Quick answer: lasting 10:00 on the Bruce treadmill protocol gives an estimated VO2 max of 34.1 ml/kg/min with the Foster (1984) equation, about 9.7 METs. The Pollock equation for women gives 39.9 for the same time. Reaching 12:00 raises the Foster estimate to 42.5.
How the Bruce test works
The test runs in 3-minute stages with no breaks. Each stage makes the treadmill both faster and steeper, starting at a brisk walk up a 10% slope and ending in a run up a 22% slope. You keep going until you cannot continue, and the result is simply your total time. Enter that time (minutes and seconds) above and choose the equation.
| Stage | Minutes | Speed | Grade | Foster VO2 max at the end of the stage |
|---|---|---|---|---|
| 1 | 0 to 3 | 1.7 mph (2.7 km/h) | 10% | 14.4 |
| 2 | 3 to 6 | 2.5 mph (4.0 km/h) | 12% | 20.2 |
| 3 | 6 to 9 | 3.4 mph (5.5 km/h) | 14% | 30.2 |
| 4 | 9 to 12 | 4.2 mph (6.8 km/h) | 16% | 42.5 |
| 5 | 12 to 15 | 5.0 mph (8.0 km/h) | 18% | 55.1 |
| 6 | 15 to 18 | 5.5 mph (8.9 km/h) | 20% | 66.1 |
| 7 | 18 to 21 | 6.0 mph (9.7 km/h) | 22% | 73.6 |
The equations
Foster et al. (1984): VO2 max = 14.8 - 1.379 T + 0.451 T² - 0.012 T³, where T is the total time in minutes. It appears as the general equation in many studies, and several of them apply it to men.
Pollock et al. (1982), for women: VO2 max = 4.38 T - 3.9. The same equation is sometimes written per second as 0.073 x seconds - 3.9.
METs are the VO2 max divided by 3.5 ml/kg/min, the value of one MET.
Worked example
A woman stops at 9:30, early in stage 4. T = 9.5 minutes. Pollock: 4.38 x 9.5 - 3.9 = 37.71 ml/kg/min, or 10.8 METs. With the Foster equation the same time gives 14.8 - 13.10 + 40.70 - 10.29 = 32.1. The gap between the two equations is a reminder that both are estimates.
Limits and safety
- The equations predict VO2 max from time alone, so they cannot see differences in body weight, walking technique or how the test was run. Compare your results on the same treadmill and the same equation.
- The calculator accepts 3:00 to 21:00 (the end of stage 7). The Foster curve is a cubic: its slope turns negative below about 1.6 minutes and above about 23.4 minutes, and 21:00 is the end of stage 7.
- The Bruce test is a maximal effort test. It is usually run in a clinic or lab with heart monitoring; do it only with medical clearance, especially with any heart condition or symptoms.
No treadmill lab nearby? A field test works too: the Rockport walk test needs only a measured mile, and the VO2 max calculator handles the Cooper and 1.5-mile run tests. The treadmill pace chart turns any mph into pace.
Sources: Foster C et al. (1984), Generalized equations for predicting functional capacity from treadmill performance, Am Heart J 107:1229-1234; BMJ Open Sport Exerc Med (2022), Normal reference values for aerobic fitness in cystic fibrosis: table quoting the Foster and Pollock equations; J Tehran Heart Cent (2018), aerobic exercise in diabetes: Foster equation for men, 4.38 x T - 3.9 for women; Sports (2026), physiological profile of recreational gym adults: Bruce stage speeds and grades. Rules checked . Found a problem? Tell us.
Questions
How do you calculate VO2 max from the Bruce protocol?
Take your total time T in minutes. With the Foster equation, VO2 max = 14.8 - 1.379 T + 0.451 T squared - 0.012 T cubed; for women, the Pollock equation is 4.38 T - 3.9. Ten minutes gives 34.1 (Foster) or 39.9 (Pollock) ml/kg/min.
What are the stages of the Bruce protocol?
Seven 3-minute stages: 1.7 mph at 10%, 2.5 mph at 12%, 3.4 mph at 14%, 4.2 mph at 16%, 5.0 mph at 18%, 5.5 mph at 20% and 6.0 mph at 22% grade.
How many METs is 9 minutes on a Bruce treadmill test?
With the Foster equation, 9 minutes gives an estimated VO2 max of 30.2 ml/kg/min, which divided by 3.5 is about 8.6 METs.
Can I do the Bruce test on my own treadmill?
It is a maximal test meant for supervised settings. If you have medical clearance and a treadmill that reaches a 22% grade, you can follow the stages, but stop at once with chest pain, dizziness or unusual breathlessness.