Oura, Whoop, Garmin, and Apple Watch all measure sleep differently and optimize their scores for different outcomes. Knowing what your device is actually calculating lets you use the score as a tool — not a daily anxiety trigger.
Key Takeaways
- Oura Readiness excels at flagging illness onset and overtraining — it is tuned for negative signals, not performance peaks
- Whoop Recovery is optimized for athletes — its Sleep Need calculation adjusts daily based on your prior strain
- Garmin Body Battery best shows cumulative multi-day recovery debt — it visibly degrades across consecutive poor nights
- Apple Watch gives raw data without a composite score — by design. Build your own 4-metric benchmark.
- Stage accuracy: 50–80% vs clinical EEG across all devices — direction is reliable, exact percentages less so
How to Read Your Score Correctly
- Oura Readiness below 70: Something is physiologically off. Check contributor bars — is it HRV, temperature, or sleep score driving the dip?
- Whoop Recovery below 33% (Red): Reduce training load. This is the device doing exactly what it was designed to do.
- Garmin Body Battery maxing at 75 not 100: Multi-day incomplete recovery. Look at sleep debt across the prior week.
- Apple Watch — build your own baseline: Track sleep duration, efficiency, REM proportion, and overnight average HR. A clear picture emerges in 2–3 weeks.
- Any device — ignore single nights: One bad score is noise. Three or more consecutive low scores are a signal worth investigating.
Device Comparison at a Glance
Oura — Readiness
Best for: illness detection, overtraining flags, long-term wellness. Primary inputs: HRV, RHR, body temp, sleep score.
Whoop — Recovery %
Best for: athletic training load management. Primary inputs: HRV, RHR, sleep performance, respiratory rate.
Garmin — Body Battery
Best for: visualizing multi-day energy depletion and recovery. Charges during sleep, depletes with activity.
Apple — Raw Data
Best for: self-interpreters. No composite score by design. Four metrics to track manually for your own baseline.