Review on sleep thermal comfort research in hot environment

The linkage between the thermal environment and sleep has a physiological basis, and the effect of inappropriate sleep thermal environment on sleep quality is significant. In the hot environment, people who are awakening can directly express their thermal sensation and thermal comfort and can adjust the thermal environment, while the thermal comfort states of sleeping people are indicated by the objective physiological parameters, and sleeping people are unlikely to control the ambient thermal environment. Considering the physical states of the sleeping and the awakening are different, the perception of the same hot environment is different accordingly. With the development of thermal comfort and sleep quality research methods, the researchers have studied the subjects concerning sleep thermal comfort in hot environment extensively in the past two decades, including the relationship between the human body thermoregulatory system and the sleep control system, the trend of the thermal physiological parameters during sleep, the evaluation method of sleep thermal comfort, the sleep thermal neutral temperature range in summer, the effect of bedding system and humidity on the sleep thermal neutral temperature in summer, the effect of airflow on sleep quality in hot environment, and the mathematical model to evaluate the integrated effect of thermal environment on sleep thermal comfort.