I see my sleep broken down into light, deep, and REM, but how does WHOOP actually track that?
WHOOP figures out your sleep stages by looking at things like your heart rate variability, breathing, and how much you move during the night. It breaks sleep down into Awake, Light, REM, and Deep stages based on those things.
The cool part is, it actually adjusts to your own sleep patterns every month to keep things accurate. It even picks up naps and shows you the sleep breakdown for those.