Work out vo2 max from running instantly with clear inputs, formula shown and shareable results.
Jack Daniels' VDOT method works backwards from a race result: the oxygen cost of the race velocity is divided by the fraction of VO2 max sustainable for that duration. A 22 minute 5 km runs at 227 m/min, costing about 42 ml/kg/min at roughly 93% of maximum, implying a VO2 max near 45. Longer races sustain a smaller fraction, which is why the duration term matters.
Oxygen cost of velocity
VO2 = -4.6 + 0.182258 v + 0.000104 v^2, v in m/min
Sustainable fraction
%VO2max = 0.8 + 0.1894 e^(-0.01278 t) + 0.2990 e^(-0.19326 t)
This is an estimate from population-average equations, not a medical or diagnostic assessment. Individual results vary with genetics, training history and technique. Seek advice from a qualified coach or clinician before making significant changes to training.
Because it measures what you can actually produce, including running economy and mental toughness, not just oxygen uptake on a treadmill.
Anything between 10 and 60 minutes of effort. Shorter races lean on anaerobic capacity and longer ones on fuelling and durability.