Metabolic Equivalent Task (MET)

Measuring Physical Activity Using METs

Physical activity is measured in metabolic equivalents task units (METs). One MET is defined as the energy it takes a 70 kg man to sit quietly. In other words, one MET is defined as the oxygen consumption of a 70-kg man at rest.

Another rendition of this definition is, “A MET is defined as the resting metabolic rate, that is, the amount of oxygen consumed at rest, sitting quietly in a chair, approximately 3.5 ml 0₂/kg/min (1.2 kcal/min for a 70-kg person).”

For the average adult (70kg person), this is about one calorie (i.e. 1kcal) for every one kilogram (2.2 pounds) of body weight per hour. That is someone who weighs 70 kg (154 lbs) would burn about 70 calories (70 kcal) in one hour while sitting or sleeping.

The U.S. Dept of Health & Human Services says, “1 MET is the rate of energy expenditure while sitting at rest. It is taken by convention to be an oxygen uptake of 3.5 milliliters per kilogram of body weight per minute. Physical activities frequently are classified by their intensity using the MET as a reference” (HHS 2008, 53).

Light-intensity activities are defined as < 3 METs.
Moderate-intensity activities are defined as ≥ 3.0 METs to < 6 METs. Walking at 3.0 miles per hour requires 3.3 METs of energy expenditure and is therefore considered a moderate-intensity activity.
Vigorous-intensity activities are defined as ≥ 6.0 METs. Running at 10 minutes per mile (6.0 mph) is a 10 MET activity and is therefore classified as vigorous-intensity (HHS 2008, 55).

Moderate-intensity activities are activities that get a person moving fast enough or strenuously enough to burn off three to six times as much energy per minute as a 70 kg person would burn when sitting quietly. In other words, these exercises require 3 to 6 METs.
Vigorous-intensity activities burn more than 6 METs.

Limitations to using METs to measure physical activity/exercise intensity.

All METs are not created equal. That is, all METs do not bring the same health benefits. “Physical activity at work is shown to not provide the same health gain as recreational PA,” (Holtermann 2018, 1).
Measuring with METs does not consider personal characteristics. “It does not consider the fact that some people have a higher level of fitness than others. Thus, walking at 3 to 4 miles per hour is considered to require 4 METs and to be a moderate-intensity activity, regardless of who is doing the activity—a young marathon runner or a 90-year-old grandmother. As you might imagine, a brisk walk would likely be an easy activity for the marathon runner, but a very hard activity for the grandmother” (Harvard, n.d.).

The table below shows different activity levels and corresponding METs.

ESTIMATED ENERGY	ACTIVITY
1 MET	Self-care
	Eating, dressing, or using the toilet
	Walking indoors and around the house
	Walking one to two blocks on level ground at 2 to 3 mph
4 METs	Light housework (e.g., dusting, washing dishes)
	Climbing a flight of stairs or walking up a hill
	Walking on level ground at 4 mph
	Running a short distance
	Heavy housework (e.g., scrubbing floors, moving heavy furniture)
	Moderate recreational activities (e.g., golf, dancing, doubles tennis, throwing a baseball or football)
Greater than 10 METs	Strenuous sports (e.g., swimming, singles tennis, football, basketball, skiing)

MET = metabolic equivalent;

Metabolic Equivalent Task (MET)

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