How many studies support VO₂max Training?

Cardiorespiratory fitness (VO2max) is one of the most extensively validated predictors of mortality in the scientific literature, supported by multiple large meta-analyses spanning tens of millions of observations and hundreds of cohort studies, including a scientific statement from the American Heart Association recommending it be tracked as a clinical vital sign. That's backed by 6 published studies in Vitaebase's database, including 3 meta-analyses, the most recent from 2025 -- a modest but real research base.