Sleep Experts Urge 30 Minutes of Morning Light Within 1 Hour of Waking

2 articles · Updated · health.yahoo.com · Aug 4

30 minutes of morning light within an hour of waking is the clearest target sleep researchers recommend to improve nighttime sleep and morning alertness, with outdoor exposure best and 15 minutes a practical minimum.
5,000 to 10,000 lux outdoors on an overcast morning far exceeds roughly 1,000 lux by a window and 30 to 500 lux in typical indoor spaces, giving the retina a much stronger signal to reset the brain’s circadian clock.
400,000-plus adults in one study who spent more time in outdoor light reported fewer insomnia symptoms, less tiredness and less difficulty getting up, while experts said benefits can start within days but may take weeks to notice.
3,000-lumen bulbs or a light-therapy box can help when sunrise, windows or outdoor access are limited, and experts also advise dimming lights about two hours before bed so evening brightness does not offset morning gains.