Sleep Temperature Optimization
Keep your bedroom at 65-68°F and take a warm shower 1-2 hours before bed. Core temperature drop is a key trigger for sleep onset and deep sleep.
Dosage & Timing
Evidence Strength
5/5 — Very StrongVery strong evidence. Core body temperature drop is one of the primary physiological triggers for sleep. Replicated across many studies.
Overview
Lower your core body temperature by 1-3°F before bed to facilitate sleep onset. A cool bedroom (65-68°F / 18-20°C) is one of the strongest environmental sleep signals. Combine with a warm shower 1-2 hours before bed to trigger rebound cooling.
How To Do It
Set bedroom temperature
Set thermostat to 65-68°F (18-20°C). Use a fan if no AC.
Take a warm shower
1-2 hours before bed, take a warm (not hot) shower for 10 min. The post-shower cooling triggers vasodilation and core temp drop.
Choose breathable bedding
Use moisture-wicking sheets and avoid heavy synthetic comforters.
Keep feet and hands exposed
Extremity vasodilation helps dump core heat. Let feet stick out from covers if comfortable.
The Evidence
Each claim is linked to its source study. Confidence reflects the study design — systematic reviews and RCTs rank highest.
Effects of thermal environment on sleep and circadian rhythm↗
Thermal conditions influence sleep initiation, sleep depth, and circadian thermoregulation.
Primary Literature
Who Popularized This
Measurable Outcomes
Equipment Needed
- • Thermostat or fan
- • Breathable bedding
Related Protocols
Glycine for Sleep Quality
3g glycine before bed lowers core temperature and enhances deep sleep. Studies show improved next-day performance even with restricted sleep.
Caffeine Curfew
No caffeine after ~2pm (for 10pm bedtime). Caffeine's 5-6 hour half-life means afternoon intake significantly reduces deep sleep even if you fall asleep fine.
Sleep Hygiene Checklist
The complete sleep environment and behavior checklist. Combine darkness, cool temperature, consistency, and a wind-down routine for best results.
Morning Sunlight Exposure
View bright light within 60 minutes of waking to set your circadian clock. This triggers a cortisol pulse and starts a timer for melatonin release 14-16 hours later.