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.


METHODS
Energy expenditure was measured in 24 subjects (17 women and 7 men x+/- SD body weight: 76 +/- 21 kg) while recumbent at rest, sitting motionless, 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 +/- 1.5 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 fidgeting while standing by 94 +/- 38% (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.


CONCLUSIONS
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.
Levine
J A
JA
Endocrine Research Unit, Mayo Clinic and Mayo Foundation, Rochester, MN 55905, USA. levine.james@mayo.edu
Schleusner
S J
SJ
Jensen
M D
MD
D000328:Adult; D001835:Body Weight; D002153:Calorimetry, Indirect; D004734:Energy Metabolism; D005260:Female; D006801:Humans; D008297:Male; D009068:Movement; D009765:Obesity / Q000378:metabolism*; D012146:Rest; D022722:Thermogenesis