title: Seasonal Acclimatization in Summer versus Winter to Changes in the Sweating Response during Passive Heating in Korean Young Adult Men.
abstract: 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 chamber (temp, 25.0±0.5℃: RH, 60.0±3.0%). Fifteen healthy men (age, 23.4±2.5 years; height, 175.0±5.9 cm; weight, 65.3±6.1 kg) participated in the study. Local sweat onset time was delayed during winter-SA compared to that after summer-SA (p< 0.001). Local sweat volume, whole body sweat volume, and evaporative loss volume decreased significantly after winter-SA compared to those after summer-SA (p<0.001). Changes in basal metabolic rate increased significantly after winter-SA (p< 0.001), and tympanic temperature and mean body temperature were significantly lower after summer-SA (p<0.05). In conclusion, central sudomotor acitivity becomes sensitive to summer-SA and blunt to winter-SA in Rebubic of Korea. These results suggest that the body adjusts its temperature by economically controlling the sweating rate but does not lower the thermal dissipation rate through a more effective evaporation scheme after summer-SA than that after winter-SA.
authors.affiliation: Department of Physiology, College of Medicine, Soonchunhyang University, Cheonan 331-946, Korea.
authors.forename: Jeong-Beom
authors.initials: JB
authors.lastname: Lee
authors.affiliation: Department of Health Care, Graduate School, Soonchunhyang University, Asan 336-745, Korea.
authors.forename: Tae-Wook
authors.initials: TW
authors.lastname: Kim
authors.affiliation: Department of Physiology, College of Medicine, Soonchunhyang University, Cheonan 331-946, Korea.
authors.forename: Young-Ki
authors.initials: YK
authors.lastname: Min
authors.affiliation: Department of Physiology, College of Medicine, Soonchunhyang University, Cheonan 331-946, Korea.
authors.forename: Hun-Mo
authors.initials: HM
authors.lastname: Yang
keywords: Mean body temperature; Passive heating; Seasonal acclimatization; Sweat onset time; Tympanic temperature