Field study on the objective evaluation of sleep quality and sleeping thermal environment in summer

Abstract

To validate the feasibility of Actiwatch 2 (AW2) to measure sleep quality in thermal comfort researches, five parameters drawn from AW2 and the subjective evaluation of sleep quality, sleep quality vote (SQV) were collected. Furthermore, to explore the effect of thermal environment and IAQ on sleep quality with AW2, the standard effective temperature (SET) was induced to evaluate the integrated effect of the sleeping thermal environment and CO2 was to indicate the freshness of air quality. Ambient temperature, relative humidity, mean radiant temperature, air velocity and CO2 concentration were monitored in 6 bedroom of different type, including natural-ventilated rooms and air-conditioned rooms, during the hot season in Beijing for nearly one month. The occupant bedding system, posture habit and thermal sensation vote before sleep (BTSV) and after sleep (ATSV) of 3 female and 3 male subjects were recorded with questionnaire. The results showed that some of the sleep quality parameters measured by AW2 accorded with the subjective evaluation; Thermal environment had an effect on sleep quality according to the significant correlations between SET and the sleep quality parameters measured by AW2; The thermoneutral range of SET in sleeping condition was between 29.1–29.7°C, based on which the thermal insulation of bedding system (Icl) was recommended to be 0.96–1.08clo.