Non-exercise activity thermogenesis (NEAT)

Date: 
12-01-2002

Non-exercise activity thermogenesis (NEAT) is the energy expended for everything we do that is not
sleeping, eating or sports-like exercise. It ranges from the energy expended walking to work, typing,
performing yard work, undertaking agricultural tasks and fidgeting. Even trivial physical activities
increase metabolic rate substantially and it is the cumulative impact of a multitude of exothermic
actions that culminate in an individual's daily NEAT. It is, therefore, not surprising that NEAT explains
a vast majority of an individual's non-resting energy needs.
Epidemiological studies highlight the importance of culture in promoting and quashing NEAT.
Agricultural and manual workers have high NEAT, whereas wealth and industrialization appear to
decrease NEAT.
Physiological studies demonstrate, intriguingly, that NEAT is modulated with changes in energy
balance; NEAT increases with overfeeding and decreases with underfeeding. Thus, NEAT could be a
critical component in how we maintain our body weight and/or develop obesity or lose weight.
The mechanism that regulates NEAT is unknown. However, hypothalamic factors have been
identified that specifically and directly increase NEAT in animals. By understanding how NEAT is
regulated we may come to appreciate that spontaneous physical activity is not spontaneous at all but
carefully programmed.

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Authors: 
James A. Levine MD, PhD