METs, or metabolic equivalents, are a simple way to measure how hard your body works during any physical activity. One MET equals the energy you burn while sitting completely still, roughly 3.5 milliliters of oxygen per kilogram of body weight per minute. An activity rated at 5 METs means your body is working five times harder than it does at rest.
How METs Measure Exercise Intensity
The MET system gives every physical activity a number based on how much energy it demands compared to rest. Sitting quietly is 1 MET. Light housework might be 2 to 3 METs. A brisk walk lands around 3.5 to 5 METs. Running at a moderate pace hits 8 to 10 METs. The higher the number, the harder your body is working.
The CDC groups activities into two main intensity categories using METs. Moderate-intensity activity falls between 3 and 5.9 METs, which includes things like brisk walking, casual cycling, and gardening. Vigorous-intensity activity is anything at 6 METs or above: running, swimming laps, or playing competitive sports. Activities below 3 METs count as light intensity.
Why METs Matter for Your Health
METs aren’t just a fitness tracking tool. They’re one of the strongest predictors of how long you’ll live. In clinical research, each 1-MET increase in a person’s peak exercise capacity is associated with a 13% reduction in all-cause mortality and a 15% reduction in heart disease events. That relationship holds whether or not someone has existing cardiovascular disease.
During treadmill stress tests, doctors use METs to gauge heart health. Patients who reach 10 METs or higher during exercise testing have an excellent prognosis over years of follow-up, regardless of peak heart rate. In fact, peak exercise capacity measured in METs is a stronger predictor of death risk than heart rate alone. For older adults, the benefit is even more pronounced: each 1-MET improvement in fitness was linked to an 18% reduction in cardiac events in people over 65, compared to 14% in younger adults.
How to Calculate Calories Burned With METs
You can convert any MET value into actual calories burned using a straightforward formula:
Calories per minute = 0.0175 × MET value × your weight in kilograms
So if you weigh 70 kg (about 154 pounds) and go for a brisk walk at 5 METs, you’d burn roughly 0.0175 × 5 × 70 = 6.1 calories per minute. Over a 30-minute walk, that’s about 184 calories. The same person running at 9 METs would burn around 11 calories per minute, or 330 calories in half an hour. Your body weight is a key variable here, which is why two people doing the same workout burn different amounts.
Tracking Weekly Exercise With MET-Minutes
MET-minutes give you a way to add up all your different activities into one number for the week. The math is simple: multiply the MET value of an activity by how many minutes you spent doing it. If you walk briskly at 5 METs for 30 minutes, that session earns you 150 MET-minutes.
U.S. physical activity guidelines recommend accumulating at least 500 MET-minutes per week, which is roughly equivalent to 150 minutes of moderate-intensity exercise. Additional health benefits continue to accumulate beyond 1,000 MET-minutes per week. The beauty of MET-minutes is that they let you mix and match activities freely. A week that includes two 30-minute brisk walks (300 MET-minutes), one 20-minute bike ride at 7 METs (140 MET-minutes), and two 40-minute sessions on an elliptical at 6 METs (480 MET-minutes) totals 920 MET-minutes, putting you well within the recommended range.
This flexibility is the real advantage of thinking in MET-minutes. You don’t have to do the same workout every day. A short, vigorous session can contribute as much to your weekly total as a longer, easier one. Twenty minutes of running at 9 METs (180 MET-minutes) gives you roughly the same credit as a 36-minute walk at 5 METs.
Limitations Worth Knowing
The standard definition of 1 MET assumes a resting oxygen consumption of 3.5 ml/kg/min, but that number was derived from a 70 kg, 40-year-old man. Research has shown this value doesn’t hold well for everyone. Older adults, for instance, often have a lower resting metabolic rate, which means the standard MET formula can overestimate how many calories they actually burn. Women, people with higher body fat percentages, and those with lower fitness levels may also see less accurate estimates.
MET values also represent averages for a given activity. Your actual effort depends on factors like terrain, speed, temperature, and how fit you are. Walking at 3.5 mph on flat ground and walking at 3.5 mph uphill are very different experiences, even if a chart assigns them similar numbers. Use MET values as useful approximations rather than precise measurements, and pay attention to how hard you’re actually breathing and working during any given session.