Oura Ring 5 DC Rainmaker In-Depth Review: Smallest Smart Ring Yet, But Athletes Should Look Elsewhere

DC Rainmaker, one of the most trusted names in sports tech reviews, has published a comprehensive in-depth review of the Oura Ring 5. The verdict is nuanced: this is Oura's best ring yet for sleep and wellness — but athletes should look elsewhere.

Design: 40% Smaller

The Ring 5 measures just 6.09mm wide, down from the Ring 4's 7.90mm — a 40% reduction. Thickness drops from 2.88mm to 2.28mm, and weight falls to 2.0–2.69g (from 3.3–5.2g). DC Rainmaker calls it a genuine engineering achievement: "you forget it's there." This is the most comfortable smart ring ever made.

Battery Life Improvement

Despite the smaller form factor, battery life improved to 6–9 days from the Ring 4's 5–8 day range. Oura squeezed meaningful efficiency from the new sensor array and chip package — impressive given the reduced volume available for the battery.

Blood Pressure Signals — Not What You Think

The new "Blood Pressure Signals" feature does not measure actual blood pressure. It monitors nighttime PPG patterns to detect whether your blood pressure "dips" normally during sleep — a healthy cardiovascular pattern. It flags 30-day trends where the dip doesn't occur. Importantly, this feature is rolling out to Ring 3 and Ring 4 via software update — you don't need a Ring 5 for it.

The Athletes' Problem

DC Rainmaker's sharpest criticism: heart rate data is missing from exported workouts sent to platforms like Strava and TrainingPeaks. Worse, connecting an external Bluetooth HR sensor to the Oura app causes the entire workout file to fail to export to third-party apps. His verdict is blunt: "If you already have a watch or smart band, there's no reason to get an Oura Ring in 2026" for sports-focused users.

What This Means for Buyers

If sleep and wellness are your priority, the Oura Ring 5 is the best in class. If you're an athlete who needs workout data in training platforms, pair any sports watch with the ring for sleep only — or consider the Ring 4 at $218 on eBay (same Blood Pressure Signals feature coming via update). The RingConn Gen 2 at $299 offers better sport data export with no subscription. Compare all options in our smart rings guide.