Estimate your VO2 max — your body's maximum oxygen uptake — using either your resting heart rate or a simple 1.5-mile run test.
VO2 Max is the maximum rate at which your body can consume oxygen during intense exercise. It's the gold standard measure of cardiovascular fitness and aerobic endurance. Elite marathon runners typically have VO2 Max values of 70–85 ml/kg/min; untrained adults average 35–45.
Yes — VO2 Max responds well to training, especially high-intensity interval training (HIIT) and consistent Zone 2 aerobic work. Beginners can see 10–15% improvements in 8–12 weeks. Experienced athletes see smaller gains. It also declines with age at roughly 1% per year after 25 if untrained.