VO2max is the gold standard for running ability.

Many sports watches claim to estimate VO2max. But you should know that these watches simply calculate it retroactively based on pace and heart rate, so the margin of error can be significant.

eal-World Comparison

I wore both the Garmin Fenix 7 and the Polar Vantage V2 during a treadmill incremental load test at a sports physiology lab, while my VO2max was measured directly using a gas analyzer.

Garmin estimated 48.2 ml/kg/min; the actual measurement was 51.3, resulting in a 6% error.

Polar’s estimated value was 50.1, while the actual measured value was 51.3, resulting in a 2.3% error.

Among 10 test subjects, the average absolute error was 5.2%, with the maximum error reaching 12%.

Factors affecting accuracy: Watch estimates rely on accurate body weight, maximum heart rate settings, and running economy. If you enter an incorrect weight or have not performed a maximum capacity test, the error will be greater.

Expert endorsement: The American College of Sports Medicine (ACSM) notes that watch-estimated VO2max can be used for long-term trend tracking but should not be the sole basis for training zones.

Don’t get hung up on absolute numbers; focus on relative changes.

Venus Smart Shop helps you use VO2max more effectively.