Effects of thermal environment on sleep

Sorts out the basic understanding of the effects of thermal environment on sleep through literature review of the studies in the recent 50 years. The bedding system is a key factor and the thermal neutral temperature for sleeping person is negatively correlated with the total insulation of bedding system. Both cold and hot stimuli disturb sleep when the total insulation of bedding system is small, occurred as increasing wakefulness and decreasing SWS and REM, and cold stimuli are more disruptive to sleep than hot ones. The sleep quality can be maintained in a wide range of low temperature by adjusting quilt and sleepwear, and the thermal neutral temperature for bed climate keeps constant. The bed climate is influenced by both mean radiant temperature and air temperature. High humidity can strengthen the effects of high temperature on sleep. Airflow can significantly improve the sleep quality under hot-humid conditions. The effects of hot stimuli mainly occur in the first segment of sleep dominated by SWS, and the effects of cold stimuli occur in the second segment of sleep dominated by REM. The small change from neutral to cool improves sleep quality, and the small change from neutral to warm and the big step change from neutral to hot have no significant effect on sleep. Changing the core and skin temperatures by controlling thermal environment may have impacts on sleep quality. The sleep quality in summer is worse than other seasons. It is better to sleep to raise the air or mean radiant temperature in cold seasons. The distal skin temperature has a tight relationship with sleep/wake schedule. In the end, gives advices and directions for the future study.