Ambient temperature and obstructive sleep apnea: effects on sleep, sleep apnea, and morning alertness.
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.
['Valham|Fredrik|F|', 'Sahlin|Carin|C|', 'Stenlund|Hans|H|', 'Franklin|Karl A|KA|']
D000368:Aged D001143:Arousal D002940:Circadian Rhythm D015331:Cohort Studies D005260:Female D006801:Humans D008297:Male D008875:Middle Aged D017286:Polysomnography D020181:Sleep Apnea, Obstructive D012894:Sleep Stages D013696:Temperature D013997:Time Factors D016896:Treatment Outcome
ambient temperature randomized controlled trial treatment polysomnography sleep time sleep stages Sleep apnea syndromes daytime sleepiness sleep quality