Bruce Protocol METs & VO2 Max Calculator

The Bruce protocol is a standard treadmill stress test introduced by Dr. Robert Bruce in 1973. It starts at 1.7 mph and a 10 percent grade, then increases both speed and incline every 3 minutes across up to seven stages. The total time you can keep going is used to estimate your aerobic fitness, so a longer time means a higher VO2 max.

It uses the sex-specific ACSM Bruce equations with your total time T in decimal minutes. For men, VO2 max equals 2.94 times T plus 7.65; for women, it equals 4.38 times T minus 3.9, both in milliliters of oxygen per kilogram per minute. A man who lasts 10 minutes gets about 37 mL/kg/min. The tool also shows the general Bruce cubic formula as a sex-neutral cross-check.

One metabolic equivalent (MET) is the resting oxygen cost of 3.5 milliliters of oxygen per kilogram per minute, so METs equal your VO2 max divided by 3.5. A result of 10 METs means your peak effort uses about ten times the energy you burn at rest. Higher peak METs are linked to better cardiorespiratory fitness and lower cardiovascular risk.

The calculator compares your estimate to the VO2 max expected for your age and sex using the FRIEND registry reference equation: predicted VO2 max equals 79.9 minus 0.39 times age, minus 13.7 for women. It then reports your result as a percentage of that predicted value, so you can see whether you are above or below the norm for your age.

Enter your exact total time in minutes and seconds, not just the stage number. The equations are continuous, so 9 minutes 30 seconds gives a more accurate estimate than rounding to the nearest completed stage. The calculator still shows which stage your time falls in for reference.

No. This calculator is for education and general fitness tracking only and is not a substitute for professional medical advice, diagnosis, or treatment. A real Bruce protocol stress test should be supervised by qualified medical staff, and any decisions about exercise or heart health should involve a clinician. Treat the result as an estimate within roughly 10 to 15 percent of a lab measurement, not a diagnosis.