Morning light and circadian entrainment: RCT

RCT showing 30 minutes of morning bright light (10,000 lux) advances circadian phase by 40 minutes and improves subjective alertness and nocturnal sleep quality.

Circadian Effects

Phase advance: 36-45 minutes
Alertness: 23% improvement
Sleep onset: 19 minutes earlier

Implementation

Bright light exposure within 2 hours of waking for optimal circadian entrainment.

Outcomes

Heart Rate Variability
7.4
ms (RMSSD)
Systolic Blood Pressure
-3.6
mmHg (Millimetres of Mercury)

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