Prolonged sitting is a major health concern, targeted via government policy and the proliferation of height-adjustable workstations and wearable technologies to encourage standing. Such interventions have the potential to influence energy balance and thus facilitate effective management of body/fat mass. It is therefore remarkable that the energy cost of sitting versus standing naturally remains unknown.METHODS
Metabolic requirements were quantified via indirect calorimetry from expired gases in 46 healthy men and women (age 27±12 y, mass 79.3±14.7 kg, body mass index 24.7±3.1 kg·m-2, waist:hip 0.81±0.06) under basal conditions (i.e. resting metabolic rate; RMR) and then, in a randomized and counterbalanced sequence, during lying, sitting and standing. Critically, no restrictions were placed on natural/spontaneous bodily movements (i.e. fidgeting) to reveal the fundamental contrast between sitting and standing in situ whilst maintaining a comfortable posture.RESULTS
The mean [95% CI] increment in energy expenditure was 0.18 [0.06 to 0.31] kJ⋅min-1 from RMR to lying, 0.15 [0.03 to 0.27] kJ⋅min-1 from lying to sitting and 0.65 [0.53 to 0.77] kJ⋅min-1 from sitting to standing. An ancillary observation was that the energy cost of each posture above basal metabolic requirements exhibited marked inter-individual variance, which was inversely correlated with resting heart rate for all postures (r=-0.5 [-0.7 to -0.1]) and positively correlated with self-reported physical activity levels for lying (r=0.4 [0.1 to 0.7]) and standing (r=0.6 [0.3 to 0.8]).CONCLUSION
Interventions designed to reduce sitting typically encourage 30-120 min⋅d-1 more standing in situ (rather than perambulation), so the 12 % difference from sitting to standing reported here does not represent an effective strategy for the treatment of obesity (i.e. weight-loss) but could potentially attenuate any continued escalation of the on-going obesity epidemic at a population level.