Oura Ring 4

The Oura Ring 4 is the single best device for sleep tracking and recovery monitoring. Multiple independent validation studies have shown its sleep staging accuracy approaches polysomnography (the clinical gold standard). The continuous temperature trend is uniquely useful for detecting early illness, tracking menstrual cycles, and identifying overtraining. The Readiness Score — derived from HRV, resting heart rate, body temperature, and sleep quality — is the most reliable daily recovery metric we have tested. Generation 4 adds VO2 max estimation, making it a more complete longevity tracker. The ring form factor is its secret weapon: it is comfortable enough that users actually wear it 24/7, producing complete data sets that wrist-based trackers rarely achieve. The main limitation is that it does not track exercise in real time — pair it with a Garmin for a complete system.