A Basic Study on the Effects of Ambient Air Temperature and Humidity on the Heat Stress of Human Body.

In order to clarify the heat stress effects, under ambient air temperature and humidity, on thermoregulation, psychological responses, autonomic nervous and salivary amylase activity of the human body, 6 young fem ale subjects we a ring only shorts and a brassiere were exposed to 9 conditions consisting of air temperature of 28°C, 31°C and 34°C and 30%, 60% and 90% relative humidity for 60 minutes. The results of the analysis of variance are summarized as follows: Mean skin temperature, sweat rate, sKin moisture were significantly increased with an increase in air temperature and humidity, but rectal temperature showed no significant differences. Thermal, humid and uncomfortable sensations changed to the uncomfortable side w ith increasing temperature and humidity. ③ Heart rate, LF (Low Frequency)/HF (High Frequency) and salivary amylase activity were significantly increased with an increase in air temperature and humidity, while HF showed only tendency to be decreased. ④ High correlation coefficients between SKin moisture and uncomfortable sensations (r=0 .888),humid sensations (r=0.982),salivary amylase activity (r=0958) and LF/HF (r=0.910), suggested a dominant indicators of the heat stress. S a livary amylase activity and LF/HF were also suggested as an effective indicator of heat stress. [ABSTRACT FROM AUTHOR]