Comparable blood velocity changes in middle and posterior cerebral arteries during and following acute high-intensity exercise in young fit women

The cerebral blood flow response to high-intensity interval training (HIIT) remains unclear. HIIT induces surges in mean arterial pressure (MAP), which could be transmitted to the brain, especially early after exercise onset. The aim of this study was to describe regional cerebral blood velocity changes during and following 30 s of high-intensity exercise. Ten women (age: 27 +/- 6 years; VO2max: 48.6 +/- 3.8 mlkgmin(-1)) cycled for 30 s at the workload reached at Vmml:momml:moverO(2max) followed by 3min of passive recovery. Middle (MCAv(mean)) and posterior cerebral artery mean blood velocities (PCAv(mean); transcranial Doppler ultrasound), MAP (finger photoplethysmography), and end-tidal carbon dioxide partial pressure (PETCO2; gaz analyzer) were measured. MCAv(mean) (+19 +/- 10%) and PCAv(mean) (+21 +/- 14%) increased early after exercise onset, returning toward baseline values afterward. MAP increased throughout exercise (p < .0001). PETCO2 initially decreased by 3 +/- 2 mmHg (p < .0001) before returning to baseline values at end-exercise. During recovery, MCAv(mean) (+43 +/- 15%), PCAv(mean) (+42 +/- 15%), and PETCO2 (+11 +/- 3 mmHg; p < .0001) increased. In young fit women, cerebral blood velocity quickly increases at the onset of a 30-s exercise performed at maximal workload, before returning to baseline values through the end of the exercise. During recovery, cerebral blood velocity augments in both arteries, along with PETCO2.