Wearables

For Oura, WHOOP, Apple Watch and Garmin users. Score contributors are checked against each company’s own public documentation. This site is not affiliated with any of them.

What sleep scores measureWhat goes into the sleep and readiness scores from Oura, WHOOP, Apple Watch and Garmin, according to each company's own documentation.
- Evidence: Some
- Low effort
- Free
- Works: today
How accurate are wearables?Sleep trackers are good at telling sleep from wake and at total sleep time. They are weaker at spotting time awake and at sleep stages.
- Evidence: Some
- Low effort
- Free
- Works: today
HRV, resting heart rate and temperatureWhat your overnight HRV, resting heart rate and skin temperature mean, what moves them, and why to compare them only with your own baseline.
- Evidence: Some
- Low effort
- Free
- Works: 1–3 weeks
Which habits change which metricA table of common sleep habits against the numbers your wearable shows, with the direction of each effect, how sure the research is, and where nobody has looked.
- Evidence: Some
- Low effort
- Free
- Works: tonight to 2 weeks
Orthosomnia, or worse sleep from score anxietyWorrying about your sleep score can make you feel worse and sleep worse. How to tell if it's happening to you, and what to do.
- Evidence: Weak
- Low effort
- Free
- Works: 1–2 weeks