VO2max calculator (Cooper test)

What it's for

VO2max measures aerobic capacity: the higher it is, the better your endurance. The Cooper test estimates it from the distance run in 12 minutes.

How to do it

On a track or flat route, after a good warm-up, run at the highest sustainable pace for 12 minutes and measure the meters.

What VO2max actually measures

It is the maximum volume of oxygen the body can consume in a minute, per kilogram of body weight. It defines the ceiling of aerobic capacity: how much oxygen the lungs can take in, the heart can pump and the muscles can use. It is measured in millilitres per kilogram per minute, and values run from a little over twenty in a sedentary person to above eighty in a top endurance athlete.

The fact that it is relative to weight explains something surprising: losing weight raises VO2max without anything having changed in the heart or the lungs. It is also why it is a useful number for comparing yourself with yourself over time and less useful for comparing yourself with others.

Why the Cooper test works

The true value is measured in a laboratory, with a mask analysing exhaled air while running on a treadmill under increasing load. The Cooper test, devised in 1968 for the American air force, replaces all that with a single question: how many metres you cover in twelve minutes.

It works because twelve minutes are long enough to force the body to work near its aerobic maximum, and short enough not to bring endurance into play. It has a strong assumption, though: you have to run at a steady and genuinely maximal pace. Anyone who starts too fast and fades, or who holds back, gets a number lower than their real value.

How to do it so the number means something

On a flat, measured course, ideally an athletics track where the metres really are counted. After a proper ten to fifteen minute warm-up, not from cold. On a day of normal conditions: heat, wind and humidity change the result more than fitness does, and a test run at thirty-five degrees is not comparable with one at fifteen.

And above all always in the same way: same course, same time of day, same state of rest. The absolute value has many sources of error, but the comparison between two tests done under the same conditions two months apart says something true about training.

What it does not say, and who should not do it

VO2max is a ceiling, not a performance: two people with the same value can have very different race times, because the anaerobic threshold, running economy and the head count too. It is well known that athletes with lower VO2max regularly beat athletes with higher values.

And it is a maximal test: twelve minutes flat out is an intense effort, not advisable for anyone who has not trained for some time, for anyone with heart or blood pressure problems, and generally for anyone without a recent medical clearance. People starting from scratch have better suited tools, beginning with brisk walking.

Nearby tools

For training zones there is Heart rate zones, for paces Pace calculator and Training paces. To estimate a race time Race time prediction.