Impact of passive vibration on pressure pulse wave characteristics.

The augmentation index (AIx), a marker of wave reflection, decreases following acute leg exercise. Passive vibration (PV) causes local vasodilation that may reduce AIx. This study investigated the effects of acute PV on wave reflection and aortic hemodynamics. In a crossover fashion 20 (M=9, F=11) healthy young (22±3 year) participants were randomized to 10 min PV or no vibration control (CON) trials. Subjects rested in the supine position with their legs over a vibration platform for the entire session. Radial waveforms were obtained by applanation tonometry before and after 3 min (Post-3) and 30 min (Post-30) of PV (∼5.37 G) or CON. No change in parameters was found at Post-3. We found significant time-by-trial interactions (P<0.01) at Post-30 for augmented pressure, AIx and second systolic peak pressure (P2), such that these parameters significantly (P<0.05) decreased (-2.3±3.0 mm Hg, -7.2±6.9% and -1.5±3.5 mm Hg, respectively) after PV but not after CON. These findings suggest that acute PV applied to the legs decreases AIx owing to a decrease in wave reflection magnitude (P2). Further research is warranted to evaluate the potential clinical application of PV in populations at an increased cardiovascular risk who are unable to perform conventional exercise.