Relationship between aortic augmentation index and blood pressure during metaboreflex activation in healthy young men

BackgroundHeightened aortic augmentation index (AIx; surrogate of arterial stiffness) is associated with an elevated risk of cardiovascular events; however, it is currently unclear whether peripheral blood pressure (BP) modulates AIx.AimGiven this, we studied the relationship between AIx and BP under resting conditions as well as during skeletal muscle metaboreflex activation, which is a maneuver that generates steady elevations in BP.MethodsIn nine healthy male participants (232 years), the graded activation of the muscle metaboreflex was achieved by postexercise ischemia (PEI) following moderate and high-intensity static handgrip performed at 30 and 40% maximum voluntary contraction. Heart rate (ECG), arterial BP, and AIx (SphygmoCor) were measured.ResultsCompared with rest, mean arterial pressure was significantly increased during PEI30% (+24 +/- 4mmHg, P<0.05 vs. rest) and was further augmented during PEI40% (+34 +/- 4mmHg, P<0.05 vs. PEI30%). Similarly, AIx@HR75 increased significantly from rest during PEI30% (rest -9 +/- 3% vs. PEI30% +9 +/- 5%, P<0.05) and was further augmented during PEI40% (17 +/- 4%, P<0.05 vs. PEI30%). At rest, there was no relationship between AIx and BP. However, at PEI30%, there was a significant association between AIx and diastolic BP and mean arterial pressure (r=0.92, 0.87, respectively; P<0.05) and this association was maintained at PEI40% (r=0.94, 0.91, respectively; P<0.05).ConclusionsOur results indicate that acute elevations in peripheral BP are an important determinant of AIx during muscle metaboreflex activation in healthy men.