If you wear an Oura Ring from Gen3 onward and pay for the membership, Cardio Effort will start rating your workouts within about two weeks. The VO2 max estimate takes longer. It needs at least 30 days of ring data and five outdoor walks, runs or hikes recorded with your phone’s location on. Oura began rolling out both features gradually on October 20, so they may not show up in your app right away.
Automatic VO2 max is part of Oura Labs, the app’s section for experimental features, so you have to enroll in it yourself. Cardio Effort needs no sign-up.
Rings, membership and language
Both features need an Oura Ring Gen3 or later and an active membership, on iPhone or Android. In the US the membership costs $5.99 a month or $69.99 a year. A new ring comes with the first month included. A Gen2 ring gets neither feature.
Oura Labs works only with the app set to English, and Oura says individual Labs features may vary by region. You’ll find Labs in the menu at the top left of the Today tab, and the VO2 max test starts from its list of available features.
How Cardio Effort scores a workout
Cardio Effort measures how hard your heart worked during a workout and for how long. Oura builds it on the training impulse, or TRIMP, a load measure from sports science that combines the minutes of a session with how high your heart rate climbed.
A 2020 paper in Frontiers in Physiology spells out the original version, Banister’s TRIMP. Each minute is weighted by where your heart rate sat between its resting and maximum values, so a hard minute counts for far more than an easy one. Oura doesn’t say which version it uses, only that it compares your heart rate with your own resting rate and baseline.
Each week’s total starts from zero on the first day of the week, and every workout shows a plus figure for what it added. There is no maximum and no score out of 100.
Live workouts count, and so do confirmed automatic detections and activities you add by hand. If the ring was off your finger or lost the heart signal, you get an estimate labeled Est. Cardio Effort. You can raise or lower that estimate by editing the workout’s intensity.
A hard week can show up in your Readiness Score while your body recovers. Oura says no Cardio Effort range sets the next morning’s score directly.
Two Oura pages, two sets of range names
After two weeks of data, Oura places each week’s total in one of five personal ranges. The announcement on Oura’s blog and the help article Oura posted the same day give those ranges different names.
| Where your week lands | Oura’s announcement | Oura’s help article |
|---|---|---|
| Well below your usual | Light | Low |
| Below your usual | Fair | Recovering |
| In line with your usual | Maintaining | Maintaining |
| Above your usual | Building | Improving |
| Well above your usual | Reaching | Reaching |
The announcement builds your ranges from a rolling six-week window of activity. The help article describes Maintaining as effort within your three-week average.
Whichever names your app shows, the order is the same. Two ranges mean less than your usual load, one matches it, and two mean more. Oura calls Maintaining a healthy goal in its own right. It presents Reaching as a cue to plan recovery and says it doesn’t automatically mean you are overtraining.
Lifting scores lower than it feels
Oura’s FAQ warns that a strength workout can feel very hard and still score lower than a session that kept your heart rate up. Cardio Effort follows the heart, not the muscles. Gripping a bar or handlebars can also interrupt the heart signal, and then you get an estimate.
In the Frontiers paper, eight trained men did one all-out functional fitness session, a high-intensity mix of lifting and conditioning moves, and one at a moderate effort. The Banister score put the all-out session only about 10 percent higher. The men’s own ratings of effort put it at more than twice the moderate one.
It was a small study of one kind of session. If lifting fills most of your week, expect lower ranges than your sore legs would suggest.
Automatic VO2 max needs your phone
Automatic VO2 max replaces the six-minute walking test behind the old Cardio Capacity screen. VO2 max is the most oxygen your body can use in hard exercise, measured in milliliters per kilogram of body weight per minute. Oura now estimates it from ordinary outdoor walks, runs and hikes, and the first estimate needs five of them.
On an Oura Ring 5 or any other Oura from Gen3 on, the app takes the route from your phone’s GPS and the ring supplies the heart rate. A walk with the phone left at home won’t count toward the five, and neither will a treadmill run. Rides don’t count either, because Oura lists only walks, runs and hikes.
The surest way to make a walk count is to start it yourself. Tap the plus button on the Today tab, choose Start live activity, pick a walk, run or hike, and keep the phone’s location on.
An automatically detected walk can carry a route if Oura’s location access is set to Always and the app was running in the background before you set off. Force-quitting the app stops location tracking until you open it again. Oura doesn’t say whether a detected walk counts toward the five.
A new ring includes one month of membership, which starts when you pair it. That is about as long as the estimate’s data requirement, so a new owner’s first VO2 max arrives at about the time of the first membership charge.
The VO2 max screen
Once it is ready, you’ll find the estimate under My Health, then Heart Health, then VO2 max. It comes with a category of Low, Fair, High or Peak, a trend line and an alert when it moves in a meaningful way.
Old walking-test results stay on that screen, each labeled by its source, and you can delete any of them. A lab result or a reading from another device can still be added by hand, and it won’t overwrite Oura’s estimate.
Oura’s help article puts a typical change at 2 to 5 percent over six to nine months, so a monthly look at the screen is enough to follow it.
