Maybe your smartwatch has been telling you your VO2 max for a while now, but you’re not sure how accurate it is. Or maybe you’ve recently been targeted by social media ads for fancy running ...

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Alex Hutchinson is a National Magazine Award-winning journalist and Outside’s Sweat Science columnist, covering the latest research on endurance and outdoor sports. Don't miss a moment of the ...

But to accurately quantify your fitness potential, it’s worth measuring your VO2 max. In the simplest terms, your VO2 max ...