Ambient temperature and obstructive sleep apnea: Effects on sleep, sleep apnea, and morning alertness

Abstract

Study Objectives: The aim of the study was to investigate the effect of ambient temperature on sleep, sleep apnea, and morning alertness in patients with obstructive sleep apnea. Design: Randomized controlled trial. Setting: In-hospital investigations. Participants: Forty patients with obstructive sleep apnea naïve to treatment, with an apnea-hypopnea index of 10-30. Interventions: Three different nights in room temperatures of 16°C, 20°C, and 24°C. Measurements: Overnight polysomnography and Karolinska Sleepiness Scale. Results: The obstructive apnea-hypopnea index was 30 ± 17 at 16° C room temperature, 28 ± 17 at 20°C, and 24 ± 18 at 24° C. The obstructive apnea-hypopnea index was higher at 16°C room temperature versus 24°C (P = 0.001) and at 20°C room temperature versus 24°C (P = 0.033). Total sleep time was a mean of 30 min longer (P = 0.009), mean sleep efficiency was higher (77 ± 11% versus 71 ± 13% respectively, P = 0.012), and the patients were significantly more alert according to the Karolinska Sleepiness Scale (P < 0.028) in the morning at 16°C room temperature versus 24°C. The amount of sleep in different sleep stages was not affected by room temperature. Conclusions: Untreated patients with obstructive sleep apnea sleep longer, have better sleep efficiency, and are more alert in the morning after a night's sleep at 16°C room temperature compared with 24°C, but obstructive sleep apnea is more severe at 16°C and 20° C compared with 24°C. Clinical Trial Information: This study is registered in ClinicalTrials.gov number NCT00544752.