FRIDAY, Dec. 12, 2025 (HealthDay News) -- Sleep length and quality suffer in hot weather, according to a study published in the December issue of Environment International.
Jiawen Liao, Ph.D., from University of Southern California in Los Angeles, and colleagues used digital wearables data collected from 14,232 participants in the All of Us Research Program from 2010 to 2022 (12.5 million nights of sleep duration) to assess associations between sleep health and heat exposure.
The researchers found that a 10-degrees Celsius increase in the daytime and nighttime temperature anomalies was associated with decreases of 2.19 and 2.63 minutes of total sleep time, respectively. Among females, Hispanics, and those with lower socioeconomic status or chronic health conditions, the effects of heat on sleep duration were greater (9.2 to 79.4 percent). There were also substantial spatial differences, with the effect estimates doubled in marine climate zones. By 2099, 8.5 to 24.0 additional hours of sleep reduction could occur per person-year in different climate zones compared with 1995 to 2014. Greater sleep duration reductions happened in June to September and on the West coast.
"This work is an important step toward understanding how sleep is affected by environmental stressors like heat, which can increase the risk of disease and even death," Liao said in a statement. "If we can help people sleep better, we may be able to reduce illness and save lives."