What is VO2max and why is it the most important fitness metric for longevity?

VO2max is the maximum rate of oxygen consumption during maximal exertion, expressed as mL/kg/min, it is the single most powerful predictor of all-cause and cardiovascular mortality in men: moving from the lowest to the second-lowest quintile of VO2max for age reduces all-cause mortality by approximately 50%, a larger reduction than quitting smoking, treating hypertension, or optimizing cholesterol (Kokkinos et al., JACC, 2022).

The 50% mortality reduction number from the landmark Kokkinos et al. (2022) paper deserves its own paragraph. Moving from "very low fitness" to "low fitness", not from sedentary to elite, cut mortality risk by half. The implication is that the most dangerous place to be on the fitness spectrum is the bottom quintile, and the largest gain is available to the men who most need it. The men most likely to be in the bottom quintile of VO2max are sedentary men 40–55 with desk careers who do not exercise consistently, precisely the SDE avatar.

Honesty Scale: Solid (1). VO2max as a mortality predictor is supported by dozens of large prospective cohort studies including the ACLS, Cooper Center Longitudinal Study, and Kokkinos et al.

What to do: Know your estimated VO2max. The Rockport 1-mile walk test, or a 12-minute Cooper run test, gives an estimate that correlates at approximately r=0.88 with laboratory measurements in untrained men. If your estimated VO2max is below 30 mL/kg/min at age 40–50, this is the single most important number to improve.

For the full picture, read The Stamina Deep Dive