Effects of daytime cold and warm ambient temperatures on sleep in men with and without obesity

Authors

• DW Zong
• RM Lomash
• CZ Chen
• MJ Song
• DD Rudnicki
• BJ Traynor
• S Michael
• CA Tristan
• A Simeonov
• W Zheng
• DA Tagle
• M Ferrer
• EM Ottinger

Abstract

Thermal environment plays a crucial role in regulating energy metabolism and sleep in humans. Deviation from thermoneutral ambient temperatures increases metabolic demand and may lead to sleep disturbances. Here we examined the effects of daytime ambient temperature on sleep in adult men with and without obesity. Twelve lean men (23.2 ± 4.9 yrs; 23.4 ± 1.6 kg/m2) and nine men with obesity (29.6 ± 4.9 yrs; 34.4 ± 3.4 kg/m2) were exposed to a single temperature between 16-31°C, randomly assigned each day for 5h (0800-1300) during a 14-day inpatient study (NCT01568671). Nighttime sleep (at 23-25°C) was assessed using wrist actigraphy. Sleep parameters, including total sleep time (TST), time in bed (TIB), wake after sleep onset (WASO), and sleep efficiency, were not significantly different between the groups after exposure to a thermoneutral baseline temperature (24.2 ± 0.3°C). There was a significant interaction between the ambient temperatures (coldest at 19.1 ± 1.5°C and warmest at 30.8 ± 0.5°C) and BMI groups for TST, TIB, and WASO (p’s ≤ 0.05), with greater TST (430.7 ± 35.6 vs. 357.0 ± 67.4 min; p=0.02), TIB (488.9 ± 38.0 vs. 383.3 ± 76.0 min; p=0.003), and WASO (57.2 ± 27.1 vs. 26.3 ± 20.3 min; p=0.02) in men with obesity compared to lean men after cold exposure. No significant differences were observed after warm ambient temperatures. Future studies assessing sleep architecture and core temperature may provide further insights into metabolic and sleep physiology in response to ambient temperatures in individuals with and without obesity.

Scientific Focus Area: Clinical Research

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