Abstract
The purpose of this study is to examine whether there is seasonal effects on the relationships between some morphological measurments and decrement of rectal temperature in a cold environment. Nine male subjects who wore thin shirts and shorts were exposed to 12iC with relative humidity of 50% for 60minutes. The experments were perforrned in Summer and in Winter. The relative large decrement of rectal temperature during the last 30 minutes of exposure to a cold air were observed only in relative lean subjects in Summer, but not in all in Winter. The decrement of rectal temperature was more affected in Summer by the variations of body fat per cent and body surface area per unit body volume. However, metabolic response to a cold air was more affected in Winter by the variations of the above two parameters. It was concluded that morphological factors were related intimately to heat loss by which rectal temperature was decreased in Summer and to heat production by which rectal temperature was maintained in Winter in a cold environment. Therefore, it was thought that an index as a cold tolerance such as lower critical temperature was more related to morphological factors in Winter than in Summer.
