Sleep trackers: what they measure and how far to trust them
Rings, straps and watches are good at telling sleep from wake and at tracking trends. They are much weaker at sleep stages. These guides compare the popular devices and show how to use the data without letting a score run your nights.
Guides
- Oura vs Whoop for Athletes: What the Validation Studies ShowOura and Whoop both track sleep timing and duration well against lab polysomnography, and both are only moderate at sleep stages. Oura has stronger published data for overnight heart rate and HRV. Whoop is a screenless strap built around daily strain and workouts. Choose by form factor, total cost and what you will use the data for.6 min read, 9 sources
- How Accurate Are Sleep Trackers? Sleep, Stages and Oura Ring AccuracySleep trackers are good at detecting sleep and estimating sleep timing and duration, but they miss much of the time you lie awake and are only moderately accurate for sleep stages. Against lab polysomnography, most devices detect over 90% of sleep yet identify wake only 18 to 54% of the time, and match stages roughly 50 to 65% of the time.6 min read, 10 sources