Effects of time of day on dressing behavior under the influence of ambient temperature fall from 30 degrees C to 15 degrees C.

The present paper is aimed at determining whether the dressing behavior for temperature regulation in cold is under the influences of circadian control. The half-naked subjects were instructed to dress in the garments they felt comfortable when the room temperature began to decrease from 30 degrees C to 15 degrees C in 1 h. To determine the effects of brain temperature fall on the dressing behavior, we used face cooling with cool air for 30 min before the room temperature began to decrease. We also studied the effects of wearing a hat on dressing behavior. Rectal temperature, tympanic temperature, skin temperature at seven sites, and thermal sensation were recorded. Major findings are summarized as follows: 1) the subjects dressed faster with thicker clothing in the morning than in the evening; 2) the subjects with face cooling dressed faster with thicker clothing than the subjects without face cooling; 3) the subjects without a hat dressed more rapidly with thicker, heavier clothing. These results were discussed in terms of load error between actual and set-point values in the core temperature.