Guide · October 23, 2026
VO2 max by age and sex: what the FRIEND registry shows
VO2 max, the most oxygen your body can use during hard exercise, is one of the strongest single predictors of long-term health. Most smartwatches now estimate it. To know whether your number is good, compare it with people your age and sex.
Median VO2 max (mL/kg/min), treadmill tests
| Age | Men | Women |
|---|---|---|
| 20–29 | 48.0 | 37.6 |
| 30–39 | 42.4 | 30.2 |
| 40–49 | 37.8 | 26.7 |
| 50–59 | 32.6 | 23.4 |
| 60–69 | 28.2 | 20.0 |
| 70–79 | 24.4 | 18.3 |
Source: Kaminsky LA et al., Reference standards for cardiorespiratory fitness measured with cardiopulmonary exercise testing: data from the FRIEND registry, Mayo Clinic Proceedings 90(11):1515–23 (2015). Later FRIEND updates report slightly different medians.
Reading your watch’s number
- Watch values are estimates from heart rate during outdoor walks and runs. They are usually within a few points of a lab test, and they are most useful for tracking your own trend.
- VO2 max falls about 10% per decade on average. Staying level as you age is a real achievement.
- Two harder cardio sessions a week (intervals, hills, a tempo run) move it more than extra easy minutes.
Connect your ring or watch data and see your VO2 max percentile for your age and sex, along with sleep, steps and resting heart rate. See your first score