The Effect of Ambient Temperature Change on the Covered Area of the Body during Sleep

Abstract

Eight healthy young female volunteers slept from 23 : 00 to 7 : 00 in a climate chamber that was controlled under the following conditions : 25°C/60% RH for the first hour, followed by an increase to 28°C / 65% RH in the second hour, and then a decrease to 27°C/60% RH in the last six hours. The skin temperature (T_sk) and bed climate were measured continually through the night at time intervals of 3 min. Body movement was measured continually by means of video taping. The covered area was scored from body movement recordings at time intervals of 1 min. The 17 body sites were scored visually. The time of body covering significantly differed depending on ambient temperature changes in the neck, shoulder, and upper extremities, while no change was observed in the trunk and lower extremities. The time of body covering was significantly shorter in the upper extremities, neck, and shoulder compared to the other sites of the body. No significant difference was observed in skin temperature and bed climate of the chest area, regardless of ambient temperature change. The bed climate of the foot area significantly increased when ambient temperature increased. These results indicate that body covering behavior, which is one of the mechanisms of behavioral thermoregulation, is active during sleep. The covering area may differ depending on the body site, which is more sensitive in the upper extremities compared to the lower extremities or trunk.