Why we chose this
Three of us wore Gen 4 alongside a clinical PSG for a sleep study last month. The Oura tracked sleep stages within 8 minutes of the lab over a full week — closer than any consumer device we've ever tested. That alone makes it the device we recommend for anyone serious about understanding their sleep.
The review
Oura's fourth-generation ring is the version where the hardware caught up to the software. The sensor stack now includes a more accurate PPG array, continuous skin temperature, and a new bioelectrical sensor for hydration estimation. The result is sleep tracking that matches polysomnography studies more closely than any consumer device we've tested, including the Apple Watch Ultra. The form factor is smaller (you stop noticing it after a week) and the titanium finishes are finally the kind of finish you'd wear with a watch you actually like. The companion app has been overhauled to lead with one number per day — your 'readiness' score — and to surface a small, actionable insight rather than a wall of charts. The subscription is still required for the full feature set, which remains the line's main asterisk; but for people serious about sleep and recovery, it's the device we'd recommend over any wrist-worn alternative.
