Research

Hormonal

Bright light exposure (>10,000 lux) timed to follow the core body temperature minimum successfully advances the circadian phase of melatonin and cortisol by approximately 8-10 hours.

To shift your body clock earlier (e.g., for morning shifts), expose yourself to very bright light (>10,000 lux) for several hours starting shortly after you wake up. This is significantly more effective than normal room lighting. Ensure the light is safe for your eyes (use filtered devices) and avoid bright light in the evening.

GoodSupportsHIGH confidence
after bright light supplementation the phase advance was 8.1 h (SEM 0.7 h)... In the bright light group, the minimum of the plasma cortisol rhythm had significantly advanced (p<0.001) by on average 10 hours...
Derk‐Jan Dijk et al. · PLoS ONE · 2012

Why this rating

Robust RCT design with clear phase shift measurements.

Source

Amplitude Reduction and Phase Shifts of Melatonin, Cortisol and Other Circadian Rhythms after a Gradual Advance of Sleep and Light Exposure in Humans

Derk‐Jan Dijk et al. · PLoS ONE · 2012

DOI 10.1371/journal.pone.0030037

rct · n=14Cited 170×
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DOI resolved against Crossref · corpus check 2026-06-10

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