The acute effect of maximal sprint exercise on dynamic cerebral autoregulation in healthy young adults

This study investigated the acute effect of maximal sprint exercise on dynamic cerebral autoregulation (dCA). Twenty-one healthy young adults (22.9 ± 3.0 years) completed a single experimental visit where dCA was assessed at rest and 25 min following an all-out 30-s Wingate Anaerobic Test (WAnT). Forced oscillations in mean arterial pressure (MAP) during 5 min of repeated sit-stands, performed at 0.05 Hz, were used to determine dCA. Middle cerebral artery blood velocity (MCAv) was measured using transcranial Doppler ultrasonography, and beat-to-beat blood pressure using finger plethysmography. dCA was analyzed using: (1) transfer function analysis and (2) a novel directional sensitivity metric (ΔMCAv_T/ΔMAP_T) for each MAP direction. There were no pre versus post-WAnT differences in gain (0.73 ± 0.30 vs. 0.69 ± 0.21 cm.s^-1/mmHg, p = 0.49), normalized gain (1.10 ± 0.41 vs. 1.20 ± 0.33%/mmHg, p = 0.19), phase (0.98 ± 0.22 vs. 1.05 ± 0.24 rad, p = 0.18), or coherence (0.82 ± 0.13 vs. 0.90 ± 0.12, p = 0.08). Pre-exercise, ΔMCAv_T/ΔMAP_T was significantly higher during acute decreases versus increases in MAP (1.05 ± 0.37 vs. 0.87 ± 0.31 cm.s^-1/mmHg, p = 0.034), and this persisted post-exercise (0.93 ± 0.23 vs. 0.81 ± 0.25 cm.s^-1/mmHg, p = 0.017). ΔMCAv_T/ΔMAP_T in either MAP direction was unaffected by the WAnT (p = 0.15). These novel findings suggest that dCA was unaltered 25 min following maximal sprint exercise in healthy young adults, while providing further support for hysteresis in the cerebral pressure-flow relationship.