Metabolic equivalent (MET)

The metabolic equivalent of task (MET) is a unit for the energy cost of an activity. It expresses that cost as a multiple of your resting metabolic rate. By definition, 1 MET is the oxygen use of a seated adult at rest, about 3.5 mL of O₂ per kilogram of body weight per minute (Jette 1990). Activities are grouped as light (under 3 METs), moderate (3 to 5.9 METs), or vigorous (6 METs or more). Walking at 4 km/h is roughly 3 METs; cycling at race pace tops 12 METs. Multiply MET intensity by time and you get MET-minutes (or MET-hours). That is a common currency for comparing different activities on one scale, as set out in the Ainsworth Compendium of Physical Activities (2011 update, over 800 coded activities). In a pooled analysis of 661,137 adults followed a median 14.2 years, Arem et al. (JAMA Internal Medicine, 2015) found a clear dose-response between leisure MET-hours per week and lower all-cause death. People hitting 7.5 to 15 MET-hours a week, the recommended minimum, had 31% lower death than inactive peers. The curve flattened around 22.5 to 40 MET-hours a week (a 39% drop), with no harm even at 10 times the minimum. One caveat: 1 MET is a population average, anchored to a 70 kg adult. Your own resting oxygen use can differ by 20 to 30%. So MET-based intensity cutoffs are an approximation, not an exact measure for any one person.

Last reviewed: June 22, 2026

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