Time asleep and time in bed are two different clocks

I build Aera.

Time asleep is how long you were actually sleeping. Time in bed is how long you were lying there, including wake. A nine-hour night in bed can hide seven hours of sleep.

Watches are generally better at telling sleep from wake than at labeling stages (Chinoy and colleagues, 2021). Duration is still an estimate, not a clinic-grade total.

Habitual sleep duration has a U-shaped pattern in population studies (Cappuccio 2010; Yin 2017; Svensson 2021): people near seven to eight hours tended to fare best, and regularly sleeping much longer often tracks with something underneath rather than a goal to chase. That is a population finding, not a personal diagnosis from one late film.

Compare typical nights. Treat a long stretch as a flag to get curious, not homework.

Full write-up: https://vargagergo-git.github.io/aera-site/notes/how-much-time-asleep-vs-time-in-bed.html

When your watch shows a long night but you still feel short-changed, do you check time asleep first, or time in bed?