The purpose of this study was to examine the difference in physiological response caused by a pedaling exercise done in three environmental conditions. The subjects were nine men (age 21.8±1.3 yrs, height 172.6±5.9 cm, weight 66.9±9.4 kg, ⩒O2max 55.5±5.8 ml/kg/min). They completed the pedaling exercise to set 60%⩒O2max and 60 rpm for 30 minutes in three environments: Control; WBGT 18℃, dry-bulb temperature (DB) 22℃, relative humidity (RH) 40%, Heat; WBGT 28℃, DB 34℃, RH 40%, and Wet; WBGT 28℃, DB 28℃, RH 80%. The measurements were oxygen uptake, heart rate, sweat loss, dehydration rate, skin temperature, and rectal temperature. The results showed that the heart rate and rectal temperature after 10 and 15 minutes in both Heat and Wet were significantly higher than Control (p<0.05). However, there were no significant differences in all variables between Heat and Wet. We concluded that the risk of heat exhaustion was increased by both Heat and Wet conditions.
