Energy expenditure of nonexercise activity


Background: We found recently that changes in nonexercise activity thermogenesis (NEAT) mediate resistance to weight gain with overfeeding in sedentary adults.  A potentially important, yet seldom investigated, component of NEAT is the energy expenditure of fidgeting-like activities.  

Objective: Our goal was to measure changes in energy expenditure with fidgeting-like activities.

Design: Energy expenditure was measured in 24 subjects (17 women and 7 men; x̅  ± SD body weight: 76± 21 kg) while recumbent at rest, sitting motinless, standing motionless, partaking of self-selected fidgeting-like movements while seated and while standing, and walking on a treadmill at 1.6, 3.2, and 4.8 km/h (1, 2, and 3 mph).  Measurements were performed by using a high-precision, indirect calorimeter connected to the subject via a transparent, lightweight facemask that enabled almost unrestricted movement.

Results: Compared with metabolic rate in the supine position (5.4 ± 1.4 kJ/min), energy expenditure increased while sitting motionless by 4 ± 6%, while fidgeting while seated by 54 ± 29% (P <0.0001), while standing motionless by 13 ± 8% (P <0.0001), while walking at 1.6 km/h by 154 ± 38% (P <0.0001), while walking at 3.2 km/h by 202 ± 45% (P <0.0001), and while walking at 4.8 km/h by 292 ± 81% (P <0.0001).  There was a significant, positive correlation between changes in energy expenditure and body weight for fidgeting-like activities while standing (r = 0.43, P = 0.02) but not while seated.

Conclusion: There is marked variance between subjects in the energy expenditure associated with self-selected fidgeting-like activities.  The thermogenic potential of fidgeting-like and low-grade activities is sufficiently great to substantively contribute to energy balance.

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James A Levine, Sara J Schleusner, and Michael D Jensen