metabolic equivalent, or MET

See also met.

The ratio of the metabolic rate of the average person while seated and resting, to the metabolic rate of a particular person while performing some task. The symbol MET comes from metabolic equivalents of task. It is commonly used in medicine to express metabolic rates measured during a treadmill test. Two definitions of the MET are met with, essentially equivalent:

1 MET is equivalent to a metabolic rate consuming 3.5 milliliters of oxygen per kilogram of body weight per minute.
1 MET is equivalent to a metabolic rate consuming 1 kilocalorie per kilogram of body weight per hour.

In a treadmill test, actually measuring METs requires that the person being tested wear a mask in order to measure his or her oxygen consumption (and the carbon dioxide exhaled). However, METs are often estimated on the basis of other factors.

METs can be converted to kilocalories consumed per minute: kcal/min = METs × body weight in kilograms ÷ 60.

Oxygen consumption in liters per hour = METs × body weight in kilograms ÷ 0.21

Some METs for various activities:

METs	Activity
2	walking at 2 miles per hour
5	walking at 4 miles per hour, level firm surface
8	jogging at 6 miles per hour
12.5	very vigorous effort on a stationary bike
16	skin diving, fast

Resources

A very full listing of energy expenditures in various activities is given by:

Ainsworth, B. E.
The Compendium of Physical Activities Tracking Guide.
Prevention Research Center, Norman J. Arnold School of Public Health, University of South Carolina (January 2002).

http://prevention.sph.sc.edu/tools/docs/documents_compendium.pdf

A page on the history and use of Ainsworth's publication is at
http://prevention.sph.sc.edu/tools/compendium.htm