Sleep

Blue light is real but smaller than the headlines claim — the bigger sleep thieves are what you watch and how long it keeps you up, and fixing those is a different job entirely.

A sleep-lab study found caffeine taken six hours before bed still cut sleep by about an hour — here is how I used that finding to pick a real cutoff without giving up coffee.

Ten minutes of outdoor light within an hour of waking is one of the cheapest sleep interventions there is — the lux numbers, the camping study behind it, and how I fit it into real mornings.

After years of abandoning elaborate evening routines, a three-block, 45-minute wind-down finally stuck — here is the exact shape of it and the evidence behind each piece.