No difference in mean middle cerebral artery blood velocity responses between lower- and upper-body unilateral resistance exercise in untrained individuals

Abstract

Dynamic resistance exercise (RE) produces sinusoidal fluctuations in blood pressure that are mirrored by middle cerebral artery blood velocity (MCAv). However, whether lower- or upper-body RE elicits a differential cerebrovascular response has not yet been examined. We investigated the cerebrovascular response to lower-body RE versus upper-body RE in 15 healthy untrained individuals (12 females and 3 males; mean ± SD; age 25 ± 6 years, height 179 ± 10 cm, weight 71 ± 15 kg and body mass index 24 ± 6 kg/m2). Participants completed four sets of 10 paced repetitions (15 repetitions/min) of unilateral leg-extension exercise and unilateral bicep-curl exercise at 60% of predicted one-repetition maximum (leg extension 30 ± 9 kg and bicep curl 7 ± 3 kg). Beat-to-beat blood pressure, bilateral MCAv and partial pressure of end-tidal carbon dioxide were measured throughout. Within-exercise mean arterial blood pressure (MAP) and mean MCAv were averaged across the set. Additionally, zenith, nadir and zenith-to-nadir difference in MAP and mean MCAv for each repetition were averaged across each set. Baseline measures preceding each set were not different for all dependent variables, with no significant interaction differences observed (all p > 0.161). The mean MCAv within exercise decreased across sets (set effect p < 0.001), but MAP did not (p = 0.071). No interaction effects were observed for any dependent variables (all p > 0.06), However, there was a zenith-to-nadir difference in mean MCAv (p = 0.008), although post hoc tests revealed no significant difference between exercises (all p > 0.078). There were no differences in the cerebrovascular and cardiovascular responses to lower- and upper-body RE, with similar sinusoidal fluctuations in MAP and MCAvmean present during both exercises.