Exercise‐induced elevations in cerebral blood velocity are greater in running compared to cycling at higher intensities
Research output: Contribution to journal › Article › peer-review
Colleges, School and Institutes
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham
The optimal exercise intensity and modality for maximizing cerebral blood flow (CBF) and hence potential exposure to positive, hemodynamically derived cerebral adaptations is yet to be fully determined. This study compared CBF velocity responses between running and cycling across a range of exercise intensities. Twenty-six participants (12 females; age: 26 ± 8 years) completed four exercise sessions; two mode-specific maximal oxygen consumption (VO 2max) tests, followed by (order randomized) two incremental exercise protocols (3-min stages at 35%, 50%, 65%, 80%, 95% VO 2max). Continuous measures of middle cerebral artery velocity (MCAv), oxygen consumption, end-tidal CO 2 (P ETCO 2), and heart rate were obtained. Modality-specific MCAv changes were observed for the whole group (interaction effect: p =.01). Exercise-induced increases in MCAv mean during cycling followed an inverted-U pattern, peaking at 65% VO 2max (Δ12 ± 7 cm/s from rest), whereas MCAv mean during running increased linearly up to 95% VO 2max (change from rest: Δ12 ± 13 vs. Δ7 ± 8 cm/s for running vs. cycling at 95% VO 2max; p =.01). In contrast, both modalities had an inverted-U pattern for P ETCO 2 changes, although peaked at different intensities (running: 50% VO 2max, Δ6 ± 2 mmHg; cycling: 65% VO 2max, Δ7 ± 2 mmHg; interaction effect: p =.01). Further subgroup analysis revealed that the running-specific linear MCAv mean response was fitness dependent (Fitness*modality*intensity interaction effect: p =.04). Above 65% VO 2max, fitter participants (n = 16; male > 45 mL/min/kg and female > 40 mL/min/kg) increased MCAv mean up to 95% VO 2max, whereas in unfit participants (n = 7, male < mL/min/kg and female < 35 mL/min/kg) MCAv mean returned toward resting values. Findings demonstrate that modality- and fitness-specific profiles for MCAv mean are seen at exercise intensities exceeding 65% VO 2max.
|Early online date||12 Aug 2020|
|Publication status||Published - 12 Aug 2020|