Oura announced Cardio Effort and automatic VO2 Max on October 20, 2026, helping ring owners distinguish workout strain from aerobic fitness—and update the latter without a dedicated walking test.
For existing owners, these are software additions: both support Oura Ring Gen3 and later with an active membership, on iOS and Android. Gen2 is excluded. Cardio Effort is rolling out gradually; automatic VO2 Max is an optional experiment in Oura Labs.
Workout effort and aerobic capacity answer different questions
Cardio Effort combines exercise duration and heart-rate intensity to estimate cardiovascular strain. Its weekly total puts that demand in context against your recent activity. A long, easy walk can accumulate similar effort to a shorter, harder session.
VO2 Max describes the maximum amount of oxygen your body can use during intense exercise. Oura expresses it in milliliters per kilogram of body weight per minute, or ml/kg/min. As Oura’s explanation of Cardio Capacity describes, it reflects the coordinated work of your heart, lungs, circulation, and muscles. Think of it as an estimate of the aerobic capacity you bring to an activity.
The distinction matters after lifting weights: Cardio Effort tracks cardiovascular demand, so a modest value does not establish that your muscles had an easy workout.
How to read your Cardio Effort week
Your weekly total starts over each week. A workout’s plus value shows its contribution; the total has no fixed maximum and is not a percentage.
According to the Cardio Effort support guide, Oura needs at least 14 days of data to establish the initial score. After calibration, look in workout summaries, the Today card, or the Activity screen’s weekly graph. Longer views cover one, three, or six months as data accumulates.
There is one wrinkle when interpreting the bands. As of October 21, the announcement lists Light, Fair, Maintaining, Building, and Reaching, with a rolling six-week baseline. The help page lists Low, Recovering, Maintaining, Improving, and Reaching, and describes Maintaining against a three-week average. Neither page explains the difference. Use the wording in your app, understanding that the bands compare you with your own recent history; the exact baseline period remains unclear.
A higher band does not guarantee improved fitness, and Reaching does not by itself establish overtraining.
Automatic VO2 Max needs its own calibration
Oura already offered VO2 Max under the name Cardio Capacity. Its existing workflow starts with a population-based estimate using profile information such as age, sex, height, and weight. A dedicated six-minute walking test then uses heart rate and distance to refine the estimate. The automatic option lets qualifying outdoor activities supply the data instead.
To try it, open the menu at the upper left of Today, choose Oura Labs, and select the feature when available. Oura’s Labs overview explains how to opt into individual experiments. Participation is voluntary; you can stop testing a feature.
The current Labs requirements specify two conditions for the first automatic estimate:
- At least 30 days of Oura data.
- At least five qualifying outdoor walks, runs, or hikes with GPS location services enabled.
Those are separate requirements. Five workouts alone are insufficient, and 30 days of ring wear alone are insufficient. Oura says 30 days of data, not a mandatory new month of waiting after enrollment. It does not specify whether earlier workouts count toward the initial five.
Once available, the estimate appears under My Health > Heart Health > VO2 max and refreshes with further qualifying activity. The rollout began October 20. Labs is currently English-only, individual feature availability can vary by region, and experiments can change or be removed. These conditions matter if another member sees an option that your app does not.
Oura says VO2 Max changes slowly, so another qualifying workout need not produce a different number.
Your phone still needs to come along
The convenience depends on how you exercise. Oura’s location-services instructions require you to carry your phone for location-based activity data. Open the Oura app before setting out and leave it running in the background. Force-quitting it stops location tracking until you launch it again.
Check both the app’s location setting and the phone’s permissions. Oura recommends allowing location access at all times so it can capture the beginning of an activity, while noting that this may increase phone battery use. You can revoke the permission. If you prefer exercising without your phone, that preference limits the usefulness of this GPS-dependent feature.
Indoor cycling and weight sessions are outside the documented outdoor walking, running, and hiking requirements. A busy gym week therefore does not necessarily supply the activities needed to refresh automatic VO2 Max.
Check the workout record before judging the number
Cardio Effort can show an estimated value when heart-rate data is missing or insufficient. Gripping weights or handlebars can leave gaps in the heart-rate trace. An entry in your weekly total does not always represent a workout with a complete pulse recording.
For everyday logging, Oura’s workout-recording guide offers several routes. You can confirm a detected activity, start an activity from the Today tab’s plus menu, or add a missed session afterward. Unrecorded or unconfirmed sessions do not contribute to Cardio Effort. Before saving, check the activity type, start time, and duration. A detected session with the wrong boundaries deserves attention before you draw conclusions from its score.
Automatic Activity Detection requires an activity to last at least 10 minutes. That explains why a short session may never appear for confirmation. This detection threshold does not establish a minimum duration for Cardio Effort or automatic VO2 Max. Oura also lets you dismiss an incorrectly detected activity, which is useful when an ordinary task has been mistaken for a workout.
If heart-rate recordings keep disappearing, check Activity Heart Rate in Settings > Activity. Turning it off leaves automatically detected activity information in the app but removes its heart-rate information. Oura also specifies at least 5% ring battery for automatic activity heart-rate recording. A workout listing and a usable pulse trace are separate things to check.
For a manually added session, enter the duration and intensity carefully. Oura’s manual-activity instructions offer easy, moderate, or hard intensity and let you revise manual entries. A manually reconstructed workout can fill a gap in your log; it cannot recreate a pulse recording the ring never captured.
Keep an estimate in perspective
The automatic feature changes how Oura obtains an estimate. Direct laboratory VO2 Max testing involves a different process: the University of Virginia’s exercise physiology laboratory describes progressively harder treadmill or bicycle exercise while wearing a metabolic mask. Convenience alone does not establish that an estimate from routine activities has equivalent accuracy.
Oura’s Cardio Capacity guide explicitly describes the older walking test as less accurate than laboratory testing, with limitations for highly trained athletes and at altitude. Those caveats describe that walking test; they do not quantify the accuracy of the new automatic method. Likewise, the Low, Fair, High, and Peak capacity categories provide age-group context, rather than an assessment of one workout.
Externally saved laboratory or wearable results remain separate and cannot overwrite Oura’s automatic estimate. Check each entry’s source before comparing numbers.
If the features have not appeared yet
If either feature is missing, start with the latest Oura app and the relevant calibration requirements. Oura’s iOS and Android release notes say new features may arrive gradually and on different platform schedules. Current app requirements are iOS 16 or later, or Android 11 or later with Google Play services, plus Bluetooth 5.0. Updating is the first check; it does not guarantee that a gradual rollout has reached your account.