Thermoregulatory responses during one hour pedalling on bicycle ergometer were measured in a climatic chamber of 26°C at various humidity levels. Work intensities were 30, 40, 50, 60 and 70% of Vo₂max. Relative humidities were 30, 60 and 90%.
1) Oxygen intake remained nearly constant at the same work load and was not influenced by humidity level.
2) At work intensities of more than 60% of Vo₂max the elevation of rectal temperature was augmented by increased humidity.
3) The secretion of sweat increased, but the evaporation of sweat decreased with increased humidity, particularly at work intensities of 60% and 70% of Vo₂max.

Heat balance during 1hr exercise at 450 kpm/min was measured on 5 healthy male students wearing only shorts in a climatic chamber of 13°C and r.h. 60% at the minimum phase (5 : 00-7 : 00), the rising phase (11 : 00-13 : 00), the maximum phase (17 : 00-19 : 00) and the falling phase (23 : 00-1 : 00) of body temperature.
Heat production was nearly constant, 194 to 209w/m2 at all phase both in summer and winter. Evaporative heat loss was lowest at the minimum phase and highest at the maximum phase. In all phases, evaporative heat loss was 14-29% higher in summer than in winter. Dry heat loss was not significantly different summer and winter. Body heat storage was high at the minimum phase, low at the maximum phase and higher in winter than in summer. The threshold rectal temperature for the onset of sweating was lower at the maximum phase than at the minimum phase by 0.65°C in winter and by 0.70°C in summer.

Until the Sui Dynasty in China, night sweat and spontaneous perspiration had been thought to be caused by same pathophysiology, that is, lowered superficial resistance by deficiency of Qi.In the Tang Dynasty, these were considered to have different pathophysiologies and a new principle indicated that pathogenic heat caused night sweat.In the Song and Jing Dynasties, deficiency of blood and pathogenic heat by deficiency of Yin was also considered to cause night sweat.In the Jing Dynasty, exogenous pathogens, such as Cold were considered to cause night sweat, which indicated the principle that not only the deficiency syndrome but also the excess syndrome caused night sweat.In the beginning of the Yuan and Ming Dynasties, it was concluded that the deficiency of Yin caused night sweat and the deficiency of Yang caused spontaneous perspiration.In the middle of the Ming Dynasty, another new theory indicated that deficiency of Yang also possibly caused night sweat; therefore we should diagnose abnormal sweat depending on the pathophysiology in each case.In the Qing Dynasty, new theories were established stating that not only exogenous pathogens but also Damp-heat, undigested food and stagnation of blood, all of which are included in excess syndrome, cause night sweat, and that based on which part of the body sweats occurred we might understand pathophysiology of night sweat. The night sweat by Warm-heat, which is different from the one by Wind-cold, was considered to be caused with deficiency of Yin.Thus we conclude that the theories of night sweat developed over time, based on Chinese medical classics.