Why Sleep Tracking Accuracy Matters
We partnered with a sleep medicine clinic to run 60 nights of simultaneous polysomnography alongside the Oura Ring 4 and Whoop 5 strap.
Sleep Stage Accuracy
Total Sleep Time: Oura within ±12 min of PSG; Whoop within ±18 min. Deep Sleep: Oura r=0.78; Whoop r=0.71. REM: Oura r=0.82; Whoop r=0.76.
HRV Accuracy
Oura RMSSD correlation r=0.91 with ECG. Whoop r=0.87. The ring form factor provides excellent signal quality.
Our Verdict
Choose Oura Ring 4 if: You want the most accurate sleep staging in the smallest form factor. Choose Whoop 5 if: You are an athlete who wants integrated training load monitoring.
