Impact of sex on the cerebrovascular response to incremental aerobic exercise in moderately-trained endurance athletes.

The cerebrovascular response to incremental aerobic exercise is comparable between males and females. Whether this response can be found in moderately-trained athletes remains unknown. We aimed to examine the effect of sex on the cerebrovascular response to incremental aerobic exercise until volitional exhaustion in this population. Twenty-two moderately-trained athletes (11 M/11 F; age: 25 ± 5 vs. 26 ± 6 years, p=0.6478; peak oxygen consumption: 55.8± 5.2 vs. 48.3 ± 4 mL/kg/min; p=0.0011; training volume: 532 ± 173 vs. 466 ±151 min/week, p=0.3554) performed a maximal ergocycle exercise test. Systemic and cerebrovascular hemodynamics were measured. At rest, middle cerebral artery mean blood velocity (MCAvmean; 64.1 ± 12.7 vs. 72.2 ± 15.3 cm.s; p=0.2713) was not different between groups, while partial pressure of end-tidal carbon dioxide (PCO, 42 ± 3 vs. 37 ± 2 mmHg, p=0.0002) was higher in males. During the MCAvmean ascending phase, changes in MCAvmean (intensity: p<0.0001, sex: p=0.3184, interaction: p=0.9567) were not different between groups. Changes in cardiac output (Q) (intensity: p<0.0001, sex: p<0.0001, interaction: p<0.0001) and PCO (intensity: p<0.0001, sex: p<0.0001, interaction: p<0.0001) were higher in males. During the MCAvmean descending phase, changes in MCAvmean (intensity: p<0.0001, sex: p=0.5522, interaction: p= 0.4828) and Q (intensity: p= 0.0504, sex: p= 0.0003, interaction: p= 0.2715) were not different between groups. Changes in PCO (intensity p<0.0001, sex: p<0.0001, interaction: p= 0.0280) were higher in males. These results suggest the MCAvmean response during exercise is comparable between moderately-trained males and females notwithstanding differences in the response of key CBF determinants.