Wearables · Health metrics
VO2 max (cardiorespiratory fitness)
VO2 max measures cardiorespiratory fitness, one of the strongest predictors of long-term health. How it is measured in a lab, how wearables estimate it, and how to improve it.
Written by LON6EVITY Editorial Team · Last updated
What it is
VO2 max is the maximum amount of oxygen the body can use during intense exercise, usually expressed in millilitres per kilogram per minute. It is the standard measure of cardiorespiratory fitness.
Why it matters
A 2009 meta-analysis in JAMA (Kodama et al.) found that higher cardiorespiratory fitness was associated with lower risk of death from all causes and of cardiovascular events. In 2016 the American Heart Association argued that fitness should be assessed as a clinical vital sign.
Lab test vs wearable estimate
In a lab, VO2 max is measured directly by analysing breathing gases during a maximal exercise test. Wearables estimate it from heart rate response to walking or running and personal data. Garmin, for example, describes its VO2 max value as an estimate. Estimates are useful for trends but can differ from lab values.
Improving it
Regular aerobic exercise, including some higher-intensity sessions, generally raises VO2 max. Improvements are possible at any age.
Factors that can affect the result
- Aerobic training
- Age
- Genetics
- Body weight
- Altitude
- Device and algorithm
Questions people commonly ask
- Is my watch's VO2 max accurate?
- It is an estimate. It tends to be most useful for following your own trend rather than as an exact value.
- Can VO2 max improve after 50?
- Yes. Regular aerobic training improves cardiorespiratory fitness at any age.
Related topics
Bring your health data together
What does this mean for your own health data? Log your results, follow trends over time and bring an organised summary to your next doctor's appointment.
Sources
- Cardiorespiratory fitness as a quantitative predictor of all-cause mortality and cardiovascular events in healthy men and women. Kodama S et al., JAMA, 2009.
- Importance of Assessing Cardiorespiratory Fitness in Clinical Practice: A Case for Fitness as a Clinical Vital Sign. Ross R et al., American Heart Association, Circulation, 2016.
- VO2 Max. Garmin.