Oura has announced the Ring 5, and the headline is size: the company says it’s up to 40% smaller. But the more useful question for anyone deciding whether to buy is what changed underneath — the sensor, the battery and a new set of cardiovascular features. Here’s a clear-eyed look at what’s actually new, and what to be sceptical about.
What’s actually new
| What’s new | What it actually means |
|---|---|
| Up to 40% smaller | Oura’s claim for thickness, weight and size. Comfort matters mainly because a ring you barely notice is one you actually keep wearing. |
| ~7 days battery | A few days longer than before — a meaningful quality-of-life gain for a device meant to be worn continuously. |
| Redesigned sensor | More powerful LEDs and better skin contact. Reports suggest fewer signal pathways (around 12 rather than 18), which sounds like a downgrade but can still improve quality if the remaining signals are better placed. |
| “Blood pressure signals” | Not a blood-pressure reading. No systolic/diastolic numbers, and no substitute for a validated cuff — see the warning below. |
| Nighttime breathing | A longer-term view of breathing patterns and disturbances during sleep. |
| Health radar, GLP-1 insights | Software-layer features. Useful potentially, but they say nothing about whether the sensor data itself got better. |
What to expect from performance
Oura’s strength has always been the night. In independent sleep-lab testing, its sleep-staging algorithm has ranked among the best available, and nighttime heart rate and HRV are measured under near-ideal conditions — you’re lying still. The reasonable expectation is that the Ring 5 stays strong here, perhaps marginally better.
Exercise is the opposite story. Optical sensing on a finger is genuinely hard: you grip things, blood flow shifts, and fit changes with temperature. No smart ring has yet performed well for exercise heart rate in this kind of testing. One telling detail: reports suggest live workout heart rate may require connecting an external heart-rate monitor rather than using the ring itself — which is not what you’d expect from a device confident in its own cardio tracking.
This breakdown is based on the announcement analysis by The Quantified Scientist (Rob, a post-doctoral scientist), who bought the Ring 5 with his own money and plans full testing against a Polar H10 ECG chest strap. No measured accuracy data existed at the time of the announcement. We summarise his analysis and add context. Watch the full video → (The Quantified Scientist on YouTube).
The honest summary
It’s a sensible, iterative launch rather than a breakthrough: smaller, longer battery, redesigned sensor, and a bigger push into cardiovascular insight — a direction Apple is moving in too. If the size has been putting you off wearing a ring, that alone might sell it. If you want proof the sensors are better, that evidence doesn’t exist yet.
Prefer a watch to a ring? Compare 36 models by sensors, battery and price in our free Smartwatch Finder →, or read smartwatch vs Oura Ring for health tracking.
Frequently asked questions
Does the Oura Ring 5 measure blood pressure?
No. It reports “blood pressure signals” — indirect cardiovascular patterns, mostly overnight. It does not give systolic/diastolic values and is not a replacement for a validated blood-pressure cuff. If you’re monitoring hypertension, use a proper cuff and speak to your doctor.
Is the Oura Ring 5 accurate?
Nobody knows yet — independent testing hadn’t been done at the time of the announcement. Based on Oura’s track record, sleep and nighttime heart rate are expected to remain strong. Exercise heart rate is the open question.
Is it good for tracking workouts?
Historically, no smart ring has performed well for heart rate during exercise, and fingers are a hard place to measure while you grip handlebars or lift. Reports also suggest live workout heart rate may require pairing an external heart-rate monitor.
Should you upgrade from the Ring 4?
If the smaller size solves a comfort problem for you, that’s the clearest reason. If you’re hoping for a leap in exercise accuracy, wait for independent testing before spending.
Sources
Announcement analysis: The Quantified Scientist — Oura Ring 5. No independent accuracy data available at time of writing. Context added by Smartwatch Trends. See our research process.