Dynamic cerebral autoregulation during and after handgrip exercise in humans.

The purpose of the present study was to examine the effect of static exercise on dynamic cerebral autoregulation (CA). In nine healthy subjects at rest before, during, and after static handgrip exercise at 30% maximum voluntary contraction, the response to an acute drop in mean arterial blood pressure and middle cerebral artery mean blood velocity was examined. Acute hypotension was induced nonpharmacologically via rapid release of bilateral thigh occlusion cuffs. Subjects were instructed to avoid executing a Valsalva maneuver during handgrip. To quantify dynamic CA, the rate of regulation (RoR) was calculated from the change in cerebral vascular conductance index during the transient fall in blood pressure. There was no significant difference in RoR between rest (mean+/-SE; 0.278+/-0.052/s), exercise (0.333+/-0.053/s), and recovery (0.305+/-0.059/s) conditions (P=0.747). In addition, there was no significant difference in the rate of absolute cerebral vasodilatory response to acute hypotension between three conditions (P=0.737). This finding indicates that static exercise and related elevations in blood pressure do not alter dynamic CA.