Are higher temperatures linked to less sleep and poorer sleep quality?

Details

The researchers searched databases and relevant journals for studies published before February 2023. They included studies of adults, adolescents, and children that used objective temperature indicators and valid sleep measures in real-life settings. They summarized the findings in words.

Across studies worldwide, higher indoor or outdoor temperatures—measured as daily averages or nighttime temperatures—were linked to less sleep and poorer sleep quality. The association was stronger in the hottest months, in the hottest regions, and among vulnerable populations. The pattern appeared consistent across several sleep indicators and measurement methods. The abstract does not specify how much sleep was lost or which populations were classified as vulnerable.

The authors identified methodological limitations in the existing research. They also noted that previous experimental studies pointed in the same direction, although this review examined real-life associations, which alone cannot establish causation. Solid evidence that people quickly adjust to heat's effects on sleep is lacking; this does not mean adjustment is impossible. The authors interpret the findings as a threat to sleep as climate change raises temperatures.