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The Verdict
Best for those who prioritize comfort and discretion. The ring form factor is ideal for sleep tracking, though the optional subscription is frustrating for a premium hardware purchase. The Gen 4 improves on accuracy and battery life over previous generations.
Pros
- Extremely comfortable and discreet
- Excellent sleep tracking
- All-titanium design
- Best-in-class PPG accuracy for a wearable
- Improved 7-8 day battery life
Cons
- Optional subscription for full features
- Ring sizing can be tricky
- Less accurate during activity
- Locked ecosystem
- Must remove for many sports and activities
How It Measures HRV
Oura uses infrared PPG sensors on the underside of the ring, measuring from your finger's palmar arteries. A 2025 accuracy study ranked Oura Ring 4 among the most accurate consumer wearables for PPG-based measurements. Finger placement provides better arterial access than wrist sensors.
Sleep Focus
Oura excels at nighttime HRV tracking. It calculates your HRV during your deepest sleep phases and presents a "Readiness Score" each morning that factors in HRV, sleep quality, and recent activity.
What's New in Gen 4
Released October 2024, the Oura Ring 4 features an all-titanium design (no plastic inner), improved sensor coverage for better accuracy during sleep, and extended battery life of 7-8 days. The concave inner surface provides better skin contact for more consistent readings.
Activity Limitations
The ring form factor has a significant drawback: you'll need to remove it for many sports and activities. Basketball, rock climbing, weightlifting, CrossFit, martial arts, and any activity involving gripping or hand impact can damage the ring or your finger. Many users keep the ring off during workouts entirely, which means missing activity data that wrist-based trackers would capture. If real-time workout tracking matters to you, consider a wrist device instead.
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