The effects of habitual resistance exercise training on cerebrovascular responses to lower body dynamic resistance exercise: A cross-sectional study.

Abstract

Dynamic resistance exercise (RE) produces sinusoidal fluctuations in blood pressure with simultaneous fluctuations in middle cerebral artery blood velocity (MCAv). Some evidence indicates that RE may alter cerebrovascular function. This study aimed to examine the effects of habitual RE training on the within-RE cerebrovascular responses. RE-trained (n=15, Female=4) and healthy untrained individuals (n=15, Female=12) completed four sets of 10 paced repetitions (15 repetitions per minute) of unilateral leg extension exercise at 60% of predicted 1 repetition maximum. Beat-to-beat blood pressure, MCAv and end-tidal carbon dioxide were measured throughout. Zenith, nadir and zenith-to-nadir difference in mean arterial blood pressure (MAP) and mean MCAv (MCAvmean) for each repetition were averaged across each set. Two-way ANOVA was used to analyse dependent variables (training × sets), Bonferroni corrected t-tests were used for post hoc pairwise comparisons. Group age (26±7 trained vs. 25±6 years untrained, P=0.683) and weight (78±15vs. 71±15kg, P=0.683) were not different. During exercise average MAP was greater for the RE-trained group in sets 2, 3 and 4 (e.g., set 4: 101±11vs. 92±7mmHg for RE trained and untrained, respectively, post hoc tests all P=<0.012). Zenith MAP and zenith-to-nadir MAP difference demonstrated a training effect (P<0.039). Average MCAvmean and MCAvmean zenith-to-nadir difference was not different between groups (interaction effect P=0.166 and P=0.459, respectively). Despite RE-trained individuals demonstrating greater fluctuations in MAP during RE compared to untrained, there were no differences in MCAvmean. Regular RE may lead to vascular adaptations that stabilise MCAv during RE.