), Japanese

    [Refereed]

  • 地域コミュニティの構造変化に対する検定理論

    KAWASAKI SONOMI, YAGUCHI TAKAHARU, MASUMOTO KOUHEI, KONDO NARIHIKO, OKADA SHUICHI

    Dec. 2015, 2015年度応用数学合同研究集会予稿集, 394 - 401, Japanese

    Symposium

  • Ichinose, Masashi, Ichinose-Kuwahara, Tomoko, Kondo, Narihiko, Nishiyasu, Takeshi

    AMER PHYSIOLOGICAL SOC, Nov. 2015, AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY, 309 (10), R1234 - R1242, English

    [Refereed]

    Scientific journal

  • Fujii, Naoto, Tsuji, Bun, Honda, Yasushi, Kondo, Narihiko, Nishiyasu, Takeshi

    AMER PHYSIOLOGICAL SOC, Sep. 2015, JOURNAL OF APPLIED PHYSIOLOGY, 119 (5), 435 - 444, English

    [Refereed]

    Scientific journal

  • Bun Tsuji, Yasushi Honda, Yusuke Ikebe, Naoto Fujii, Narihiko Kondo, Takeshi Nishiyasu

    Hyperthermia during prolonged exercise leads to hyperventilation, which can reduce arterial CO2 pressure (Pa-CO2) and, in turn, cerebral blood flow (CBF) and thermoregulatory response. We investigated 1) whether humans can voluntarily suppress hyperthermic hyperventilation during prolonged exercise and 2) the effects of voluntary breathing control on Pa-CO2, CBF, sweating, and skin blood flow. Twelve male subjects performed two exercise trials at 50% of peak oxygen uptake in the heat (37 degrees C, 50% relative humidity) for up to 60 min. Throughout the exercise, subjects breathed normally (normal-breathing trial) or they tried to control their minute ventilation (respiratory frequency was timed with a metronome, and target tidal volumes were displayed on a monitor) to the level reached after 5 min of exercise (controlled-breathing trial). Plotting ventilatory and cerebrovascular responses against esophageal temperature (T-es) showed that minute ventilation increased linearly with rising T-es during normal breathing, whereas controlled breathing attenuated the increased ventilation (increase in minute ventilation from the onset of controlled breathing: 7.4 vs. 1.6 l/min at +1.1 degrees C T-es; P < 0.001). Normal breathing led to decreases in estimated Pa-CO2 and middle cerebral artery blood flow velocity (MCAV) with rising T-es, but controlled breathing attenuated those reductions (estimated Pa-CO2 -3.4 vs. -0.8 mmHg; MCAV -10.4 vs. -3.9 cm/s at -1.1 degrees C T-es; P = 0.002 and 0.011, respectively). Controlled breathing had no significant effect on chest sweating or forearm vascular conductance (P = 0.67 and 0.91, respectively). Our results indicate that humans can voluntarily suppress hyperthermic hyperventilation during prolonged exercise, and this suppression mitigates changes in Pa-CO2 and CBF.

    AMER PHYSIOLOGICAL SOC, Apr. 2015, AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY, 308 (8), R669 - R679, English

    [Refereed]

    Scientific journal

  • 地域包括ケアシステム導入に関する活動分析ーその4−

    JOH HITOSHI, HOU ANAN, FIJIWARA YOSHIAKI, OKADA SHUICHI, KONDO NARIHIKO, INOUE MARI

    本研究報告では、本事業の2年間の運営でまだ解決していない問題や今後の課題を考慮し、引き続き2014年3月から7月までの5ヶ月の事業運営過程を追跡する。その運営過程の中での課題とその対処を整理しながら、岩戸ホームと紫豊館の事業活動がケア24事業を通してどのように変化していくのかを考察することを研究の目的とする。

    神戸大学大学院人間発達環境学研究科, Mar. 2015, 神戸大学大学院人間発達環境学研究科研究紀要, 8 (2), 131 - 135, Japanese

    Research institution

  • Koga S, Poole DC, Kondo N, Oue A, Ohmae E, Barstow TJ

    2, Feb. 2015, European journal of applied physiology, 115, 335 - 343

    [Refereed]

  • Naoto Fujii, Yasushi Honda, Ken Komura, Bun Tsuji, Akira Sugihara, Kazuhito Watanabe, Narihiko Kondo, Takeshi Nishiyasu

    Two thermolytic thermoregulatory responses, cutaneous vasodilation and sweating, begin when core temperature reaches a critical threshold, after which response magnitudes increase linearly with increasing core temperature; thus the slope indicates response sensitivity. We evaluated the influence of hypocapnia induced by voluntary hyperventilation on the core temperature threshold and sensitivity of thermoregulatory responses. Ten healthy males performed 15 min of cycling at 117 W (29.5 degrees C, 50% RH) under three breathing conditions: 1) spontaneous ventilation, 2) voluntary normocapnic hyperventilation, and 3) voluntary hypocapnic hyperventilation. In the hypocapnic hyperventilation trial, end-tidal CO2 pressure was reduced throughout the exercise, whereas it was maintained around the normocapnic level in the other two trials. Cutaneous vascular conductances at the forearm and forehead were evaluated as laser-Doppler signal/mean arterial blood pressure, and the forearm sweat rate was measured using the ventilated capsule method. Esophageal temperature threshold was higher for the increase in cutaneous vascular conductance in the hypocapnic than normocapnic hyperventilation trial at the forearm (36.88 +/- 0.36 vs. 36.68 +/- 0.34 degrees C, P < 0.05) and forehead (36.89 +/- 0.31 vs. 36.75 +/- 0.31 degrees C, P < 0.05). The slope relating esophageal temperature to cutaneous vascular conductance was decreased in the hypocapnic than normocapnic hyperventilation trial at the forearm (302 +/- 177 vs. 420 +/- 178% baseline/degrees C, P < 0.05) and forehead (236 +/- 164 vs. 358 +/- 221% baseline/degrees C, P < 0.05). Neither the threshold nor the slope for the forearm sweat rate differed significantly between the hypocapnic or normocapnic hyperventilation trials. These findings indicate that in exercising humans, hypocapnia induced by voluntary hyperventilation does not influence sweating, but it attenuates the cutaneous vasodilatory response by increasing its threshold and reducing its sensitivity.

    AMER PHYSIOLOGICAL SOC, Dec. 2014, JOURNAL OF APPLIED PHYSIOLOGY, 117 (11), 1317 - 1324, English

    [Refereed]

    Scientific journal

  • Matthew D. Spencer, Tatsuro Amano, Narihiko Kondo, John M. Kowalchuk, Shunsaku Koga

    The present study compared peak muscle deoxygenation ([HHb](peak)) responses at three quadriceps sites during occlusion (OCC), ramp incremental (RI), severe-(SVR) and moderate-intensity (MOD) exercise. Seven healthy men (25 +/- 4 yr) each completed a stationary cycling RI (20 W/min) test to determine [HHb](peak) [at distal and proximal vastus lateralis (VLD and VLP) and rectus femoris (RF)], peak (V) over dotO(2) ((V) over dotO(2peak)), gas exchange threshold (GET), and peak work rate (WRpeak). Subjects also completed MOD (WR = 80% GET) and SVR exercise (WR corresponding to 120% (V) over dotO(2peak)) with absolute [HHb] (quantified by multichannel, time-resolved near-infrared spectroscopy) and pulmonary VO2 ((V) over dotO(2p)) monitored continuously. Additionally, [HHb] and total hemoglobin ([Hb](tot)) were monitored at rest and during subsequent OCC (250 mmHg). Site-specific adipose tissue thickness was assessed (B-mode ultrasound), and its relationship with resting [Hb](tot) was used to correct absolute [HHb]. For VLD and RF, [HHb](peak) was higher (P < 0.05) during OCC (VLD = 111 +/- 38, RF = 114 +/- 26 mu M) than RI (VLD 64 +/- 14, RF = 85 +/- 20) and SVR (VLD = 63 +/- 13, RF = 81 +/- 18). [HHb](peak) was similar (P > 0.05) across these conditions at the VLP (OCC = 67 +/- 17, RI = 69 +/- 17, SVR = 63 +/- 17 mu M). [HHb] peaked and then decreased prior to exercise cessation during SVR at all three muscle sites. [HHb](peak) during MOD was consistently lower than other conditions at all sites. A "[HHb] reserve" exists during intense cycling at the VLD and RF, likely implying either sufficient blood flow to meet oxidative demands or insufficient diffusion time for complete equilibration. In VLP this [HHb] reserve was absent, suggesting that a critical PO2 may be challenged during intense cycling.

    AMER PHYSIOLOGICAL SOC, Nov. 2014, JOURNAL OF APPLIED PHYSIOLOGY, 117 (10), 1199 - 1206, English

    [Refereed]

    Scientific journal

  • 地域包括ケアシステム導入に関する活動分析ーその3−

    JOH HITOSHI, HOU ANAN, FIJIWARA YOSHIAKI, OKADA SHUICHI, KONDO NARIHIKO, INOUE MARI

    本研究報告では、引き続き2013年4月から翌年2014年2月までの11ヶ月間の事業運営過程を追跡する。この追跡を通じて、試行2年目の運営過程の中で発生した様々な問題点を整理し、それらの問題点に対してどのように対処したのか記録にとどめ、今後の事業展開の参考とすることを目的とする。

    神戸大学大学院人間発達環境学研究科, Sep. 2014, 神戸大学大学院人間発達環境学研究科研究紀要, 8 (1), 135 - 140, Japanese

    Research institution

  • Tatsuro Amano, Masashi Ichinose, Takeshi Nishiyasu, Yoshimitsu Inoue, Shunsaku Koga, Mikio Miwa, Narihiko Kondo

    Activation of muscle metaboreceptors and mechanoreceptors has been shown to independently influence the sweating response, while their integrative control effects remain unclear. We examined the sweating response when the two muscle receptors are concurrently activated in different limbs, as well as the blood pressure response. In total, 27 young males performed passive calf muscle stretches (muscle mechanoreceptor activation) for 30 s in a semisupine position with and without postisometric handgrip exercise muscle ischemia (PEMI, muscle metaboreceptor activation) at exercise intensities of 35 and 50% of maximum voluntary contraction (MVC) under hot conditions (ambient temperature, 35 degrees C, relative humidity, 50%). Passive calf muscle stretching alone increased the mean sweating rate significantly on the forehead, chest, and thigh (SRmean) and mean arterial blood pressure (MAP), but not the heart rate (HR), from prestretching levels by 0.04 +/- 0.01 mg center dot cm(2)center dot min(-1), 4.0 +/- 1.3 mmHg (P < 0.05), and -1.0 +/- 0.5 beats/min (P > 0.05), respectively. The SRmean and MAP during PEMI were significantly higher than those at rest. The passive calf muscle stretch during PEMI increased MAP significantly by 3.4 +/- 1.0 and 2.0 +/- 0.7 mmHg for 35 and 50% of MVC, respectively (P < 0.05), but not that of SRmean or HR at either exercise intensity. These results suggest that sweating and blood pressure responses to concurrent activation of the two muscle receptors in different limbs differ and that the influence of calf muscle mechanoreceptor activation alone on the sweating response disappears during forearm muscle metaboreceptor activation.

    AMER PHYSIOLOGICAL SOC, May 2014, AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY, 306 (10), R728 - R734, English

    [Refereed]

    Scientific journal

  • 独居高齢者の実態と生活満足度に関する調査研究

    TAKENAKA YUKO, HOUNOKI KAORU, OKADA SYUICHI, INOUE MARI, INAGAKI SHIGENORI, KAWABATA TETSUROU, KATO YOSHIKO, KONDO NARIHIKO, JO HITOSHI, CHOGAHARA MAKOTO, HIRAYAMA YOSUKE, MASUMOTO KOUHEI, MATSUOKA KOJI, MORIOKA MASAYOSHI

    Mar. 2014, 神戸大学大学院人間発達環境学研究科研究紀要, 7 (2), 139 - 148, Japanese

    [Refereed]

    Research institution

  • 都市部高齢化地域居住者の運動意欲に関連する要因について

    INUI JYUNKI, CHOGAHARA MAKOTO, OKADA SHUICHI, KONDO NARIHIKO, MASUMOTO KOUHEI, TAKENAKA YUKO, HOUNOKI KAORU

    Mar. 2014, 神戸大学大学院人間発達環境学研究科研究紀要, 7 (2), 1 - 10, Japanese

    [Refereed]

    Research institution

  • Activity analysis on introductory attempt of comprehensive regional care systems Ⅱ

    JOH HITOSHI, HOU ANAN, FUJIWARA YOSHIAKI, OKADA SHUICHI, KONDO NARIHIKO, INOUE MARI

    本研究報告は、2012年6月から2013年3月まで、時間経過にそってケア24の事業活動の中で生じた課題やそれへの対処を追跡した記録である。

    Graduate School of Human Development and Environment, Kobe University, Mar. 2014, Bulletin of Graduate School of Human Development and Environment, Kobe University, 7 (2), 133 - 138, Japanese

    Scientific journal

  • Tatsuro Amano, Shunsaku Koga, Yoshimitsu Inoue, Takeshi Nishiyasu, Narihiko Kondo

    The purpose of this study was to compare sweating function in sprinters who have trained for several years with untrained subjects and trained endurance runners. Two separate experiments were conducted. Nine sprinters, eight untrained men, and nine distance runners (VO2max 50.9 ± 1.4, 38.2 ± 1.8, and 59.1 ± 1.2 mL/kg/min, respectively P < 0.05) were passively heated for 50 min (Experiment 1), and ten sprinters, 11 untrained men and nine distance runners (similar VO2max levels compared with Experiment 1 in each group) had their sweat gland capacity assessed based on acetylcholine-induced sweating rate (SR) (Experiment 2). The slope of the mean non-glabrous SR plotted against change in mean body temperature during passive heating did not differ significantly between sprinters and untrained men (1.21 ± 0.10 and 0.97 ± 0.12 mg cm-2/min/ C, respectively) in contrast, compared with untrained men, distance runners exhibited a significantly greater slope (1.42 ± 0.11 mg cm-2/min/ C, P < 0.05). The mean body temperature threshold for SR was not significantly different among the groups. Acetylcholine-induced SR did not differ significantly between sprinters and untrained men, whereas distance runners showed a significantly higher induced SR compared with untrained men. The sweating function was not improved in sprinters who have trained 2-3 h/day, 5 days/week, for at least 3 years compared with untrained men, although the VO2max was markedly greater in sprinters. Thus, there is a case that daily training was not sufficient to improve sweating function in sprinters relative to those in distance runners. © 2013 Springer-Verlag Berlin Heidelberg.

    Aug. 2013, European Journal of Applied Physiology, 113 (8), 2067 - 2075, English

    [Refereed]

    Scientific journal

  • Masashi Ichinose, Kazuhito Watanabe, Naoto Fujii, Narihiko Kondo, Takeshi Nishiyasu

    It has been suggested that the arterial baroreflex and muscle metaboreflex are both activated during heavy exercise and that they interact to modulate primary cardiovascular reflex responses. This proposed interaction and its consequences are not fully understood, however. The purpose of present study was to test our hypothesis that dynamic arterial baroreflex-mediated cardiovascular responses to acute systemic hypotension in humans are augmented when the muscle metaboreflex is active and that this results in a faster recovery of arterial blood pressure. Acute hypotension was induced nonpharmacologically in 12 healthy subjects by releasing bilateral thigh cuffs after 9 min of suprasystolic resting ischemia, with and without muscle metaboreflex activation via postexercise muscle ischemia (PEMI) after 1 min of isometric hand-grip exercise at 50% maximum voluntary contraction. The thigh-cuff release evoked rapid reductions in mean arterial pressure (MAP) and increases in heart rate, cardiac output (Doppler), and total vascular conductance (TVC) under control conditions and during PEMI. The reductions in MAP from baseline were greater and the increases in TVC were smaller during PEMI than control. In addition, arterial baroreflex-mediated peripheral vasoconstriction was augmented during PEMI, as evidenced by a near doubling of the rate of recovery of MAP and TVC. These results show that when the muscle metaboreflex is activated in humans, arterial baroreflex-mediated peripheral vasoconstriction elicited in response to acute hypotension is augmented, which halves the time needed for MAP recovery. Such modulation of baroreflex function would be advantageous for maintaining an elevated arterial blood pressure during activation of the muscle metaboreflex.

    AMER PHYSIOLOGICAL SOC, Jun. 2013, AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY, 304 (11), H1568 - H1575, English

    [Refereed]

    Scientific journal

  • KONDO Narihiko

    Kobe University, 29 Mar. 2013, 神戸大学大学院人間発達環境学研究科研究紀要, 6 (3), 31 - 35, Japanese

  • Activity analysis on introductory attempt of comprehensive regional care systems

    JOH HITOSHI, TSUCHIYA TOMOKA, FUJIWARA YOSHIAKI, OKADA SHUICHI, KONDO NARIHIKO, INOUE MARI

    Graduate School of Human Development and Environment, Kobe University, Mar. 2013, Bulletin of Graduate School of Human Development and Environment, Kobe University, 6 (2), 71 - 76, Japanese

    Scientific journal

  • Naoto Fujii, Masashi Ichinose, Yasushi Honda, Bun Tsuji, Kazuhito Watanabe, Narihiko Kondo, Takeshi Nishiyasu

    The arterial blood pressure and ventilatory responses to severe passive heating at rest varies greatly among individuals. We tested the hypothesis that the increase in ventilation seen during severe passive heating of resting humans is associated with a decrease in arterial blood pressure. Passive heating was performed on 18 healthy males using hot water immersion to the level of the iliac crest and a water-perfused suit. We then divided the subjects into two groups: MAP(NOTINC) (n = 8), whose mean arterial blood pressure (MAP) at the end of heating had increased by a parts per thousand currency sign3 mmHg, and MAP(INC) (n = 10), whose MAP increased by > 3 mmHg. Increases in esophageal temperature (T (es)) elicited by the heating were similar in the two groups (+2.3 +/- A 0.3 vs. +2.4 +/- A 0.4 A degrees C). Early during heating (increase in T (es) was < 1.5 A degrees C), MAP, minute ventilation (), and end-tidal CO2 pressure () were similar between the groups. However, during the latter part of heating (increase in T (es) was a parts per thousand yen1.5 A degrees C), the increase in and decrease in were significantly greater or tended to be greater, while the increase in MAP was significantly smaller in MAP(NOTINC) than MAP(INC). Among all subjects, heating-induced changes in significantly and negatively correlated with heating-induced changes in MAP during the latter part of heating (r = -0.52 to -0.74, P < 0.05). These results suggest that, in resting humans, 25-50 % of the variation in the magnitude of the arterial blood pressure response to severe passive heating can be explained by the magnitude of hyperthermia-induced hyperventilation.

    SPRINGER, Jan. 2013, EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY, 113 (1), 51 - 62, English

    [Refereed]

    Scientific journal

  • KOGA Shunsaku, INOUE Yoshimitsu, KONDO Narihiko

    Acquiring the ability to maintain whole-body integration of physiological-system functions during exercise enabled human beings to evolve exercise tolerance and adaptability to environment, with those who possessed this capability being able to accelerate in an integrated manner their physiological functions whose habitual status is so strongly correlated with health. In modern developed nations, however, the spread of artificial environments and comfortable living and working environments has reduced the adaptive capacity and in particular the endurance work capacity as well as adaptability to environment that human beings had historically acquired, resulting in hypokinetic diseases and maladaptation to heat.

    Japan Society of Physiological Anthropology, 2013, Japanese Journal of Physiological Anthropology, 18 (4), 187 - 191, Japanese

  • Naoto Fujii, Yasushi Honda, Stephane Delliaux, Bun Tsuji, Kazuhito Watanabe, Akira Sugihara, Narihiko Kondo, Takeshi Nishiyasu

    Fujii N, Honda Y, Delliaux S, Tsuji B, Watanabe K, Sugihara A, Kondo N, Nishiyasu T. Effect of voluntary hypocapnic hyperventilation on cutaneous circulation in resting heated humans. Am J Physiol Regul Integr Comp Physiol 303: R975-R983, 2012. First published September 12, 2012; doi:10.1152/ajpregu.00169.2012.-Hypocapnia attenuates the sweat response normally seen in hyperthermic resting subjects, but its effect on the blood flow response in their nonglabrous skin under the same hyperthermic conditions remains unclear. In the present study, we investigated whether hypocapnia induced by voluntary hyperventilation affects the blood flow response to heat stress in the nonglabrous skin of resting humans. Nine healthy male subjects were passively heated using legs-only hot water immersion and a water-perfused suit, which caused esophageal temperature (T-es) to increase by as much as 1.0 degrees C. During normothermia and at +0.6 degrees C T-es and +1.0 degrees C T-es, the subjects performed two voluntary 7-min hyperventilation (minute ventilation = 40 l/min) trials (hypocapnic and eucapnic) in random order. End-tidal CO2 pressure was reduced by 23-25 torr during hypocapnic hyperventilation, but it was maintained at the spontaneous breathing level during eucapnic hyperventilation. Cutaneous blood flow was evaluated as the cutaneous red blood cell flux in the forearm (CBFforearm) or forehead (CBFforehead) and was normalized to the normothermic spontaneous breathing value. Hypocapnic hyperventilation at +0.6 degrees C T-es was associated with significantly reduced CBFforearm, compared with eucapnic hyperventilation, after 5-7 min of hyperventilation (395 to 429 vs. 487 to 525% baseline, P < 0.05). No significant difference in CBFforehead was seen during hypocapnic hyperventilation compared with eucapnic hyperventilation at +0.6 degrees C T-es or +1.0 degrees C T-es. These results suggest that in resting humans, hypocapnia achieved through voluntary hyperventilation attenuates the increase in cutaneous blood flow elicited by moderate heat stress in the nonglabrous skin of the forearm, but not the forehead.

    AMER PHYSIOLOGICAL SOC, Nov. 2012, AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY, 303 (9), R975 - R983, English

    [Refereed]

    Scientific journal

  • Bun Tsuji, Yasushi Honda, Naoto Fujii, Narihiko Kondo, Takeshi Nishiyasu

    Tsuji B, Honda Y, Fujii N, Kondo N, Nishiyasu T. Comparison of hyperthermic hyperventilation during passive heating and prolonged light and moderate exercise in the heat. J Appl Physiol 113: 1388-1397, 2012. First published August 23, 2012; doi:10.1152/japplphysiol.00335.2012.-Elevation of core temperature leads to increases in ventilation in both resting subjects and those engaged in prolonged exercise. We compared the characteristics of the hyperthermic hyperventilation elicited during passive heating at rest and during prolonged moderate and light exercise. Twelve healthy men performed three trials: a rest trial in which subjects were passively heated using hot-water immersion (41 degrees C) and a water-perfused suit and two exercise trials in which subjects exercised at 25% (light) or 50% (moderate) of peak oxygen uptake in the heat (37 degrees C and 50% relative humidity) after first using water immersion (18 degrees C) to reduce resting esophageal temperature (T-es). This protocol enabled detection of a T-es threshold for hyperventilation during the exercise. When minute ventilation ((V) over dotE) was expressed as a function of T-es, 9 of the 12 subjects showed T-es thresholds for hyperventilation in all trials. The T-es thresholds for increases in (V) over dotE during light and moderate exercise (37.1 +/- 0.4 and 36.9 +/- 0.4 degrees C) were both significantly lower than during rest (38.3 +/- 0.6 degrees C), but the T-es thresholds did not differ between the two exercise intensities. The sensitivity of (V) over dotE to increasing T-es (slope of the T-es-(V) over dotE relation) above the threshold was significantly lower during moderate exercise (8.7 +/- 3.5 l.min(-1).degrees C-1) than during rest (32.5 +/- 24.2 l.min(-1).degrees C-1), but the sensitivity did not differ between light (10.4 +/- 13.0 l.min(-1).degrees C-1) and moderate exercise. These results suggest the core temperature threshold for hyperthermic hyperventilation and the hyperventilatory response to increasing core temperature in passively heated subjects differs from that in exercising subjects, irrespective of whether the exercise is moderate or light.

    AMER PHYSIOLOGICAL SOC, Nov. 2012, JOURNAL OF APPLIED PHYSIOLOGY, 113 (9), 1388 - 1397, English

    [Refereed]

    Scientific journal

  • Research on Living Environment Needs of Nursing Facility for the Elderly

    JOH HITOSHI, TSUCHIYA TOMOKA, FUJIWARA YOSHIAKI, OKADA SHUICHI, KONDO NARIHIKO, INOUE MARI

    Graduate School of Human Development and Environment, Kobe University, Sep. 2012, Bulletin of Graduate School of Human Development and Environment, Kobe University, 6 (1), 117 - 124, Japanese

    Scientific journal

  • Konrad Binder, Aaron G. Lynn, Daniel Gagnon, Narihiko Kondo, Glen P. Kenny

    Binder K, Lynn AG, Gagnon D, Kondo N, Kenny GP. Hyperthermia modifies muscle metaboreceptor and baroreceptor modulation of heat loss in humans. Am J Physiol Regul Integr Comp Physiol 302: R417-R423, 2012. First published November 16, 2011; doi:10.1152/ajpregu.00463.2011.-The relative influence of muscle metabo- and baroreflex activity on heat loss responses during post-isometric handgrip (IHG) exercise ischemia remains unknown, particularly under heat stress. Therefore, we examined the separate and integrated influences of metabo- and baroreceptor-mediated reflex activity on sweat rate and cutaneous vascular conductance (CVC) under increasing levels of hyperthermia. Twelve men performed 1 min of IHG exercise at 60% of maximal voluntary contraction followed by 2 min of ischemia with simultaneous application of lower body positive pressure (LBPP, +40 mmHg), lower body negative pressure (LBNP, -20 mmHg), or no pressure (control) under no heat stress. On separate days, trials were repeated under heat stress conditions of 0.6 degrees C (moderate heat stress) and 1.4 degrees C (high heat stress) increase in esophageal temperature. For all conditions, mean arterial pressure was greater with LBPP and lower with LBNP than control during ischemia (all P <= 0.05). No differences in sweat rate were observed between pressure conditions, regardless of the level of hyperthermia (P > 0.05). Under moderate heat stress, no differences in CVC were observed between pressure conditions. However, under high heat stress, LBNP significantly reduced CVC by 21 +/- 4% (P <= 0.05) and LBPP significantly elevated CVC by 14 +/- 5% (P < 0.05) relative to control. These results show that sweating during post-IHG exercise ischemia is activated by metaboreflex stimulation, and not by baroreflexes. In contrast, our results suggest that baroreflexes can influence the metaboreflex modulation of CVC, but only at greater levels of hyperthermia.

    AMER PHYSIOLOGICAL SOC, Feb. 2012, AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY, 302 (4), R417 - R423, English

    [Refereed]

    Scientific journal

  • Naoto Fujii, Yasushi Honda, Takeshi Ogawa, Bun Tsuji, Narihiko Kondo, Shunsaku Koga, Takeshi Nishiyasu

    We tested the hypothesis that short- term exercise- heat acclimation (EHA) attenuates hyperthermiainduced hyperventilation in humans exercising in a hot environment. Twenty- one male subjects were divided into the two groups: control (C, n = 11) and EHA (n = 10). Subjects in C performed exercise- heat tests [ cycle exercise for similar to 75 min at 58% Vover dotO(2peak) (37 degrees C, 50% relative humidity)] before and after a 6- day interval with no training, while subjects in EHA performed the tests before and after exercise training in a hot environment (37 degrees C). The training entailed four 20- min bouts of exercise at 50% Vover dotO(2peak) separated by 10 min of rest daily for 6 days. In C, comparison of the variables recorded before and after the no- training period revealed no changes. In EHA, the training increased resting plasma volume, while it reduced esophageal temperature (T-es), heart rate at rest and during exercise, and arterial blood pressure and oxygen uptake (Vover dot(O2)) during exercise. The training lowered the T-es threshold for increasing forearm vascular conductance (FVC), while it increased the slope relating FVC to T-es and the peak FVC during exercise. It also lowered minute ventilation (Vover dot(E)) during exercise, but this effect disappeared after removing the influence of Vover dot(O2) on Vover dot(E). The training did not change the slope relating ventilatory variables to T-es. We conclude that short- term EHA lowers ventilation largely by reducing metabolism, but it does not affect the sensitivity of hyperthermia- induced hyperventilation during submaximal, moderate- intensity exercise in humans.

    SPRINGER, Jan. 2012, EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY, 112 (1), 295 - 307, English

    [Refereed]

    Scientific journal

  • Bun Tsuji, Yasushi Honda, Naoto Fujii, Narihiko Kondo, Takeshi Nishiyasu

    Tsuji B, Honda Y, Fujii N, Kondo N, Nishiyasu T. Effect of initial core temperature on hyperthermic hyperventilation during prolonged submaximal exercise in the heat. Am J Physiol Regul Integr Comp Physiol 302: R94-R102, 2012. First published September 28, 2011; doi:10.1152/ajpregu.00048.2011.-We investigated whether a core temperature threshold for hyperthermic hyperventilation is seen during prolonged submaximal exercise in the heat when core temperature before the exercise is reduced and whether the evoked hyperventilatory response is affected by altering the initial core temperature. Ten male subjects performed three exercise trials at 50% of peak oxygen uptake in the heat (37 degrees C and 50% relative humidity) after altering their initial esophageal temperature (T(es)). Initial T(es) was manipulated by immersion for 25 min in water at 18 degrees C (Precooling), 35 degrees C (Control), or 40 degrees C (Preheating). T(es) after the water immersion was significantly higher in the Preheating trial (37.5 +/- 0.3 degrees C) and lower in the Precooling trial (36.1 +/- 0.3 degrees C) than in the Control trial (36.9 +/- 0.3 degrees C). In the Precooling trial, minute ventilation ((V) over dotE) showed little change until T(es) reached 37.1 +/- 0.4 degrees C. Above this core temperature threshold, (V) over dotE increased linearly in proportion to increasing T(es). In the Control trial, (V) over dotE increased as T(es) increased from 37.0 degrees C to 38.6 degrees C after the onset of exercise. In the Preheating trial, (V) over dotE increased from the initially elevated levels of T(es) (from 37.6 to 38.6 degrees C) and (V) over dotE. The sensitivity of (V) over dotE to increasing T(es) above the threshold for hyperventilation (the slope of the T(es)-(V) over dotE relation) did not significantly vary across trials (Precooling trial = 10.6 +/- 5.9, Control trial = 8.7 +/- 5.1, and Preheating trial = 9.2 +/- 6.9 L.min(-1).degrees C(-1)). These results suggest that during prolonged submaximal exercise at a constant workload in humans, there is a clear core temperature threshold for hyperthermic hyperventilation and that the evoked hyperventilatory response is unaffected by altering initial core temperature.

    AMER PHYSIOLOGICAL SOC, Jan. 2012, AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY, 302 (1), R94 - R102, English

    [Refereed]

    Scientific journal

  • Effect of CO₂ on the ventilatory sensitivity to rising body temperature during exercise

    Hayashi K, Honda Y, Miyakawa N, Fujii N, Ichinose M, Koga S, Narihiko Kondo, Nishiyasu T

    2012, J Appl Physiol, 110(5):1334-41, English

    [Refereed]

    Scientific journal

  • A model of heat and moisture transfer in and around clothing, coupled with a human thermal model for the analysis of the transient state, including the process of sweat evaporation

    Satoru Takada, Mari Inoue, Narihiko Kondo

    2012, Proceedings of the 9th International Meeting for Manikins and Modeling, pp.70-75

    International conference proceedings

  • Lisa M. K. Chin, John M. Kowalchuk, Thomas J. Barstow, Narihiko Kondo, Tatsuro Amano, Tomoyuki Shiojiri, Shunsaku Koga

    Chin LM, Kowalchuk JM, Barstow TJ, Kondo N, Amano T, Shiojiri T, Koga S. The relationship between muscle deoxygenation and activation in different muscles of the quadriceps during cycle ramp exercise. J Appl Physiol 111: 1259-1265, 2011. First published July 28, 2011; doi:10.1152/japplphysiol.01216.2010.-The relationship between muscle deoxygenation and activation was examined in three different muscles of the quadriceps during cycling ramp exercise. Seven young male adults (24 +/- 3 yr; mean +/- SD) pedaled at 60 rpm to exhaustion, with a work rate (WR) increase of 20 W/min. Pulmonary oxygen uptake was measured breath-by-breath, while muscle deoxygenation (HHb) and activity were measured by time-resolved near-infrared spectroscopy (NIRS) and surface electromyography (EMG), respectively, at the vastus lateralis (VL), rectus femoris (RF), and vastus medialis (VM). Muscle deoxygenation was corrected for adipose tissue thickness and normalized to the amplitude of the HHb response, while EMG signals were integrated (iEMG) and normalized to the maximum iEMG determined from maximal voluntary contractions. Muscle deoxygenation and activation were then plotted as a percentage of maximal work rate (%WR(max)). The HHb response for all three muscle groups was fitted by a sigmoid function, which was determined as the best fitting model. The c/d parameter for the sigmoid fit (representing the %WR(max) at 50% of the total amplitude of the HHb response) was similar between VL (47 +/- 12% WR(max)) and VM (43 +/- 11% WR(max)), yet greater (P < 0.05) for RF (65 +/- 13% WR(max)), demonstrating a "right shift" of the HHb response compared with VL and VM. The iEMG also showed that muscle activation of the RF muscle was lower (P < 0.05) compared with VL and VM throughout the majority of the ramp exercise, which may explain the different HHb response in RF. Therefore, these data suggest that the sigmoid function can be used to model the HHb response in different muscles of the quadriceps; however, simultaneous measures of muscle activation are also needed for the HHb response to be properly interpreted during cycle ramp exercise.

    AMER PHYSIOLOGICAL SOC, Nov. 2011, JOURNAL OF APPLIED PHYSIOLOGY, 111 (5), 1259 - 1265, English

    [Refereed]

    Scientific journal

  • T. Amano, Y. Kato, C. A. Machado-Moreira, N. A. Taylor, Y. Inoue, T. Nishiyasu, N. Kondo

    Aim: The goals of this study were to investigate changes in the sweating and cutaneous vascular responses on the palm and the volar aspect of the index finger during sustained static exercise of increasing intensity and to determine whether the former can be attributed to altered sweat gland activity. Methods: Five male and five female subjects performed maximal voluntary handgrip contractions (MVC: right hand) for 60 s at 20, 35 and 50% MVC (ambient temperature 25 degrees C, relative humidity 50%). Results: The sweat rate and the number of activated sweat glands on the non-exercised hand showed intensity-dependent increases (P < 0.05). At 35 and 50% MVC, finger sweat secretion was significantly higher than on the palm, which was primarily associated with the number of activated sweat glands (P < 0.05). In addition, there was a marked simultaneous decrease in the cutaneous vascular conductance for the finger at 35 and 50% MVC (P < 0.05), but not for the palm. Conclusion: Our results suggest that a difference exists between intensity-dependent increases of sudomotor responses within more than one glabrous skin site. Specifically, markedly greater sweating occurs on the volar finger than on the palmar surface during sustained static exercise. These differences in sweat rate mainly resulted from changes in the number of activated sweat glands. In addition, intra-segment variations in cutaneous blood flow on the glabrous hand are shown.

    WILEY-BLACKWELL, Aug. 2011, ACTA PHYSIOLOGICA, 202 (4), 649 - 655, English

    [Refereed]

    Scientific journal

  • Tatsuro Amano, Masashi Ichinose, Shunsaku Koga, Yoshimitsu Inoue, Takeshi Nishiyasu, Narihiko Kondo

    Amano T, Ichinose M, Koga S, Inoue Y, Nishiyasu T, Kondo N. Sweating responses and the muscle metaboreflex under mildly hyperthermic conditions in sprinters and distance runners. J Appl Physiol 111: 524-529, 2011. First published June 9, 2011; doi:10.1152/japplphysiol.00212.2011.-To investigate the effects of different training methods on nonthermal sweating during activation of the muscle metaboreflex, we compared sweating responses during postexercise muscle occlusion in endurance runners, sprinters, and untrained men under mild hyperthermia (ambient temperature, 35 C; relative humidity, 50%). Ten endurance runners, nine sprinters, and ten untrained men (maximal oxygen uptakes: 57.5 +/- 1.5, 49.3 +/- 1.5, and 36.6 +/- 1.6 ml.kg(-1).min(-1), respectively; P < 0.05) performed an isometric handgrip exercise at 40% maximal voluntary contraction for 2 min, and then a pressure of 280 mmHg was applied to the forearm to occlude blood circulation for 2 min. The Delta change in mean arterial blood pressure between the resting level and the occlusion was significantly higher in sprinters than in untrained men (32.2 +/- 4.4 vs. 17.3 +/- 2.6 mmHg, respectively; P < 0.05); however, no difference was observed between distance runners and untrained men. The Delta mean sweating rate (averaged value of the forehead, chest, forearm, and thigh) during the occlusion was significantly higher in distance runners than in sprinters and untrained men (0.38 +/- 0.07, 0.19 +/- 0.03, and 0.11 +/- 0.04 mg.cm(-2).min(-1), respectively; P < 0.05) and did not differ between sprinters and untrained men. Our results suggest that the specificity of training modalities influences the sweating response during activation of the muscle metaboreflex. In addition, these results imply that a greater activation of the muscle metaboreflex does not cause a greater sweating response in sprinters.

    AMER PHYSIOLOGICAL SOC, Aug. 2011, JOURNAL OF APPLIED PHYSIOLOGY, 111 (2), 524 - 529, English

    [Refereed]

    Scientific journal

  • Shunsaku Koga, David C. Poole, Yoshiyuki Fukuoka, Leonardo F. Ferreira, Narihiko Kondo, Etsuko Ohmae, Thomas J. Barstow

    Koga S, Poole DC, Fukuoka Y, Ferreira LF, Kondo N, Ohmae E, Barstow TJ. Methodological validation of the dynamic heterogeneity of muscle deoxygenation within the quadriceps during cycle exercise. Am J Physiol Regul Integr Comp Physiol 301: R534-R541, 2011. First published June 1, 2011; doi:10.1152/ajpregu.00101.2011.-The conventional continuous wave near-infrared spectroscopy (CW-NIRS) has enabled identification of regional differences in muscle deoxygenation following onset of exercise. However, assumptions of constant optical factors (e. g., path length) used to convert the relative changes in CW-NIRS signal intensity to values of relative concentration, bring the validity of such measurements into question. Furthermore, to justify comparisons among sites and subjects, it is essential to correct the amplitude of deoxygenated hemoglobin plus myoglobin [deoxy(Hb + Mb)] for the adipose tissue thickness (ATT). We used two time-resolved NIRS systems to measure the distribution of the optical factors directly, thereby enabling the determination of the absolute concentrations of deoxy(Hb + Mb) simultaneously at the distal and proximal sites within the vastus lateralis (VL) and the rectus femoris muscles. Eight subjects performed cycle exercise transitions from unloaded to heavy work rates (> gas exchange threshold). Following exercise onset, the ATT-corrected amplitudes (A(p)), time delay (TDp), and time constant (tau(p)) of the primary component kinetics in muscle deoxy(Hb + Mb) were spatially heterogeneous (intersite coefficient of variation range for the subjects: 10-50 for A(p), 16-58 for TDp, 14-108% for tau(p)). The absolute and relative amplitudes of the deoxy(Hb + Mb) responses were highly dependent on ATT, both within subjects and between measurement sites. The present results suggest that regional heterogeneity in the magnitude and temporal profile of muscle deoxygenation is a consequence of differential matching of O-2 delivery and O-2 utilization, not an artifact caused by changes in optical properties of the tissue during exercise or variability in the overlying adipose tissue.

    AMER PHYSIOLOGICAL SOC, Aug. 2011, AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY, 301 (2), R534 - R541, English

    [Refereed]

    Scientific journal

  • Keiji Hayashi, Yasushi Honda, Natsuki Miyakawa, Naoto Fujii, Masashi Ichinose, Shunsaku Koga, Narihiko Kondo, Takeshi Nishiyasu

    Hayashi K, Honda Y, Miyakawa N, Fujii N, Ichinose M, Koga S, Kondo N, Nishiyasu T. Effect of CO2 on the ventilatory sensitivity to rising body temperature during exercise. J Appl Physiol 110: 1334-1341, 2011. First published March 10, 2011; doi: 10.1152/japplphysiol.00010.2010.-We examined the degree to which ventilatory sensitivity to rising body temperature (the slope of the regression line relating ventilation and body temperature) is altered by restoration of arterial PCO2 to the eucapnic level during prolonged exercise in the heat. Thirteen subjects exercised for similar to 60 min on a cycle ergometer at 50% of peak O-2 uptake with and without inhalation of CO2-enriched air. Subjects began breathing CO2-enriched air at the point that end-tidal PCO2 started to decline. Esophageal temperature (T-es), minute ventilation ((V) over dot E), tidal volume (V-T), respiratory frequency (f(R)), respiratory gases, middle cerebral artery blood velocity, and arterial blood pressure were recorded continuously. When V. E, VT, fR, and ventilatory equivalents for O-2 uptake ((V) over dot E/(V) over dot O-2) and CO2 output ((V) over dot E/(V) over dot CO2) were plotted against changes in Tes from the start of the CO2-enriched air inhalation (Delta T-es), the slopes of the regression lines relating (V) over dot E, VT, (V) over dot E/(V) over dot O-2, and (V) over dot E/(V) over dot CO2 to Delta T-es (ventilatory sensitivity to rising body temperature) were significantly greater when subjects breathed CO2 enriched air than when they breathed room air ((V) over dot E: 19.8 +/- 10.3 vs. 8.9 +/- 6.7 l . min(-1) . degrees C (-1), VT: 18 +/- 120 vs. -81 +/- 92 ml/degrees C; (V) over dot E/(V) over dot O-2: 7.4 +/- 5.5 vs. 2.6 +/- 2.3 units/degrees C, and (V) over dot E/(V) over dot CO2: 7.6 +/- 6.6 vs. 3.4 +/- 2.8 units/degrees C). The increase in (V) over dot E was accompanied by increases in V-T and f(R). These results suggest that restoration of arterial PCO2 to nearly eucapnic levels increases ventilatory sensitivity to rising body temperature by around threefold.

    AMER PHYSIOLOGICAL SOC, May 2011, JOURNAL OF APPLIED PHYSIOLOGY, 110 (5), 1334 - 1341, English

    [Refereed]

    Scientific journal

  • 運動時における発汗調節特性とそれを収縮する要因(ワークショップ)

    KONDO NARIHIKO, 井上芳光

    2011, 発汗学, 18 (2), 80 - 81, Japanese

    [Refereed]

    Scientific journal

  • ヒトの発汗調節特性と部位差

    KONDO NARIHIKO, 井上芳光, Havenith G, Machad-Moreira CA, Taylor NS

    2011, 繊維機械学会誌, 64, 25 - 31, Japanese

    [Refereed]

    Scientific journal

  • エネルギー代謝と運動時の体温調節

    KONDO NARIHIKO, Kenny GP, 天野達郎, 藤井直人, 西保 岳

    (株)杏林書院, 2011, 体育の科学, 61 (8), 589 - 594, Japanese

    [Refereed]

    Scientific journal

  • Tomoko Ichinose-Kuwahara, Yoshimitsu Inoue, Yoshiko Iseki, Sachi Hara, Yukio Ogura, Narihiko Kondo

    We assessed sex differences in the sweat gland response to changes in exercise intensity with respect to subjects' physical training status. In total, 37 subjects participated (10 trained and 10 untrained females, and 8 trained and 9 untrained males). Each subject cycled continuously at 35, 50 and 65% of their maximal O(2) uptake ((V)over dot O(2max)) for 60 min at an ambient temperature of 30 degrees C and a relative humidity of 45%. The mean local sweating rate (SR) on the forehead, chest, back, forearm and thigh was significantly greater in the trained subjects than in the untrained subjects of both sexes. The degree of the increase in SR with physical training was greater in males than in females at higher levels of exercise intensity. This increase in SR depended primarily on an increase in the sweat output per gland (SGO) in both sexes. However, control of the SR increase with increasing exercise intensity was altered by training in females, i.e. the increase in SR from exercise at 50 to 65% (V)over dot O(2max) depended only on an increase in SGO in trained females and males and untrained males, but it depended on increases in activated sweat glands and the SGO in untrained females. It was concluded that training improved the sweating response, and a sex difference was observed in the degree of improvement in the sweating response due to physical training. This sex difference became more pronounced with increasing exercise intensity. A sex difference was observed in the control of sweating rate to an increase in exercise intensity, i.e. the maximal activated sweat gland responses of untrained females required a higher body temperature or work intensity than the other groups.

    WILEY-BLACKWELL, Oct. 2010, EXPERIMENTAL PHYSIOLOGY, 95 (10), 1026 - 1032, English

    [Refereed]

    Scientific journal

  • Narihiko Kondo, Takeshi Nishiyasu, Yoshimitsu Inoue, Shunsaku Koga

    This review focuses on the characteristics of heat-loss responses during exercise with respect to non-thermal factors. In addition, the effects of physical training on non-thermal heat-loss responses are discussed. When a subject is already sweating the sweating rate increases at the onset of dynamic exercise without changes in core temperature, while cutaneous vascular conductance (skin blood flow) is temporarily decreased. Although exercise per se does not affect the threshold for the onset of sweating, it is possible that an increase in exercise intensity induces a higher sensitivity of the sweating response. Exercise increases the threshold for cutaneous vasodilation, and at higher exercise intensities, the sensitivity of the skin-blood-flow response decreases. Facilitation of the sweating response with increased exercise intensity may be due to central command, peripheral reflexes in the exercising muscle, and mental stimuli, whereas the attenuation of skin-blood-flow responses with decreased cutaneous vasodilation is related to many non-thermal factors. Most non-thermal factors have negative effects on magnitude of cutaneous vasodilation; however, several of these factors have positive effects on the sweating response. Moreover, thermal and non-thermal factors interact in controlling heat-loss responses, with non-thermal factors having a greater impact until core temperature elevations become significant, after which core temperature primarily would control heat loss. Finally, as with thermally induced sweating responses, physical training seems to also affect sweating responses governed by non-thermal factors.

    SPRINGER, Oct. 2010, EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY, 110 (3), 447 - 458, English

    [Refereed]

    Scientific journal

  • 中枢性疲労と体温上昇時の換気亢進反応

    藤井直人, KONDO NARIHIKO, 西保 岳

    2010, 体育の科学, 60, 824-827, Japanese

    [Refereed]

    Scientific journal

  • 快適なキャビンを実現するための評価批評の開発

    吉澤公理, 高橋美晴, 平尾章成, 江上真弘, KONDO NARIHIKO

    2010, 自動車技術会秋季大会学術講演会Proceedings, 104-10, 7 - 12, Japanese

    [Refereed]

    International conference proceedings

  • Tadashi Saitoh, Anna Oue, Narihiko Kondo, Kyuichi Niizeki, Shunsaku Koga

    Near-infrared spectroscopy is a noninvasive optical technique used to monitor tissue oxygenation. Generally, the modified Beer-Lambert's law (MBL) using continuous-wave light has been used to measure active muscle oxygenation during exercise; however, it cannot measure absolute changes in the oxy- (oxy-[Hb + Mb]), deoxy- (deoxy-[Hb + Mb]), and total hemoglobin/myoglobin concentrations (total-[Hb + Mb]) because the pathlength and scattering coefficient are not measured. In contrast, the time-resolved spectroscopy (TRS) using a ultra short pulsed laser can be used to determine absolute changes in the concentration, although the temporal resolution is inferior to that in MBL. This study evaluated the absolute changes in active muscle oxygenation and the optical mean pathlength and scattering and absorption coefficient during high-intensity exercise by using the TRS system. In addition, the difference between the changes determined using TRS and MBL measurements was assessed. When the TRS and MBL measurements obtained during high-intensity exercise were compared, the total-[Hb + Mb] and oxy-[Hb + Mb] dynamics differed markedly during high-intensity exercise, while the deoxy[Hb + Mb] dynamics and kinetics did not differ.

    SPRINGER-VERLAG BERLIN, 2010, OXYGEN TRANSPORT TO TISSUE XXXI, 662, 225 - 230, English

    [Refereed]

    Scientific journal

  • Keiji Hayashi, Yasushi Honda, Takeshi Ogawa, Narihiko Kondo, Takeshi Nishiyasu

    To test the hypothesis that the hyperthermia-induced ventilatory response relates to aerobic power and/or the cutaneous vasodilatory response during exercise, we asked 18 subjects to perform 3 kinds of exercise: an incremental exercise to determine peak oxygen consumption ((V) over dotO(2peak)), a steady state exercise at 50% of (V) over dotO(2peak) to determine the ventilatory response to increasing body temperature, and a steady state exercise at 60% of (V) over dotO(2peak) to determine the cutaneous vasodilatory response to increasing body temperature. The ventilatory and cutaneous vasodilatory responses were evaluated by plotting the increase in minute ventilation or in forearm vascular conductance against the increase in oesophageal temperature. Regression analysis revealed that: (1) there was a negative relationship between the hyperthermic ventilatory response and cutaneous vasodilatory response, (2) there was a negative relationship between the hyperthermic ventilatory response and (V) over dotO(2peak), and (3) there was a positive relationship between the cutaneous vasodilatory response and (V) over dotO(2peak). These results support our hypothesis and suggest that exercise training suppresses the hyperthermic ventilatory response and improves the thermoregulatory response.

    SPRINGER, Nov. 2009, EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY, 107 (5), 527 - 534, English

    [Refereed]

    Scientific journal

  • Tadashi Saitoh, Leonardo F. Ferreira, Thomas J. Barstow, David C. Poole, Anna Ooue, Narihiko Kondo, Shunsaku Koga

    Saitoh T, Ferreira LF, Barstow TJ, Poole DC, Ooue A, Kondo N, Koga S. Effects of prior heavy exercise on heterogeneity of muscle deoxygenation kinetics during subsequent heavy exercise. Am J Physiol Regul Integr Comp Physiol 297: R615-R621, 2009. First published June 17, 2009; doi: 10.1152/ajpregu.00048.2009.-We investigated the effects of prior heavy exercise on the spatial heterogeneity of muscle deoxygenation kinetics and the relationship to the pulmonary O(2) uptake (p(V) over dot(O2)) kinetics during subsequent heavy exercise. Seven healthy men completed two 6-min bouts of heavy work rate cycling exercise, separated by 6 min of unloaded exercise. The changes in the concentration of deoxyhemoglobin/myoglobin (Delta deoxy-[Hb + Mb]) were assessed simultaneously at 10 different sites on the rectus femoris muscle using multichannel near-infrared spectroscopy. Prior exercise had no effect on either the time constant or the amplitude of the primary component p(V) over dot(O2), whereas it reduced the amplitude of the slow component (SC). Delta Deoxy-[Hb + Mb] across all 10 sites for bout 2 displayed a shorter time delay (mean and SD for subjects: 13.5 +/- 1.3 vs. 9.3 +/- 1.4 s; P < 0.01) and slower primary component time constant (tau : 9.3 +/- 1.3 vs. 17.8 +/- 1.0 s; P < 0.01) compared with bout 1. Prior exercise significantly reduced both the intersite coefficient of variation (CV) of the tau of Delta deoxy-[Hb + Mb] (26.6 +/- 11.8 vs. 13.7 +/- 5.6%; P < 0.01) and the point-by-point heterogeneity [root mean square error (RMSE)] during the primary component in the second bout. However, neither the change in the CV for tau nor RMSE of Delta deoxy-[Hb + Mb] correlated with the reduction in the SC in p(V) over dot(O2) kinetics during subsequent heavy exercise. In conclusion, prior exercise reduced the spatial heterogeneity of the primary component of muscle deoxygenation kinetics. This effect was not correlated with alterations in the p(V) over dot(O2) response during subsequent heavy exercise.

    AMER PHYSIOLOGICAL SOC, Sep. 2009, AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY, 297 (3), R615 - R621, English

    [Refereed]

    Scientific journal

  • 素材の吸湿性・吸水性の有無がタイトフィットスポーツ ウェア着用時における運動時の衣服内気候に及ぼす影響

    井上 真理, 大上 安奈, 近藤 徳彦

    Jun. 2009, デサントスポーツ科学, 第30巻,pp. 33-44, Japanese

    [Refereed]

    Scientific journal

  • Tomoko K. Ichinose, Yoshimitsu Inoue, Mari Hirata, A. K. M. Shamsuddin, Narihiko Kondo

    We investigated the effects of short-term endurance training and detraining on sweating and cutaneous vasodilatation during exercise in young women, taking into account changes in maximal oxygen uptake (V(O2max)) and the phase of the menstrual cycle. Eleven untrained women participated in endurance training; cycle exercise at similar to 60%. V(O2max) for 60min day(-1), 4-5 days week(-1) (30 degrees C, 45% relative humidity) for three complete menstrual cycles. The standard exercise test consisted of exercise at 50%. V(O2max) for 30min (25 degrees C, 45% relative humidity), and was conducted before training (Pre), during training sessions (T1, T2 and T3) and after cessation of training (D1 and D2). Values of. V(O2max) increased significantly from 32.7 +/- 1.2 to 37.8 +/- 1.2 ml min(-1) kg(-1) at the end of the training. Local sweat rate in the chest and thigh, but not in the back and forearm, were significantly greater during T1 and T2 only in women who started training from the midfollicular phase. Cutaneous blood flow did not change with training. The threshold oesophageal temperatures for heat loss responses were significantly decreased during T1 versus Pre (averaged values for each body site: sweating, 37.49 +/- 0.08 versus 37.22 +/- 0.12 degrees C; and cutaneous vasodilatation, 37.40 +/- 0.07 versus 37.17 +/- 0.10 degrees C) and maintained through T3; the sensitivities of heat loss responses were not altered. These changes returned to the Pre level by D1. Our data indicate that physical training improves heat loss responses by decreasing the threshold temperatures and that these effects occur within a month of training and disappear within a month after cessation of training. The degree of increase in sweating with training differs among body sites and might be affected by the phase of the menstrual cycle.

    WILEY-BLACKWELL PUBLISHING, INC, Jan. 2009, EXPERIMENTAL PHYSIOLOGY, 94 (1), 90 - 102, English

    [Refereed]

    Scientific journal

  • 活動筋の酸素供給と消費の過渡応答を非侵襲計測するシステムの開発

    古賀俊策, KONDO NARIHIKO, 福場良之, 福岡義之, 斉藤 直

    2009, デサントスポーツ科学, 30, 156 - 162, Japanese

    [Refereed]

    Scientific journal

  • Thermoregulatory adaptation in humans and its modifying factors (review).

    KONDO NARIHIKO, Taylor NAS, Shibasaki M, Aoki K, Muhamed AMC

    2009, Global Environmental Research, 13, 35 - 41, English

    [Refereed]

    Scientific journal

  • Yoshimitsu Inoue, Tomoko Ichinose-Kuwahara, Syunichi Nakamura, Hiroyuki Ueda, Hideshi Yasumatsu, Narihiko Kondo, Tsutomu Araki

    The cutaneous vasodilation and sweating responses of prepubertal children to heat stress were examined. Seven prepubertal boys (9-11 years old) and 9 young men (20-24 years old) were seated wearing only swimming trunks while the air temperature (Ta) was linearly increased from 28°C to 40°C over 50 min and then maintained at 40°C for an additional 10 min. Skin temperature, cutaneous vascular conductance (CVC), and local sweating rate (msw) were measured at multiple sites on the body. The boys had a significantly greater mean surface area-to-mass ratio compared with the young men. The rectal temperature did not change in either group with increasing Ta, although it was significantly higher in the boys. During the first half of the exposure period, when Ta was less than the mean skin temperature (Tsk), the boys had significantly higher CVC on the chest and significantly lower msw on the chest and thigh as compared with the young men. During the latter half of the exposure, when heat stress was increased as Ta exceeded Tsk, the boys had significantly higher Tsk, greater CVC on the chest and finger, greater rate of increase in the CVC on the forehead and finger, lower msw on the chest and thigh, greater increase in heart rate, and higher thermal sensation. The mean body temperature at the onset of sweating was significantly greater in the boys than in the men. These results suggest that, compared with young men, prepubertal boys manifest greater physiological and perceptual strain under heat stress induced by Ta exceeding Tsk, which is most probably attributable to a combination of lower evaporative heat loss, as evidenced by lower msw, and greater heat gain owing to a larger surface areato-mass ratio. The maturation-related differences in heat loss responses vary according to body site.

    2009, Journal of Physiological Anthropology, 28 (3), 137 - 144, English

    [Refereed]

    Scientific journal

  • Yoshimitsu Inoue, Tomoko Ichinose-Kuwahara, Syunichi Nakamura, Hiroyuki Ueda, Hideshi Yasumatsu, Narihiko Kondo, Tsutomu Araki

    The cutaneous vasodilation and sweating responses of prepubertal children to heat stress were examined. Seven prepubertal boys (9-11 years old) and 9 young men (20-24 years old) were seated wearing only swimming trunks while the air temperature (Ta) was linearly increased from 28°C to 40°C over 50 min and then maintained at 40°C for an additional 10 min. Skin temperature, cutaneous vascular conductance (CVC), and local sweating rate (msw) were measured at multiple sites on the body. The boys had a significantly greater mean surface area-to-mass ratio compared with the young men. The rectal temperature did not change in either group with increasing Ta, although it was significantly higher in the boys. During the first half of the exposure period, when Ta was less than the mean skin temperature (Tsk), the boys had significantly higher CVC on the chest and significantly lower msw on the chest and thigh as compared with the young men. During the latter half of the exposure, when heat stress was increased as Ta exceeded Tsk, the boys had significantly higher Tsk, greater CVC on the chest and finger, greater rate of increase in the CVC on the forehead and finger, lower msw on the chest and thigh, greater increase in heart rate, and higher thermal sensation. The mean body temperature at the onset of sweating was significantly greater in the boys than in the men. These results suggest that, compared with young men, prepubertal boys manifest greater physiological and perceptual strain under heat stress induced by Ta exceeding Tsk, which is most probably attributable to a combination of lower evaporative heat loss, as evidenced by lower msw, and greater heat gain owing to a larger surface areato-mass ratio. The maturation-related differences in heat loss responses vary according to body site.

    2009, Journal of Physiological Anthropology, 28 (3), 137 - 144, English

    [Refereed]

    Scientific journal

  • Masashi Ichinose, Mitsuru Saito, Narihiko Kondo, Takeshi Nishiyasu

    During heavy exercise, the arterial baroreflex and the reflexes evoked by the activation of those afferent nerve endings in the working skeletal muscles that are sensitive to metabolic changes (the so-called muscle metaboreflex) are hypothesized to be activated and, moreover, to interact in ways that lead to the modulation of the primary cardiovascular reflex responses. For the past few years, our group has been investigating the interaction between the arterial baroreflex and the muscle metaboreflex. We have focused our efforts in identifying the effects of muscle metaboreflex activation on the arterial baroreflex regulation of the cardiovascular hemodynamics and muscle sympathetic nerve activity (MSNA) in humans. In a series of studies, we have found that during muscle metaboreflex activation, dynamic carotid baroreflex responses are modulated, as exemplified by the augmentation of the MSNA, leg vascular conductance and blood pressure responses to carotid baroreflex unloading and the shorter suppression period of MSNA, diminished vasodilation, and reduced blood pressure response to carotid baroreflex stimulation. Furthermore, we have found that the modification of the arterial baroreflex-mediated beat-to-beat control of MSNA, which is seen during activation of tire muscle metaboreflex (i.e., resetting and an increase in sensitivity), could be a consequence of the alteration in the arterial baroreflex control of both the occurrence and strength of the MSNA burst. In addition, we have demonstrated that the arterial baroreflex beat-to-beat control of MSNA is tune-dependently modulated during isometric exercise. We suggest that the modulation of arterial baroreflex function during the activation of muscle metaboreflex is one of the mechanisms for increasing, or maintaining, blood pressure at the required pressure and thereby contributes to the regulation of the cardiovascular system during exercise.

    LIPPINCOTT WILLIAMS & WILKINS, Dec. 2008, MEDICINE AND SCIENCE IN SPORTS AND EXERCISE, 40 (12), 2037 - 2045, English

    [Refereed]

    Scientific journal

  • 360. 暑熱下運動時における換気亢進反応の深部体温閾値に関する研究(環境,一般口演,第63回日本体力医学会大会)

    辻, 文, 藤井, 直人, 近藤, 徳彦, 西保, 岳

    The Japanese Society of Physical Fitness and Sport Medicine, Dec. 2008, Japanese Journal of Physical Fitness and Sports Medicine, 57 (6), 812, Japanese

    International conference proceedings

  • Naoto Fujii, Yasushi Honda, Keiji Hayashi, Narihiko Kondo, Takeshi Nishiyasu

    Fujii N, Honda Y, Hayashi K, Kondo N, Nishiyasu T. Effect of hypohydration on hyperthermic hyperpnea and cutaneous vasodilation during exercise in men. J Appl Physiol 105: 1509-1518, 2008. First published September 11, 2008; doi:10.1152/japplphysiol.01206.2007.-We tested the hypothesis that, in humans, hypohydration attenuates hyperthermic hyperpnea during exercise in the heat. On two separate occasions, thirteen male subjects performed a fluid replacement (FR) and a no-fluid replacement (NFR) trial in random order. The subjects performed two bouts of cycle exercise (Ex1 and Ex2, 30-60 min) at 50% peak oxygen uptake ((V) over doto(2peak)) in 35 degrees C separated by a 70- to 80-min rest period, during which they drank water containing 25 mosmol/l sodium in the FR trial but not the NFR trial. The drinking in the FR trial nearly restored the body fluid to the euhydrated condition, so that the body fluid status differed between the trials before Ex2 (the difference in plasma osmolality before Ex2 was 9.4 mosmol/kgH(2)O; plasma volume was 7.6%, and body weight was 2.5%). The slopes of the linear relationships between ventilatory variables (minute ventilation, ventilatory equivalents for oxygen uptake and carbon dioxide output, tidal volume, respiratory frequency, and end-tidal CO2 pressure) and esophageal temperature (T-es) did not significantly differ between Ex1 and Ex2, or between the FR and NFR trials. On the other hand, during Ex2 in the NFR trial, the T-es threshold for the onset of increased forearm vascular conductance (FVC) was higher, and the slope and peak values of the relationship between FVC and T-es were lower than during Ex1 in the NFR trial and during Ex2 in the FR trial. These findings suggest that hypohydration does not affect the hyperthermic hyperpnea during exercise, although it markedly attenuates the cutaneous vasodilatory response.

    AMER PHYSIOLOGICAL SOC, Nov. 2008, JOURNAL OF APPLIED PHYSIOLOGY, 105 (5), 1509 - 1518, English

    [Refereed]

    Scientific journal

  • Naoto Fujii, Yasushi Honda, Keiji Hayashi, Narihiko Kondo, Shunsaku Koga, Takeshi Nishiyasu

    We tested the hypothesis that hyperthermic hyperventilation in part reflects enhanced chemoreceptor ventilatory O(2) drive, and that the resultant hypocapnia attenuates ventilatory responses and/or middle cerebral artery mean blood velocity (MCAV(mean)) in resting humans. Eleven healthy subjects were passively heated for 50-80 min, causing oesophageal temperature (T(oes)) to increase by 1.6 degrees C. During heating, minute ventilation ((V) over dot(E)) increased (P < 0.05), while end-tidal CO(2) pressure (P(ET,CO2)) and MCAV(mean) declined. A hyperoxia test in which three breaths of hyperoxic air were inspired was performed once before heating and three times during the heating. When we observed hypocapnia (P(ET,CO2) below 40 mmHg), P(ET,CO2) was restored to the eucapnic level by adding 100% CO(2) to the inspired air immediately before the last two tests. Minute ventilation was significantly reduced by hyperoxia, and that reduction gradually increased with increasing T(oes). However, the percentage decrease in (V) over dot(E) from the normoxic level was small (20-29%) and unchanged during heating. When P(ET,CO2) was restored to eucapnic levels, (V) over dot(E) was unchanged, but MCAV(mean) was partly restored to the level seen prior to heating (28.1% restoration at T(oes) 37.6 degrees C and 38.1% restoration at T(oes) 38.0 degrees C). These findings suggest that although hyperthermia increases chemoreceptor ventilatory O(2) drive in resting humans, the relative contribution of the chemoreceptor ventilatory O(2) drive to hyperthermic hyperventilation is small (similar to 20%) and unaffected by increasing core temperature. Moreover, hypocapnia induced by hyperthermic hyperventilation reduces cerebral blood flow but not ventilatory responses.

    WILEY-BLACKWELL PUBLISHING, INC, Aug. 2008, EXPERIMENTAL PHYSIOLOGY, 93 (8), 994 - 1001, English

    [Refereed]

    Scientific journal

  • Masashi Ichinose, Mitsuru Saito, Naoto Fujii, Takeshi Ogawa, Keiji Hayashi, Narihiko Kondo, Takeshi Nishiyasu

    We tested the hypotheses that arterial baroreflex (ABR) control over muscle sympathetic nerve activity (MSNA) in humans does not remain constant throughout a bout of leg cycling ranging in intensity from very mild to exhausting. ABR control over MSNA (burst incidence, burst strength and total MSNA) was evaluated by analysing the relationship between beat-to-beat spontaneous variations in diastolic arterial pressure (DAP) and MSNA in 15 healthy subjects at rest and during leg cycling in a seated position at five workloads: very mild (10 W), mild (82 +/- 5.0 W), moderate (126 +/- 10.2 W), heavy (156 +/- 14.3 W), and exhausting (190 +/- 21.2 W). The workload was incremented every 6 min. The linear relationships between DAP and MSNA variables were significantly shifted downward during very mild exercise, but then shifted progressively upward as exercise intensity increased. During heavy and exhausting exercise, moreover, the DAP-MSNA relationships were also significantly shifted rightward from the resting relationship. The sensitivity of ABR control over burst incidence and total MSNA was significantly lower during very mild exercise than during rest, and the sensitivity of the burst incidence control remained lower than the resting level at all higher exercise intensities. By contrast, the sensitivity of the total MSNA control recovered to the resting level during mild and moderate exercise, and was significantly increased during heavy and exhausting exercise (versus rest). We conclude that, in humans, ABR control over MSNA is not uniform throughout a leg cycling exercise protocol in which intensity was varied from very mild to exhausting. We suggest that this non-uniformity of ABR function is one of the mechanisms by which sympathetic and cardiovascular responses are matched to the exercise intensity.

    WILEY-BLACKWELL, Jun. 2008, JOURNAL OF PHYSIOLOGY-LONDON, 586 (11), 2753 - 2766, English

    [Refereed]

    Scientific journal

  • Anna Ooue, Tomoko K. Ichinose, Yoshimitsu Inoue, Takeshi Nishiyasu, Shunsaku Koga, Narihiko Kondo

    This study investigated changes in blood flow in the conduit artery, superficial vein, and deep vein of the upper arm during increase in internal temperature due to leg cycling. Additionally, we sought to demonstrate the contributions of blood velocity and vessel diameter on blood flow responses. Fourteen subjects performed supine cycling exercise at 60-69% maximal oxygen uptake for 30 min at an ambient temperature of 28 degrees C and relative humidity of 50%. Blood velocity and diameter in the brachial artery, basilic vein (superficial vein), and brachial vein (deep vein) were measured using ultrasound Doppler, and blood flow was calculated. Blood flow in the artery and superficial vein increased linearly with rising oesophageal temperature (Delta T-oes) after Delta T-oes was about 0.3 degrees C (within threshold), as well as cutaneous vascular conductance on the forearm. Changes in blood velocity in these vessels were similar to those in blood flow. Conversely, the brachial artery and superficial vein diameter did not affect the blood flow response. Blood flow variables in the deep vein did not change remarkably with rising Delta T-oes. These results suggest that blood flow response, by an increase in velocity, in the conduit artery with rising Delta T-oes during exercise is similar to that in the superficial vein, but not deep vein. Also, it is indicated that these increases in blood flow relate to the increase in skin blood flow on the forearm with the rise in body temperature during exercise.

    SPRINGER, Jun. 2008, EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY, 103 (3), 367 - 373, English

    [Refereed]

    Scientific journal

  • Naoto Fujii, Yasushi Honda, Keiji Hayashi, Hideaki Soya, Narihiko Kondo, Takeshi Nishiyasu

    We tested the hypothesis that, in humans, hyperthermic hyperpnea elicited in resting subjects differs from that elicited during submaximal, moderate-intensity exercise. In the rest trial, hot-water legs-only immersion and a waterperfused suit were used to increase esophageal temperature (T-es) in 19 healthy male subjects; in the exercise trial, T-es was increased by prolonged submaximal cycling [50% peak O-2 uptake ((V) over dot O-2)] in the heat (35 degrees C). Minute ventilation ((V) over dot E), ventilatory equivalent for (V) over dot O-2 ((V) over dot E/(V) over dot O-2) and CO2 output ((V) over dot E/(V) over dot O-2), tidal volume (VT), and respiratory frequency (f) were plotted as functions of T-es. In the exercise trial, (V) over dot E increased linearly with increases (from 37.0 to 38.7 degrees C) in T-es in all subjects; in the rest trial, 14 of the 19 subjects showed a T-es threshold for hyperpnea (37.8 +/- 0.5 degrees C). Above the threshold for hyperpnea, the slope of the regression line relating (V) over dot E and T-es was significantly greater for the rest than the exercise trial. Moreover, the slopes of the regression lines relating (V) over dot E/(V) over dot O-2, (V) over dot E/(V) over dot CO2, and T-es were significantly greater for the rest than the exercise trial. The increase in (V) over dot E reflected increases in VT and f in the rest trial, but only f in the exercise trial, after an initial increase in ventilation due to VT. Finally, the slope of the regression line relating T-es and VT or f was significantly greater for the rest than the exercise trial. These findings indicate that hyperthermic hyperpnea does indeed differ, depending on whether one is at rest or exercising at submaximal, moderate intensity.

    AMER PHYSIOLOGICAL SOC, Apr. 2008, JOURNAL OF APPLIED PHYSIOLOGY, 104 (4), 998 - 1005, English

    [Refereed]

    Scientific journal

  • Regulation of blood pressure and sympathetic nerve activity during exercise in humans -muscle metaboreflex and arterial baroreflex function-

    Takeshi, Nishiyasu, Mitsuru, Saito, Narihiko, Kondo, Masashi, Ichinose

    Jan. 2008, Proceeding of 2008 Korean Society of Exercise Physiology Summer Conference,, 1-6, English

    International conference proceedings

  • Shunsaku Koga, David C. Poole, Leonard F. Ferreira, Brian J. Whipp, Narihiko Kondo, Tadashi Saitoh, Etsuko Ohmae, Thomas J. Barstow

    Spatial heterogeneity of quadriceps muscle deoxygenation kinetics during cycle exercise. J Appl Physiol 103: 2049-2056, 2007. First published September 20, 2007; doi: 10.1152/japplphysiol.00627.2007.-To test the hypothesis that, during exercise, substantial heterogeneity of muscle hemoglobin and myoglobin deoxygenation [deoxy(Hb + Mb)] dynamics exists and to determine whether such heterogeneity is associated with the speed of pulmonary O-2 uptake (pVo(2)) kinetics, we adapted multi-optical fibers near-infrared spectroscopy (NIRS) to characterize the spatial distribution of muscle deoxygenation kinetics at exercise onset. Seven subjects performed cycle exercise transitions from unloaded to moderate [< gas exchange threshold (GET)] and heavy (> GET) work rates and the relative changes in deoxy(Hb + Mb), at 10 sites in the quadriceps, were sampled by NIRS. At exercise onset, the time delays in muscle deoxy(Hb + Mb) were spatially inhomogeneous [intersite coefficient of variation (CV), 3 similar to 56% for <GET, 2 similar to 21% for >GET]. The primary component kinetics (time constant) of muscle deoxy(Hb + Mb) reflecting increased O2 extraction were also spatially inhomogeneous (intersite CV, 6 similar to 48% for <GET, 7 similar to 47% for >GET) and faster (P < 0.05) than those of phase 2 pV(O2). However, the degree of dynamic intersite heterogeneity in muscle deoxygenation did not correlate significantly with phase 2 pV(O2) kinetics. In conclusion, the dynamics of quadriceps microvascular oxygenation demonstrates substantial spatial heterogeneity that must arise from disparities in the relative kinetics of V-O2 and O-2 delivery increase across the regions sampled.

    AMER PHYSIOLOGICAL SOC, Dec. 2007, JOURNAL OF APPLIED PHYSIOLOGY, 103 (6), 2049 - 2056, English

    [Refereed]

    Scientific journal

  • 2-2 Relationships among Ventilatory Response during Exercise in the Heat, Thermoregulation, and Aerobic Capacity(Proceedings of the 56th Meeting of Japan Society of Physiological Anthropology)

    HAYASHI, Keiji, HONDA, Yasushi, OGAWA, Takeshi, KOGA, Shunsaku, KONDO, Narihiko, NISHIYASU, Takeshi

    Japan Society of Physiological Anthropology, Nov. 2007, Journal of physiological anthropology, 26 (6), 610 - 611, English

    Scientific journal

  • Anna Ooue, Tomoko Ichinose-Kuwahara, A. K. M. Shamsuddin, Yoshimitsu Inoue, Takeshi Nishiyasu, Shunsaku Koga, Narihiko Kondo

    The purposes of this study were (1) to evaluate changes in blood flow in the brachial artery and basilic vein of the upper arm with a rise in internal temperature during passive heating; and (2) to investigate the contributions of blood velocity and anteroposterior vessel diameter to these blood flow changes. Ten subjects rested in the supine position between a pair of tube-lined sheets. Thermoneutral water was circulated through the tubes to keep a mean skin temperature ((T) over bar (sk)) of 34-35 degrees C, and then hot water was circulated to maintain (T) over bar (sk) of 37-38 degrees C. The blood velocity and diameter in the brachial artery and basilic vein were continuously monitored by Doppler ultrasound technique and used to calculate blood flow. Blood flow in the brachial artery and basilic vein increased linearly as the oral temperature (T-or) rose by <= 0.6 degrees C. The magnitude of the change in blood flow did not differ significantly between the two vessels. In addition, plots of Delta T-or versus blood flow yielded slopes that did not differ significantly between the brachial artery and the basilic vein. As Tor increased, blood velocity, but not diameter, also increased. In conclusion, blood flow in the brachial artery and the basilic vein increased linearly as the internal temperature variable T, increased <= 0.6 degrees C. In both vessels, the passive heating-induced increases in blood flow resulted primarily from a change in blood velocity, rather than from a change in diameter.

    SPRINGER, Sep. 2007, EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY, 101 (1), 97 - 103, English

    [Refereed]

    Scientific journal

  • Masashi Ichinose, Shunsaku Koga, Naoto Fujii, Narihiko Kondo, Takeshi Nishiyasu

    Continuous measurement of leg blood flow (LBF) using Doppler ultrasound with simultaneous noninvasive mean arterial blood pressure (MAP) measurement permits beat-to-beat estimates of leg vascular resistance (LVR) in humans. We tested the hypothesis that the beat-to-beat fluctuations in LVR and the dynamic relationship between MAP and LVR are modulated by the activation of muscle metaboreflex. Twelve healthy subjects performed a 1-min isometric handgrip exercise at 50% maximal voluntary contraction, which was followed by a period of imposed postexercise muscle ischemia (PEMI). We then employed transfer function analysis to examine the dynamic relationships between MAP and LBF and between MAP and LVR, both at rest (control) and during PEMI. We found the following. 1) The spectral power for LBF and LVR in low-frequency (similar to 0.03-0.15 Hz) range significantly increased from control during PEMI without a significant change in the high-frequency (similar to 0.15-0.35 Hz) power. 2) During PEMI, the transfer function gains for MAP-LBF and MAP-LVR relationships in the low-frequency (similar to 0.05-0.15 Hz) range were significantly increased during PEMI (vs. control) but were unchanged in the high-frequency (similar to 0.2-0.3 Hz) range. 3) The phases for MAPLBF and MAP-LVR relationships were not different during control and PEMI. The phase for MAP-LVR relationship revealed that changes in MAP were followed by directionally similar changes in LVR, which is consistent with the characteristics of intrinsic vascular regulatory mechanisms such as the myogenic response of the resistance arteries. We suggest that, in humans, modulation of the dynamic MAP-LVR relationship during activation of the muscle metaboreflex reflects complex interactions between intrinsic vascular regulatory mechanisms and sympathetic vascular regulation.

    AMER PHYSIOLOGICAL SOC, Jul. 2007, AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY, 293 (1), H416 - H424, English

    [Refereed]

    Scientific journal

  • 運動時の発汗と体温調節

    KONDO NARIHIKO

    2007, MB Derm, 124, 20 - 26, Japanese

    [Refereed]

    Scientific journal

  • The effect of non-thermal factors on heat loss responses during exercise in humans.

    KONDO NARIHIKO, Inoue Y, Koga S, Nishiyasu T

    2007, Environmental Ergonomics, 12, 241 - 244, English

    [Refereed]

    Scientific journal

  • Sex differences in the effects of physical training on sweat gland function.

    Inoue Y, Ichinose KT, Ogura Y, Kubota T, Ueda H, Ooue A, KONDO NARIHIKO

    2007, Environmental Ergonomics, 12, 276 - 279, English

    [Refereed]

    Scientific journal

  • Changes in blood flow in the superficial and deep veins of the upper arm during leg exercise in humans.

    Ooue A, Ichinose KT, Saito T, Inoue Y, Nishiyasu T, Koga S, KONDO NARIHIKO

    2007, Environmental Ergonomics, 12, 255 - 258, English

    [Refereed]

    Scientific journal

  • Masashi Ichinose, Mitsuru Saito, Naoto Fujii, Narihiko Kondo, Takeshi Nishiyasu

    We tested the hypothesis that arterial baroreflex (ABR)-mediated beat-to-beat control over muscle sympathetic nerve activity (MSNA) is progressively modulated as orthostatic stress increases in humans, but that this control becomes impaired just before the onset of orthostatic syncope. In 17 healthy subjects, the ABR control over MSNA (burst incidence, burst strength and total MSNA) was evaluated by analysing the relationship between beat-to-beat spontaneous variations in diastolic blood pressure (DAP) and MSNA during supine rest (control) and during progressive, stepwise increases in lower body negative pressure (LBNP) that were incremented by -10 mmHg every 5 min until presyncope (nine subjects) or -60 mmHg was reached. (1) The linear relationships between DAP and burst strength and between DAP and total MSNA were shifted progressively upward as LBNP increased until the level at which syncope occurred. The relationship between DAP and burst incidence, however, gradually shifted upward from control only to LBNP = -30 mmHg; there was no further upward shift at higher LBNPs. (2) Although the slope of the relationship between DAP and burst strength and between DAP and total MSNA remained constant at all LBNPs tested, except at the level where syncope occurred, the slope of the relationship between DAP and burst incidence was reduced at LBNPs of -40 mmHg and higher (versus control). (3) In syncopal subjects, the slopes of the relationships between DAP and burst incidence, burst strength, and total MSNA were all substantially reduced during the 1-2 min period prior to the onset of syncope. Taken together, these results suggest baroreflex control over MSNA is progressively modulated as orthostatic stress increases, so that its sensitivity is substantially reduced during the period immediately preceding the severe hypotension associated with orthostatic syncope.

    BLACKWELL PUBLISHING, Nov. 2006, JOURNAL OF PHYSIOLOGY-LONDON, 576 (3), 947 - 958, English

    [Refereed]

    Scientific journal

  • M Ichinose, M Saito, N Kondo, T Nishiyasu

    We investigated the time-dependent modulation of arterial baroreflex (ABR) control of muscle sympathetic nerve activity (MSNA) that occurs during isometric handgrip exercise (IHG). Thirteen healthy subjects performed a 3-min IHG at 30% maximal voluntary contraction, which was followed by a period of imposed postexercise muscle ischemia (PEMI). The ABR control of MSNA ( burst incidence and strength and total activity) was evaluated by analyzing the relationship between spontaneous variations in diastolic arterial pressure (DAP) and MSNA during supine rest, at each minute of IHG, and during PEMI. We found that 1) the linear relations between DAP and MSNA variables were shifted progressively rightward until the third minute of IHG (IHG3); 2) 2 min into IHG (IHG2), the DAP-MSNA relations were shifted upward and were shifted further upward at IHG3; 3) the sensitivity of the ABR control of total MSNA was increased at IHG2 and increased further at IHG3; and 4) during PEMI, the ABR operating pressure was slightly higher than at IHG2, and the sensitivity of the control of total MSNA was the same as at IHG2. During PEMI, the DAP-burst strength and DAP-total MSNA relations were shifted downward from the IHG3 level to the IHG2 level, whereas the DAP-burst incidence relation remained at the IHG3 level. These results indicate that during IHG, ABR control of MSNA is modulated in a time-dependent manner. We suggest that this modulation of ABR function is one of the mechanisms underlying the progressive increase in blood pressure and MSNA during the course of isometric exercise.

    AMER PHYSIOLOGICAL SOC, Apr. 2006, AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY, 290 (4), H1419 - H1426, English

    [Refereed]

    Scientific journal

  • T Nishiyasu, T Maekawa, R Sone, N Tan, N Kondo

    We examined the way in which the duration of rhythmic muscle compressions affects cardiovascular responses and muscle oxygenation at rest and during dynamic exercise. We measured the mean arterial pressure (MAP), heart rate (HR) and oxygenation of the vastus lateralis muscle (by near-infrared spectroscopy) in eight healthy male subjects at rest and during supine bicycle exercise (50 and 100 W at 60 r.p.m.) while applying pulsed muscle compressions at 1000 ms intervals. Compression pressure and durations were 150 mmHg and 300, 600, 900 and 1000 ms (1000 ms being static continuous compression), respectively. During exercise, the pulsed leg compression was synchronized to each thigh extensor muscle contraction. The observed changes in muscle oxygenation were dependent on compression duration (increased at 300 ms, no change at 600 ms and decreased at 900 or 1000 ms) and were different from those seen at rest (increases at < 1000 ms and decrease at 1000 ms). This suggests that the effects of external pulsed muscle compression may have a duration threshold below which muscle pumping counteracts the obstruction to flow caused by the compression, and that the threshold is set at a shorter compression duration during exercise than at rest. Although HR and MAP did not change during pulsed compression at rest, during exercise they both increased progressively as compression duration increased. Thus, while exercising, the increased MAP and HR seen during the compression could be due to the combination and interaction of mechanical effects and the muscle mechanoreflex and/or metaboreflex.

    BLACKWELL PUBLISHING, Jan. 2006, EXPERIMENTAL PHYSIOLOGY, 91 (1), 103 - 109, English

    [Refereed]

    Scientific journal

  • Relationship between ventilatory response and body temperature during prolonged submaximal exercise

    Hayashi K, Honda Y, Ogawa T, Kondo Narihiko, Nishiyasu T

    2006, J Appl Physiol, 100(2):414-420, English

    [Refereed]

    Scientific journal

  • K Aoki, M Yokoi, R Masago, K Iwanaga, N Kondo, T Katsuura

    Bright light (BL) exposure at night leads to suppressed secretion of melatonin and an attenuated fall in internal temperature at rest from the night to the early morning. However, it is unknown at the present whether typical diurnal variations in reflex responses to thermal challenges are similarly affected by BL exposure at night. We investigated the control of cutaneous vasodilator and sweating responses to hyperthermia in the early morning after artificial BL exposure at night, compare with dim light (DL) exposure. Six subjects stayed awake in a semi-supine position under DL (120 1x) or BL (2800 1x) conditions between 21.00 and 04.30 h. Urine samples were collected at 04.30 h. Beginning at 05.30 h, the lower legs were immersed for 50 min in 42 C water. The subjects remained awake for 21 h until the end of hot water immersion. Urinary 6-sulphatoxymelatonin levels following BL were significantly lower than after DL. Oesophageal temperature (T-es) before heating was significantly higher following BL [36.41 +/- 0.10 (DL) vs. 36.55 +/- 0.09 (BL) degrees C]. The T-es thresholds for the onset of cutaneous vasodilation and sweating were significantly higher with BL than with DL conditions (approximately 0.15 degrees C, respectively). We found that the internal temperature threshold for thermoregulatory control of cutaneous vasodilation and sweating responses to passive heating in the early morning can be modified by the level of light exposure the prior night. Thus both basal internal temperature and the regulation of internal temperature are modified by BL exposure at night.

    SPRINGER, Sep. 2005, EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY, 95 (1), 57 - 64, English

    [Refereed]

    Scientific journal

  • The effects of non-thermoregulatory factors on heat loss responses during exercise

    KONDO, N

    Jul. 2005, 日本生気象学会雑誌, 42, 39-53

    [Refereed]

    Scientific journal

  • T Kuwahara, Y Inoue, M Taniguchi, Y Ogura, H Ueda, N Kondo

    To examine the effects of physical training on cutaneous vasodilation and sweating responses of young women in the follicular and luteal phase, 11 physically trained (T group) and 13 untrained (U group) women were passively heated by lower-leg immersion into hot water of 42 degrees C (ambient temperature of 30 degrees C and 45% RH) for 60 min in their mid-follicular and mid-luteal phases of the menstrual cycle. Female hormones increased significantly from the mid-follicular to the mid-luteal phase in T and U groups, but the degree of increase was significantly lower in T group. Mean body temperature ((T) over bar (b)) thresholds for cutaneous vasodilation and sweating responses were significantly lower in T group than in U group, in both the menstrual phases, and the differences between the groups were greatest during the mid-luteal phase. The slope of the relationship between frequency of sweat expulsion (F-sw) and (T) over bar (b), and between local sweating rate and Fsw was significantly greater in T group, although the slope of the relationship between cutaneous blood flow and (T) over bar (b) did not differ between the groups, regardless of body site or menstrual phase. These results suggest that regular physical activity enhanced sweating and cutaneous vasodilation in young women. The enhancement of sweating was due to both central and peripheral mechanisms, and the enhancement of cutaneous vasodilation was possibly due to a central mechanism. Enhancement of heat loss responses via central mechanisms was greater during the mid-luteal phase than in the mid-follicular phase because the elevation of female reproductive hormone levels during the mid- luteal phase was relatively low in T group.

    SPRINGER, Jul. 2005, EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY, 94 (4), 376 - 385, English

    [Refereed]

    Scientific journal

  • AKM Shamsuddin, T Kuwahara, A Oue, C Nomura, S Koga, Y Inoue, N Kondo

    The effect of skin temperature on the ion reabsorption capacity of sweat glands during exercise in humans is unknown. In this study, eight healthy subjects performed a 60-min cycling exercise at a constant intensity (60% VO2max) under moderate (25 degrees C) and cool (15 degrees C) ambient temperatures at a constant relative humidity of 40%. The sweating rate (SR), index of sweat ion concentration (ISIC) by using sweat conductivity, esophageal temperature (Tes), mean skin temperature, and heart rate (HR) were measured continuously under both ambient temperatures. The SR and ISIC were significantly lower at the cool ambient temperature versus the moderate temperature. There were no significant differences in the changes in HR and esophageal temperature between these ambient temperature conditions, while the mean skin temperature was significantly lower at the cool ambient temperature by almost 3 degrees C (P < 0.05). The slopes of the relationships between Tes and the SR and ISIC were significantly lower and the thresholds of these relationships were significantly higher at the cool ambient temperature (P < 0.05). The ion reabsorption capacity of the sweat glands was significantly lower (P < 0.05) in a cool environment (0.21 +/- 0.04 vs. 0.52 +/- 0.06 mg/cm(2)/min at 15 and 25 degrees C, respectively) as evaluated using the relationships for SR and ISIC. The results suggest that the ion reabsorption capacity of the sweat glands is influenced by skin temperature during exercise in humans.

    SPRINGER, Jul. 2005, EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY, 94 (4), 442 - 447, English

    [Refereed]

    Scientific journal

  • AKM Shamsuddin, S Yanagimoto, T Kuwahara, Y Zhang, C Nomura, N Kondo

    To investigate the pattern changes in the index of sweat ion concentration at skin surface with increasing sweat during passive heat stress in humans, we measured conductivity of the perfused water with sweat as the index of sweat ion concentration and sweat rate, continuously at the chest skin surface. Eight healthy subjects (22.41.0 years) were passively heated by lower-leg immersion in a hot water bath of 42C for 50 min in an ambient temperature of 28C and relative humidity of 50%. The internal temperature (Tor) thresholds of sweat rate and index of sweat ion concentration were almost similar. Concomitant onset for the index of sweat ion concentration and sweat rate occurred but two types of linear regression lines were identified in the relationship between the index of sweat ion concentration and sweat rate at a boundary sweat rate value of 0.300.08 mg cm-2 min-1. The slope of the regression line at low levels of sweat (slope 0.020.01mg-1 cm-2 min-1) was significantly gradual compared with that at moderate levels of sweat (slope 0.300.08 V mg-1 cm-2 min-1) (P<0.05). These results suggest that at low levels of sweat the index of sweat ion concentration responds gradually with respect to sweat rate, which may be due to the ion reabsorption capacity of the sweat duct, and then the index of sweat ion concentration increased steeply with sweat rate.

    SPRINGER, Jun. 2005, EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY, 94 (3), 292 - 297, English

    [Refereed]

    Scientific journal

  • T Kuwahara, Y Inoue, M Abe, Y Sato, N Kondo

    We evaluated the effects of the menstrual cycle and physical training on heat loss (sweating and cutaneous vasodilation) responses during moderate exercise in a temperate environment. Ten untrained (group U) and seven endurance-trained (group T) women (maximal O-2 uptake of 36.7 +/- 1.1 vs. 49.4 +/- 1.7 ml.kg(-1).min(-1), respectively; P < 0.05) performed a cycling exercise at 50% maximal O-2 uptake for 30 min during both the midfollicular and midluteal menstrual phase in a temperate environment (ambient temperature of 25 degrees C, relative humidity of 45%). In group U, plasma levels of estrone, estradiol, and progesterone at rest and esophageal temperature (T-es) during exercise were significantly higher during the midluteal than during the midfollicular phase (P < 0.05). Sweating rate and cutaneous blood flow (measured via laser-Doppler flowmetry) on the chest, back, forearm, and thigh were lower during the midluteal than during the midfollicular phase during exercise. Tes threshold for heat loss responses was significantly higher and sensitivity of the heat loss responses was significantly lower in the midluteal than in the midfollicular phase, regardless of body site. These effects of the menstrual cycle in group U were not observed in group T. The sweating rate and cutaneous blood flow were significantly higher in group T than in group U, regardless of menstrual phase or body site. Tes threshold for heat loss responses was significantly lower and sensitivity of heat loss responses was significantly greater in group T than in group U in the midluteal phase; however, sensitivity of the sweating response was significantly greater in the midfollicular phase. These results suggest that heat loss responses in group U were inhibited in the midluteal phase compared with in the midfollicular phase. Menstrual cycle had no remarkable effects in group T. Physical training improved heat loss responses, which was more marked in the midluteal than in the midfollicular phase.

    AMER PHYSIOLOGICAL SOC, May 2005, AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY, 288 (5), R1347 - R1353, English

    [Refereed]

    Scientific journal

  • S Koga, DC Poole, T Shiojiri, N Kondo, Y Fukuba, A Miura, TJ Barstow

    The knee extension exercise (KE) model engenders different muscle and fiber recruitment patterns, blood flow, and energetic responses compared with conventional cycle ergometry (CE). This investigation had two aims: 1) to test the hypothesis that upright two-leg KE and CE in the same subjects would yield fundamentally different pulmonary O-2 uptake (p(V)over dotO(2)) kinetics and 2) to characterize the muscle blood flow, muscle (V)over dotO(2) (m(V)over dotO(2)), and p(V)over dotO(2) kinetics during KE to investigate the rate-limiting factor(s) of p(V)over dotO(2) on kinetics and muscle energetics and their mechanistic bases after the onset of heavy exercise. Six subjects performed KE and CE transitions from unloaded to moderate [<ventilatory threshold (VT)] and heavy (>VT) exercise. In addition to p(V)over dotO(2) during CE and KE, simultaneous pulsed and echo Doppler methods, combined with blood sampling from the femoral vein, were used to quantify the precise temporal profiles of femoral artery blood flow (LBF) and m(V)over dotO(2) at the onset of KE. First, the gain (amplitude/work rate) of the primary component of p(V)over dotO(2) for both moderate and heavy exercise was higher during KE (similar to12 ml.W-1.min(-1)) compared with CE (similar to10), but the time constants for the primary component did not differ. Furthermore, the mean response time (MRT) and the contribution of the slow component to the overall response for heavy KE were significantly greater than for CE. Second, the time constant for the primary component of m(V)over dotO(2) during heavy KE [25.8+/-9.0 s (SD)] was not significantly different from that of the phase II p(V)over dotO(2). Moreover, the slow component of p(V)over dotO(2) evident for the heavy KE reflected the gradual increase in m(V)over dotO(2). The initial LBF kinetics after onset of KE were significantly faster than the phase II p(V)over dotO(2) kinetics (moderate: time constant LBF=8.0+/-3.5 s, p(V)over dotO(2)=32.7+/-5.6 s, P<0.05; heavy: LBF=9.7&PLUSMN;2.0 s, p(V)over dotO(2)=29.9&PLUSMN;7.9 s, P<0.05). The MRT of LBF was also significantly faster than that of p(V)O-2. These data demonstrate that the energetics (as gain) for KE are greater than for CE, but the kinetics of adjustment (as time constant for the primary component) are similar. Furthermore, the kinetics of muscle blood flow during KE are faster than those of p(V)over dotO(2), consistent with an intramuscular limitation to (V)over dotO(2) kinetics, i.e., a microvascular O-2 delivery-to-O-2 requirement mismatch or oxidative enzyme inertia.

    AMER PHYSIOLOGICAL SOC, Jan. 2005, AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY, 288 (1), R212 - R220, English

    [Refereed]

    Scientific journal

  • 体温と運動の機能的連関

    KONDO NARIHIKO, 彼末一之

    2005, 体力科学, 54, 19 - 20, Japanese

    [Refereed]

    Scientific journal

  • 運動時の血流量制御

    西保 岳, 一之瀬真志, KONDO NARIHIKO, 斉藤 満

    2005, 体育の科学, 55, 781 - 787, Japanese

    [Refereed]

    Scientific journal

  • The effects of non-thermal factors on heat loss responses during exercise in humans.

    KONDO NARIHIKO

    2005, Proceedings of the 3rd International Conference on the Human-Environment System, 155 - 159, English

    [Refereed]

    Scientific journal

  • Heat loss responses during exercise and sports performance (keynote lecture).

    KONDO NARIHIKO

    2005, The Proceedings of 1st Asian Pacific Sports Science Conference 2005, The University of Malaysia Sabah, Malaysia, English

    [Refereed]

    International conference proceedings

  • Effects of short-term endurance training on heat loss responses during a moderate exercise at a temperate environment in young women

    KUWAHARA, T, INOUE, Y, HIRATA, M, KONDO, N

    2005, American Journal of Physiology Regulatory Integrated Comparative Physiology (in submit), ,

    [Refereed]

    Scientific journal

  • Change in heat loss responses after three month endurance training in young women.

    Kuwahara T, Inoue Y, Ooue A, Ogura Y, KONDO NARIHIKO

    2005, Proceedings of the 3rd International Conference on the Human-Environment System, 160 - 163, English

    [Refereed]

    Scientific journal

  • M Ichinose, M Saito, T Ogawa, K Hayashi, N Kondo, T Nishiyasu

    We tested the hypothesis that orthostatic stress would modulate the arterial baroreflex (ABR)mediated beat-by-beat control of muscle sympathetic nerve activity (MSNA) in humans. In 12 healthy subjects, ABR control of MSNA ( burst incidence, burst strength, and total activity) was evaluated by analysis of the relation between beat-by-beat spontaneous variations in diastolic blood pressure (DAP) and MSNA during supine rest ( CON) and at two levels of lower body negative pressure ( LBNP: - 15 and - 35 mmHg). At - 15 mmHg LBNP, the relation between burst incidence ( bursts per 100 heartbeats) and DAP showed an upward shift from that observed during CON, but the further shift seen at - 35 mmHg LBNP was only marginal. The relation between burst strength and DAP was shifted upward at - 15 mmHg LBNP ( vs. CON) and further shifted upward at - 35 mmHg LBNP. At - 15 mmHg LBNP, the relation between total activity and DAP was shifted upward from that obtained during CON and further shifted upward at - 35 mmHg LBNP. These results suggest that ABR control of MSNA is modulated during orthostatic stress and that the modulation is different between a mild (nonhypotensive) and a moderate ( hypotensive) level of orthostatic stress.

    AMER PHYSIOLOGICAL SOC, Nov. 2004, AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY, 287 (5), H2147 - H2153, English

    [Refereed]

    Scientific journal

  • K Hayashi, Y Honda, T Ogawa, H Wada, N Kondo, T Nishiyasu

    We investigated the effects of brief leg cooling after moderate exercise on the cardiorespiratory responses to subsequent exercise in the heat. Following 40 min of ergometer cycling [65% peak oxygen uptake (.O-2peak)] at 35degreesC (Ex. 1), seven male subjects [21.9 (1.1) years of age; 170.9 (1.9) cm height; 66.0 (2.0) kg body mass; 46.7 (2.0) ml kg(-1) min(-1) .O-2peak] immersed their legs in 35degreesC (control condition, CONT) or 20degreesC (cooling condition, COOL) water for 5 min and then repeated the cycling (as before, but for 10 min) (Ex. 2). Just before Ex. 2, esophageal temperature (T-es) was lower in COOL than in CONT [36.9 (0.2) vs 37.5 (0.1)degreesC] (P<0.01), as also were both mean skin temperature [33.9 (0.2) vs 35.2 (0.2)degreesC] (P<0.01), and heart rate (HR) [93.2 (6.0) vs 102.7 (4.9) beats min(-1)] (P<0.05). During Ex. 2, no differences between CONT and COOL were observed in oxygen uptake, arterial blood pressure, blood lactate concentration, or ratings of perceived exertion; however, T-es, skin temperature, and HR were lower in COOL than in CONT. Further, during the first 5 min of Ex. 2, minute ventilation was significantly lower in COOL than in CONT [50.3 (2.0) vs 53.4 (2.6) l min(-1)] (P<0.01). These results suggest that brief leg cooling during the recovery period may be effective at reducing thermal and cardiorespiratory strain during subsequent exercise in the heat.

    SPRINGER, Aug. 2004, EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY, 92 (4-5), 414 - 420, English

    [Refereed]

    Scientific journal

  • A comparison of oxygen uptake kinetics during knee extension and cycle exercise

    KOGA, S, POOLE, D, SHIOJIRI, T, KONDO, N, FUKUBA, Y, MIURA, Y A

    Aug. 2004, American Journal of Physiology Regulatory Integrated Comparative Physiology, 288, R212-220

    [Refereed]

    Scientific journal

  • The Effects of Ambient Humidity on Thermoregulatory Responses during Exercise in Man Clothed a Sport Wear

    INOUE, Mari, YANAGIMOTO, Shuji, KUWAHARA, Tomoko, YAMADA, Yukako, KONDO, Narihiko

    Jun. 2004, デサントスポーツ科学, 25, 49-61, Japanese

    [Refereed]

    Scientific journal

  • M Ichinose, M Saito, A Kitano, K Hayashi, N Kondo, T Nishiyasu

    We tested the hypothesis that in humans, carotid-baroreflex dynamic responses (evaluated by examining the time course of the carotid-baroreflex-induced alterations in muscle sympathetic nerve activity (MSNA), mean arterial blood pressure (MAP) and heart rate (HR)) would be altered during mild orthostatic stress in ways that serve to limit orthostatic hypotension. In 12 healthy subjects (10 male, 2 female), 5-s periods of neck pressure (NP) (50 mmHg) and neck suction (NS) (- 60 mmHg) were used to evaluate carotid baroreflex function at rest (CON) and during lower body negative pressure (LBNP) (- 15 mmHg). During LBNP (as compared with CON) (a) the augmentations in MSNA and MAP elicited by NP were greater, (b) the NS-induced period of MSNA suppression was, if anything, shorter, (c) the peak decrement in MAP elicited by NS, although not different in amplitude, occurred earlier and recovered to its initial level more quickly after NS, and (d) the HR responses to NP and NS were greater. These results suggest that during mild orthostatic stress, carotid-baroreflex dynamic responses are modulated in ways that should help maintain blood pressure and limit orthostatic hypotension.

    BLACKWELL PUBLISHING LTD, May 2004, JOURNAL OF PHYSIOLOGY-LONDON, 557 (1), 321 - 330, English

    [Refereed]

    Scientific journal

  • A Classification of Lecture and Component's of Lecture at Department of Human Development in KOBE University \p

    INABA, Taichi, ICHIHASHI, Hideki, KONDO, Narihiko, CHOGAHARA, Makoto, OZAKI, Toshiaki

    Feb. 2004, 神戸大学発達科学部研究紀要, 第11巻第2号, 101p-113p, Japanese

    [Refereed]

    Scientific journal

  • M Ichinose, M Saito, H Wada, A Kitano, N Kondo, T Nishiyasu

    We aimed to investigate the interaction [with respect to the regulation of muscle sympathetic nerve activity (MSNA) and blood pressure] between the arterial baroreflex and muscle metaboreflex in humans. In 10 healthy subjects who performed a 1-min sustained handgrip exercise at 50% maximal voluntary contraction followed by forearm occlusion, arterial baroreflex control of MSNA ( burst incidence and strength and total activity) was evaluated by analyzing the relationship between beat-by-beat spontaneous variations in diastolic arterial blood pressure (DAP) and MSNA both during supine rest (control) and during postexercise muscle ischemia (PEMI). During PEMI (vs. control), 1) the linear relationship between burst incidence and DAP was shifted rightward with no alteration in sensitivity, 2) the linear relationship between burst strength and DAP was shifted rightward and upward with no change in sensitivity, and 3) the linear relationship between total activity and DAP was shifted to a higher blood pressure and its sensitivity was increased. The modification of the control of total activity that occurs in PEMI could be a consequence of alterations in the baroreflex control of both MSNA burst incidence and burst strength. These results suggest that the arterial baroreflex and muscle metaboreflex interact to control both the occurrence and strength of MSNA bursts.

    AMER PHYSIOLOGICAL SOC, Feb. 2004, AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY, 286 (2), H701 - H707, English

    [Refereed]

    Scientific journal

  • Sweating responses during activation of the muscle metaboreflex in humans is altered by time of day

    K Aoki, N Kondo, Y Shimomura, M Yokoi, K Iwanaga, H Harada, T Katsuura

    Aim: The aim of the present study was to test for a time-of-day effect on sweating responses to activation of the muscle metaboreflex. Methods: Eight male subjects each participated in two exercise sessions, one in the morning and one in the evening. Within each session there were two 60-s bouts of isometric handgrip (IHG) exercise at 50% maximal voluntary contraction. Prior to IHG, whole body warming by a water-perfused suit initiated mild sweating. The first bout of IHG exercise began at 06.00 hours (am) and 18.00 hours (pm). Blood circulation to the forearm was occluded for 120 s, beginning 5 s before the end of the second bout of IHG to activate the muscle metaboreflex. Results: During both bouts of exercise, sweating rate (SR) on both the chest and right forearm significantly increased from the pre-exercise period in both am and pm sessions. SR rapidly decreased during first minute of recovery after the first bout of IHG exercise. However, during post-exercise ischaemia (PEI) after the second bout of IHG exercise, SR was maintained significantly above the pre-exercise level only in the pm session. The increases in SR on the chest and right forearm during PEI were significantly greater in the pm, than in the am, session. However, SR of the palm was not maintained during PEI. Conclusions: We conclude that under mild hyperthermic conditions, the sweating response in non-glabrous skin to activation of the muscle metaboreflex exhibits a time-of-day effect.

    BLACKWELL PUBLISHING LTD, Jan. 2004, ACTA PHYSIOLOGICA SCANDINAVICA, 180 (1), 63 - 70, English

    [Refereed]

    Scientific journal

  • 体温上昇と運動パフォーマン

    KONDO NARIHIKO, 西保 岳

    2004, 体育の科学, 54, 781 - 787, English

    [Refereed]

    Scientific journal

  • 女性の体温調節と運動

    井上芳光, 桑原智子, 小倉幸雄, KONDO NARIHIKO

    2004, 体育の科学, 54, 797 - 803, Japanese

    [Refereed]

    Scientific journal

  • M Shibasaki, NH Secher, C Selmer, N Kondo, CG Crandall

    Isometric handgrip, exercise (IHG) increases sweating rate without changing core or skin temperatures. The contribution of central command resulting in increases in sweating rate during IHG is unknown. To investigate this question, seven subjects performed IHG (35% maximum voluntary contraction (MVC) for 2 min) followed by 2-min of post-exercise ischaemia (PEI), with and without partial neuromuscular blockade (PNB). PNB was performed to augment central command during the IHG bout. These trials were conducted while the subject was normothermic, mildly heated, and moderately heated. On the non-exercising arm, forearm sweating rate was monitored over a microdialysis membrane perfused with neostigmine (acetylcholinesterase inhibitor), and at an adjacent untreated site. In normothermia with PNB, despite reduced force production during IHG (17 +/- 9 versus 157 +/- 13 N; P < 0.001), the elevation in sweating rate at the neostigmine-treated site was greater relative to the control IHG bout (P < 0.05). During subsequent PEI, for the PNB trial mean arterial blood pressure (MAP) and sweating rate returned towards pre-IHG levels, while during the control trial these variables remained elevated. During IHG while mildly heated, the elevation in sweating rate was greater during the PNB trial relative to the control trial. In contrast, during moderate heating sweating increased during IHG for both trials, however the elevation in sweating rate during the PNB trial was not greater than during the control trial. These results suggest that central command is capable of modulating sweating rate in all thermal conditions, however its effect is reduced when body temperatures and/or sweating rate are substantially elevated.

    CAMBRIDGE UNIV PRESS, Dec. 2003, JOURNAL OF PHYSIOLOGY-LONDON, 553 (3), 999 - 1004, English

    [Refereed]

    Scientific journal

  • N Kondo, S Yanagimoto, T Nishiyasu, CG Crandall

    Given differences in sympathetic innervation to glabrous and nonglabrous skin, we tested the hypothesis that muscle metaboreceptor regulation of cutaneous vascular conductance (CVC) differs between these skin regions. Subjects (n = 21) performed isometric handgrip exercise (IHG; 50% maximal voluntary contraction for 60 s), followed by 2 min of postexercise ischemia. Throughout IHG and postexercise ischemia, CVC was measured from glabrous ( palm) and nonglabrous ( forearm and chest) regions contralateral to the exercising arm. These procedures were conducted after the subjects had been exposed to an ambient temperature of 35degreesC and a relative humidity of 50% for 60 min. These thermal conditions were intended to cause slight increases in cutaneous blood flow via sympathetic withdrawal. Esophageal, sublingual, and mean skin temperatures did not change markedly during IHG or postexercise ischemia. During IHG, forearm CVC did not change, chest CVC increased slightly, and palm CVC decreased substantially ( from 100 to 34.8 +/- 3.5%; P = 0.001). During muscle metaboreceptor stimulation due to postexercise ischemia, CVC from nonglabrous regions returned to preexercise baselines, whereas CVC at the palm remained below preexercise baseline (68.2 +/- 4.2%; P = 0.001 relative to preexercise baseline). These results indicate that in mildly heated humans muscle metaboreflex stimulation is capable of modulating CVC in glabrous, but not in nonglabrous, skin.

    AMER PHYSIOLOGICAL SOC, May 2003, JOURNAL OF APPLIED PHYSIOLOGY, 94 (5), 1829 - 1835, English

    [Refereed]

    Scientific journal

  • Non-thermoregulatory modulation of sweating in humans

    M Shibasaki, N Kondo, CG Crandall

    SHIBASAKI, M., N. KONDO, and C.G. CRANDALL. Non-thermoregulatory modulation of sweating in humans. Exerc. Sport Sci. Rev., Vol. 31, No. 1, pp. 34-39, 2003. Sweating in humans is critical for appropriate thermoregulation during exercise and/or exposure to warm environmental temperatures. In addition to thermal controllers of sweating, a number of non-thermal factors modulate the sweating response. This review summarizes the primary non-thermal neural modifiers of sweating in humans.

    LIPPINCOTT WILLIAMS & WILKINS, Jan. 2003, EXERCISE AND SPORT SCIENCES REVIEWS, 31 (1), 34 - 39, English

    [Refereed]

    Scientific journal

  • Effects of muscle metaboreceptor stimulation on cutaneous blood flow from glabrous and nonglabrous skin in mildly heated humans. 94(5):1829-35, 2003

    Kondo, N, Yanagimoto, S, Nishiyasu, T, Crandall, CG

    Jan. 2003, J Appl Physiol., 94 (5), 1829-35, English

    [Refereed]

    Scientific journal

  • Effects of exercise intensity on sweating and skin blood flow responses at the onset of dynamic exercise in mildly heated humans

    YANAGIMOTO, S, KUWAHARA, T, ZHANG, Y, KOGA, S, INOUE, Y, KONDO, N

    2003, American Journal of Physiology Regulatory Integrated Comparative Physiology, 285, R200-R207

    [Refereed]

    Scientific journal

  • M Ichinose, M Saito, H Wada, A Kitano, N Kondo, T Nishiyasu

    We aimed to investigate the interaction between the arterial baroreflex and muscle metaboreflexes (as reflected by alterations in the dynamic responses shown by muscle sympathetic nerve activity (MSNA), mean arterial blood pressure (MAP) and heart rate (HR)) in humans. In nine healthy subjects (eight male, one female) who performed a sustained 1 min handgrip exercise at 50% maximal voluntary contraction followed by forearm occlusion, a 5 s period of neck pressure (NP) (30 and 50 mmHg) or neck suction (NS) (-30 and -60 mmHg) was used to evaluate carotid baroreflex function at rest (CON) and during post-exercise muscle ischaemia (PEMI). In PEMI (as compared with CON): (a) the augmentations in MSNA and MAP elicited by 50 mmHg NP were both greater; (b) MSNA seemed to be suppressed by NS for a shorter period, (c) the decrease in MAP elicited by NS was smaller, and (d) MAP recovered to its initial level more quickly after NS. However, the HR responses to NS and NP were not different between PEMI and CON. These results suggest that during muscle metaboreflex activation, the dynamic arterial baroreflex response is modulated, as exemplified by the augmentation of the MSNA response to arterial baroreflex unloading (i.e. NP) and the reduction in the suppression of MSNA induced by baroreceptor stimulation (i.e. NS).

    CAMBRIDGE UNIV PRESS, Nov. 2002, JOURNAL OF PHYSIOLOGY-LONDON, 544 (3), 939 - 948, English

    [Refereed]

    Scientific journal

  • Sweating responses to a sustained static exercise is dependent on thermal load in humans

    N Kondo, N Horikawa, K Aoki, M Shibasaki, Y Inoue, T Nishiyasu, CG Crandall

    The purpose of this project was to test the hypothesis that internal temperature modulates the sweating response to sustained handgrip exercise. Ten healthy male subjects immersed their legs in 43 degreesC water for 30-40 min at an ambient temperatures of 30 degreesC and a relative humidity of 50%. Sweating responses to 50% maximal voluntary contraction isometric handgrip exercise (IH) were measured following the onset of sweating (i.e. following slight increases in internal temperature), and after more pronounced increases in internal temperature. Oesophageal temperature (T (es) ) was significantly lower during the first bout of exercise (37.54 +/- 0.07 degreesC) relative to the second bout (37.84 +/- 0.12 degreesC; P < 0.05). However, the increase in mean sweating rate (SR) from both the chest and forearm (non-glabrous skin) was significantly greater during the first IH bout relative to the second bout (P < 0.05). Increases in mean arterial blood pressure and palm SR (glabrous skin) did not differ significantly between exercise bouts, while heart rate and rating of perceived effort were significantly greater during the second bout of IH. As T (es) and mean skin temperature did not change during either bout of exercise, the changes in SR from non-glabrous skin between the bouts of IH were likely because of non-thermal factors. These data suggest that sweating responses from non-glabrous skin during IH vary depending on the magnitude of thermal input as indicated by differing internal temperatures between bouts of IH. Moreover, these data suggest that the contribution of non-thermal factors in governing sweating from non-glabrous skin may be greatest when internal temperature is moderate (37.54 degreesC), but has less of an effect after greater elevations in internal temperature (i.e. 37.84 degreesC).

    WILEY, Aug. 2002, ACTA PHYSIOLOGICA SCANDINAVICA, 175 (4), 289 - 295, English

    [Refereed]

    Scientific journal

  • Effect of activated sweat glands on the intensity-dependent sweating response to sustained static exercise in mildly heated humans

    N Kondo, S Yanagimoto, K Aoki, S Koga, Y Inoue

    Changes in the number of activated sweat glands (ASGs) and sweat output per gland (SGO) with increased exercise intensity during sustained static exercise were investigated. Fourteen male subjects performed 20, 35, and 50% maximal voluntary contraction (MVC) for 60 s with the right hand (exercised arm) at an ambient temperature of 35degreesC and 50% relative humidity. Although sublingual, local skin, and mean skin temperatures remained essentially constant throughout the exercise at each intensity, the sweating rate (SR) of nonglabrous skin on the nonexercised left forearm increased significantly with a rise in exercise intensity (p<0.05). Changes in the number of ASGs with rising exercise intensity paralleled changes in the SR, but the SGO did not change markedly with altered exercise intensity. These results suggest that in mildly heated humans, at less than 50% MVC, the increase in the SR from nonglabrous skin with rising exercise intensity during sustained static exercise is dependent on changes in the number of ASGs and not on SGO.

    CENTER ACADEMIC PUBL JAPAN, Apr. 2002, JAPANESE JOURNAL OF PHYSIOLOGY, 52 (2), 229 - 233, English

    [Refereed]

    Scientific journal

  • Time of day effect on thermoregulatory responses to sustained static exercise.

    Aoki K, KONDO NARIHIKO, Shimomura Y, Yokoi M, Iwanaga K, Harada H, Katsuura T

    2002, Eur J Appl Physiol, 86, 388 - 393, English

    [Refereed]

    Scientific journal

  • The modulation of non-thermoregulatory sweat rate in humans

    SHIBASAKI, M, KONDO, N A

    2002, Exercise Sport Science Review, 31, 34-39

    [Refereed]

    Scientific journal

  • Sweating response to sustained handgrip exercise in physically trained men.

    Yanagimoto S, Aoki K, Horikawa N, Shibasaki M, Inoue Y, Nishiyasu T, KONDO NARIHIKO

    2002, Acta Physiol Scand, 174, 31 - 39, English

    [Refereed]

    Scientific journal

  • Effects of rhythmic muscle compression on arterial blood pressure at rest and during dynamic exercise in humans

    T Nishiyasu, R Sone, N Tan, T Maekawa, N Kondo

    This study was designed to examine the hypothesis that a rhythmic mechanical compression of muscles would affect systemic blood pressure regulation at rest and during dynamic exercise in humans. We measured the changes in mean arterial pressure (MAP) occurring (a) at rest with pulsed (350 ms pulses at 50 pulses min(-1)) or static compression (50 and 100 mmHg) of leg muscles with or without upper thigh occlusion, and (b) during 12-min supine bicycle exercise (75 W, 50 r.p.m.) with or without pulsed compression (50, 100, 150 mmHg) of the legs in synchrony with the thigh extensor muscle contraction. At rest with thigh occlusion, MAP increased by 4-8 mmHg during static leg compression, and by 5-9 mmHg during pulsed leg compression. This suggests that at rest pulsed leg compression elicits a reflex pressor response of similar magnitude to that evoked by static compression. During dynamic exercise without leg compression, MAP (having risen initially) gradually declined, but imposition of graded pulsed leg compression prevented this decline, the MAP values being significantly higher than those recorded without pulsed leg compression by 7-10 mmHg. These results suggest that the rhythmic increase in intramuscular pressure that occurs during dynamic exercise evokes a pressor response in humans.

    BLACKWELL SCIENCE LTD, Nov. 2001, ACTA PHYSIOLOGICA SCANDINAVICA, 173 (3), 287 - 295, English

    [Refereed]

    Scientific journal

  • Evidence for metaboreceptor stimulation of sweating in normothermic and heat-stressed humans

    M Shibasaki, N Kondo, CG Crandall

    1. Isometric handgrip (IHG) exercise increases sweat rate and arterial blood pressure, and both remain elevated during post-exercise ischaemia. The purpose of this study was to identify whether the elevation in arterial blood pressure during post-exercise ischaemia contributes to the increase in sweating. 2. In normothermia, and during whole-body heating, 2 min IHG exercise at 40 % maximal voluntary contraction, followed by 2 min post-exercise ischaemia, was performed with and without bolus intravenous administration of sodium nitroprusside during the ischaemic period. Sodium nitroprusside was administered to reduce blood pressure during post-exercise ischaemia to pre-exercise levels. Sweat rate was monitored over two microdialysis membranes placed in the dermal space of forearm skin. One membrane was perfused with the acetyleholinesterase inhibitor neostigmine, while the other was perfused with the vehicle. 3. In normothermia, IHG exercise increased sweat rate at the neostigmine-treated site but not at the control site. Sweat rate remained elevated during post-exercise ischaemia even after mean arterial blood pressure returned to the pre-IHG exercise baseline. Subsequent removal of the ischaemia stimulus returned sweat rate to pre-IHG exercise levels. Sweat rate during postexercise ischaemia without sodium nitroprusside administration followed a similar pattern. 4. During whole-body heating, IHG exercise increased sweat rate at both neostigmine-treated and untreated sites. Similarly, regardless of whether mean arterial blood pressure remained elevated or was reduced during post-exercise ischaemia, sweat rate remained elevated during the ischaemic period. 5. These results suggest that sweating in non-glabrous skin during post-IHG exercise ischaemia is activated by metaboreflex stimulation and not via baroreceptor loading.

    CAMBRIDGE UNIV PRESS, Jul. 2001, JOURNAL OF PHYSIOLOGY-LONDON, 534 (2), 605 - 611, English

    [Refereed]

    Scientific journal

  • Function of human eccrine sweat glands during dynamic exercise and passive heat stress

    N Kondo, M Shibasaki, K Aoki, S Koga, Y Inoue, CG Crandall

    The purpose of this study was to identify the pattern of change in the density of activated sweat glands (ASG) and sweat output per gland (SGO) during dynamic constant-workload exercise and passive heat stress. Eight male subjects (22.8 +/- 0.9 yr) exercised at a constant workload (117.5 +/- 4.8 W) and were also passively heated by lower-leg immersion into hot water of 42 degreesC under an ambient temperature of 25 degreesC and relative humidity of 50%. Esophageal temperature, mean skin temperature, sweating rate (SR), and heart rate were measured continuously during both trials. The number of ASG was determined every 4 min after the onset of sweating, whereas SGO was calculated by dividing SR by ASG. During both exercise and passive heating, SR increased abruptly during the first 8 min after onset of sweating, followed by a slower increase. Similarly for both protocols, the number of ASG increased rapidly during the first 8 min after the onset of sweating and then ceased to increase further (P > 0.05). Conversely, SGO increased linearly throughout both perturbations. Our results suggest that changes in forearm sweating rate rely on both ASG and SGO during the initial period of exercise and passive heating, whereas further increases in SR are dependent on increases in SGO.

    AMER PHYSIOLOGICAL SOC, May 2001, JOURNAL OF APPLIED PHYSIOLOGY, 90 (5), 1877 - 1881, English

    [Refereed]

    Scientific journal

  • Effect of muscle mass on Vo(2) kinetics at the onset of work

    S Koga, TJ Barstow, T Shiojiri, T Takaishi, Y Fukuba, N Kondo, M Shibasaki, DC Poole

    The dependence of O-2 uptake ((V) over dot o(2)) kinetics on the muscle mass recruited under conditions when fiber and muscle recruitment patterns are similar following the onset of exercise has not been determined. We developed a motorized cycle ergometer that facilitated one-leg (1L) cycling in which the electromyographic (EMG) profile of the active muscles was not discernibly altered from that during two-leg (2L) cycling. Six subjects performed 1L and 2L exercise transitions from unloaded cycling to moderate [<ventilatory threshold (VT)] and heavy (>VT) exercise. The 1L condition yielded kinetics that was unchanged from the 2L condition [the phase 2 time constants (tau (1), in s) for <VT were as follows: 1L = 16.8 +/- 8.4 (SD), 2L = 18.4 +/- 8.1, P > 0.05; for >VT: 1L = 26.8 +/- 12.0; 2L = 27.8 +/- 16.1, P > 0.05]. The overall (V) over dot o(2) kinetics (mean response time) was not significantly different for the two exercise conditions. However, the gain of the fast component (the amplitude/work rate) during the 1L exercise was significantly higher than that for the 2L exercise for both moderate and heavy work rates. The slow-component responses evident for heavy exercise were temporally and quantitatively unaffected by the 1L condition. These data demonstrate that, when leg muscle recruitment patterns are unchanged as assessed by EMC analysis, on-transient ire, kinetics for both moderate and heavy exercise are not dependent on the muscle mass recruited.

    AMER PHYSIOLOGICAL SOC, Feb. 2001, JOURNAL OF APPLIED PHYSIOLOGY, 90 (2), 461 - 468, English

    [Refereed]

    Scientific journal

  • Effects of exercise intensity on the sweating response to a sustained static exercise

    N Kondo, H Tominaga, M Shibasaki, K Aoki, S Okada, T Nishiyasu

    To investigate how the sweating response to a sustained handgrip exercise depends on changes in the exercise intensity, the sweating response to exercise was measured in eight healthy male subjects. Each subject lay in the supine position in a climatic chamber (35 degrees C and 50% relative humidity) for similar to 60 min. This exposure caused sudomotor activation by increasing skin temperature without a marked change in internal temperature. After this period, each subject performed isometric handgrip exercise [15, 30, 45, and 60% maximal voluntary contraction (MVC)] for 60 s. Although esophageal and mean skin temperatures did not change with a rise in exercise intensity and were similar at all exercise intensities, the sweating rate (SR) on the forearm increased significantly (P < 0.05) from baseline (0.094 +/- 0.021 mg cm(-2) min(-1) at 30% MVC, 0.102 +/- 0.022 mg cm(-2) min(-1) at 45% MVC, 0.059 +/- 0.009 mg cm(-2) min(-1) at 60% MVC) in parallel with exercise intensity above exercise intensity at 30% MVC (0.121 +/- 0.023 mg cm(-2) min(-1) at 30% MVC, 0.242 +/- 0.051 mg cm(-2) min(-1) at 45% MVC, 0.290 +/- 0.056 mg cm(-2) min(-1) at 60% MVC). Above 45% MVC, SR on the palm increased significantly from baseline (P < 0.05). Although SR on the forearm and palm tended to increase with a rise in exercise intensity, there was a difference in the time courses of SR between sites. SR on the palm showed a plateau after abrupt increase, whereas SR on the forearm increased progressively during exercise. These results suggest that the increase in SR with the increase in sustained handgrip exercise intensity is due to nonthermal factors and that the magnitude of these factors during the exercise may be responsible for the magnitude of SR.

    AMER PHYSIOLOGICAL SOC, May 2000, JOURNAL OF APPLIED PHYSIOLOGY, 88 (5), 1590 - 1596, English

    [Refereed]

    Scientific journal

  • 人における運動時の熱放散反応

    近藤 徳彦, 芝崎 学, 青木 健

    Mar. 2000, 兵庫体育・スポーツ科学, 9, 1-13

    Scientific journal

  • 人の熱放散反応を改善する可能性がある温度以外の要因

    KONDO NARIHIKO, 富永寛隆, 芝崎 学, 青木 健

    2000, 第21巻デサントスポーツ科学, Japanese

    [Refereed]

    Scientific journal

  • 人における運動時の熱放散反応

    KONDO NARIHIKO, 芝崎 学, 青木 健

    2000, 体育・スポーツ科学, 9, 1 - 13, Japanese

    [Refereed]

    Scientific journal

  • 運動時の酸素摂取応答動態の個人差を規定する要因

    古賀俊策, 福場良之, 福岡義之, 塩尻智之, KONDO NARIHIKO

    2000, 小野スポーツ科学, 8, 25 - 34, Japanese

    [Refereed]

    Scientific journal

  • マイクロダイアリシスを用いた汗腺機能の評価

    芝崎 学, Crandall CG, KONDO NARIHIKO

    2000, 第21巻デサントスポーツ科学, Japanese

    [Refereed]

    Scientific journal

  • Relationship between skin blood flow and sweating rate in prepubertal boys and young men

    M Shibasaki, Y Inoue, N Kondo, K Aoki, K Hirata

    We sought the mechanisms in the maturation-related change of skin blood flow to heat stress. Eight prepubertal boys (7-11 years) and 11 young men (21-25 years) were exposed to a mild passive heating [by placing the lower legs and feet in a 42 degrees C water bath for 60 min while sitting in a neutral air condition (25 degrees C, 45% relative humidity)]. No age-related differences were observed for the increase in rectal temperature [0.61 +/- 0.05 (SEM) vs. 0.62 +/- 0.09 degrees C in the boys and men at the end of the passive heating, respectively], mean skin temperature (34.51 +/- 0.28 vs. 34.81 +/- 0.27 degrees C) or metabolic heat production (68 +/- 4 vs. 60 +/- 3 W m(-2)) during the passive heating. During the healing age-related differences in skin blood flow by laser Doppler flowmetry (LDF) and local sweating rate (m) over dot(sw)) varied by site; the boys had greater LDF on the chest and back, similar LDF on the forearm and thigh, lower (m) over dot(sw) on the chest and thigh, similar (m) over dot(sw) on the back, and greater (m) over dot(sw) on the forearm, compared with the men. The relationship between IDF and (m) over dot(sw) during the heat exposure was divided into three temporal phases: (a) an increase of LDF without an increase in (m) over dot(sw) (b) an increase of (m) over dot(sw) without the secondary increase of LDF, (c) a proportional increase of LDF and (m) over dot(sw). The increase of LDF in phase (a) and the slopes of the regression lines between the LDF and (m) over dot(sw) in phase (c) were significantly greater on the chest and back for the boys (P < 0.05), compared with the men, but not on the forearm and thigh. These results suggest: that the greater LDF observed on the trunk in the boys may be owing to a greater withdrawal of vasoconstrictor tone and a greater active vasodilation. Regional differences may exist in the maturation-related alterations in vasoconstriction and vasodilation.

    BLACKWELL SCIENCE LTD, Oct. 1999, ACTA PHYSIOLOGICA SCANDINAVICA, 167 (2), 105 - 110, English

    [Refereed]

    Scientific journal

  • Kinetics of oxygen uptake during supine and upright heavy exercise

    S Koga, T Shiojiri, M Shibasaki, N Kondo, Y Fukuba, TJ Barstow

    Kinetics of oxygen uptake during supine and upright heavy exercise. J. Appl. Physiol. 87(1). 253-260, 1999.-It is presently unclear how the fast and slow components of pulmonary oxygen uptake (V overdot O-2) kinetics would be altered by body posture during heavy exercise [i.e., above the lactate threshold (LT)]. Nine subjects performed transitions from unloaded cycling to work rates representing moderate (below the estimated LT) and heavy exercise (V overdot O-2 equal to 50% of the difference between LT and peak Vet) under conditions of upright and supine positions. During moderate exercise, the steady-state increase in V overdot O-2 was similar in the two positions, but V overdot O-2 kinetics were slower in the supine position. During heavy exercise, the rate of adjustment of V overdot O-2 to the B-min value was; also slower in the supine position but was characterized by a significant reduction in the amplitude of the fast component, of V overdot O-2 without a significant slowing of the phase 2 time constant. However, the amplitude of the slow component was significantly increased, such that the end-exercise V overdot O-2 was the same in the two positions. The changes in V overdot O-2 kinetics for the supine vs. upright position were paralleled by a blunted response of heart rate at 2 min into exercise during supine compared with upright heavy exercise. Thus the supine position was associated with not only a greater amplitude of the slow component for V overdot O-2 but also, concomitantly, with a reduced amplitude of the fast component; this latter effect may be due, at least in part, to an attenuated early rise in heart rate in the supine position.

    AMER PHYSIOLOGICAL SOC, Jul. 1999, JOURNAL OF APPLIED PHYSIOLOGY, 87 (1), 253 - 260, English

    [Refereed]

    Scientific journal

  • Near-infrared monitoring of tissue oxygenation during application of lower body pressure at rest and during dynamical exercise in humans

    T Nishiyasu, N Tan, N Kondo, M Nishiyasu, H Ikegami

    During the application of a wide range of graded lower body pressures (LBP) (-50 to 50 mmHg), we examined how (1) the tissue oxygenation in the lower and upper parts of the body changes at rest, and (2) how tissue oxygenation changes in the lower extremities during dynamical leg exercise. We used near-infrared spectroscopy (NIRS) to measure the changes induced by LBP in total Hb content and Hb oxygenation in seven subjects. At rest total Hb increased and Hb oxygenation decreased in the thigh muscles during -25 and -50 mmHg LBP, while both decreased during +25 and +50 mmHg LBP. However, in the forearm muscles during graded LBP, the pattern of change in total Hb was the reverse of that in the thigh. Measurements from the forehead showed changes only during +50 mmHg LBP. These results demonstrated that the pattern of change in total Hb and Hb oxygenation differed between upper and lower parts with graded LBP at rest. During dynamical leg exercise, total Hb and Hb oxygenation in the thigh muscles decreased during stepwise increases in LBP above -25 mmHg, Hb oxygenation decreasing markedly during +50 mmHg LBP. These results suggest that during dynamical exercise ii) LBP at +25 mmHg or more causes a graded decline in blood volume and/or flow in the thigh muscles. and (ii) especially at +50 mmHg LBP, the O-2 content may decrease markedly in active muscles. Our results suggest that NIRS can be used to monitor in a non-invasive and continuous fashion the changes in oxygenation occurring in human skeletal muscles and head during the graded changes in blood flow and/or volume caused by changes in external pressure and secondary reflexes both at rest and during dynamical exercise.

    BLACKWELL SCIENCE LTD, Jun. 1999, ACTA PHYSIOLOGICA SCANDINAVICA, 166 (2), 123 - 130, English

    [Refereed]

    Scientific journal

  • Modulation of the thermoregulatory sweating response to mild hyperthermia during activation of the muscle metaboreflex in humans

    N Kondo, H Tominaga, M Shibasaki, K Aoki, S Koga, T Nishiyasu

    1. To investigate the effect of the muscle metaboreflex on the thermoregulatory sweating response in humans, eight healthy male subjects performed sustained isometric handgrip exercise in an environmental chamber (35 degrees C and 50% relative humidity) at 30 or 45% maximal voluntary contraction (MVC), at the end of which the blood circulation to the forearm was occluded for 120 s. The environmental conditions were such as to produce sweating by increase in skin temperature without a marked change in oesophageal temperature. 2. During circulatory occlusion after handgrip exercise at 30% MVC for 120 s or at 45% MVC for 60 s, the sweating rate (SR) on the chest and forearm (hairy regions), and the mean arterial blood pressure were significantly above baseline values (P < 0.05). There were no changes from baseline values in the oesophageal temperature, mean skin temperature, or SR on the palm (hairless regions). 3. During the occlusion after handgrip exercise at 30% MVC for 60 s and during the occlusion alone, none of the measured parameters differed from baseline values. 4. It is concluded that, under mildly hyperthermic conditions, the thermoregulatory sweating response on the hairy regions is modulated by afferent signals from muscle metaboreceptors.

    WILEY, Mar. 1999, JOURNAL OF PHYSIOLOGY-LONDON, 515 (2), 591 - 598, English

    [Refereed]

    Scientific journal

  • Modulation of the thermoregulatory sweating response to mild hyperthermia during activation of the muscle metaboreflex in humans

    N Kondo, H Tominaga, M Shibasaki, K Aoki, S Koga, T Nishiyasu

    1. To investigate the effect of the muscle metaboreflex on the thermoregulatory sweating response in humans, eight healthy male subjects performed sustained isometric handgrip exercise in an environmental chamber (35 degrees C and 50% relative humidity) at 30 or 45% maximal voluntary contraction (MVC), at the end of which the blood circulation to the forearm was occluded for 120 s. The environmental conditions were such as to produce sweating by increase in skin temperature without a marked change in oesophageal temperature. 2. During circulatory occlusion after handgrip exercise at 30% MVC for 120 s or at 45% MVC for 60 s, the sweating rate (SR) on the chest and forearm (hairy regions), and the mean arterial blood pressure were significantly above baseline values (P < 0.05). There were no changes from baseline values in the oesophageal temperature, mean skin temperature, or SR on the palm (hairless regions). 3. During the occlusion after handgrip exercise at 30% MVC for 60 s and during the occlusion alone, none of the measured parameters differed from baseline values. 4. It is concluded that, under mildly hyperthermic conditions, the thermoregulatory sweating response on the hairy regions is modulated by afferent signals from muscle metaboreceptors.

    WILEY, Mar. 1999, JOURNAL OF PHYSIOLOGY-LONDON, 515 (2), 591 - 598, English

    [Refereed]

    Scientific journal

  • 身体の適応能-人にしかない,汗のすぐれた機能を中心に-

    KONDO NARIHIKO

    1999, 人間科学研究, 7, 59 - 69, Japanese

    [Refereed]

    Scientific journal

  • 光ファイバーを用いた赤外線鼓膜体温計の有用性

    KONDO NARIHIKO, 芝崎 学, 堀川直幹

    1999, デサントスポーツ科学, 20, 177 - 183, Japanese

    [Refereed]

    Scientific journal

  • Recent Advances in Physiological Anthropology. Sato M, Tokura H and Watanuki S, ed., The effect of circadian variation on regional difference in vasomotor response to heat stress.

    AOKI, K, KONDO, N A

    1999, Kyushu University Press, chapt. 17,, 129-132

    Scientific journal

  • Exercise, Nutrition and Environmental Stress Volume 1, Nose H, Gisolfi CV and Imaizumi K, ed., The control of sweating rate and skin blood flow during exercise

    KONDO, N

    1999, Cooper Publishing Group LLC, , 153-178

    Scientific journal

  • 赤外線透過ファイバを用いた非接触型鼓膜体温計の開発

    芝崎 学, 近藤 徳彦, 森脇 俊道

    Oct. 1998, 人間工学, 34, 247-253

    [Refereed]

    Scientific journal

  • Regional differences in the effect of exercise intensity on thermoregulatory sweating and cutaneous vasodilation

    N Kondo, S Takano, K Aoki, M Shibasaki, H Tominaga, Y Inoue

    To investigate regional body differences in the effect of exercise intensity on the thermoregulatory sweating response, nine healthy male subjects (23.2 +/- 0.4 year) cycled at 35, 50 and 65% of their maximal O-2 uptake ((V) over dot o(2max)) for 30 min at an ambient temperature of 28.3 +/- 0.2 degrees C and a relative humidity of 42.6 +/- 2.4%. Local sweating rate ((m) over dot(sw)) on the forehead, chest, back, forearm and thigh increased significantly with increases in the exercise intensity from 35 to 50% (V) over dot o(2max) and from 50 to 65% (V) over dot o(2max) (P < 0.05). The mean values for the density of activated sweat glands (ASG) at 50 and 65% (V) over dot o(2max) at the five sites were significantly greater than at 35% (V) over dot o(2max). The mean value of the sweat output per gland (SGO) also increased significantly with the increase in exercise intensity (P < 0.05). The patterns of changes in ASG and SGO with an increase in exercise intensity differed from one region of the body to another. Although esophageal temperature (T-es) threshold for the onset of sweating at each site was not altered by exercise intensity, the sensitivity of the sweating response on the forehead increased significantly from 35 to 50 and 65% (V) over dot o(2max) (P < 0.05). The threshold for cutaneous vasodilation lend to increase with exercise intensity, although the exercise intensity did not affect the sensitivity (the slope in the relationship T-es vs. percentage of the maximal skin blood flow) at each site. T-es threshold for cutaneous vasodilation on the forearm was significantly higher at 65% (V) over dot o(2max) than at either 35 or 50% (V) over dot o(2max). but this was not observed at the other sites, such as on the forehead and chest. These results suggest that the increase in (m) over dot(sw) seen with an increasing intensity of exercise depends first on ASG, and then on SGO, and the dependence of ASG and SGO on the increase in (m) over dot(sw) differs for different body sites. In addition, there are regional differences in the T-es threshold for vasodilation in response to an increase in exercise intensity.

    BLACKWELL SCIENCE LTD, Sep. 1998, ACTA PHYSIOLOGICA SCANDINAVICA, 164 (1), 71 - 78, English

    [Refereed]

    Scientific journal

  • Continuous measurement of tympanic temperature with a new infrared method using an optical fiber

    M Shibasaki, N Kondo, H Tominaga, K Aoki, E Hasegawa, Y Idota, T Moriwaki

    The purpose of this study was to investigate the utility of an infrared tympanic thermometry by using an optical fiber for measuring tympanic temperature (T-ty). In the head cooling and facial fanning tests during normothermia, right T-ty, measured by this method (infrared-T-ty) and esophageal temperature (T-es) were not affected by decreased temple and forehead skin temperatures, suggesting that the infrared sensor in this system measured the infrared radiation from the tympanic membrane selectively. Eight male subjects took part in passive-heat-stress and progressive-exercise tests. No significant differences among infrared-T-ty, the left T-ty measured by thermistor (contact-T-ty), and T-es were observed at rest or at the end of each experiment, and there was no significant difference in the increase in these core temperatures from rest to the end. Furthermore, there were no significant differences in the core temperature threshold at the onset of sweating and slope (the relationship of sweating rate vs. infrared-T-ty and vs. contact-T-ty). These results suggest that this method makes it possible to measure T-ty accurately, continuously, and more safely.

    AMER PHYSIOLOGICAL SOC, Sep. 1998, JOURNAL OF APPLIED PHYSIOLOGY, 85 (3), 921 - 926, English

    [Refereed]

    Scientific journal

  • Control of circadian variation in skin blood flow response to heat stress

    K Aoki, N Kondo, M Shibasaki, S Takano, T Katsuura, K Hirata

    Six male subjects had their lower legs immersed in water at 42 degrees C for 60 min at 4 different times of the day to study whether the skin blood flow response to passive heat stress shows circadian variation in the relationship between skin blood flow and local sweating rate. When skin blood flow was plotted against local sweating rate, three distinct phases were observed. Phase A, an increase in skin blood flow without sweating was maximal at night. But the slope of the regression line did not change over the day in Phase C. These findings suggest that there is circadian variation in the skin blood flow response before onset of sweating during passive heat stress. This variation might be related, in part, to the circadian rhythm in vasoconstrictor activity.

    CENTER ACADEMIC PUBL JAPAN, Feb. 1998, JAPANESE JOURNAL OF PHYSIOLOGY, 48 (1), 95 - 98, English

    [Refereed]

    Scientific journal

  • Ken Aoki, Narihiko Kondo, Manabu Shibasaki, Seiji Takano, Tetsuo Katsuura, Kozo Hirata

    Six male subjects had their lower legs immersed in water at 42°C for 60 min at 4 different times of the day to study whether the skin blood flow response to passive heat stress shows circadian variation in the relationship between skin blood flow and local sweating rate. When skin blood flow was plotted against local sweating rate, three distinct phases were observed. Phase A, an increase in skin blood flow without sweating was maximal at night. But the slope of the regression line did not change over the day in Phase C. These findings suggest that there is circadian variation in the skin blood flow response before onset of sweating during passive heat stress. This variation might be related, in part, to the circadian rhythm in vasoconstrictor activity.

    The Physiological Society of Japan, 1998, Japanese Journal of Physiology, 48 (1), 95 - 98, English

    [Refereed]

    Scientific journal

  • The 1997 Nagano symposium on sports sciences. Nose H, Nadel ER and Morimoto T, ed.The effect of density of activated sweat glands and sweat output per gland on the change in sweating rate.

    KONDO, N, SHIBASAKI, M, TAKANO, S, AOKI, K, MORIWAKI, T A, Inoue Y

    1998, Cooper Publishing Group LLC, Sec. 6, chapt. 43,, 326-331, English

    Scientific journal

  • The 1997 Nagano symposium on sports sciences. Nose H, Nadel ER and Morimoto T, ed.1) Effect of altered muscle temperature on oxygen uptake kinetics during exercise,

    KOGA, S, SHIOJIRI, T, KONDO, N, SHIBASAKI, M, POOLE, DC A, Barstow TJ

    1998, Cooper Publishing Group LLC, Sec. 2, chapt. 17,, 139-143, English

    Scientific journal

  • Circadian variation of sweating responses to passive heat stress

    K Aoki, N Kondo, M Shibasaki, S Takano, H Tominaga, T Katsuura

    The aim of present study was to examine whether sweating responses to passive heat stress change with the circadian rhythm of internal temperature. Six men bad their legs immersed in water at 42 degrees C for 60 min in an ambient temperature of 29 degrees C on four separate days. Experiments were conducted at four different times [06.00 h (morning), 12.00 h (daytime), 18.00 h (evening) and 24.00 h (night)]. We measured oesophageal temperature (T-oes), mean body temperature ((T) over bar(b)) local sweating rate ((m) over dot (sw)) on the forehead, back, forearm and thigh, the densities of activated sweat gland (ASG) on the back, forearm and thigh, and the frequency of sweat expulsion per minute (F-SW) which has been suggested to represent central sudomotor activity. Sweat gland output (SGO) on each site was calculated by dividing (m) over dot (sw) by ASG. ASG was significantly higher on the forearm than on the back and thigh, and SGO was significantly lower on the forearm than cn the back and thigh. However, ASG and SGO did not significantly change over the day. (T) over bar(b) and T-oes thresholds for the onset of sweating showed a significant change with both the temperature rhythms at rest prior to each procedure, while the slopes of the relationships F-SW - (T) over bar(b) and (m) over bar (sw) - F-SW showed no significant difference over the day. We suggest that the circadian variation of sweating response to passive heat stress is regulated by a central sudomotor mechanism rather than by sweat gland function.

    BLACKWELL SCIENCE LTD, Nov. 1997, ACTA PHYSIOLOGICA SCANDINAVICA, 161 (3), 397 - 402, English

    [Refereed]

    Scientific journal

  • Effect of increased muscle temperature on oxygen uptake kinetics during exercise

    S Koga, T Shiojiri, N Kondo, TJ Barstow

    To test whether increased muscle temperature (T-m) would improve O-2 uptake ((V) over dotO(2)) kinetics, seven men performed transitions from rest to a moderate work rate [below the estimated lactate threshold (LTest)] and a heavy work rate ((V) over dotO(2) = 50% of the difference between LTest and peak (V) over dotO(2)) under conditions of normal T-m (N) and increased T-m (ii), produced by wearing hot water-perfused pants before exercise. Quadriceps T-m was significantly higher in H, but rectal temperature was similar for the two conditions. There were no significant differences in the amplitudes of the fast component of (V) over dotO(2) or in the time constants of the on and off transients for moderate and heavy exercise between the two conditions. The increment in (V) over dotO(2) between the 3rd and 6th min of heavy exercise was slightly but significantly smaller for Il than for N. These data suggest that elevated T-m before exercise onset, which would have been expected to increase O-2 delivery and off-loading to the muscle, had no appreciable effect on the fast exponential component of (V) over dotO(2) kinetics (invariant time constant). These data further suggest that elevated T-m does not contribute to the slow component of (V) over dotO(2) during heavy exercise.

    AMER PHYSIOLOGICAL SOC, Oct. 1997, JOURNAL OF APPLIED PHYSIOLOGY, 83 (4), 1333 - 1338, English

    [Refereed]

    Scientific journal

  • Sweating responses to passive and active limb movements

    KONDO, N, TOMINAGA, H, SHIOJIRI, T, SHIBASAKI, M, AOKI, K, TAKANO, S, KOGA, S A

    Sep. 1997, Journal of Thermal Biology, 22, 351-356

    [Refereed]

    Scientific journal

  • Mechanisms of underdeveloped sweating responses in prepubertal boys

    SHIBASAKI, M, INOUE, Y, KONDO, N

    Sep. 1997, European Journal of Applied Physiology, 76, 340-345

    [Refereed]

    Scientific journal

  • Thermoregulation responses of prepubertal boys and young men during moderate exercise

    SHIBASAKI, M, INOUE, Y, KONDO, N A

    Aug. 1997, European Journal of Applied Physiology, 75, 212-218

    [Refereed]

    Scientific journal

  • The effect of change in skin temperature due to evaporative cooling on sweating response during exercise

    N Kondo, M Nakadome, KR Zhang, T Shiojiri, M Shibasaki, K Hirata, A Iwata

    The purpose of this study was to investigate whether there are any effects of skin temperature changes on sweating response in the first few minutes of mild exercise. Six healthy males performed a bicycle exercise at 100 W (50 rpm) for 30 min under an ambient temperature of 23 degrees C (40% RH). Esophageal temperature (T-es), mean skin temperature ((T) over bar(sk)), local skin temperature at the lower left scapula (T-sl), local sweating rate ((M)over dot (sw)), and cutaneous blood flow by laser-Doppler flowmetry (LDF) were measured continuously. Although T-sl decreased markedly. just after the onset of sweating, (T) over bar(sk) did not change, (M)over dot (sw) did not increase constantly in the early stag es of exercise, and there was a temporary interruption in the increase of (M)over dot (sw). This interruption in sweating was affected by the rate of change in T-sl rather than by the absolute value of T-sl, since there was a positive and significant correlation between the time of the interruption in the increase of (M)over dot (sw) and the rate of decrease in T-sl (y=6.47x+0.04; r=0.86, P<0.05). The results suggest that sweating response in the early stages of exercise may be influenced by changes in local skin temperature due to evaporative cooling.

    SPRINGER VERLAG, Apr. 1997, INTERNATIONAL JOURNAL OF BIOMETEOROLOGY, 40 (2), 99 - 102, English

    [Refereed]

    Scientific journal

  • Effects of reduced muscle temperature on the oxygen uptake kinetics at the start of exercise

    T Shiojiri, M Shibasaki, K Aoki, N Kondo, S Koga

    The purpose of this study was to examine the effects of reduced muscle temperature (T-m) on gas exchange kinetics and haemodynamics al the start of exercise. Six male subjects performed moderate cycle exercise under reduced (C) and normal (N) T-m conditions. T-m and rectal temperature were significantly reduced by immersion in cold water (by 6.6 degrees C and 1.8 degrees C, respectively). The increases in oxygen uptake (VO2) and oxygen pulse (VO2/HR) during phase 1 (abrupt increase after the start of exercise) were significantly tower under C than under N. The time constant for O-2 under C (36.0 +/- 7.7 (SD) s) was significantly greater than under N (27.5 +/- 4.4 s); however. the time constants of cardiac output under C (38.3 +/- 16.6 s) and N (33.7 +/- 18.5 s) were similar. These results suggest that the slower VO2 on-response under reduced T-m conditions is caused by decreased O-2 extraction in working muscle and/or by impairment of oxidative reactions by reduced muscle temperature.

    BLACKWELL SCIENCE LTD, Apr. 1997, ACTA PHYSIOLOGICA SCANDINAVICA, 159 (4), 327 - 333, English

    [Refereed]

    Scientific journal

  • The regional differences in sweating responses between athletes trained on land and in water

    KONDO, N, NISHIYASU, T, NISHIYASU, M

    Dec. 1996, European Journal of Applied Physiology, 74, 67-71

    [Refereed]

    Scientific journal

  • The influence of work loads on regional differences in sweating rates

    S Takano, N Kondo, M Shibasaki, K Aoki, Y Inoue, A Iwata

    The influence of work loads (20, 40 and 60% V-O2max) on regional differences in sweating rates was investigated in six healthy male students, The ratios of local sweating rate (m(sw)) on the chest and back to estimated total sweating rate (mean m(sw) of four sites examined X body surface area) at 20% work load were significantly greater than those on the forearm and forehead, whereas the ratio on the forehead at 60% work load was greater than at the other sites, The ratios on the forearm at 40 and 60% work loads were significantly greater than at 20% work load. The regional differences in sweating rates change with the increase in work load as seen by the greater variation in the ratios of m(sw) on each site at 20% work load compared with 40 and 60% work loads. The results indicate that redistribution of this sweat activity to whole body or head with the rise in work load induces favorable conditions for evaporation and controlling brain temperature.

    CENTER ACAD PUBL JAPAN, Apr. 1996, JAPANESE JOURNAL OF PHYSIOLOGY, 46 (2), 183 - 186, English

    [Refereed]

    Scientific journal

  • Reexamination of tympanic membrane temperature as a core temperature

    KT Sato, NL Kane, G Soos, CV Gisolfi, N Kondo, K Sato

    Controversies surrounding tympanic temperature (T-ty) itself and techniques for measuring it have dampened the potential usefulness of T-ty in determining core temperature (operationally defined here as the body temperature taken at a deep body site). The present study was designed to address the following questions. 1) Can a tympanic membrane probe be made that is safer and more reliable than its predecessors? 2) Why is the effect of facial cooling and heating on T-ty so inconsistent in reports from different laboratories? 3) Is T-ty still useful as a measure of core temperature? Data from this study, obtained with a modified thermocouple probe, suggest that the widely reported facial skin cooling effect on T-ty is most probably due to thermal contamination from the surrounding ear canal wall and/or suboptimal contact of the probe sensor with the tympanic membrane because 1) T-ty that fell during facial cooling was increased to the precooling level by the repositioning of the probe sensor; 2) T-ty determined by using a probe with a larger sensor area (the sensor soldered to a steel wire ring) tended to fall in response to facial cooling, whereas T-ty determined with a thermally insulated probe ring did not; and 3) T-ty obtained under careful positioning of the insulated probe was relatively insensitive to facial cooling or heating. Because T-ty was practically identical to esophageal temperature (T-es) in the steady state, i.e., 36.83 +/- 0.20 (SD)degrees C for T-ty and 36.87 +/- 0.16 degrees C for T-es at room temperature (n = 11), and because facial cooling had little effect on both T-ty and T-es (36.86 +/- 0.17 degrees C for T-ty and 36.86 +/- 0.26 degrees C for T-es during facial or scalp skin cooling), we support the postulate that T-ty is a good measure of core temperature. The temperature transient in response to foot warming was detected 5 min (n = 2) faster with T-ty than with T-es. Thus, with further improvements in the design of the probe, T-ty can become a standard for determination of core body temperature.

    AMER PHYSIOLOGICAL SOC, Apr. 1996, JOURNAL OF APPLIED PHYSIOLOGY, 80 (4), 1233 - 1239, English

    [Refereed]

    Scientific journal

  • The influence of exercise intensity on sweating efficiency of the whole body in a mild thermal condition

    N Kondo, T Nishiyasu, H Ikegami

    To investigate whether the exercise intensity affects sweating efficiency (eta(sw)) during exercise under mild environmental conditions, six healthy males, aged 22 +/- 2 years, performed three bicycle ergometer exercises at varying intensities (73W: Ex-1, 103W: Ex-2 and 133W: Ex-3) for 40 min under the conditions of 25 degrees C room temperature, 50% relative humidity and 0.3-0.4 m s(-1) wind velocity. Heart rate, oxygen consumption, rectal temperature (T-re), mean skin temperature ((T) over bar(sk); 4 skin sites) and total sweat rate were determined intermittently throughout the experiments. Moreover, heat loss by evaporation (E), radiation (R), convection (C) and eta(sw) were calculated using the heat balance equations. The findings concerning thermoregulatory parameters under the three experimental conditions were summarized as follows: (1) the higher the exercise intensity, the larger the values of T-re and (T) over bar(sk) at the end of exercise and E, R and C during exercise (2) the mean values +/- SE of eta(sw) were 55.4 +/- 5.1, 63.2 +/- 5.2 and 58.5 +/- 1.9% for Ex-1, Ex-2 and Ex-3, respectively. The results suggest that exercise intensity would have no effect on eta(sw) in this mild thermal environment.

    TAYLOR & FRANCIS LTD, Feb. 1996, ERGONOMICS, 39 (2), 225 - 231, English

    [Refereed]

    Scientific journal

  • Kinetics of oxygen uptake and cardiac output at onset of arm exercise

    S Koga, T Shiojiri, M Shibasaki, Y Fukuba, Y Fukuoka, N Kondo

    Pulmonary oxygen uptake (Vover dot(O2)) kinetics at onset of exercise is reported to be slower for arm than for leg exercise. This could be attributed to reduced cardiac output (Qover dot) or reduced arteriovenous O-2 content difference or both. To test this, Vover dot(O2), mean tissue oxygen consumption (Vover dot(O2T)), and Qover dot kinetics in arm cranking were compared with corresponding values found in leg cycling. The increase in Vover dot(O2) during phase 1 (abrupt increase after onset of exercise) was less in arm than in leg exercise, suggesting that immediate Qover dot adjustments to arm exercise were less pronounced. Mean response times (MRT, the relative rates at which a steady state was attained) for Vover dot(O2), Vover dot(O2T), and Qover dot were prolonged during arm exercise. The MRT of Vover dot(O2) in arm exercise at a given blood lactate increase was higher than in leg exercise. The delayed Vover dot(O2) kinetics in arm exercise might be due to delayed Qover dot kinetics and higher anaerobic glycolysis occurring early during arm exercise.

    ELSEVIER SCIENCE BV, Feb. 1996, RESPIRATION PHYSIOLOGY, 103 (2), 195 - 202, English

    [Refereed]

    Scientific journal

  • Koga S, Shiojiri T, Fukuba Y, Fukuoka Y, Kondo N

    1, Jan. 1996, Applied human science : journal of physiological anthropology, 15 (1), 1 - 4

    [Refereed]

  • コンピュータゲームが子どもの自律神経系反応に及ぼす影響

    城 仁士, 近藤 徳彦

    Dec. 1995, 教育心理学研究, 43, 418-423, Japanese

    [Refereed]

    Scientific journal

  • THE EFFECT OF DIURNAL-VARIATION ON THE REGIONAL DIFFERENCES IN SWEATING AND SKIN BLOOD-FLOW DURING EXERCISE

    K AOKI, T SHIOJIRI, M SHIBASAKI, S TAKANO, N KONDO, A IWATA

    The aim of the present study was to examine changes in the control of heat-dissipation responses to exercise associated with the diurnal variation in core temperature from the viewpoint of the regional response patterns. We studied seven men during exercise on a cycle ergometer at 100 W for 40 min at 25 degrees C at 0630 (morning) 1630 (evening) hours on 2 separate days. Oesophageal temperature (T-oes), local skin temperature, local sweating rate (m(sw)) on the forehead, back, forearm and thigh, and skin blood flow by laser Doppler flowmeter (LDF) on the back and forearm were measured continuously. The T-oes at rest was significantly higher in the evening than in the morning, the difference averaging approximately 0.4 degrees C (P < 0.05). The T-oes thresholds for each site in m(sw) and that for back in LDF were significantly different between the two times of day (P < 0.05). The change in T-oes thresholds for sweating and vasodilatation for morning and evening were similar to T-oes at rest. Although m(sw) on the forehead was significantly higher in the morning than in the evening, m(sw) on the back was significantly higher in the evening than in the morning (P < 0.05). Total local sweating rate (m(sw,tot)) for each site during exercise was significantly higher on the forehead than on the forearm in the morning, and on the back than on the forearm in the evening, respectively (P < 0.05). The results would suggest that the diurnal variation of heat-dissipation responses to exercise is influenced not only by a central controlling mechanism but also by changes in the regional differences.

    SPRINGER VERLAG, Aug. 1995, EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY AND OCCUPATIONAL PHYSIOLOGY, 71 (2-3), 276 - 280, English

    [Refereed]

    Scientific journal

  • THE SWEATING RESPONSES OF ATHLETES TRAINED ON LAND AND IN WATER

    N KONDO, T NISHIYASU, H IKEGAMI

    In order to examine whether different sweating responses of athletes trained on land and in water may be ascribed to changes in the central sudomotor mechanisms and/or those of the peripheral mechanisms of sweat glands, we measured the local sweating rate at the left forearm (m(swf)) and the left scapula (m(sws)), the frequence of sweat expulsion (F-SW) and body temperatures (mean skin temperature and rectal temperature: T-re) in six runners and five soccer players (R group) and six swimmers (S group) during progressive thermal stress at rest (2 degrees C increase in ambient temperature every 15 min from 35 to 45 degrees C RH = 30-40%). T-re and heart rate at the end of experiment did not differ significantly between the groups (37.31 +/- 0.04 degrees C, 74.5 +/- 7.9 beats . min(-1) in the S group and 37.27 +/- 0.07 degrees C, 71.1 +/- 9.0 beats . min(-1) in the R group, respectively). The m(sws) and m(swf) at any given mean body temperature (($) over bar Tb) were greater in the S group than in the R group. Although the regression line showing the relationship between F-SW and ($) over bar Tb in the S group was shifted to the left of that in the R group, there was no significant difference in the slope of the lines. The m(sws)-F-SW or m(swf)-F-SW regression line was not different between the two groups. These results indicate that the higher sweating rate in the S group may be ascribed to a difference in the centrally derived sudomotor neural activity, but not to that in the peripheral mechanisms of sweat gland activity.

    CENTER ACAD PUBL JAPAN, 1995, JAPANESE JOURNAL OF PHYSIOLOGY, 45 (4), 571 - 581, English

    [Refereed]

    Scientific journal

  • インピーダンス法による運動中の心拍出量の連続測定-非定常状態における心拍出量応答動態の評価への応用-

    塩尻 智之, 島名 孝次, 古賀 俊策, 近藤 徳彦, 岩田 敦

    May 1994, 日本生理人類学雑誌, 13, 169-178

    [Refereed]

    Scientific journal

  • 呼吸数によるAT推定法の限界に関する研究-呼吸と運動リズムとの同期が起こりにくい条件下において-

    島名 孝次, 塩尻 智之, 古賀 俊策, 近藤 徳彦, 岩田 敦

    Feb. 1994, 体力科学, 43, 84-91

    [Refereed]

    Scientific journal

  • 中強度自転車運動初期におけるガス交換動態の日内変動

    塩尻 智之, 島名 孝次, 古賀 俊策, 近藤 徳彦, 岩田 敦

    Oct. 1993, 体力科学, 42, 455-460

    [Refereed]

    Scientific journal

  • 流速に応じたニューモタコグラフの補正法の開発-この方法を用いた呼気ガス連続測定システム-

    島名 孝次, 古賀 俊策, 近藤 徳彦, 岩田 敦

    1992, 日本生理人類学雑誌, 11, 443-450

    [Refereed]

    Scientific journal

  • 呼吸数によるAT推定の限界に関する研究.

    島名 孝次, 近藤 徳彦, 古賀 俊策, 樫本 朋子, 岩田 敦

    Nov. 1991, 日本生理人類学雑誌, 10, 237-242

    [Refereed]

    Scientific journal

  • 運動時の発汗量の変化に対する中枢機構と末梢機構の関与.

    山崎 文夫, 近藤 徳彦, 池上 晴夫

    Oct. 1991, 日本生気象学会雑誌, 28, 95-106

    [Refereed]

    Scientific journal

  • 反復する環境温の変化に対する皮膚温の応答性について

    山崎 文夫, 近藤 徳彦, 藤井 宣晴, 本間 幸子, 池上 晴夫

    Mar. 1991, いばらき体育・スポーツ科学, 5, 58-66

    [Refereed]

    Scientific journal

  • 正弦波運動負荷に対するガス交換の応答特性-振幅応答及び位相差応答と有酸素能力との関係について-

    福岡 義之, 近藤 徳彦, 後藤 真二, 池上 晴夫

    Feb. 1991, 体力科学, 40, 60-63

    [Refereed]

    Scientific journal

  • 乳酸消失からみたクーリング・ダウンの効果に関する研究-間欠的回復運動の場合

    稲沢 見矢子, 西保 岳, 近藤 徳彦, 池上 晴夫, 勝田 茂

    Sep. 1988, 体育学研究, 33, 145-153

    [Refereed]

    Scientific journal

  • 汗の拍出頻度よりみた安静時と運動時の発汗調節の比較-非定常状態の場合について-

    近藤 徳彦, 西保 岳, 鍋倉 賢治, 池上 晴夫

    Dec. 1987, 日本生気象学会雑誌, 24, 135-144

    [Refereed]

    Scientific journal

  • 筋ポンプが血液循環動態に及ぼす影響 (第3報)‐LBNP下の運動時に見られるtransientsな循環動態の変化

    西保 岳, 近藤 徳彦, 稲沢 見矢子, 池上 晴夫

    Aug. 1987, 体力科学, 36, 186-194

    [Refereed]

    Scientific journal

  • 環境温が持久性運動時の体温調節に及ぼす影響-個人差に着目して-

    近藤 徳彦, 池上 晴夫

    Oct. 1986, 体力科学, 35, 229-240

    [Refereed]

    Scientific journal

  • Tatsuro Amano, Naoto Fujii, Glen P Kenny, Yumi Okamoto, Yoshimitsu Inoue, Narihiko Kondo

    NEW & NOTEWORTHY: What is the central question of this study? Does inhibition of K+ channels modulate the exercise-training-induced augmentation in cholinergic and thermal sweating? What is the main finding and its importance? Iontophoretic administration of tetraethylammonium, a K+ channel blocker, blunted sweating induced by a low dose (0.001%) of cholinergic agent pilocarpine, but not heat-induced sweating. However, no differences in the cholinergic sweating were observed between young endurance trained and untrained men. Thus, while K+ channels play a role in the regulation of eccrine sweating, they do not contribute to the increase in sweating commonly observed in endurance trained adults. Our findings provide important new insights into the mechanisms underlying the regulation of sweating by endurance conditioning. ABSTRACT: We evaluated the hypothesis that the activation of K+ channels mediate the exercise-training-induced augmentation in cholinergic and thermal sweating. On separate days, 11 endurance trained and 10 untrained men participated in two experimental protocols. Prior to each protocol, we administered 2% tetraethylammonium (TEA, K+ channels blocker) and saline (Control) at forearm skin sites on both arms via transdermal iontophoresis. In protocol 1, a low (0.001%) and high (1%) doses of pilocarpine was administered at the TEA-treated and Control sites over a 60-min period. In protocol 2, participants were passively heated by immersing their lower limbs in hot water (43°C) until core (rectal) temperature (Tco ) increased by 0.8°C above resting levels. Administration of TEA attenuated cholinergic sweating (P = 0.001) during the initial 20-min after the treatment of low dose of pilocarpine only whilst the response was similar between the groups (P = 0.163). Cholinergic and thermal sweating were higher in trained relative to the untrained men (all P≤0.033). Thermal sweating reached ∼90% of the response at a Tco elevation of 0.8°C during initial 20-min of passive heating, which corresponds to the period wherein TEA attenuated cholinergic sweating in protocol 1. However, sweating did not differ between the Control and TEA sites in either group (P = 0.704). We showed that activation of K+ channels does not appear to mediate the elevated sweating response induced by a low dose of pilocarpine in trained men. We also demonstrated that K+ channels do not contribute to sweating during heat stress in either group. This article is protected by copyright. All rights reserved.

    27 Mar. 2022, Experimental physiology, English, International magazine

    Scientific journal

MISC

  • A study of the relation between Japanese elderly people's satisfaction with their current life and their level of social participation: Based on the role of social networks

    Ai Fukuzawa, Keiko Katagiri, Kouhei Masumoto, Narihiko Kondo, Makoto Chogahara, Shuichi Okada

    ROUTLEDGE JOURNALS, TAYLOR & FRANCIS LTD, Jul. 2016, INTERNATIONAL JOURNAL OF PSYCHOLOGY, 51, 51 - 51, English

    Summary international conference

  • Interventions increase community interactions among elderly adults: Evidence from an urban area in Japan

    Keiko Katagiri, Kouhei Masumoto, Shuichi Okada, Narihiko Kondo, Makoto Chogahara, Ai Fukuzawa

    ROUTLEDGE JOURNALS, TAYLOR & FRANCIS LTD, Jul. 2016, INTERNATIONAL JOURNAL OF PSYCHOLOGY, 51, 45 - 46, English

    Summary international conference

  • 音楽を用いたグループ・エクササイズがシニア世代のコミュニケーション・ネットワークに及ぼす効果

    OKADA SHUICHI, MASUMOTO KOUHEI, 原田 和宏, KONDO NARIHIKO, CHOGAHARA MAKOTO, KATAGIRI KEIKO, HIRAKAWA KAZUFUMI

    Jun. 2016, 大阪ガスグループ福祉財団研究報告書, 29, 33 - 38, Japanese

    Report research institution

  • 1-B-03 Effect of pre-exercise core temperature on circadian variation in hyperthermic hyperventilation during exercise(The Proceedings of the 19th Annual Meetings of Japan Society of Exercise and Sports Physiology August 25・26, (Tokushima)) :

    TSUJI Bun, FUJII Naoto, KONDO Narihiko, NISHIYASU Takeshi

    Japan Society of Exercise and Sports Physiology, 2011, Advances in exercise and sports physiology, 17 (2), 56 - 56, English

  • 運動に関わる要因と熱放散システム

    近藤徳彦

    NAP, 2010, 体温II-体温調節システムとその適応, 72 - 97

  • 運動とエネルギー消費

    KONDO NARIHIKO, 大上安奈

    2009, 健康食品管理士会報, 4 (3), 1 - 8, Japanese

    [Refereed]

    Others

  • Blood Flow Responses In Conduit Vessels Of The Inactive Limb During Passive Heating And Exercise

    Anna Ooue, Tomoko K. Ichinose, Yoshimitsu Inoue, Takeshi Nishiyasu, Shunsaku Koga, Narihiko Kondo

    LIPPINCOTT WILLIAMS & WILKINS, May 2008, MEDICINE AND SCIENCE IN SPORTS AND EXERCISE, 40 (5), S335 - S335, English

    Summary international conference

  • 運動時の発汗と体温調節

    Kondo Narihiko

    Mar. 2007, MB Derma, 124: 20-20, Japanese

    Introduction scientific journal

  • S-601 Change in Heat Loss Responses after Three Month Endurance Training in Young Women

    Kuwahara Tomoko, Inoue Yoshimitsu, Ooue Anna, Ogura Yukio, Kondo Narihiko

    Japanese Society of Human-Environment System, 12 Sep. 2005, Proceedings of the ... Symposium on Human-Environment System, 5, 36 - 36, English

  • Development and its evaluation of independent supporting care Services at Care Facilities for the Elderly

    JOH, Hitoshi, AOKI, Tsutomu, NINOMIYA, Atsumi, OKADA, Yuka, KONDO, Narihiko, SUGIMAN, Toshio, ODA, Toshikatu, OBANAWA, Naoko

    Mar. 2004, 科学研究費補助金(基盤研究 B1)研究成果報告書, , 全251p(1p-7p,137p-164p,213p-2, Japanese

    Others

  • 呼吸パタ-ンが漸増負荷運動時の吸気ガスパラメ-タ-に及ぼす影響について-1-

    中留 学, 近藤 徳彦, 岩田 敦

    神戸大学教育学部, Mar. 1993, 神戸大学教育学部研究集録, (90), p43 - 47, Japanese

Books etc

  • 健康運動指導士養成講習会テキスト上巻 環境と運動(1)(2)

    KONDO NARIHIKO, INOUE YOSHIMITSU

    Others, 南江堂, Mar. 2019, Japanese

    Textbook

  • アクティブ・エイジング・プロジェクト縦断調査報告書〜大学による介入プログラムの効果〜

    HONOKI KAORU, OKADA SYUICHI, KONDO NARIHIKO, CHOGAHARA MAKOTO, KATAGIRI KEIKO, MASUMOTO KOUHEI, TAKENAKA YUKO, FUKUZAWA AI

    Joint work, 神戸大学大学院人間発達環境学研究科, Jun. 2015, Japanese

    Report

  • キーワード 人間と発達[増補改訂版] III. 行動と健康

    秋元 忍, 石川 哲也, 伊東 惠子, 稲場 圭信, 岡田 由香, 小田 利勝, 川畑 徹朗, 河辺 章子, 近藤 徳彦, 齋藤 健司, 高田 義弘, 高見 和至, 武井 義明, 田中 洋一, 長ヶ原 誠, 中村 晴信, 平川 和文, 藤田 大輔, 前田 正登, 柳田 泰義, 山口 泰雄, 吉田 圭吾

    Joint work, 大学教育出版, Apr. 2007, Japanese

    Scholarly book

  • 体温調節

    Kondo Narihiko

    最新スポーツ科学事典, Sep. 2006, Japanese

    Others

  • 高齢者の発達を支援する環境づくり,城 仁士編集,生理学的適応からみた高齢者の温度環境

    KONDO, N

    Joint work, ナカニシヤ, Jun. 2005

    Scholarly book

  • キーワード 人間と発達 III. 行動と健康

    秋元 忍, 石川 哲也, 伊東 惠子, 稲場 圭信, 岡田 由香, 小田 利勝, 川畑 徹朗, 河辺 章子, 近藤 徳彦, SAITO KENJI, 高田 義弘, 武井 義明, 田中 洋一, 長ヶ原 誠, 平川 和文, FUJITA DAISUKE, 前田 正登, 柳田 泰義, 山口 泰雄, 吉田 圭吾

    Joint work, 大学教育出版, Apr. 2005, Japanese

    Scholarly book

  • 健康スポーツ科学,浅野勝己,田中喜代次編集,体温調節と運動・スポーツ

    KONDO, N, INOUE, Y

    Joint work, 文光堂, Jan. 2004

    Scholarly book

  • Measuring PO3 kinetics: the practicalities. In Kinetics in Sport,Exercise and Medicine,Jones AM and Pool DC ed

    KOGA, S, SHIOJIRI, T, KONDO, N

    Joint work, Cooper Publishing Group LLC, 2004

    Scholarly book

  • Exercise,Nutrition and Environmental Stress Volume 2,Nose H,Gisolfi CV and Imaizumi K,ed.,Pulmonary and muscle oxygen uptake kinetics at the onset of exercise,

    KOGA, S, BARSTOW, TJ, SHIOJIRI, T, FUKUBA, Y, KONDO, N, FUKUOKA, Y, SHIBASAKI, M A

    Joint work, Cooper Publishing Group LLC, 2003

    Scholarly book

  • 体温-運動時の体温調節システムとそれを修飾する要因

    平田 耕一, 井上 芳光, 近藤 徳彦

    Joint work, ナップ, Sep. 2002

    Scholarly book

  • 使えるスポーツサイエンス, 征矢英昭,本山 貢,石井好二郎編集,分担:スポーツと体温

    芝崎 学, 近藤 徳彦

    Joint work, 講談社, May 2002

    Scholarly book

  • 新運動生理学 (上下巻),宮村実晴編集,分担:運動と体温

    近藤 徳彦

    Single work, 真興交易医書, 2001

    Scholarly book

  • 身体機能の調節性,池上 晴夫編集,分担:運動と発汗調節

    近藤 徳彦, 山崎 文夫

    Joint work, 朝倉書店, Mar. 1997

    Scholarly book

  • 人間科学計測ハンドブック,分担:発汗(ヒトの代謝,呼吸,循環,体温調節機能)

    近藤 徳彦, 井上 芳光, 芝崎 学

    Joint work, 技報道, Oct. 1996

    Scholarly book

  • Pulmonary oxygen uptake kinetics in nonsteady state

    KOGA, S, SHIOJIRI, T, FUKUBA, Y, FUKUOKA, Y, KONDO, N

    Joint work, Journal of Physiological Anthropology and Applied Human Science, Jan. 1996

    Scholarly book

Presentations

  • 就業とワーク・エンゲイジメントが中高齢夫婦の精神的健康に及ぼす影響

    HARADA KAZUHIRO, MASUMOTO Kouhei, KONDO NARIHIKO

    第61回日本老年社会科学会大会, Jun. 2019, Japanese, Domestic conference

    Poster presentation

  • 中高齢者における家事・仕事時間と運動・身体活動量との関連:横断分析および縦断分析

    HARADA KAZUHIRO, MASUMOTO Kouhei, KONDO NARIHIKO

    第73回日本体力医学会大会, Sep. 2018, Japanese, Domestic conference

    Oral presentation

  • 運動・身体活動の実践が高齢夫婦の精神的健康と夫婦関係に及ぼす影響

    HARADA KAZUHIRO, MASUMOTO Kouhei, KONDO NARIHIKO

    日本心理学会第82回大会, Sep. 2018, Japanese, Domestic conference

    Poster presentation

  • アンケートデータを用いた交流ネットワーク推定手法

    佐藤 智久, YAGUCHI TAKAHARU, MASUMOTO Kouhei, KONDO NARIHIKO, OKADA SHUICHI

    日本応用数理学会2018年度年会, Sep. 2018, Japanese, 愛知, Domestic conference

    Oral presentation

  • 進化の過程で獲得した汗の役割

    KONDO NARIHIKO

    第26日本発汗学会総会, Jul. 2018, Japanese, Domestic conference

    Public discourse

  • 運動時における発汗調節研究のこれまでとこれから

    KONDO NARIHIKO

    第26回日本発汗学会総会, Jul. 2018, Japanese, Domestic conference

    Invited oral presentation

  • 中高齢夫婦における身体活動・座位行動の相互関連性

    HARADA KAZUHIRO, MASUMOTO Kouhei, KONDO NARIHIKO

    第60回日本老年社会科学会大会, Jun. 2018, Japanese, Domestic conference

    Oral presentation

  • 外出が高齢者の健康関連Quality of Lifeに及ぼす影響

    原田 和宏, MASUMOTO KOUHEI, KATAGIRI KEIKO, 福沢 愛, CHOGAHARA MAKOTO, KONDO NARIHIKO, OKADA SHUICHI

    第18回日本健康支援学会年次学術大会, Mar. 2017, Japanese, 東京工業大学, Domestic conference

    Oral presentation

  • QOLの規定因に関する世代間比較:物質的豊かさの不足を補う要因に関する検討

    福沢 愛, KATAGIRI KEIKO, MASUMOTO KOUHEI, CHOGAHARA MAKOTO, KONDO NARIHIKO, OKADA SHUICHI

    社会心理学会第57回大会, Sep. 2016, Japanese, 関西学院大学, Domestic conference

    Poster presentation

  • Interventions increase community interactions among elderly adults: Evidence from an urban area in Japan.

    KATAGIRI KEIKO, MASUMOTO KOUHEI, OKADA SHUICHI, KONDO NARIHIKO, CHOGAHARA MAKOTO, FUKUZAWA AI

    31st International Conference of Psychology (ICP2016), Jul. 2016, English, Yokohama, International conference

    Poster presentation

  • A study of the relation between Japanese elderly people's satisfaction with their current life and their level of social participation: Based on the role of social networks.

    FUKUZAWA AI, KATAGIRI KEIKO, MASUMOTO KOUHEI, KONDO NARIHIKO, CHOGAHARA MAKOTO, OKADA SHUICHI

    31st International Conference of Psychology (ICP2016), Jul. 2016, English, Yokohama, International conference

    Poster presentation

  • 地域コミュニティ構造の変化と改善に対する統計解析手法

    KAWASAKI SONOMI, YAGUCHI TAKAHARU, MASUMOTO KOUHEI, KONDO NARIHIKO, OKADA SHUICHI

    日本応用数理学会第12回研究部会連合発表会, Mar. 2016, Japanese, 神戸学院大学, Domestic conference

    Oral presentation

  • 地域コミュニティの構造変化に対する検定理論

    KAWASAKI Sonomi, YAGUCHI Takaharu, MASUMOTO Kouhei, KONDO Narihiko, OKADA Shuichi

    応用数学合同研究集会, Dec. 2015, Japanese, 龍谷大学, Domestic conference

    Oral presentation

  • 地域高齢者を対象とした健康教室による参加者間交流ネットワーク形成に関する研究

    MASUMOTO KOUHEI, KONDO NARIHIKO, MATHUDA HIROSHI, TANI HIDEAKI, YAGUCHI TAKAHARU, TAKENAKA YUKO, TOZUKA KEISUKE, OKADA SHUICHI

    日本老年社会科学会第57回大会, Jun. 2015, Japanese, Domestic conference

    Poster presentation

  • 地域住民における世代間交流志向の関連要因

    KATAGIRI KEIKO, 竹中 優子, OKADA SHUICHI, KONDO NARIHIKO, CHOGAHARA MAKOTO, MASUMOTO KOUHEI, HOUNOKI KAORU

    日本社会心理学会, Nov. 2014, Japanese, 北海道大学, Domestic conference

    Oral presentation

  • 高齢期の生産的活動と主観的健康

    KATAGIRI KEIKO, 竹中 優子, OKADA SHUICHI, KONDO NARIHIKO, CHOGAHARA MAKOTO, MASUMOTO KOUHEI, HOUNOKI KAORU

    老年社会科学会第56回大会, Jun. 2014, Japanese, Domestic conference

    Poster presentation

  • THE INFLUENCE OF MUSIC ON ACTIVE AGING IN JAPANESE COMMUNITY RESIDENTS: THE FOCUS ON LISTENING MUSIC AND MUSICAL ATTITUDE

    TAKENAKA YUKO, HOUNOKI KAORU, OKADA SHUICHI, CHOGAHARA MAKOTO, KONDO NARIHIKO, MASUMOTO KOUHEI

    The 20th IAGG World Congress of Gerontology and Geriatrics, Jun. 2013, English, International conference

    Poster presentation

  • 長時間間欠運動時におけるヒトの体温調節反応

    近藤 徳彦

    第61回日本体力医学会大会, Sep. 2007, Japanese, 神戸市, Domestic conference

    Poster presentation

  • 近赤外分光法による活動筋酸素摂取動態測定に対する高強度運動の影響

    齊藤 直, 大上 安奈, 近藤 徳彦, 古賀 俊策

    生体医工学シンポジウム2007, Sep. 2007, Japanese, 北海道大学, Domestic conference

    Poster presentation

  • The effect of non-thermal factors on heat loss responses during exercise in humans

    Kondo N, Inoue Y, Koga S, Nishiyasu T

    12th International Conference for Enviromental Ergonomics, Aug. 2007, English, Slovenia, International conference

    Invited oral presentation

  • 運動時からみた人の熱放散特性

    近藤 徳彦

    人間-生活環境系学会『屋外熱環境デザイン研究委員会第2回研究交流会』, Mar. 2007, Japanese, 神戸大学, Domestic conference

    [Invited]

    Invited oral presentation

  • 運動に関わる要因がヒトの熱放散反応に及ぼす影響

    近藤 徳彦

    体温調節、温度受容研究会, Jan. 2007, Japanese, 自然科学研究機構, Domestic conference

    Oral presentation

  • Heat loss responses during exercise and sports performance (keynote lecture

    KONDO, N

    1st Asian Pacific Sports Science Conference 2005, The University of Malaysia Sabah, Sep. 2005, Malaysia,, International conference

    Invited oral presentation

  • The effects of non-thermal factors on heat loss responses during exercise (keynote lecture)

    KONDO, N

    3rd International Conference on the Human-Environment System, Jul. 2005, 東京, 日本, International conference

    Invited oral presentation

  • 運動時の循環・体温調節特性とスポーツウエア

    KONDO, N

    第13回運動生理学会, Jun. 2005, 東京, 日本, Domestic conference

    Invited oral presentation

  • The effects of non-thermal factors on heat loss responses during exercise

    KONDO, N

    Department of Kinesiology, University of West Ontario, Mar. 2005, Canada,, International conference

    Invited oral presentation

  • 体温と運動の機能的連関 (教育講座:近藤徳彦, 彼末一之)

    KONDO, N, KANOSUE, K

    第59回日本体力医学会, Sep. 2004, 埼玉, 日本, Domestic conference

    Invited oral presentation

  • The Effects of Ambient Humidity on Thermoregulatory Responses during Exercise in Man Clothed a T-shirt

    INOUE, Mari, KONDO, Norihiko

    日本家政学会 第56回大会, Aug. 2004, Japanese, 日本家政学会, 京都, 日本, Domestic conference

    Poster presentation

  • The Effects of Ambient Humidity on Microclimate within Clothing during Exercise in Man Clothed a T-shirt

    INOUE, Mari, AKM, Shamsuddi, YAMAGIMOTO, Shuji, KUWAHARA, Tomoko, YAMADA, Yukako, KONDO, Norihiko

    日本繊維製品消費科学会2004年年次大会, Jun. 2004, Japanese, 日本繊維製品消費科学会, 大阪, 日本, Domestic conference

    Oral presentation

  • Heat loss responses at the onset of dynamic exercise in endurance-trained men under mildly heated conditions

    KONDO, N, YANAGIMOTO, S, KUWAHARA, T, ZHANG, Y, KOGA, S A

    American College of Sports Medicine 51th Annual Meeting, 2004, ,, International conference

    Poster presentation

  • Effects of ambient temperature on sweat conductivity during exercise in humans

    SHAMSUDDIN, AKM, KUWAHARA, T, ZHANG, Y, OUE, A, NOMURA, C, KONDO, N

    American College of Sports Medicine 51th Annual Meeting, 2004, ,, International conference

    Poster presentation

  • The heat loss responses during exercise and its control

    KONDO, N

    第17回運動と体温の会研究会, Jul. 2003, 名古屋,, Domestic conference

    Invited oral presentation

  • 深部体温と皮膚温が筋交感神経活動に及ぼす影響

    HAYASHI, K, SAITO, M, OGAWA, T, ICHINOSE, M, KONDO, N, NISHIYASU, T

    第58回日本体力医学会, 2003, 静岡,, Domestic conference

    Poster presentation

  • 起立性ストレス下での筋交感神経活動と心拍調節の関係

    ICHINOSE, M, SAITO, M, HAYASI, K, WADA, H, KONDO, N, NISHIYASU, T

    第58回日本体力医学会, 2003, 静岡,, Domestic conference

    Poster presentation

  • 運動時の発汗反応に貢献するセントラルコマンドと代謝性の筋からの求心性入力

    SHIBASAKI, M, KONDO, N

    第58回日本体力医学会, 2003, 静岡,, Domestic conference

    Poster presentation

  • 運動トレーニングが若年女性の運動強度と汗腺活動の関係に及ぼす影響

    KUWAHARA, T, UCHIYAMA, T, KONDO, N, INOUE, Y

    第58回日本体力医学会, 2003, 静岡,, Domestic conference

    Poster presentation

  • 異なる2種類の陽圧呼吸法が循環系に及ぼす影響

    WADA, H, SAITO, M, ICHINOSE, M, KONDO, N, NISHIYASU, T

    第58回日本体力医学会, 2003, 静岡,, Domestic conference

    Poster presentation

  • Changes in sweat rate and sweat conductivity during passive heating in humans

    SHAMSUDDIN, AKM, YANAGIMOTO, S, KUWAHARA, T, ZHANG, Y, NOMURA, C, KONDO, N

    American College of Sports Medicine 50th Annual Meeting, 2003, ,, International conference

    Poster presentation

  • Changes in skin sympathetic nerve activity and heat loss responses to passive heating in humans

    KONDO, N, NISHIYASU, T

    American College of Sports Medicine 50th Annual Meeting, 2003, ,, International conference

    Oral presentation

  • 運動と体温 (司会と演者) 運動時の熱放散反応とその調節

    近藤 徳彦

    第11回日本運動生理学会, Mar. 2002, ,, Domestic conference

    Invited oral presentation

  • 性周期および運動トレーニングが常温環境下での運動時の熱放散反応に及ぼす影響

    桑原 智子, 野村 知加, 柳本 周治, 小倉 幸雄, 近藤 徳彦, 井上 芳光

    第57回日本体力医学会, 2002, ,, Domestic conference

    Poster presentation

  • 暑熱環境下の運動における活動部位冷却に関する研究

    林 恵嗣, 近藤 徳彦, 小川 剛司, 西保 岳

    第57回日本体力医学会, 2002, ,, Domestic conference

    Poster presentation

  • 持久性運動トレーニング者と非トレーニング者の高温環境下における動的運動開始時の熱放散反応特性

    柳本 周治, 桑原 智子, 張 遠, 井上 芳光, 近藤 徳彦

    第57回日本体力医学会, 2002, ,, Domestic conference

    Poster presentation

  • 高温環境下における動的運動開始時の熱放散反応と運動強度との関係

    柳本 周治, 近藤 徳彦

    第10回日本運動生理学会, 2002, ,, Domestic conference

    Oral presentation

  • 筋代謝受容器反射が動脈圧受容器反射による筋交感神経活動調節に及ぼす影響

    一之瀬 真志, 斉藤 満, 北野 旭美, 和田 浩幸, 近藤 徳彦, 西保 岳

    第10回日本運動生理学会, 2002, Domestic conference

    Oral presentation

  • 寒冷環境下における体温調節反応の性周期・性差

    野村 知加, 桑原 智子, 小倉 幸雄, 近藤 徳彦, 井上 芳光

    第57回日本体力医学会, 2002, ,, Domestic conference

    Poster presentation

  • 温熱負荷時におけるヒトの皮膚交感神経活動と熱放散反応との対応関係

    近藤 徳彦, 西保 岳, Shamsuddin AKM, 斉藤 満

    第57回日本体力医学会, 2002, ,, Domestic conference

    Poster presentation

  • Effects of muscle metaboreceptor stimulation on skin blood flow in glabrous and non-glabrous skin during mild heating in humans

    KONDO, N, YANAGIMOTO, S, INOUE, M, SHIBASAKI, M, KOGA, S, NISHIYASU, T

    American College of Sports Medicine 49th Annual Meeting, 2002, International conference

    Poster presentation

  • Differences of sweating pattern by simultaneously measuring sweat rate and single-sweat-gland activity during exercise in humans

    Shamsuddin AKM, 柳本 周治, 桑原 智子, 近藤 徳彦

    第57回日本体力医学会, 2002, Domestic conference

    Poster presentation

  • 近赤外分光画像法による指静脈の可視化と末梢循環動態の計測

    斉藤 太計雄, 近藤 徳彦, 西保 岳

    56回日本体力医学会, 2001, ,, Domestic conference

    Poster presentation

  • 筋代謝受容器反射活性時における頸動脈圧受容器反射を介した筋交感神経活動の調節

    一之瀬 真志, 斉藤 満, 北野 旭美, 和田 浩幸, 近藤 徳彦, 西保 岳

    第56回日本体力医学会第, 2001, ,, Domestic conference

    Poster presentation

  • 運動トレーニングが若年女性の熱放散反応に及ぼす影響

    桑原 智子, 井上 芳光, 小倉 幸雄, 近藤 徳彦

    第56回日本体力医学会, 2001, ,, Domestic conference

    Poster presentation

  • The effect of pedaling rate on thermoregulatory responses to dynamic cycle exercise in humans

    KONDO, N, YAMAGUCHI, Y, YANAGIMOTO, S, INOUE, INOUE, Y A

    International Thermal Physiology Symposium, 2001, ,, International conference

    Poster presentation

  • Sweating responses during activation of the muscle metaboreflex in endurance trained human

    YANAGIMOTO, S, INOUE, M, AOKI, K, KONDO, N

    American College of Sports Medicine 48th Annual Meeting, 2001, ,, International conference

    Poster presentation

  • The effect of endurance training on sweating responses to sustained static exercise in humans

    KONDO, N, YANAGIMOTO, S, AOKI, K, SHIBASAKI, M, INOUE, Y A

    American College of Sports Medicine 47th Annual Meeting, Sep. 2000, ,, International conference

    Poster presentation

  • 持久性トレーニングが静的掌握運動時の熱放散反応に及ぼす影響

    柳本 周治, 青木 健, 近藤 徳彦

    第8回日本運動生理学会, 2000, ,, Domestic conference

    Oral presentation

  • The time of day effect on sweating response during activation of muscle metaboreflex

    AOKI, K, KONDO, N, SHIMOMURA, Y, IWANAGA, K, HARADA, H A

    American College of Sports Medicine 47th Annual Meeting, 2000, ,, International conference

    Poster presentation

  • The dependence of activated sweat glands on changing sweating rate during sustained static exercise in humans

    KONDO, N, YANAGIMOTO, S, AOKI, K, SHIBASAKI, M A

    The Integrative Biology of Exercise, American Physiology Society Intersociety Meeting, 2000, ,, International conference

    Poster presentation

  • The control of sweating and skin blood flow responses to exercise in humans

    KONDO, N

    1999 Sports Science Network Forum, Nagano, Oct. 1999, 長野, 日本, International conference

    Invited oral presentation

Research Projects

  • 岡田 修一

    科学研究費補助金/挑戦的研究(開拓), Jun. 2018 - Mar. 2021

    Competitive research funding

  • 近藤 徳彦

    特別研究員奨励費, Apr. 2018 - Mar. 2020, Principal investigator

    Competitive research funding

  • 近藤 徳彦

    科学研究費補助金/基盤研究(B), Apr. 2017 - Mar. 2021, Principal investigator

    Competitive research funding

  • 近藤 徳彦

    特別研究員奨励費, Apr. 2016 - Mar. 2019, Principal investigator

    Competitive research funding

  • 増本 康平

    科学研究費補助金/基盤研究(B), Apr. 2015 - Mar. 2018

    Competitive research funding

  • 近藤 徳彦

    学術研究助成基金助成金/挑戦的萌芽研究, Apr. 2015 - Mar. 2017, Principal investigator

    Competitive research funding

  • 片桐 恵子

    学術研究助成基金助成金/挑戦的萌芽研究, Apr. 2014 - Mar. 2017

    Competitive research funding

  • 近藤 徳彦

    学術研究助成基金助成金/挑戦的萌芽研究, Apr. 2013 - Mar. 2015, Principal investigator

    Competitive research funding

  • 朴木 佳緒留

    科学研究費補助金/基盤研究(A), Oct. 2012 - Mar. 2015

    Competitive research funding

  • 近藤 徳彦

    学術研究助成基金助成金/挑戦的萌芽研究, 2011, Principal investigator

    Competitive research funding

  • 近藤 徳彦

    科学研究費補助金/基盤研究(B), 2011, Principal investigator

    Competitive research funding

  • 城 仁士

    科学研究費補助金/基盤研究(B), 2008

    Competitive research funding

  • 近藤 徳彦

    科学研究費補助金/萌芽研究, 2007, Principal investigator

    Competitive research funding

  • 近藤 徳彦

    科学研究費補助金/基盤研究(B), 2007, Principal investigator

    Competitive research funding

  • 城 仁士

    科学研究費補助金/基盤研究(B), 2005

    Competitive research funding

  • 近藤 徳彦

    科学研究費補助金/基盤研究(B), 2005, Principal investigator

    Competitive research funding

  • Does neuropeptide in synpathetic chilinergic nerve modulate development and aging of human eccrine sweat glands?

    井上 芳光, 天野 達郎, 近藤 徳彦, 奥島 大

    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B), Grant-in-Aid for Scientific Research (B), Osaka International University, 01 Apr. 2021 - 31 Mar. 2025

  • 熱中症予防と皮膚の健康に欠かせないフレッシュな汗の量と成分の測定法開発

    近藤 徳彦, 笠間 敏博, 井上 芳光, 藤井 直人, 天野 達郎

    日本学術振興会, 科学研究費助成事業 挑戦的研究(萌芽), 挑戦的研究(萌芽), 神戸大学, 09 Jul. 2021 - 31 Mar. 2023

  • ヒト熱放散反応におけるTRPチャネルの役割解明 -熱中症予防法確立を目指して-

    藤井 直人, 天野 達郎, 近藤 徳彦, 西保 岳

    日本学術振興会, 科学研究費助成事業 基盤研究(B), 基盤研究(B), 筑波大学, 01 Apr. 2020 - 31 Mar. 2023

    TRPA1チャネルの活性化は、in vivoでヒトの皮膚の血管拡張を引き起こす。しかし、この反応のメカニズムについては不明な点が多い。本年度は、TRPA1チャネルによる皮膚血管拡張に、一酸化窒素(NO)合成酵素(NOS)とCa2+依存性K+(KCa)チャネルが寄与し、シクロオキシゲナーゼ(COX)は関与しないという仮説のもと実験を行った。健康な若年成人9名を対象に、前腕部の皮膚血管コンダクタンス(CVC)を評価した。CVCは、皮内マイクロダイアリシスを施した以下の4部位で評価した:1)コントロール(98%プロピレングリコール+1.985%ジメチルスルホキシド+0.015%リンゲル液)、2)10mM L-NAME(非選択的NOS阻害剤)、3)10mM ketorolac(非選択的COX阻害剤)、4)50mM tetraethylammonium(非選択的KCaチャネル遮断剤)。TRPA1チャネル活性化薬であるシンナムアルデヒドは、用量依存的に各皮膚部位に投与した(2.9、8.8、26、80%、それぞれ30分以上投与)。8.8%以上のシンナムアルデヒドを投与すると、コントロール部位のCVCがベースラインから27.4%[5.3]増加した(P<0.05)。NOS阻害剤は、26%および80%のシンナムアルデヒド濃度で、CVCの増加を抑制した(いずれもP<0.05)。COX阻害剤およびKCaチャネル遮断剤は、いずれの濃度においても、シンナムアルデヒドによるCVCの上昇を抑制しなかった(いずれもP>0.05)。以上のことから,ヒト皮膚において,TRPA1チャネルの活性に伴う皮膚血管拡張には,COXおよびKCaチャネルは関与しないが,NOSが大きな役割を果たしていると考えられる。

  • 健康増進に資する社会的ネットワーク可視化手法の開発と地域介入の効果検証

    岡田 修一, 谷口 隆晴, 増本 康平, 原田 和弘, 近藤 徳彦

    日本学術振興会, 科学研究費助成事業 挑戦的研究(開拓), 挑戦的研究(開拓), 神戸大学, 01 Apr. 2020 - 31 Mar. 2022

    社会的ネットワーク(人と人とのつながり)が、心身の健康増進に重要な役割を果たすことが報告されているが、日常生活での社会的ネットワークを定量的に測定する方法はいまだ開発されていない。そこで本研究では、以下の3点を達成することを目的としている。 目的1)ウェアラブルセンサを用いた社会的ネットワークの自動的・定量的計測と可視化システムの構築。 目的2)都市部高齢化地域を対象とした社会実験によるデータの信頼性の検証と健康指標との関連の検討。 目的3)2のデータをベースラインとし,社会的ネットワークの形成・促進を目的とした地域介入の客観的な効果検証の実施。 すなわち、上記の目的を達成するために、第一に社会的ネットワーク定量的計測システムの開発を行い、第二に大学生の小集団を対象とした予備的実験を行う。第3に都市部高齢化地域を対象とした社会実験による社会的ネットワークデータの測定および健康指標との関連性の検討を行うとともに、地域介入の客観的な効果検証を実施する。

  • 化学的・物理的促進法を用いた経皮的薬剤投与に基づく新たな発汗研究手法の開発

    井上 芳光, 天野 達郎, 近藤 徳彦

    日本学術振興会, 科学研究費助成事業 挑戦的研究(萌芽), 挑戦的研究(萌芽), 大阪国際大学, 28 Jun. 2019 - 31 Mar. 2022

    本研究は将来的に子どもや高齢者のための新たな発汗機能検査法を確立することを見据え,痛みを伴わずに大きな分子でも汗腺に届けたり,角質層が厚い部位でも薬剤を投与できる新しい研究手法を開発することを目的としている. これまでの研究で電圧80V,1Hz,パルス幅0.1msのエレクトロポレーション装置であれば前腕部で痛みを感じないことを明らかにしているが,この刺激では十分な効果(皮膚バリア機能の低下)がなかった.そのため,まずは従来の装置を改良したハイパワーのエレクトロポレーションを制作した(試作3号機).また,理論上は電極間の距離が狭い程痛みが感じなくなることから,先行研究を参考に,電極間距離や配列を変えて電極を作成して痛みの有無について検討を行った. 申請者自身でパルス幅や電圧を調節しながら検討を進めたが,200Vの電圧をパルス幅1.0ms,周波数1Hzで5分間手掌部に当てても手掌部の角質層のバリア機能(不感蒸泄から測定)は低下しなかった.また200Vは前腕部では我慢できないほど痛く使えなかった.装置の電圧を~500Vまで上げることで手掌部への処置も可能になるかもしれないが,安全性の観点から実用性が低いという結論に達した. このことから皮膚のバリア機能を低下させる別の方策を検討した.マイクロニードルパッチはインフルエンザなどのワクチン接種法として過去に人を対象とした実績があったため,この方法を応用することを試みた.まずマイクロニードルパッチを手掌部に処置した後,染色して手掌部の穿刺孔を確認した.また不感蒸泄量を測定して,ニードル処置で一時的にバリア機能が大きく低下することを確認した.これらのことから,エレクトロポレーションに代わり,マイクロニードルパッチ使って皮膚に穿孔を形成できる可能性が見出された.次年度はいくつかの課題を解決した上でこの新しい方法の確立を進める予定である.

  • Mechsanisms of oxygen deficit of exercsing muscles

    古賀 俊策, 近藤 徳彦, 奥島 大

    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), Grant-in-Aid for Scientific Research (C), Kobe Design University, 01 Apr. 2019 - 31 Mar. 2022

    本研究では、活動筋の局所レベルにおける酸素消費量(VO2)応答の不均一性に着目して、活動筋の酸素不足発生に及ぼす影響を明らかにする。活動筋のVO2を規定する要因として、①筋肉細胞の酸素利用と②微小循環における酸素の需要と供給のミスマッチ・空間不均一性 (部位差)が示唆されている。 立位・座位姿勢に比べて仰臥位姿勢では、重力負荷の減少によって下肢の循環潅流圧と血流量(酸素供給量、Q)が低下するので、運動耐容能が減少する。しかし、活動筋の局所的な酸素需給ミスマッチが活動筋全体の酸素不足にどの程度の影響を与えるのか不明である。今年度は、仰臥位・自転車運動における活動筋の局所的なQの減少と酸素需給ミスマッチが、活動筋の酸素不足に及ぼす影響を明らかにした。
    結果:座位運動に比べて、仰臥位運動では活動筋の表層筋に加えて深層筋においても局所的な酸素需給ミスマッチが生じた。したがって、活動筋レベルでは拡散による酸素運搬がある程度増加したが、潅流による酸素運搬が減少したために活動筋全体のVO2応答が遅れたと推測される。さらに、仰臥位における事前運動は、主運動(第2運動)における活動筋全体のVO2応答を速くした。とくに、主運動における活動筋の酸素抜取りの程度(脱酸素化ヘモグロビン)は座位運動よりも大きくなった。仰臥位において事前運動よりも主運動のVO2応答が速くなった理由として、活動筋の酸素運搬量の増加とともに筋肉細胞内の酸素利用の促進が示唆された。今回の結果は、事前運動に続く主運動VO2応答の迅速化が、活動筋への酸素運搬量の増加のみに依存しないことを示唆する。したがって、活動筋局所におけるVO2応答の調節は、微小循環レベルの酸素運搬、および筋肉細胞内の酸素利用、両方の相互作用に関連すると考えられる。

  • 高温高湿環境下での暑熱順化と脱順化が汗腺機能と皮膚血管拡張に及ぼす影響

    近藤 徳彦, LEI TZE-HUAN

    日本学術振興会, 科学研究費助成事業 特別研究員奨励費, 特別研究員奨励費, 神戸大学, 24 Apr. 2020 - 31 Mar. 2021

    運動トレーニング者を対象(男子学生,10名程度)に,14日間の暑熱順化(最大酸素摂取量の50%~55%負荷の自転車運動を60分間,34°C・40%RHと34°C・80%RHの環境下で実施)と脱順化を行い,順化の影響をみるために34°C・80%RHの環境下で最大酸素摂取量50%~55%負荷の60分間の自転車運動を行う予定であった.しかし,新型コロナウイルス感染拡大に伴い研究継続が不可能となった.2019年度の研究結果をもとに次の実績が得られた.14日間の暑熱順化でいずれの環境条件でも安静時の体温低下,運動時の発汗量・皮膚血流量の増加がみられた.両条件での違いとして発汗反応より皮膚血流反応に差異がみられる傾向にあった.また,運動時の体温上昇は高湿・環境での暑熱順化の方がいくらか小さくなった.一方,環境条件での違いによる脱順化の差異はみられなかった.これらのことから,高温・高湿環境での暑熱順化は同環境下での運動時の生体負担を軽減する可能性が考えられるが,被験者数が少なく,結論は得られなかった.
    2019年度に追加実験で実施した高温・高湿環境への季節順化と脱順化が発汗とその他の体温調節機能に及ぼす影響に関する研究の分析を進め,次の結果が得られた.夏への季節順化は冬と比較して局所・全身の発汗反応(体温に対する発汗反応)や汗の塩分濃度低下などの改善が認められた.改善程度は夏>秋であった.一方,高温・高湿環境下での汗の蒸発量(有効発汗量)には両季節で差がなく,無効発汗量は夏>秋>冬となり,汗が蒸発する効率は夏<秋<冬となり,夏で最も低下した.しかし,運動時の体温上昇には季節差がなかった.また,風速の影響も検討し,いずれの季節も風速の増加により発汗効率は改善されたが,この改善は運動時の体温には影響しなかった.

  • Amano Tatsuro

    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B), Grant-in-Aid for Scientific Research (B), Niigata University, 01 Apr. 2018 - 31 Mar. 2021

    We have been investigated the underlying mechanisms of adaptative sweat production to habitual exercise training. Our results briefly indicate that noradrenergic sympathetic nerve, alpha adrenergic stimulation, and L-type voltage gated Ca2+ channels could contribute to a high sweat production in habitually trained individuals. We also demonstrated that beta-adrenergic sweating is potentiated by an exposure to heat stress in which the response mediated by the co-activation of muscarinic acetylcholine receptors. Sex difference modulates adrenergic sweating. Collectively, these results developed some of the mechanisms of a high sweat production observed in habitually trained men.

  • 高温高湿環境下での暑熱順化と脱順化が汗腺機能と皮膚血管拡張に及ぼす影響

    近藤 徳彦, LEI TZE-HUAN

    日本学術振興会, 科学研究費助成事業 特別研究員奨励費, 特別研究員奨励費, 神戸大学, 09 Nov. 2018 - 31 Mar. 2020

    高温下における運動時の熱放散システムは体温の過度上昇を避けるばかりか,アスリートや労働者などの身体パフォーマンスにも関係する.運動時の熱放散反応(発汗や皮膚血管拡張反応)は暑熱順化によって改善され,この改善により高温下での持久的運動や労働時のパフォーマンスが向上する.暑熱順化の研究では順化時の環境として湿度に着目した研究は少なく,高温低湿と高温高湿環境での暑熱順化が熱放散反応改善にどのような違いを生じるのか不明である.また,日本の夏は高温高湿環境であり,夏の熱放散反応の適応をみることで,高湿度に暑熱順化が熱放散反応に及ぼす影響を検討することが可能となる.そこで,本研究では暑熱順化時の湿度に着目し,高湿条件が熱放散システムの適応に及ぼす影響を明らかにすることとする.
    運動時の有効・無効発汗量の評価方法の検討から運動中の測定においては間欠的な運動を行い,運動中に安静時を保持することで,これらの発汗量が正確に測定できるようになった.暑熱順化方法として高温高湿(32℃,60-70%RH)で9日間の運動による暑熱順化を実施する予定で準備を進めた.暑熱順化中の運動は最大酸素摂取量40-60%を実施し,体温をある一定のレベルに上昇させ,それを維持する方法を用いることとした.運動時間は1回60-90分である.暑熱順化の効果等を検討するため,暑熱順化前後に運動負荷と下肢温浴を実施した.暑熱順化実験を一人の被験者に実施した.暑熱順化で発汗機能は向上したが,全身でみた無効発汗量が増加し,この増加は有効発汗量の増加を引き起こすほどではなかった.

  • Inoue Yoshimitsu

    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B), Grant-in-Aid for Scientific Research (B), Osaka International University, 01 Apr. 2016 - 31 Mar. 2020

    We found that the elderly people with high endurance performance through long time marathon training compared to the young long-distance runners had similar or superior sweat gland function in exercise- and acetylcholine-induced sweating responses and sweat ion reabsorptive ability. It was suggested that the degree of sweat gland's improvement in the elderly runners was smaller on the lower limbs, at which the age-related decrements in sweat gland function occurs earlier. Similar improvement characteristics of the sweat gland function were observed in both sexes and the degree of improvement was almost equal between the elderly male and female runners. However, the elderly female runners maintained the female sweating characteristic that compensate lower sweat gland output in higher active sweat glands. Our findings in the present study can contribute to development of measures for preventing heat illness in the elderly.

  • 年齢や暑熱順化がイオン再吸収能力から評価した発汗機能に及ぼす影響

    近藤 徳彦, GERRETT NICOLA

    日本学術振興会, 科学研究費助成事業 特別研究員奨励費, 特別研究員奨励費, 神戸大学, 07 Nov. 2016 - 31 Mar. 2019

    年齢と高齢者の暑熱順化が汗イオン濃度調節機構に及ぼす影響を検討するため,昨年度から継続的に以下の研究を実施した. 1.年齢が汗イオン濃度調節機構に及ぼす影響 50~85歳の年齢範囲の男女36名を被験者とした.環境温25℃,相対湿度50%の環境下で安静温熱負荷(43℃の下肢温浴と水循環スーツ)を45~60分間実施した.また,各被験者の身体特性(最大酸素摂取量含む)と局所発汗テストを別の日に実施した.一つの結果として年齢と汗イオンの最大再吸収能の間には関係か認められなかった.分析をさらに進め年齢が汗イオン濃度調節機構に及ぼす影響を明らかにしたい. 2.高齢者の暑熱順化が汗イオン濃度調節機構に及ぼす影響 高齢者の被験者10名(男性8, 女性2, 年齢; 67 ± 1.5 yrs, 身長; 60.8 ± 9.0 kg, 体重; 165.9 ± 7.3 cm, 推定最大酸素摂取量; 32.6 ± 4.5 ml/kg/min)に9日間の暑熱順化実験を実施し,その前後と暑熱順化後1週間の計3回,下肢温浴により汗イオン濃度調節機構やその他の発汗機能(これまでの方法と同じ)を測定した.暑熱順化は環境温35℃,相対湿度45%の環境下で自転車運動により体温を約1℃上昇させ,その後,運動と安静を組み合わせてこの体温を約1時間維持する方法を用いた.暑熱順化により安静時体温低下,血漿量増加,温度感覚低下の変化がみられた.汗イオン再吸収能は胸で有意に増加した. 温熱負荷中の総発汗量が増加し,汗NaCl濃度は有意に低下した.また,発汗開始閾値は大きく変化せず,個人差が大きかった.このことから,9日間の暑熱順化では汗イオンの最大再吸収能は身体の部位によってその改善程度が異なるが.高齢者においてもこの能力の改善が認められた.さらに分析を進め高齢者に対する暑熱順化効果を検討したい.

  • Yukio Ogura

    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), Grant-in-Aid for Scientific Research (C), 01 Apr. 2016 - 31 Mar. 2019

    To examine the effect of dehydration on anaerobic high and middle power output, three experiments were performed: (1) subjects conducted field performance tests with two dehydrated conditions (0.8% and 2.0% of body weight) by fluid intake control during summer athletic practice, (2) In hot condition, subjects performed two tests assessing the anaerobic power output with two dehydrated conditions (0.8 % and 1.9 %), and (3) Sprint and endurance runners performed the same tests as (2) in order to compare different events. (1) Compared to the 0.8% dehydration, the 2.0% dehydration reduced anaerobic middle power performance. Moreover, (2) the decrease of anaerobic high and middle power output in hot condition was greater for the 1.9% dehydration than 0.8% dehydration. However, (3) the effect of dehydration on anaerobic power output was not affected by athletic events. These suggest that the 2.0% dehydration reduces anaerobic high and middle power output.

  • Masumoto Kouhei

    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B), Grant-in-Aid for Scientific Research (B), Kobe University, 10 Jul. 2015 - 31 Mar. 2018

    Many developed countries are faced with the rapid aging of their populations and as a result, they have encountered severe problems. Mutual support and cooperation in neighborhoods and communities are essential for solving these problems. However, effective intervention strategies aimed at increasing older adults’ social networks have not yet been established. The present study examined whether a university-led community intervention that provided communication opportunities could increase older Japanese adults’ neighborhood social networks. The present study found that participants of the intervention expanded their neighborhood social network, but non-participants did not. Additionally, we successfully measured face-to-face interactions by using wearable sensors, and identified conditions and changes in communication networks, and we developed a method of statistical testing to evaluate a program to promote communication among residents.

  • Kondo Narihiko

    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research, Grant-in-Aid for Challenging Exploratory Research, Kobe University, 01 Apr. 2015 - 31 Mar. 2018

    To investigate a relationship between sweating function and EDAR370A gene associated with activated sweat gland in humans, we compared activated sweat gland and sweat function in a subject with EDAR370A with a subject without this gene. We recruited 40 healthy subjects (age range of 20-80 years old). We found only 4 subjects with EDAR370A. Although number of activated sweat glands in the subjects with EDAR370A gene tended to be greater than that in the subjects without this gene, sweat function was not markedly different between the groups. However, we could not conclude the effect of EDAR370A on human sweat function because sample size of subjects without EDAR370A was extremely small.

  • NISHIYASU Takeshi

    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A), Grant-in-Aid for Scientific Research (A), University of Tsukuba, 01 Apr. 2013 - 31 Mar. 2017

    Elevations in body temperature at rest and during exercise lead to increase in ventilation, which can reduce arterial CO2 pressure (PaCO2) and, in turn, cerebral blood flow (CBF) and thermoregulatory response. We investigated 1) whether humans can voluntarily suppress hyperthermic hyperventilation during prolonged exercise and passive heating at rest, and 2) the effects of voluntary breathing control on PaCO2, CBF, sweating and skin blood flow. Our results indicated that during prolonged exercisein the heat and passive heating at rest, humans can voluntarily suppress hyperthermic hyperventilation, and this suppression mitigates changes in PaCO2 and CBF.

  • Koga Shunsaku

    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A), Grant-in-Aid for Scientific Research (A), Kobe Design University, 31 Oct. 2012 - 31 Mar. 2017

    A key capability in hominid survival arose from the development of an erect, striding bipedal locomotion that could be sustained for prolonged periods and be readily responsive to rapid changes of velocity, i.e. the trait of “exercise tolerance”. We found that acquiring the ability to maintain whole-body integration of the physiological system (cardiopulmonary-, muscle metabolic-, and thermal functions) during exercise enabled human beings to evolve endurance work capacity, which is strongly correlated with health. In particular, systematic study on non-steady state responses to exercise (as seen in our daily life) is a key issue, because the non-steady state stimuli elicit the potentials of the body homeostasis and its polymorphism.

  • Kaoru Honoki, OKADA Shuichi, KONDO Narihiko, CHOGAHARA Makoto, KATAGIRI Keiko, KATO Yoshiko, MATSUOKA Koji, INOUE MARI, JYO Hitoshi, HIRAYAMA Yosuke, HIRAKAWA Kasufumi, MASUMOTO Kouhei

    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A), Grant-in-Aid for Scientific Research (A), Kobe University, 31 Oct. 2012 - 31 Mar. 2016

    Many developed countries are faced with the rapid aging of their populations and as a result, they have encountered sever problems. For example, in Japan, which has the most rapidly aging society in the world, the number of households consisting only of elderly couples, and households with elderly people living alone have increased annually. The number of elderly people dying alone , as well as requests to search for missing persons that have disappeared, possible due to dementia-related wandering have increased to approximately 10,000 people annually. Moreover, problems in responding to elderly people facing emergencies have been focused in recent years. Mutual support and cooperation in neighborhoods, and communities are essential for solving these problems and for allowing elderly people to live free from worry. In this study, we developed and conducted programs to enhance the interest in community involvement and promote social networks among community-dwelling people.