What VO₂ max means
VO₂ max is the maximum amount of oxygen your body can use during intense exercise, measured in millilitres of oxygen per kilogram of body weight per minute (ml/kg/min). It is one of the best single indicators of aerobic fitness: the higher your VO₂ max, the more work your heart, lungs and muscles can sustain.
The two methods here
The Cooper test estimates VO₂ max from how far you run in 12 minutes: VO₂ max = (distance in metres − 504.9) ÷ 44.73. The resting heart rate method needs no running — it uses VO₂ max ≈ 15.3 × (maximum heart rate ÷ resting heart rate), with maximum heart rate estimated as 208 − 0.7 × age. Both are estimates; the Cooper test is usually closer for trained runners.
How does Garmin calculate VO₂ max?
Garmin watches don't make you run a fixed test. Using technology from Firstbeat, they continuously compare your running pace (or power) against your heart-rate response during normal activities. When your heart works less to hold a given pace, your estimated VO₂ max rises. It is essentially the same principle as the tests here — the relationship between effort and heart rate — but sampled automatically over many runs rather than in one 12-minute block.
Frequently asked questions
Is a calculator as accurate as a lab test?
No. A laboratory test with a gas-analysis mask is the gold standard. Field formulas like these are useful estimates for tracking change over time, typically within a few points of the true value.
What is a good VO₂ max?
It depends heavily on age and sex, but broadly, values above about 45 ml/kg/min are excellent for most adults, while endurance athletes often exceed 55–60. Compare against your own trend rather than a single benchmark.