VO₂max is the maximum volume of oxygen your body can use per minute per kilogram of body weight (ml/kg/min). It reflects aerobic capacity and is one of the best predictors of cardiorespiratory fitness.

How accurate is the Cooper test?

Cooper's original 1968 study reported r ≈ 0.90 with treadmill VO₂max for healthy young men. Real-world precision is ±10–15% — sufficient to categorise fitness but not to replace lab measurement.

Which test should I pick?

Both are field tests with similar accuracy. The Cooper 12-min run is timed; the 1.5-mile run uses a fixed distance. Choose whichever matches your track or familiar route.