Evaluation method and experimental study of sleep thermal sensation based on heart rate

Accurate assessment of sleep thermal sensation is the premise of analyzing the thermal environment of bedroom. And human metabolic rate is one of the key parameters affecting thermal sensation. This study aims to explore the evaluation method of sleep thermal sensation. The sleep metabolic rate based on heart rate are studied. And the feasibility of the evaluation method is validated by the performance of the sleep thermal sensation prediction model. The experiment was carried out in the sleep climate chamber at 23, 26, and 29 °C in summer. The sleep thermal environment parameters, physiological parameters, and subjective evaluation of 14 subjects were monitored. The experimental results showed that the mean sleep metabolic rate was 39 W/m2. And this evaluation method based on heart rate can improve the prediction performance of sleep thermal sensation model. The metabolic rate during sleep presents the U-shaped curve with time. However, compared with falling asleep, the metabolic rate was lower when waking up. This resulted in a thermal neutral temperature of sleep being 26.7°C which was 1°C higher than pre-sleep. This study will provide a reference for the operation strategy of sleep air conditioning.