Reduction in Arterial Stiffness Is Related to Exercise Intensity

Abstract

Increased arterial stiffness is associated with cardiovascular risk and mortality. Central and peripheral arterial stiffness measured with pulse wave velocity (PWV) are known to be reduced 5 min after a single bout of dynamic exercise using a large muscle mass. The effect of small muscle mass rhythmic handgrip exercise on peripheral stiffness is unknown. In addition, it is not known whether the magnitude of reduction in peripheral arterial stiffness is related to the intensity of exercise. We hypothesized that a higher exercise intensity would result in a larger reduction in post-exercise peripheral arterial stiffness. Eight healthy young volunteers participated in this study (5 females, 28 ± 4 yrs, mean ± SD). Two Millar tonometers were placed simultaneously on the brachial and radial arteries of the exercising arm for measurement of peripheral arterial stiffness. Beat-by-beat arterial pressure was obtained by a photoplethysmographic sensor on the middle finger of the contralateral hand. Brachial-radial PWV and mean arterial pressure (MAP) were recorded before exercise then at 5-, 15-, and 30-min post-exercise. The exercise consisted of two 5-min bouts of rhythmic handgrip exercise (2sec contraction/2sec relaxation) at either 30% or 50% of their maximal voluntary contraction (MVC) performed in randomized order. Baseline brachial-radial PWV before handgrip exercise at 30% MVC was 10.7 ± 2.8 m/sec. Postexercise at 30% MVC, PWV was 9.6±2.6 m/sec at 5min, 9.8 ± 2.7 m/sec at 15min, and 11.5 ± 2.9 m/sec at 30 min (all p>0.05 compared to baseline). Before handgrip exercise at 50% MVC baseline brachial-radial PWV was 13.1 ± 3.2 m/sec. Post-exercise at 50% MVC, PWV was 9.9 ± 3.7 m/sec at 5min (p<0.05), 9.1 ± 2 m/sec at 15min (p<0.05), and 10.2 ± 3 m/sec at 30 min (p>0.05). MAP was not statistically significantly different across all time points (p > 0.05). These results show that peripheral arterial stiffness measured as brachial-radial PWV was reduced after 5-min and 15 min of rhythmic handgrip exercise at 50% MVC, but not at 30% MVC. Thus, the magnitude of reduction in PWV was related to the intensity of exercise. The observed reduction of brachial-radial PWV was not a function of changes in blood pressure which would have confounded the PWV results. This study is the first to show that small muscle mass handgrip exercise reduces peripheral PWV. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.