Cardio fitness in Apple Health
VO2 max on Apple Watch and iPhone.
Apple Watch estimates cardio fitness. The VO2 Max app reads these Apple Health values and adds trends, reference ranges, widgets and running and cycling estimates.
Dashboard and trends
- Latest value, seven-day average and selected-range average
- Personal best and percentage changes
- Filters from one week to all available values
- Age- and sex-based reference ranges
Running and cycling estimates
VO2 max, weight and optional power data are used for W/kg, FTP and modeled race-time estimates. Existing HealthKit power and FTP values remain visible for comparison.
On the phone and watch
- Home Screen and Lock Screen widgets follow the selected range
- Apple Watch app and supported complication families
- Manual refresh and Health permission diagnostics
Where can I find Apple Watch VO2 max?
Apple stores the estimate in the Health app on iPhone under Heart and Cardio Fitness. The VO2 Max app reads the values you permit and makes them available as trends, widgets and watch complications.
How does Apple Watch estimate VO2 max?
Apple Watch Series 3 or later uses heart and motion sensors during Outdoor Walk, Outdoor Run or Hiking workouts. Indoor sessions and cycling workouts do not create this cardio-fitness estimate.
How accurate is Apple Watch VO2 max?
It is an estimate, not a direct laboratory measurement. A trend across several comparable outdoor workouts is usually more useful than one value. Current Health details, a good watch fit and calibration improve the input data.
Why is there no VO2 max value?
Apple says a first estimate can require at least 24 hours of wear followed by several suitable outdoor workouts and passive measurements. Also check Health details, heart-rate access, Wrist Detection and the fit of the watch.
What is a good cardio-fitness value?
There is no single threshold for everyone. Apple classifies cardio fitness by age and sex. The supported range is 14 to 65 ml/kg/min and classifications are available from age 20. The app shows the reference range for the current value.
Current App Store screenshots
Data source and limits
The app displays existing cardio-fitness values from Apple Health; it does not measure VO2 max itself. Running times, W/kg and FTP are separately labelled model estimates, not medical measurements.