Worth knowing Sleep

Get light in your eyes early

Indoor lighting is roughly a hundredth of what is available outside on a cloudy morning.

Moderate evidenceReal support, but smaller effects or fewer replications than you would want.
What it costs 10 minutes outdoors

Do this

Get outdoors within an hour or so of waking, for ten to twenty minutes, without sunglasses. Overcast still works. In genuinely dark winters, a 10,000 lux light box in the morning is the studied substitute.

Why it works

Morning light advances the circadian clock through specialised retinal cells, which brings sleep onset earlier and consolidates the rhythm. Bright light therapy has solid evidence in seasonal affective disorder and in circadian rhythm disorders such as delayed sleep phase.

Where it fails

Much of the popular protocol detail - exact minutes, exact timing - is extrapolated well beyond what the trials tested. It will not overcome a badly irregular schedule, and light in the evening undoes it.

How you’ll know

Falling asleep earlier without trying is the signal. Feeling more alert immediately afterwards is not the same thing.