We Studied Sleep With 15 Wearables. This is the WINNER!

Study Overview and Initial Results00:00

Together with the University of Salzburg, ran one of the biggest wearable sleep studies ever to determine which wearable best tracks sleep stages: deep sleep, light sleep, REM sleep, and awake time. Initial analysis shows clear winners and losers. Overview plot positions best devices top right: horizontal axis Cohen's Kappa, vertical axis average sensitivity (agreement with individual sleep stages). Clear winners: Apple Watch, Oura Ring, latest Whoop algorithm. Below: old Fitbit algorithm, old Whoop. Worst: Garmin, Circular Plus Ring. Included Sleep 2 (University of Salzburg app), take with grain of salt due to vested interest. Check devices (all light sleep average night, median polysomnography) perform worse than wearables.

Top Performers and Metrics Explanation01:02

Devices: Oura Ring, Apple Watch, Fitbit, Whoop, Garmin. Rob is post-doctoral scientist specializing in biological data analysis. Sleep 2 did best by these metrics, but potential bias. Manufacturers likely optimize for Cohen's Kappa and average sensitivity. Apple, Oura, Whoop (new) outperform Garmin. Fitbit has newer algorithm (untested here) that shows improvement in early testing, potentially top performer.

Study Setup02:31

20 participants (18 after 2 dropouts), tracked 5 days: Monday-Friday. Each night different focus:

• Night 1: Habituation to polysomnography (PSG) reference device at home.