Effect of Intake of Different Water Temperatures on Thermoregulatory Responses during Sauna Exposure

Rungchai Chaunchaiyakul ； Saiphon Kongkhum ； Suwadee Chaunchaiyakul ； Jirawat Parathakornkul

《Adaptive Medicine》 6卷2期 (2014/06) Pp. 80-85

https://doi.org/10.4247/AM.2014.ABD063

並列摘要

Drinking during heat exposure alters thermoregulatory responses of core and skin temperatures and compensatory mechanisms, including sweating. This study aims to investigate the effect of drinking water in different temperatures on core and skin temperatures and the amount of sweat under high heat stress in sauna. Nine healthy sedentary males were exposed to sauna room at 60-70°C for 30 min. After 10 min of acclimatization, intervention was randomly conducted, at least 1 week apart which asked subjects to drink water at 2% of nude body weights of 4 different temperatures: ambient temperature water (29.6 ± 0.2°C, AW group), cold water (4 ± 1°C, CW group), body temperature water (37 ± 1°C, BW group) and warm water (50 ± 1°C, WW group). Another trial of no water (NW group) supplement was conducted as control group. Skin temperatures (TS) and the amount of sweat at forehead (Tf, Sf), back (Tb, Sb), leg (Tl, Sl) and arm (Ta, Sa) were measured using digital thermistors connected to thermal sensor monitor (YSI Instruments Co., Yellow Spring, OH, USA) and wet-dry weights toweling method respectively. Rectal thermistor probe was used to monitor core temperature. Rectal temperature (Tr) in all groups changed in a narrow range from 36.41 to 36.93°C. There were different patterns of changes of Tr in all groups compared to initial values: steady throughout the study in AW group, gradually increased in BW group (at 25 and 30 min, P ＜ 0.05) and WW group (at 15, 25, and 30 min, P ＜ 0.05), and steeply declined in CW group (at 15, 25, and 30 min, P ＜ 0.05). After water intake, TS in all groups showed significant increase compared to corresponding initial values throughout the study (P ＜ 0.05). TS steeply changed at forehead, then slightly rose, and were finally steady throughout the rest of the study. In all skin areas, BW induced greater amounts of sweat (grams/min) than other groups did. The lowest amount of sweat was observed in CW group at all skin sites (P ＜ 0.05) throughout the study. The lowest amount of sweat was detected at forehead (P ＜ 0.05) and the highest one was detected at back region (Sb) (P ＜ 0.05) no matter which water temperatures had been consumed. Human body appropriately adjusted itself during 30 min of sauna exposure with narrow changes in core temperatures in all situations. Different water temperatures induced similar changes on skin at the selected sites. However forehead, which representd higher center, showed the highest increment in temperature. Compensation via sweating prevented a rise in core temperature and high amounts of sweat were observed at the limbs and trunk. We believed that vasomotor dilations via trunk and limbs are responsible for minimizing increase in higher center and core temperatures.

並列關鍵字

core temperature ； sauna ； skin temperature ； sweat ； thermoregulation