VO2 max can be measured through direct testing or estimated using protocols like the Cooper test or a mile run on a track.

“it's a $100 test maybe $150 you know test you can go and find any in most cities they would be able to do this for you there are also free versions you can estimate it you could run a Cooper's test or various versions of these tests which we've talked about elsewhere and you can just look that up to if you want to run know how to do that protocol so you don't need to even spend a dollar to estimate your V2 max if you're willing to go down to a track and run a mile or something”