Effect of Local Cooling on Thermal Comfort of People in a Sleeping Posture

Abstract

Local cooling has been shown to have the potential to adjust human thermal comfort. Previous studies on local cooling are mainly conducted with subjects in sitting posture. When in a sleeping posture, the distribution of blood flow and the contact area between human body and the environment are different. In this study, the effects of local cooling on thermal comfort were investigated when people in a sleeping posture in a 30℃ environment. Thirty-six healthy adults participated into this experiment. Local cooling was applied to five parts, including the head-and-neck part, chest-and-abdomen part, upper arm, back and thigh, each for 10 min. The cooling conditions were separated by 30 min of ‘no-cooling’. Thermal sensation and thermal comfort were evaluated with visual analog scales. Physiological parameter (skin temperature) was measured during the exposure. The results show that: when people in sleeping posture, local cooling of the back is an effective way to improve thermal sensation and thermal comfort. Thus back is recommended to be selected as the exposure part when the effect of local conductive cooling on sleep quality and thermal comfort in a hot environment are studied.