Aerobic Training And Vascular Protection: Insight From Altering Blood Flow Patterns

Abstract

Adequate blood flow patterns are essential in maintaining vascular homeostasis. Exercise-induced increases in antegrade, or forward, blood flow is a major modulator of vascular health; however, as vascular function in the conduit arteries is normalized as aerobic training progresses it is unknown if aerobically-trained vessels can adequately counteract vascular insults. PURPOSE: The study sought to determine the ability of aerobically-trained individuals to counteract an acute vascular insult (increased retrograde shear). METHODS: Ten young male trained rowers (20±1 yrs) and ten male recreationally active controls (24±1 yrs) were recruited for this study. Subjects completed two brachial artery (BA) flow mediated dilation (FMD) tests separated by a 30 minutes of sub-diastolic cuff inflation (60 mmHg) of the forearm. BA diameter, blood flow, and shear rate were evaluated prior to and throughout both FMD tests. RESULTS: The sub-diastolic cuff inflation intervention resulted in significant increases in retrograde shear rate (p < 0.001) and oscillatory shear index (p < 0.001) over time (pre- to post-FMD measures). Significant reductions across time were revealed in brachial artery (BA) dilation (absolute: p = 0.008; relative change: p = 0.011) and the post-cuff release hyperemic response (BA blood flow AUC: p < 0.001; BA shear rate AUC: p = 0.001), but no group differences were observed in these variables. CONCLUSIONS: This study revealed that individuals with prior upper limb training were unable to attenuate the vascular dysfunction associated with acute increases in retrograde shear.