The Effects of Ischemic Preconditioning on Hemodynamic and Neural Responses to Static Handgrip and Muscle Metaboreflex Activation

Abstract

This thesis investigated the effects of ischemic preconditioning (IPC), a blood flow restriction procedure demonstrated to exert cytoprotection and reduce metabolic demand during ischemia-reperfusion injury, on hemodynamic and neural (muscle sympathetic nerve activity; MSNA) responses to static handgrip and muscle metaboreflex activation (post-exercise circulatory occlusion; PECO). Thirty-seven men were randomized to a sham (n=16) or IPC (n=21) group. Participants completed a 2 min static handgrip followed by 3 min of PECO, and a static handgrip time-to-failure to elicit peak responses. IPC had no effect on hemodynamics during static handgrip or PECO, but significantly increased peak systolic blood pressure. IPC had no effect on MSNA during PECO, but significantly increased total MSNA during the first minute of static handgrip and peak MSNA burst frequency and incidence. These findings suggest that IPC does not attenuate the muscle metaboreflex, however, may facilitate sympathetic activation at exercise onset and volitional fatigue.