Your Apple Watch Just Got Better!

Apple Updates Sleep Stage Tracking Algorithm00:00

Apple updated their sleep stage tracking algorithm across their entire lineup, from Apple Watch Ultra to Apple Watch SE, for better sleep stage tracking. This follows a recent video highlighting issues with deep sleep tracking on Apple Watch. Provides nuance and shows new results from Apple.

New Appendix in Apple's Sleep Stage Tracking Paper00:32

Days after uploading the deep sleep problem video, Apple added an appendix to their sleep stage tracking paper. Original printed version (2-3 weeks ago) ended without appendix; now online version on iPad includes it. Appendix states: in 2025, improvements made to sleep stage classification algorithm as part of iOS 26.0 and watchOS 26.0. Unclear exact rollout timing or if immediate with 26.0 worldwide.

Improvements Discussed

Discusses improvements, comparison to competition, and that it's still good despite ongoing deep sleep issues.

Introduction and Background01:02

Rob, post-doctoral scientist specializing in biological data analysis.

Apple improved detection of quiet wake moments (very still before/after sleep but awake). Common issue across devices; example: sitting still in cinema misdetected as asleep. Less common now, but persisted with older Oura algorithm. Apple Watch uses only accelerometer sensor data (movement), not heart rate or beat-to-beat intervals, which sleep researchers say are important for good staging. Likely for battery life savings.