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Amano T, Fujii N, Kenny GP, Inoue Y, Kondo N. Do nitric oxide synthase and cyclooxygenase contribute to sweating response during passive heating in endurance-trained athletes? Physiol Rep 2017; 5:5/17/e13403. [PMID: 28899912 PMCID: PMC5599863 DOI: 10.14814/phy2.13403] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2017] [Accepted: 08/08/2017] [Indexed: 11/24/2022] Open
Abstract
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.
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Affiliation(s)
- Tatsuro Amano
- Laboratory for Exercise and Environmental Physiology, Faculty of Education, Niigata University, Niigata, Japan
| | - Naoto Fujii
- Institute of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit University of Ottawa, Ottawa, Canada
| | - Yoshimitsu Inoue
- Laboratory for Human Performance Research Osaka International University, Osaka, Japan
| | - Narihiko Kondo
- Laboratory for Applied Human Physiology Graduate School of Human Development and Environment Kobe University, Kobe, Japan
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Todd G, Gordon CJ, Groeller H, Taylor NAS. Does intramuscular thermal feedback modulate eccrine sweating in exercising humans? Acta Physiol (Oxf) 2014; 212:86-96. [PMID: 24934867 DOI: 10.1111/apha.12327] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2014] [Revised: 04/30/2014] [Accepted: 06/10/2014] [Indexed: 11/27/2022]
Abstract
AIM Few investigators have considered the possibility that skeletal muscles might contain thermosensitive elements capable of modifying thermoeffector responses. In this experiment, the temporal relationships between dynamic changes in deep-body and intramuscular temperatures and eccrine sweat secretion were explored during rhythmical and reproducible variations in heat production. METHODS Eight subjects performed semi-recumbent cycling (25 °C) at a constant load to first establish whole-body thermal and sudomotor steady states (35 min), followed by a 24-min block of sinusoidal workload variations (three, 8-min periods) and then returning to steady-state cycling (20 min). Individual oesophageal, mean skin and intramuscular (vastus lateralis) temperatures were independently cross-correlated with simultaneously measured forehead sweat rates to evaluate the possible thermal modulation of sudomotor activity. RESULTS Both intramuscular and oesophageal temperatures showed strong correlations with sinusoidal variations in sweating with respective maximal cross-correlation coefficients of 0.807 (±0.044) and 0.845 (±0.035), but these were not different (P = 0.40). However, the phase delay between intramuscular temperature changes and sweat secretion was significantly shorter than the delay between oesophageal temperature and sweating [25.6 s (±12.6) vs. 46.9 s (±11.3); P = 0.03]. CONCLUSION The temporal coupling of eccrine sweating to intramuscular temperature, combined with a shorter phase delay, was consistent with the presence of thermosensitive elements within skeletal muscles that appear to participate in the modulation of thermal sweating.
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Affiliation(s)
- G. Todd
- Centre for Human and Applied Physiology; School of Medicine; University of Wollongong; Wollongong NSW Australia
| | - C. J. Gordon
- Centre for Human and Applied Physiology; School of Medicine; University of Wollongong; Wollongong NSW Australia
| | - H. Groeller
- Centre for Human and Applied Physiology; School of Medicine; University of Wollongong; Wollongong NSW Australia
| | - N. A. S. Taylor
- Centre for Human and Applied Physiology; School of Medicine; University of Wollongong; Wollongong NSW Australia
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Inoue Y, Ichinose-Kuwahara T, Funaki C, Ueda H, Tochihara Y, Kondo N. Sex differences in acetylcholine-induced sweating responses due to physical training. J Physiol Anthropol 2014; 33:13. [PMID: 24887294 PMCID: PMC4050411 DOI: 10.1186/1880-6805-33-13] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Accepted: 05/09/2014] [Indexed: 05/28/2023] Open
Abstract
Purpose The present study examined sex differences in the sweat gland response to acetylcholine (ACh) in physically trained and untrained male and female subjects. Methods Sweating responses were induced on the forearm and thigh in resting subjects by ACh iontophoresis using a 10% solution at 2 mA for 5 min at 26°C and 50% relative humidity. Results The ACh-induced sweating rate (SR) on the forearm and thigh was greater in physically trained male (P < 0.001 for the forearm and thigh, respectively) and female (P = 0.08 for the forearm, P < 0.001 for the thigh) subjects than in untrained subjects of both sexes. The SR was also significantly greater in physically trained males compared to females at both sites (P < 0.001) and in untrained males compared to females on the thigh (P < 0.02) only, although the degree of difference was greater in trained subjects than in untrained subjects. These sex differences can be attributed to the difference in sweat output per gland rather than the number of activated sweat glands. Conclusion We conclude that physical training enhances the ACh-induced SR in both sexes but that the degree of enhancement is greater in male than in female subjects. The effects of physical training and sex on the SR may be due to changes in peripheral sensitivity to ACh and/or sweat gland size.
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Affiliation(s)
- Yoshimitsu Inoue
- Laboratory for Human Performance Research, Osaka International University, 6-21-57 Tohda-cho, Moriguchi, Osaka 570-8555, Japan.
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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 (1985) 2011; 111:524-9. [PMID: 21659489 DOI: 10.1152/japplphysiol.00212.2011] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
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 Δ 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 Δ 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.
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Affiliation(s)
- Tatsuro Amano
- Laboratory for Applied Human Physiology, Graduate School of Human Development and Environment, Kobe University, 3-11 Tsurukabuto, Nada-ku, Kobe 657-8501, Japan
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Kondo N, Nishiyasu T, Inoue Y, Koga S. Non-thermal modification of heat-loss responses during exercise in humans. Eur J Appl Physiol 2010; 110:447-58. [PMID: 20512585 DOI: 10.1007/s00421-010-1511-x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/11/2010] [Indexed: 10/19/2022]
Abstract
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.
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Affiliation(s)
- Narihiko Kondo
- Laboratory for Applied Human Physiology, Graduate School of Human Development and Environment, Kobe University, 3-11 Tsurukabuto, Nada-ku, Kobe 657-8501, Japan.
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Abstract
Human body temperature is regulated within a very narrow range. When exposed to hyperthermic conditions, via environmental factors and/or increased metabolism, heat dissipation becomes vital for survival. In humans, the primary mechanism of heat dissipation, particularly when ambient temperature is higher than skin temperature, is evaporative heat loss secondary to sweat secretion from eccrine glands. While the primary controller of sweating is the integration between internal and skin temperatures, a number of non-thermal factors modulate the sweating response. In addition to summarizing the current understanding of the neural pathways from the brain to the sweat gland, as well as responses at the sweat gland, this review will highlight findings pertaining to studies of proposed non-thermal modifiers of sweating, namely, exercise, baroreceptor loading state, and body fluid status. Information from these studies not only provides important insight pertaining to the basic mechanisms of sweating, but also perhaps could be useful towards a greater understanding of potential mechanisms and consequences of disease states as well as aging in altering sweating responses and thus temperature regulation.
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Affiliation(s)
- Manabu Shibasaki
- Department of Environmental and Life Sciences, Nara Women’s University Graduate School of Humanities and Sciences, Nara Japan
| | - Craig G. Crandall
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital of Dallas, TX
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Kuwahara T, Inoue Y, Taniguchi M, Ogura Y, Ueda H, Kondo N. Effects of physical training on heat loss responses of young women to passive heating in relation to menstrual cycle. Eur J Appl Physiol 2005; 94:376-85. [PMID: 15864636 DOI: 10.1007/s00421-005-1329-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/25/2005] [Indexed: 10/25/2022]
Abstract
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(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(B)), and between local sweating rate and F(sw) was significantly greater in T group, although the slope of the relationship between cutaneous blood flow and (T(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.
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Affiliation(s)
- Tomoko Kuwahara
- Laboratory for Human Performance Research, Osaka International University, Moriguchi, Japan
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Yamazaki F, Sone R. Skin vascular response in the hand during sinusoidal exercise in physically trained subjects. Eur J Appl Physiol 2003; 90:159-64. [PMID: 14504948 DOI: 10.1007/s00421-003-0864-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/11/2003] [Indexed: 11/27/2022]
Abstract
The effect of physical training on the cutaneous vascular response during transient exercise load is unclear. We determined the phase response and amplitude response of cutaneous vascular conductance (CVC) in the hand during sinusoidal exercise in endurance exercise-trained and untrained subjects. Subjects exercised on a cycle ergometer with a sinusoidal load for 32 min. The load variation ranged from 10% [23 (1) W in the trained group, 19 (1) W in the untrained group] to 60% [137 (4) W, 114 (6) W] of peak O(2) uptake, and five different time periods (1, 2, 4, 8, and 16 min) were selected. Skin blood flow in the dorsal hand and palm were monitored by laser-Doppler flowmetry. CVC was evaluated from the ratio of blood flow to mean arterial pressure. During sinusoidal exercise, the amplitude of CVC was smaller in the dorsal hand than palm for shorter periods (1, 2, and 4 min) ( P<0.05). The phase lag of CVC was smaller in the dorsal hand than palm for longer periods (8 and 16 min) ( P<0.05). The amplitude response did not differ significantly between the two groups. The phase lag of CVC in the dorsal hand ( P<0.05) and palm ( P=0.06) was larger in the trained group than untrained group. These findings suggest that glabrous and nonglabrous skin vascular responses in the hand differ during transient exercise load, and physically trained subjects show a slower vascular response in the two skin areas to exercise stimulation than do untrained subjects.
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Affiliation(s)
- Fumio Yamazaki
- Department of Clinical Pathophysiology, School of Health Sciences, Univ. of Occupational and Environmental Health (UOEH), 1-1 Iseigaoka, Yahatanishi-ku, 807-8555 Kitakyushu, Japan.
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Guest Editorial to accompany Vasomotor responses in glabrous and nonglabrous skin during sinusoidal exercise. Med Sci Sports Exerc 2002. [DOI: 10.1097/00005768-200205000-00007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Yamazaki F. Vasomotor responses in glabrous and nonglabrous skin during sinusoidal exercise. Med Sci Sports Exerc 2002; 34:767-72; discussion 773. [PMID: 11984292 DOI: 10.1097/00005768-200205000-00006] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To test whether vasomotor responses to dynamic exercise differ in glabrous and nonglabrous human skin, we determined the phase response and amplitude response of cutaneous vascular conductance in the forearm (CVCforearm), dorsal hand (CVCdorsal hand), and palm (CVCpalm) to sinusoidal exercise. METHODS Nine healthy subjects exercised on a cycle ergometer with a constant load (35% of peak O2 uptake) for 20 min at an ambient temperature of 25 degrees C and relative humidity of 60%; for the next 40 min, they exercised with a sinusoidal load. The sinusoidal load variation ranged from 10% to 60% of peak O2 uptake over a 4-min period. Skin blood flow was monitored by laser-Doppler flowmetry. CVC was calculated from the ratio of blood flow to mean arterial pressure (MAP). RESULTS During sitting rest and exercise, CVCpalm showed consistently higher value than CVCforearm and CVCdorsal hand. During sinusoidal exercise, the amplitude in CVCpalm was 7.4 times and 3.2 times greater than those in CVCforearm and CVCdorsal hand, respectively (P < 0.05). The phase difference in CVCforearm and CVCdorsal hand were smaller than that in CVCpalm (P < 0.05). CONCLUSION These findings of significant differences in phase and amplitude of responses in CVC between glabrous and nonglabrous skin during cyclic changes of dynamic exercise load suggest functionally important differences in the reflex control of these regions of skin.
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Affiliation(s)
- Fumio Yamazaki
- Department of Clinical Pathophysiology, School of Health Sciences, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, 807-8555 Kitakyushu, Japan.
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Shibasaki M, Kondo N, Crandall CG. Evidence for metaboreceptor stimulation of sweating in normothermic and heat-stressed humans. J Physiol 2001; 534:605-11. [PMID: 11454976 PMCID: PMC2278722 DOI: 10.1111/j.1469-7793.2001.00605.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
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 acetylcholinesterase 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 post-exercise 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.
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Affiliation(s)
- M Shibasaki
- Institute for Exercise and Environmental Medicine, Presbyterian Hospital of Dallas, Suite 435, 7232 Greenville Avenue, Dallas, TX 75231, USA
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