Abstract
Introduction
The summer of 2023 in the northern hemisphere saw the highest global temperatures in over 2000 years. This study uses big data from an under-mattress sensor and global ambient temperature records to estimate the impact of high temperatures on poor sleep and associated wellbeing costs.
Methods
Data were from 219,808 consumers who used an under-mattress sensor (Withings Sleep Analyzer; 89,219) or a smartwatch (Withings ScanWatch; 130,589) regularly between January 2020 and September 2023. Generalized non-linear mixed effect models tested the effects of 24h average ambient temperature on sleep duration and poor sleep (<6h) adjusting for potential confounders. Health economics models quantified wellbeing cost due to sleep loss from high temperatures.
Results
Extreme temperatures were associated with a ~30 to 300% increase in the prevalence of poor sleep and a 10-40 min average sleep duration loss compared to median temperatures, depending on the country, and this effect was stronger in older participants. The global burden (35 locations; 3.5 billion total population) associated with sleep loss due to higher than historical average temperatures in 2023 was ~2.2 million disability adjusted life years, including 82,000 years of life lost, which was 2.5-fold higher compared to 2000.
Conclusions
High ambient temperatures are associated with reduced sleep duration and a marked increase in poor sleep prevalence. Wellbeing cost associated with sleep loss due to high temperatures is substantial – equivalent to medical conditions such as bipolar disorders, chronic kidney diseases, and alcohol use disorders.