In order to get basic data for preventing heat stroke accident during exercise in a hot environment, we analysed the relation between environmental temperature, and drinking and sweating. We also analyed the effect of water intake on body temperature regulation during exercise.
The environmental temperature started to rise in April, reached the maximumin August, and then decreased. Water intake and sweating increased significantly with increase in WBGT, but there was no correlation between weight loss and WBGT. The rise in body temperature during exercise (0.52±0.080°C) was constant and independent of WBGT. The rise in oral temperature during exercise was affected by the water intake and it was significantly higher when water was not supplied than that with water supply (p<0.001) . Sweat rate was significantly greater when water was supplied than when it was not supplied (p<0.01) .
The above results suggest that the amount of water intake increased with the increase in WBGT, which guarantees the increase in sweating and as a result maintenance of constant oral temperature.
Therefore it is suggested that it is better to supply water during exercise to facilitate evaporative heat loss, which prevent rise in oral temperature.