No Sex Differences in Cerebral Blood Velocity Responses During Resistance Exercise

Abstract

IntroductionThe brain requires intricate regulation of blood flow to maintain adequate perfusion to the tissue. Resistance exercise (RE) causes large increases in mean arterial pressure that challenges the regulation of cerebral blood flow. It is unknown, however, if the sex differences in blood pressure regulation may alter how cerebral blood flow responds to the large increases in blood pressure induced during RE.PurposeTo determine if the cerebral blood velocity response during an acute bout of RE differs by sex.MethodsTwenty‐nine young, healthy adults (M/F: 17/12; 25 ± 5 yrs; 23.9 ± 3.3 kg/m2) performed 3 sets of 10 repetitions maximal isokinetic knee flexion/extension exercise. Systolic (SBP), diastolic (DBP), and mean (MAP) arterial pressure were measured using finger photoplethysmography and used to calculate pulse pressure (PP). Transcranial Doppler ultrasound (2 MHz) was used to measure right middle cerebral artery mean blood velocity (MCAmv) and calculate pulsatility index ([MCAsystolic ‐ MCAdiastolic velocity]/MCAmv). Conductance was calculated as MCAmv/MAP. The last 30‐sec of a 10‐min baseline and last 10‐sec of the 3rd RE set were averaged for analyses.ResultsOverall, females had higher MCAmv and conductance compared to males (p<0.05). SBP, DBP, MAP, PP, MCAmv increased and conductance decreased similarly for males and females during RE (p<0.05). Pulsatility index did not change during RE in either sex (p>0.05).ConclusionsThe blood pressure and cerebral hemodynamic response during RE was not different between sexes. These data suggest sex may not effect cerebrovascular responses to a large increase in blood pressure incurred during maximal RE in young healthy adults. Blood pressure and cerebral blood velocity responses at baseline and during an acute bout of resistance exercise in young adults. Male (n= 17) Female (n= 12) p for Interaction Baseline Resistance Exercise Baseline Resistance Exercise SBP (mmHg) * 124 ± 10 172 ± 18 123 ± 7 170 ± 27 0.92 DBP (mmHg) * 73 ± 7 99 ± 10 74 ± 7 103 ± 17 0.58 MAP (mmHg) * 93 ± 8 128 ± 13 96 ± 7 132 ± 10 0.80 PP (mmHg) * 52 ± 7 72 ± 11 50 ± 6 67 ± 14 0.42 MCA Mean Velocity (cm/sec) *, ‡ 55 ± 9 65 ± 12 70 ± 15 81 ± 30 0.89 MCA Pulsatility Index 0.90 ± 0.16 0.82 ± 0.14 0.81 ± 0.15 0.82 ± 0.27 0.27 Conductance (cm/sec/mmHg) *, ‡ 0.60 ± 0.09 0.51 ±0.10 0.74 ± 0.17 0.62 ± 0.24 0.39 All data are presented mean ± standard deviation *Main effect for time (p<0.05) ‡Main effect for sex (p<0.05)