Mechanisms of exercise-induced reduction in peripheral arterial stiffness.

Introduction: Peripheral arterial stiffness measured with pulse wave velocity (PWV) is reduced 5-min after an acute bout of dynamic exercise. The mechanism for the reduction in peripheral arterial stiffness is unknown. We hypothesized that increased blood flow and compression of the vasculature are potential mechanisms involved in post-exercise reduction in peripheral arterial stiffness.

Methods: Brachial-radial PWV was measured with tonometers on the exercising arm of 20 healthy young volunteers (10 females, 30 ± 5 yrs, mean ± SD) before and after 5 min of rhythmic handgrip exercise at 30% of maximal voluntary contraction (MVC), 50% MVC, and a 5 min set of passive forearm compressions. Brachial blood flow was monitored with Doppler ultrasound during exercise/compression.

Results: Brachial-radial PWV was lower than baseline at 5 min post (p < 0.001) for 30% MVC, 50% MVC, and compression, with responses similar among all conditions (p > 0.05). PWV remained lower than baseline at 15 min and 30 min only for 50% MVC. Blood flow and changes in brachial diameter during exercise/compression were not factors in the PWV reduction (p > 0.05).

Conclusion: These findings suggest that compression of the forearm vasculature contributes to the initial reduction in peripheral PWV after handgrip exercise, but the reductions in peripheral PWV are not associated with changes in blood flow.