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Longevity Atlas
Sleep

Morning light, evening dark

Light is the master reset for the circadian clock: 10–20 minutes outdoors after waking and dimmed evening lighting is the cheapest sleep upgrade.

Impact 3/53/5Effort: free, today
First step today

Tomorrow, drink your coffee on the balcony or the street.

How

Get outside within an hour of waking (even overcast sky gives 10× indoor lux). After 9 pm warm, low light; no glowing LEDs in the bedroom.

Evidence

Large UK Biobank analysis (n=88,905, 2024): low daytime light plus bright nights meant 20–30% higher mortality. Morning light exposure advances the melatonin curve and shortens sleep onset in RCTs.

Goals

SleepEnergy, fatigueBrain, memory

Sources

  1. Windred DP et al. Brighter nights and darker days predict higher mortality risk – UK Biobank. PNAS (2024) ↗
  2. Blume C et al. Effects of light on human circadian rhythms, sleep and mood. Somnologie (2019) ↗

Last reviewed: 6 September 2026

This site is educational and does not replace medical advice. Start any supplement or drug only after consulting a doctor or pharmacist.