A heat transfer model for sleep quality evaluation

It is well known that the heat exchange mode between human body and environment during sleep is quite different from that during wakefulness; and while temperature has been identified as one of the important factors affecting sleep quality, the relation between human body's heat flow and sleep quality is rarely studied. This research comprehensively considered the distribution position of various thermal insulations (including hair, pajamas and bedding) outside the human body and their influence on the heat transfer process. On the basis of previous studies and heat balance equation, a model was constructed to evaluate the amount of heat transfer during sleep. A series of measured data were input into the new model and the previously proposed model separately, and reported good credibility in the current version. Linear fitting and paired sample t-test were used to analyze the relations between heat losses (sensible, latent and total) and percent of sleep periods. It is found, with the increase of heat loss, the duration of deep sleep was significantly shortened (p < 0.05) and light sleep was significantly grown (p < 0.05), which means that there is a certain mathematical relation between heat flow and objective sleep quality. This study has important implications for thermal environment design of bedroom and building energy conservation, and heat transfer has potential as a bridge between sleep quality and sleep thermal comfort in the future.