The Korean Journal of Physiology and Pharmacology

The Korean Society of Pharmacology (대한약리학회)
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Long-Term Tropical Residency Diminishes Central Sudomotor Sensitivities in Male Subjects

  • Lee, Jeong-Beom (Department of Physiology, College of Medicine, Soonchunhyang University) ;
  • Bae, Jun-Sang (Department of Physiology, College of Medicine, Soonchunhyang University) ;
  • Shin, Young-Oh (Department of Physiology, College of Medicine, Soonchunhyang University) ;
  • Kang, Jong-Chul (Department of Physiology, College of Medicine, Soonchunhyang University) ;
  • Matsumoto, Takaaki (The Second Department of Physiology, Aichi Medical University) ;
  • Toktasynovna, Aliopva Aziza (Kazakh Research Institute of Cardiology and Internal Medicine, Department of Internal Medicine) ;
  • Kaimovich, Alipov Gabit (Kazkhstan Medical University, Department of Pathology) ;
  • Kim, Wan-Jong (Department of Biology, Soonchunhyang University) ;
  • Min, Young-Ki (Department of Physiology, College of Medicine, Soonchunhyang University) ;
  • Yang, Hun-Mo (Department of Physiology, College of Medicine, Soonchunhyang University)
  • Published : 2007.12.31
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Abstract

Tropical natives (TROP) are capable of tolerating tropical heat because of their long-term adaptation to tropical environments. When exposed to heat stress, these natives tend to respond with lower sweat output, which is generally thought to be the result of heat acclimatization. The main objective of this study was to clarify central mechanisms inherent to suppressed thermal sweating in tropical natives (Malaysians) by comparing their sweating responses to those of temperate native (TEMP) (Koreans). This experiment was conducted in a thermoneutral climatic chamber ($24{\pm}0.5^{\circ}C,\;40{\pm}3%$ relative humidity). Heat loads were applied to each subject by the immersion of their lower legs in a hot water bath ($43^{\circ}C$ for 30 min). Sweat onset-time and sweat volume were compared between TROP and TEMP. The sweat onset-times on four selected points on the body ranged from 10.25 to 13.47 min in TEMP subjects, and from 16.24 to 17.83 min in TROP subjects (p<0.001). The local sweat volumes at the same sites ranged from 4.30 to $9.74 mg/cm^2$ in TEMP subjects, and from between 1.80 to $4.40mg/cm^2$ in TROP subjects (p<0.001). These results demonstrated a significant difference between TROP and TEMP subjects with regard to the manner in which they regulate their body temperatures when exposed to heat loads, and verified that long-term thermal adaptation blunts sweating sensitivities.

Keywords

References

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