Bruce Protocol METs Calculator

Key Takeaways

What Is the Bruce Protocol?

The Bruce Protocol is a standardized graded exercise test performed on a treadmill. Originally described by Robert A. Bruce in 1963, it remains one of the most widely used fitness assessment protocols worldwide.^[1] The test consists of seven 3-minute stages, each increasing in both speed and incline.

The total time achieved is used to estimate VO2max — the gold standard measure of cardiorespiratory fitness. This calculator uses ACSM-validated regression equations to convert your treadmill time into VO2max and METs, then classifies your result against age/sex norms. For additional fitness metrics, see our VO2 Max Calculator.

The Seven Stages

Each stage lasts 3 minutes. Speed starts at 1.7 mph (a slow walk) and increases to 6.0 mph (a run) by Stage 7. The grade also increases from 10% to 22%, which dramatically raises the metabolic demand with each stage.

Most recreationally active individuals complete between 6 and 12 minutes (Stages 2–4). Competitive endurance athletes may reach Stages 5–7. The test ends when you reach volitional exhaustion — the point where you can no longer continue.

VO2max Estimation Formulas

Two ACSM-validated regression equations are used depending on sex:^[2]

• General/Male: VO2max = 14.8 − 1.379T + 0.451T² − 0.012T³ (Foster polynomial)
• Female: VO2max = 4.38T − 3.9 (linear model)

Where T = total time in minutes. METs are derived by dividing VO2max by 3.5 ml/kg/min (the oxygen cost of sitting at rest). These formulas have been extensively validated against direct VO2max measurement.^[1]

How to Perform the Test

1. Warm up with 3–5 minutes of easy walking on the treadmill.
2. Start Stage 1 at 1.7 mph and 10% grade. Stay at each stage for exactly 3 minutes.
3. Progress through each stage until you cannot continue.
4. Record your total time in minutes and seconds.
5. Enter your time, age, and sex into the calculator for your VO2max estimate.

For a different running-based assessment, try the Cooper 12-Minute Run Calculator or the VO2 Max Runners Calculator.

What Are METs?

One MET (Metabolic Equivalent of Task) represents the oxygen consumption at rest — approximately 3.5 ml/kg/min. An activity rated at 6 METs requires 6 times the resting metabolic rate. The higher your MET capacity on the Bruce Protocol, the greater your cardiorespiratory fitness.

For context: walking at 3 mph is about 3.5 METs, jogging at 5 mph is about 8 METs, and running at 7 mph is about 11.5 METs. Reaching 10+ METs on the Bruce Protocol indicates good fitness for most age groups. Check how many calories various MET-rated activities burn with our Exercise Calorie Calculator.