What Exactly Are METs, and What Should You Know About Them?

You likely know that your body is constantly using energy, regardless of your activity level.

But have you considered how much energy you expend during a typical day, or during high-calorie activities like running or resistance training?

Metabolic equivalents, commonly called METs, are one method to estimate your body’s energy use. You may encounter MET values on gym machines or hear them referenced by trainers to quantify physical activity intensity.

This article digs into what METs mean, how they’re determined, and how to employ them to support your fitness objectives.

What is a MET?

A MET represents the ratio of your active metabolic rate compared with your resting metabolic rate. Metabolic rate describes the amount of energy used per unit of time and is a way to convey exercise or activity intensity.

One MET corresponds to the energy expended while sitting quietly — your resting or basal metabolic rate. Therefore, an activity with a MET value of 4 indicates you’re using four times the energy you would when sitting still.

To illustrate, a brisk walk at roughly 3 to 4 miles per hour is about 4 METs. A more intense exercise like jumping rope has an approximate MET value of 12.3.

Summary: MET stands for metabolic equivalents. One MET equals the energy you use while resting. An activity rated 4 METs requires four times the energy of sitting quietly.

How are METs calculated?

Understanding METs is easier if you know a bit about how your body consumes energy.

Muscle cells use oxygen to generate the energy needed for movement. One MET is roughly 3.5 milliliters of oxygen used per kilogram (kg) of body mass per minute.

For example, a person who weighs 160 pounds (about 72.5 kg) uses close to 254 milliliters of oxygen per minute at rest (72.5 kg × 3.5 mL).

Energy needs vary among individuals due to factors such as age and fitness. A young, regularly active athlete won’t expend the same energy walking briskly as an older, inactive person.

For most healthy adults, MET values serve as a useful guide when planning workouts or estimating the effectiveness of an exercise routine.

Summary: One MET approximates 3.5 milliliters of oxygen consumption per kilogram of body weight per minute.

Examples of METs for various activities

Scientists who have tracked oxygen use during different activities have assigned MET values to those tasks. These estimates are based on a reference person weighing 70 kg (154 lbs).

Below is a table showing typical MET values for light, moderate, and vigorous activities.

What’s a good goal to shoot for with METs?

The American Heart Association advises aiming for at least 150 minutes of moderate-intensity aerobic activity weekly to support heart health. That corresponds to about 500 MET minutes per week, according to the U.S. Department of Health and Human Services.

How you achieve that target — whether through running, hiking, resistance work, or other exercises — matters less than consistently reaching the goal.

What’s the connection between METs and calories?

Calories may be a more familiar metric if you track energy intake and expenditure.

Generally, the more oxygen your muscles use, the more calories you burn. You might also know that burning roughly 3,500 calories corresponds to losing about 1 pound of body weight.

So trimming 500 calories from your daily intake or increasing your daily calorie burn by 500 could yield a weight loss of about a pound a week.

Knowing an activity’s MET value allows you to estimate how many calories you expend during that exercise.

Use this formula: METs × 3.5 × (your weight in kilograms) ÷ 200 = calories burned per minute.

For instance, if you weigh 160 pounds (about 73 kg) and play singles tennis (8 METs):

The calculation is 8 × 3.5 × 73 ÷ 200 = 10.2 calories per minute. Playing tennis for an hour would burn roughly 613 calories.

You could also express that session as 480 MET minutes (8 METs × 60 minutes).

The bottom line

METs provide a method to quantify how much energy your body uses for different activities. Activities with higher METs demand more energy from your muscles.

Knowing MET values can help estimate calorie burn during workouts.

A target of about 500 MET minutes per week is a practical aim for cardiovascular health. How you accumulate those minutes — through moderate activity like brisk walking over longer durations or vigorous exercise like running for shorter stints — is up to you.