Temperature and Sleep

Why the body cools to initiate sleep and how ambient temperature influences sleep quality.

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Preliminary research suggests…

A modest body of research links the natural evening drop in core body temperature to sleep onset and associates uncomfortable ambient temperatures with poorer sleep. Evidence is limited and partly indirect. We present temperature as one environmental factor among several.

Informational; a cool bedroom (~18–20°C / 65–68°F) suits most all levels home

better sleeprecoverygeneral adultsolder adults

Common misconceptions

“A warm bedroom is cozier for sleep.” Overly warm rooms tend to fragment sleep.
“Temperature doesn't affect sleep.” Thermal comfort influences onset and continuity.

What we won't claim

Do not claim to diagnose, treat, or cure insomnia, sleep apnea, or any sleep disorder
Do not promise guaranteed, instant, or permanent improvements in sleep
Do not present these general hygiene techniques as clinical therapy (e.g., CBT-I) or a substitute for medical care

When to seek a professional

Loud snoring with witnessed gasping/choking or breathing pauses plus daytime sleepiness (possible obstructive sleep apnea), refer to a clinician
Difficulty falling or staying asleep at least 3 nights/week for 3+ months with daytime impairment (possible chronic insomnia disorder), refer to a clinician
Excessive daytime sleepiness despite adequate time in bed, or falling asleep involuntarily during activities, refer to a clinician

Key sources (2), grade mix A:2 · B:0 · C:0

Every source below carries its own grade and links to the original study. This is the audit trail.

ASam Karsky, Carina Gronlund, Peter Larson, Michaela Marincic, Dayna A. Johnson, Philippa J. Clarke, Ketlyne Sol, Konstantinos Papaefthymiou (2025) · Innovation in aging · 10.1093/geroni/igaf122.3278

AK. Kräuchi, A. Wirz-Justice (2001) · Neuropsychopharmacology · 10.1016/s0893-133x(01)00315-3

✓Explore all 891 studies in Sleep →

The full evidence base this focus area draws on, every study with its grade and DOI.