Abstract
This study investigated the effects of bathing method and time to bedtime on sleep in winter, and examined the relationship between indoor thermal environment and sleep. A total of 21 subjects, 10 male students and 11 female students in their 20s, participated in the study. The experiment was conducted in the subjects' homes under four conditions: 39°C and 42°C for bathing, 30 minutes and 90 minutes from bathing to bedtime, and the bedroom environment during sleep. For the bedroom environment, we combined a condition in which the air conditioner heater was turned on during sleep, a condition in which the air conditioner was set to run on a timer for 1 hour, and a condition in which the heater was not used. The results showed a gender difference, with men sleeping better at higher bath temperatures, which was associated with better sleep. The latency to fall asleep was shorter for women under the condition of air conditioner heating, suggesting that the effect of heating was greater than that of bath temperature.
