Effects of the environment of a simulated shelter in a gymnasium on sleep in children.

Effects of the environment of a simulated shelter in a gymnasium on sleep were investigated in 20 healthy school-aged children. Measurements were obtained during a one-night stay in a school gymnasium during the summer (C). Activity levels were monitored using a wrist actigraph, and temperature and humidity of the bedrooms in the subjects' homes were monitored from 3 days before to 3 days after C. The subjects were asked to provide information regarding subjective sleep estimations and thermal sensations. The results for the days before C (BC), C, the first day after C (A1), and the second day after C (A2) were compared. The bedroom temperature was significantly lower on BC than on the other nights. No significant difference was observed in bedtime, whereas wake-up time was significantly earlier on C and later on A1 than on the other nights. Total sleep time was significantly decreased on C (3.6 h) and increased on A1 when compared to the other nights. Daytime nap was significantly increased on A1 when compared to the other days. Subjective estimation of sleep quality was decreased and sweat sensation before sleep was increased on C when compared to the other nights. The main reason for sleep disturbances on C was heat. These results indicate that the environment of the simulated shelter in the gymnasium severely disturbed sleep in children. The resulting loss of sleep was compensated for by increased nocturnal sleep time and daytime napping on the next day.