abstract
- This study examined how successive sets of high-intensity leg press (LP) resistance exercise impact the cerebral pressure-flow relationship in untrained males and eumenorrheic females not taking oral contraceptives, and assessed how menstrual cycle (MC) phase influences the cerebral pressure-flow relationship and cerebral hemodynamics (middle cerebral artery blood velocity; MCAv; via transcranial Doppler ultrasound) during and after LP exercise in females. Young adults (11M;11F) performed three sets of leg-press exercises at 90% of their 1-repetition maximum. Data from males and females in early follicular phase were pooled together. Directional sensitivity of the cerebral pressure-flow relationship was calculated as the ratio of rate of changes in MCAv and mean arterial pressure (MAP) (ΔMCAvT/ΔMAPT) per transition between eccentric and concentric muscular contractions during each repetition of LP exercise. ΔMCAvT/ΔMAPT was higher during concentric than eccentric phases (p<0.001) in males and early follicular phase (EF) females. There were no effects of successive leg press sets on any systemic or cerebral hemodynamic measures. MC phase affected directional sensitivity and cerebral hemodynamics, with greater responses in the mid-luteal (ML) phase than EF. We observed a MAP direction by MC phase interaction on relative directional sensitivity, with greater sensitivity during concentric contractions in the ML phase (p=0.02). Our results suggest successive sets of LP exercise do not impact the cerebral pressure-flow relationship or cerebral hemodynamics during and immediately following LP exercise. MC phase appears to influence the cerebral pressure-flow relationship and cerebral hemodynamics both during and following LP exercise, mediated by vasoprotective effects of increased estrogen concentration in the ML phase compared to EF.