Effect of Sex on arterial hemodynamics and Cerebral Blood Flow Dynamics Following Acute Resistance Exercise.

Abstract

Resistance exercise (RE) is recommended for men and women and is important for improving cardiovascular (CV) and metabolic disease risk factors. High-intensity RE acutely increases arterial stiffness and blood pressure (BP), coupled with reduced cerebral blood flow velocity (CBFv) and greater flow pulsatility in the cerebral circulation, which may be detrimental to cerebral microvasculature. Because females have different CV control mechanisms, it is important to assess potential sex differences in cerebral vascular responses to acute RE. PURPOSE: To examine the effect of sex on hemodynamics and cerebral vascular responses following acute RE in young recreationally active men and women. METHODS: Healthy men (n = 11, 28 yrs, BMI = 24.6) and women (n = 9, 25 yrs, BMI = 23.2) performed RE (3 sets of 10 repetitions of isokinetic concentric/concentric unilateral knee flexion/extension). Measurements were obtained at baseline and post-exercise (1, 5, 30 min). Beat-to-beat heart rate (HR), brachial BP (bSBP, bDBP, bMAP), cardiac output (CO), stroke volume (SV) and end-tidal CO2 were collected. CBFv was measured by transcranial Doppler. Carotid BP (cSBP, cDBP, cMAP) measurements were obtained using applanation tonometry. Central pulse wave velocity (PWV) was measured by an automated ambulatory BP monitor. RESULTS: See table. Mean CBFv increased 1-min post-exercise and decreased below baseline 5-min post-exercise (p<0.01) in both groups. CBFv pulsatility increased following RE and was elevated above baseline 5-min post-exercise (p<0.01) in both groups. PWV increased 1-min post-exercise (p<0.01) in both groups. Most variables returned to baseline at 30 min. CONCLUSION: RE increased central arterial stiffness, mean CBFv and CBFv pulsatility similarly for both sexes. Although CO increased at 5-min, CBFv dropped below baseline and pulsatility continued to rise above baseline. This temporary disruption in cerebral autoregulation may impact brain health in both sexes.