Abstract
The subjects wearing cool clothing (C group) or warm clothing (W stoup) in daily life from September to February of the following year were tested to examine whether cold acclimatization takes place by clothing habits. Subjects rested at 25$\pm$1$^{\circ}C$, then were exposed to 15$\pm$1$^{\circ}C$, 50$\pm$5% R.H. for 90 min in September, November, December, and February. Rectal temperature (Tre) of C group after 90 min cold exposure did not drop below the Tre in $25^{\circ}C$ throughout the study. W group's Tre, however, dropped below the temperature in 25t from December. Shivering stopped after December in C group while W group continued to show it for the whole study. In resting, C group showed higher heat production than W group in February, and the rate of increase in heat production during cold exposure was smaller in C group than W group in February. C group showed less cold sensation than W group in the same coldness. These results suggest that the level of cold acclimatization may be improved by the habits wearing less clothes in daily life.