VO2 max – the highest rate at which your body can use oxygen during hard exercise – is one of the most validated fitness metrics there is.
The American Heart Association scientific statement called cardiorespiratory fitness a stronger predictor of long-term mortality than smoking, high blood pressure, or high cholesterol, and argued it should be checked as routinely as any other vital sign.
In this guide, we explain what counts as a good VO2 max at different ages from Ultrahuman Ring users.
What’s a good VO2 max by age?
Aerobic capacity declines steadily through adulthood, which means there’s no single fixed number that counts as “good” – a score has to be read against your own age and sex, not a flat scale.
Across 159,203 Ultrahuman Ring members, estimated VO2 max runs consistently higher in men than women and falls in both sexes from the 18–29 group into the 40s:
| Age band | Men (mL/kg/min) | Women (mL/kg/min) |
|---|---|---|
| 18–29 | 44.3 | 40.2 |
| 30–39 | 41.3 | 38.1 |
| 40–49 | 39.0 | 37.0 |
Source: Ultrahuman Ring data, overnight VO2 max estimate by age band and sex, median values.
Ultrahuman’s own published breakdown doesn’t yet extend past the 40s, but the direction beyond that is well established elsewhere: a large registry of laboratory fitness tests across thousands of adults puts the average decline at roughly 10% per decade, and the Baltimore Longitudinal Study of Aging found that pace accelerates sharply after 70, to more than 20% per decade.
Track the direction your own number moves over months rather than the absolute figure on any single day.
How to improve your VO2 max
Aerobic conditioning is the main lever – the kind of training Zone 2 work is built around , since it’s the intensity that most directly trains the heart and lungs’ capacity to deliver oxygen.
In a 12-month Ultrahuman study of 442 members, those who improved consistently saw their estimated fitness age fall by an average of 3.24 years, alongside a genuine drop in resting heart rate .
Better sleep efficiency, more REM sleep, longer total sleep, and more daily steps were each independently linked to the same improvement, beyond training alone.
Reviewed by Mukul Mittal, MD.
THE AUTHOR
