Uninterrupted prolonged sitting and arterial stiffness: moderating effect of prior aerobic exercise in physically active adults

Purpose Prolonged sitting acutely increases arterial stiffness, with interruption strategies only providing limited success in offsetting these rises. Acute aerobic exercise is a potent stimulus to decrease arterial stiffness. However, limited information exists on the effectiveness of acute exercise to maintain arterial stiffness when performed prior to prolonged sitting, particularly within physically active individuals. Methods Using a randomized crossover design, 22 young, active individuals (50% female) performed two conditions 30 min of walking at 55-65% of heart rate reserve (EX) and 30 min of standing (STAND) followed by 2.5-h of sitting. Brachial-femoral (bfPWV) and femoral-ankle pulse wave velocity (faPWV) were assessed at Baseline, post-exercise and pre-sitting (Pre), and post-sitting (Post) as estimates of central and peripheral arterial stiffness, respectively. Results For bfPWV, no interaction, condition, or time effects were observed. For faPWV, an interaction was present (p < 0.001); compared to Baseline, there was a 6.1% decrease for EX (- 0.4 m/s, p < 0.001) and a 4.6% increase for STAND (0.3 m/s, p = 0.016) for STAND such that there was an 11.3% difference between conditions at Pre (0.7 m/s, p < 0.001). From Pre to Post, EX then increased by 11.7% (0.9 m/s p < 0.001) while STAND remained unchanged, resulting in no difference between conditions (0.1 m/s, p = 0.569). Conclusions While aerobic exercise resulted in a significant decrease in faPWV prior to sitting, the prior exercise bout did not confer a protective effect against the deleterious effects of uninterrupted sitting. Future work should investigate the combined effect of prior exercise and sitting interruption strategies on markers of arterial stiffness.