VO2 Max is the latest fitness metric getting runners all worked up. It’s the measure of your body’s ability to burn aerobic energy, so in theory, it should help you run faster while expending less effort. But how accurate are VO2 Max estimates on fitness trackers like the Apple Watch, Garmin, Polar and Suunto? We recently asked Dave to test the accuracy of these devices and compare them with a specialized lab VO2 Max score.

While the best vo2 max watch is only as good as its heart rate tracking, some trackers come pretty close to a lab score. In order to calculate a VO2 Max estimate, a fitness tracker needs a few different stats like your age and gender, GPS activity for speed and distance and heart rate data. The more of these stats you can provide to the tracker, the better the VO2 Max estimate will be.

Breath by Breath: Unveiling the Best VO2 Max Monitoring Watches in 2024

To get the most accurate VO2 Max estimate, you should always use a chest strap heart rate monitor when exercising instead of the wrist-based sensor. This will give you up to a 2% improvement in the accuracy of your VO2 Max estimate.

The best vo2 max watch on the market is the Garmin Forerunner 45. It provides a VO2 max estimate that’s based on several of your personal stats and the data collected by the GPS and heart rate sensors on your Forerunner. In addition to VO2 max level tracking, this model also has great battery life and offers sleep, stress and hydration monitoring as well as a whole host of other advanced sports and health metrics.