Metabolic equivalent

Metabolic Equivalent (MET) is a unit of measure within physiology used to quantify the intensity of physical activities. It is defined as the ratio of the rate of energy expended during an activity to the rate of energy expended at rest. One MET is equivalent to a caloric burn rate of approximately 1 kcal/kg/hour in an average individual.

Definition and Calculation

The Metabolic Equivalent (MET) is a simple, practical, and easily understood system for expressing the energy cost of physical activities as a multiple of the Basal Metabolic Rate (BMR). The BMR is the rate of energy expenditure by the body at rest and is approximately 1 kcal/kg/hour in adults. Therefore, an activity with a MET value of 1 is roughly equivalent to an individual's energy expenditure when they are at rest, while an activity with a MET value of 2 would require twice the energy expenditure, and so on.

Applications

MET values are used in a variety of fields, including exercise physiology, cardiology, and public health. They are used to estimate the energy expenditure of various activities, to prescribe exercise intensity for cardiac rehabilitation patients, and to develop physical activity guidelines for the general population.

Limitations

While the MET system is widely used and accepted, it has some limitations. The main limitation is that it does not account for individual differences in resting metabolic rate, body composition, or efficiency of movement. Therefore, the actual energy cost of an activity may be higher or lower than the MET value suggests for a given individual.

See Also

• Physical Activity Level
• Energy Expenditure
• Exercise Intensity