The only accurate way to measure VO2 max is to wear a face mask and actually measure the amount of oxygen flowing through the mask and to your lungs. Obviously, the Apple Watch doesn’t come with a face mask attachment you can connect via Bluetooth, yet. So how does Apple Watch measure V02 Max?
Apple watch uses a metric known as “Predicted V02 Max” and is based on your heart rate activity during exercise. Since the relationship of the heart rate and the VO2 max varies between everyone, it’s not a perfect indicator of your VO2 max, but with regular testing, you can see the trends of improvement or decline in relation to your own VO2 max baseline.
There have also been reported issues with Apple Watch’s heart rate sensor and its lack of accuracy, especially when comparing heart rate sensors you strap on directly to your chest. We’ve been experimenting with the chest strap ourselves so we’ll update you on the findings and comparisons between chest straps and the Apple Watch soon.
Although the VO2 max measured on the Apple Watch is an interesting metric, the lack of accuracy in comparison to your real VO2 max makes it a less useful stat to track. Hopefully, as technology and sensors improve, the VO2 max measurement on the Apple Watch will come closer to your actual VO2 max.
Nevertheless, for those who love numbers and like to track as many stats as they can, this is an article on how to measure your VO2 max using the Apple Watch.