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Decreased thermal sweating of central sudomotor mechanism in African and Korean men.

Published on May 1, 2018in American Journal of Human Biology1.438
· DOI :10.1002/ajhb.23091
Jeong Beom Lee1
Estimated H-index: 1
,
Jeong Ho Kim1
Estimated H-index: 1
Abstract
OBJECTIVE: Tropical natives sweat less and preserve more body fluid than temperate natives, tolerating heat stress. However, the mechanisms involved in such sweating reduction have not been fully elucidated. We examined the sudomotor responses of men of African (n = 36) and Korean (n = 41) ancestry during hot water (43 °C) leg immersion (central sudomotor response). Correlations between mean body temperature, basal metabolic rate (BMR), and sweat rate were also examined. METHODS: All procedures were done in an automated climate chamber. Local skin temperatures and BMR were measured and mean body temperature was calculated. Sweating activities which include evaporative loss rate, sweat onset time, sweat rate, sweat volume, and whole-body sweat loss volume were examined. RESULTS: In the heat load test, Africans showed lower mean body and local skin temperatures than Koreans before and after heating. Before and after heating, BMR declined significantly in Africans, while that of Koreans declined less. Local sweat onset time increased more in Africans than in Koreans. Local evaporative loss rate, local sweat volume, local sweat rate, and whole body sweat loss volume were reduced in Africans compared with Koreans. There were positive associations of mean body temperature and resting BMR with mean sweat rate. CONCLUSION: In conclusion, we observed a larger reduction of sudomotor activity in tropical Africans than in temperate Koreans, which was associated with their lower mean body temperature and lower resting BMR.
  • References (32)
  • Citations (1)
References32
Newest
#1Jeong-Beom Lee (SCH: Soonchunhyang University)H-Index: 13
#2Young-Oh Shin (SCH: Soonchunhyang University)H-Index: 8
Abstract Modification of sweating could be due to changes in activated sweat gland density (ASGD) and/or activated sweat gland output (ASGO). The present study determined regional and inter-ethnic differences in ASGD and ASGO during passive heating between tropical natives (African, n = 22) and temperate natives (Republic of Korean, n = 25). Heat load was carried out by immersing the half body into a hot water bath for 30 min. Tympanic temperature (Tty) and skin temperature (Ts) were measured. M...
4 CitationsSource
#1Jeong-Beom LeeH-Index: 13
#2Jeong-Ho KimH-Index: 1
Last. Hiroyuki MurotaH-Index: 25
view all 3 authors...
The sudomotor mechanism, wich contributes to tolerating thermal environments, is affected by not only the body temperature, but also sex, ethnicity, exercise training, region, season, and heat adaptat
6 CitationsSource
#1Jeong-Beom Lee (SCH: Soonchunhyang University)H-Index: 13
#2Tae-Wook Kim (SCH: Soonchunhyang University)H-Index: 5
Last. Hun-Mo Yang (SCH: Soonchunhyang University)H-Index: 13
view all 4 authors...
We investigated the sweating response during passive heating (partial submersion up to the umbilical line in 42±0.5℃ water, 30 min) after summer and winter seasonal acclimatization (SA). Testing was performed in July during the summer, 2011 [summer-SA; temp, 25.6±1.8℃; relative humidity (RH), 82.1±8.2%] and in January during the winter, 2012 (winter-SA; temp, -2.7±2.9℃; RH, 65.0±13.1%) in Cheonan (126°52'N, 33.38'E), Republic of Korea. All experiments were carried out in an automated climatic ch...
6 CitationsSource
#1Jeong-Beom Lee (SCH: Soonchunhyang University)H-Index: 13
#2Tae-Wook KimH-Index: 5
Last. Hun-Mo Yang (SCH: Soonchunhyang University)H-Index: 13
view all 4 authors...
Abstract The main objective of this study was to determine the central mechanisms involved in suppression of thermal sweating after seasonal acclimatization (SA) during passive heating (immersing the legs in 43 °C hot water for 30 min). Testing was performed in July (before-SA) and August (after-SA) [25.2±2.2 °C, 73.9±10.3% relative humidity (RH), Cheonan (Chungnam,126° 52′N, 33.38′E), in the Republic of Korea. All experiments were carried out in an automated climatic chamber (25.0±0.5 °C and RH...
8 CitationsSource
#1Young Oh Shin (SCH: Soonchunhyang University)H-Index: 5
#2Jeong Beom Lee (SCH: Soonchunhyang University)H-Index: 6
Last. Hun Mo Yang (SCH: Soonchunhyang University)H-Index: 5
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Abstract We examined serum levels of prostaglandin E 2 (PGE 2 ), cyclooxygenase (COX)-2 and orexin before and after heat acclimation (HA) to test the hypothesis that decreased basal body temperature due to HA correlate with circulating levels of these key thermoregulatory molecules. Nine healthy human male volunteers were recruited (age, 21.9 ± 2.7 years). The subjects were exposed to half-body immersion in hot water (42 ± 0.5 °C) at the same time of day (2–5 p.m.) on alternate days for 3 weeks....
13 CitationsSource
Basal metabolic rate (BMR) is the rate of metabolism of a resting, postabsorptive, non-reproductive, adult bird or mammal, measured during the inactive circadian phase at a thermoneutral temperature. BMR is one of the most widely measured physiological traits, and data are available for over 1,200 species. With data available for such a wide range of species, BMR is a benchmark measurement in ecological and evolutionary physiology, and is often used as a reference against which other levels of m...
97 CitationsSource
#1Hitoshi Wakabayashi (Kyushu University)H-Index: 14
#2Titis Wijayanto (Kyushu University)H-Index: 7
Last. Yutaka Tochihara (Kyushu University)H-Index: 22
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This study investigated the differences in heat dissipation response to intense heat stress during exercise in hot and humid environments between tropical and temperate indigenes with matched physical characteristics. Ten Japanese (JP) and ten Malaysian (MY) males participated in this study. Subjects performed exercise for 60 min at 55% peak oxygen uptake in 32°C air with 70% relative humidity, followed by 30 min recovery. The increase in rectal temperature (T re) was smaller in MY during exerci...
22 CitationsSource
#1Joo-Young Lee (Kyushu University)H-Index: 23
#2Hitoshi Wakabayashi (Kyushu University)H-Index: 14
Last. Yutaka Tochihara (Kyushu University)H-Index: 22
view all 6 authors...
For the coherent understanding of heat acclimatization in tropical natives, we compared ethnic differences between tropical and temperate natives during resting, passive and active heating conditions. Experimental protocols included: (1) a resting condition (an air temperature of 28°C with 50% RH), (2) a passive heating condition (28°C with 50% RH; leg immersion in a hot tub at a water temperature of 42°C), and (3) an active heating condition (32°C with 70% RH; a bicycle exercise). Morphological...
14 CitationsSource
#1John R. Speakman (Aberd.: University of Aberdeen)H-Index: 84
#2Elżbieta Król (Aberd.: University of Aberdeen)H-Index: 26
Summary 1. The role of energy in ecological processes has hitherto been considered primarily from the standpoint that energy supply is limited. That is, traditional resource-based ecological and evolutionary theories and the recent ‘metabolic theory of ecology’ (MTE) all assume that energetic constraints operate on the supply side of the energy balance equation. 2. For endothermic animals, we provide evidence suggesting that an upper boundary on total energy expenditure is imposed by the maximal...
223 CitationsSource
#1Jeong-Beom Lee (SCH: Soonchunhyang University)H-Index: 13
#2Jun-Sang Bae (SCH: Soonchunhyang University)H-Index: 7
Last. MinYoung-Ki (SCH: Soonchunhyang University)H-Index: 14
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Natives of the tropics are able to tolerate high ambient temperatures. This results from their long-term residence in hot and often humid tropical climates. This study was designed to compare the peripheral mechanisms of thermal sweating in tropical natives with that of their temperate counterparts. Fifty-five healthy male subjects including 20 native Koreans who live in the temperate Korean climate (Temperate-N) and 35 native tropical Malaysian men that have lived all of their lives in Malaysia...
39 CitationsSource
Cited By1
Newest
#1Dahee Jung (SNU: Seoul National University)H-Index: 1
#2Yung-Bin Kim (SNU: Seoul National University)H-Index: 4
Last. Joo-Young Lee (SNU: Seoul National University)H-Index: 23
view all 5 authors...
Purpose We investigated the effects of humidity on regional sweating secretion and active sweat gland density on the scalp during passive heating in hot environments.
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