Does a Smart Ring Have VO2 Max? (2026 Answer)
Oura, Ultrahuman and Amazfit rings estimate VO2 max in 2026 - none measures it. How the estimates work, and when a watch or lab does better.
VO2 max - the maximum oxygen your body can use during hard exercise - has become the headline longevity metric, so it is fair to ask whether the ring on your finger can track it. The honest answer is: sort of, with caveats worth understanding before you trust the number. Here is what each ring actually offers in 2026, how the estimates are made, and when a watch (or a lab) is the better tool.
How can a ring estimate VO2 max without a mask?
Submaximal estimation, explained
A laboratory VO2 max test has you exercise to exhaustion while a mask measures the oxygen in every breath. No wearable does this. Instead, wearables use submaximal estimation: they watch how your heart rate responds to a known, moderate workload and map that response onto population equations. A fit heart does the same work at a lower rate, so the relationship between effort and heart rate predicts aerobic capacity reasonably well - within roughly 10-15% for most people, which is fine for tracking trends and rough for absolute numbers.
The catch for rings is the 'known workload' part: without GPS pace or power data from real workouts, a ring has less to anchor its estimate against than a running watch does, which is why ring estimates lean on structured tests or profile assumptions.
Which smart rings offer a VO2 max estimate in 2026?
Oura, Ultrahuman and Amazfit - each differently
Oura (Ring 4 and 5): Cardio Capacity. The most developed implementation. Your first number is a population estimate from age, sex, height and weight; the app then prompts a six-minute outdoor walk test, using distance travelled (via your phone's GPS) and heart rate to personalise it. Because it needs real distance, the test will not work on a treadmill. You can also type in a lab result or another wearable's value, and Oura will use that instead.
Ultrahuman (Ring Air and Pro): VO2 max PowerPlug. An optional add-on inside the app that derives an estimate from your physiological data. No subscription needed.
Amazfit Helio Ring. Surfaces a VO2 max estimate through the Zepp app it shares with Amazfit watches.
Samsung Galaxy Ring and RingConn: no native VO2 max figure from the ring alone as of mid-2026 - in Samsung's ecosystem the estimate comes from a Galaxy Watch's workout data, and RingConn's app focuses on recovery metrics rather than an aerobic-capacity score.
Should you trust a ring's VO2 max number?
Trends yes, absolute values less so
Treat any wearable VO2 max as a trend instrument. The absolute number may sit several points from a lab value, but if your estimate climbs from 38 to 42 over six months of training, that direction is meaningful. Rings are at their weakest for absolute accuracy (no workout pace data), and at their strongest for consistency - you wear them constantly, so the inputs are stable. If you are a runner or cyclist optimising training, a GPS sports watch estimates VO2 max better; if you want a longevity-oriented trend line with zero effort, a ring estimate is genuinely useful. For the metric rings do lead on, see our resting heart rate accuracy guide.
