For many of us we’re running for fun, recreational sports or health. We’re not clocking elite level VO2s. But we still notice the little value pop up on our running watches and wonder “what does this mean” or “is this even accurate?”.

I’ve tested 100’s of VO2 maxes over the years. And my first ever scientific study was actually on wrist based heart rate measurements back when they were newer. While these have come a long long way — our watches can’t QUIET replace a true VO2 max test. However, with a few tips and tricks we can get them pretty darn close!

In labs many practitioners or researcher use VO2 max prediction tests due to inaccessibility to metabolic testing equipment. We can get these predictions pretty close to true values (or within range) if we can assume 1) heart rate is accurate 2) people are moving efficiently and 3) intensity vs heart rate are matched.

I would assume these watches use similar or these classic lab based prediction approaches in their algorithms. Which means the biggest things here that will help you get a more accurate measure is 1) more accurate heart rate 2) being efficient in your activity!

With using a chest strap to be THEEE most accurate way to assess heart rate during exercise. Many companies offer these to purchase as an add on to your watch! But if you don’t want to buy one … simply subtract 10% give or take!

Now I know it’s an ego blow to hear that these may be over predicting your VO2 max by upward of 10% with your wrist based watches …. But don’t let that defeat you! Your VO2 is not the end all he all of your running performance. And while genetics limits this people can improve it by 10-50% with training depending on their exercise history!

We cover this science, how to test your VO2, how to improve it and how this relates to RUNNING ZONES + smart training all in my ebook ENDURE if you want to learn more!

And as always, if you found this helpful please consider sharing!