sleep
How your band guesses whether you're in deep sleep or REM
Without seeing your brain, a band slices the night into 30-second chunks and guesses your sleep stage from pulse, HRV and movement. Here's how it works.
Sleep
What time Spain falls asleep: data from 36,700 real nights
Spain falls asleep at 00:30, an hour later than Germany. Data from 36,700 nights in five countries, ahead of the 25 October clock change.