Forward and Reflected Waveform Amplitudes during Static Handgrip Exercise


1Wiltshire, M.H., 1Farquhar, W.B., 1Edwards, D.G., 1,2Greaney, J.L.,1University of Delaware, Newark, DE, 2Pennsylvania State University, State College, PA

Purpose: Central aortic systolic and pulse pressures are clinically important predictors of cardiovascular disease and are determined by the interaction of a forward-traveling and a reflected wave. We tested the hypothesis that exercise pressor reflex (EPR) activation would increase wave reflection in older normotensive adults by examining the effects of static hand grip exercise on ascending aortic forward and reflected wave amplitudes. Importantly, the pressor response to EPR activation alters wave reflection in young adults; however, to our knowledge, this has not been examined in healthy older adults. Methods: Beat-by-beat peripheral blood pressure (BP; Finometer) was measured continuously during EPR activation, which was elicited by static handgrip (HG) at 40% maximal voluntary contraction followed by post-exercise ischemia (PEI) to isolate the metabolic component of the EPR. Central aortic waveforms were derived from the peripheral pressure waveforms (HemoLab; Harald Strauss Scientific). Waveform analysis, which separates aortic pressure into its forward and backward components using a measured peripheral pressure wave and an estimated triangular flow wave, was used to non-invasively quantify wave reflection. Data were analyzed at baseline, during the last minute of HG, and during PEI. Results: Data were collected from thirteen older normotensive subjects (63± 2 years; resting BP 117 ± 2 / 70 ± 2 mmHg). Central systolic pressure increased during HG (Δ28 ± 4 mmHg) and remained elevated during PEI (Δ26 ± 4 mmHg; PConclusions:The reflected wave magnitude increased during isometric exercise as hypothesized, likely due to increased peripheral vasoconstriction during exercise. These data suggest that forward traveling and reflected waves contribute to the central blood pressure response to EPR activation in older healthy adults.

Research supported by an AHA 11PRE7580029 and an ACSM Foundation Grant.

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