The objective of this study was to examine whether breaking up prolonged sitting with intermittent standing or underdesk pedaling prevents sitting-induced popliteal artery endothelial dysfunction in middle-age sedentary, overweight/obese office workers.Hypothesis
We tested the hypothesis that sitting-induced leg endothelial dysfunction would be prevented by intermittent standing or desk pedaling.Methods
Thirteen middle-age, sedentary overweight/obese subjects (10 men, 3 women; age, 38 ± 3 yr; body mass index, 29.7 ± 2 kg·m−2) participated in three separate testing sessions in a randomized order: 1) 4 h of uninterrupted sitting, 2) 4 h of sitting interrupted with four 10-min bouts of standing, and 3) 4 h of sitting interrupted with four 10-min bouts of light-intensity desk pedaling. Doppler ultrasound–measured popliteal artery flow-mediated dilation and associated measures (e.g., shear rate, blood velocity) were measured immediately before and immediately after each intervention (sit, stand, and desk pedaling).Results
Four hours of uninterrupted sitting induced a significant impairment in popliteal artery flow-mediated dilation (baseline: 3.1% ± 0.3%, post: 1.6% ± 0.5%; P < 0.05). Interestingly, neither intermittent standing (baseline: 3.2% ± 0.4%, post: 1.9% ± 0.5%; P < 0.05) nor intermittent desk pedaling (baseline: 3.2% ± 0.4%, post: 1.9% ± 0.4%; P < 0.05) was effective at preventing excessive sitting–induced endothelial dysfunction.Conclusions
Prolonged sitting–induced leg endothelial dysfunction cannot be prevented by brief intermittent bouts of standing or desk pedaling in middle-age sedentary overweight/obese adults.