Acute effect of high-intensity cycling exercise on carotid artery hemodynamic pulsatility.

Purpose: Investigate the effects of acute high-intensity exercise on common carotid artery (CCA) dimensions, stiffness, and wave intensity.

Methods: Fifty-five healthy men and women (22 ± 5 year; 24.5 ± 2.7 kg m(-2)) underwent 30 s of high-intensity cycling (HIC; Wingate anaerobic test). CCA diameter, stiffness [β-stiffness, Elastic Modulus (E p)], pulsatility index (PI), forward wave intensities [due to LV contraction (W 1) and LV suction (W 2)], and reflected wave intensity [negative area (NA)] were assessed using a combination of Doppler ultrasound, wave intensity analysis, and applanation tonometry at baseline and immediately post-HIC.

Results: CCA β-stiffness, E p, PI and pulse pressure increased significantly immediately post-HIC (p < 0.05). CCA diameter decreased acutely post-HIC (p < 0.05). There were also significant increases in W 1 and NA and a significant decrease in W 2 (p < 0.05). A significant correlation was found between change in W 1 and PI (r = 0.438, p < 0.05), from rest to recovery as well as a significant inverse correlation between W 2 and PI (r = -0.378, p < 0.05). Change in PI was not associated with change in CCA stiffness or NA (p > 0.05).

Conclusions: Acute HIC results in CCA constriction and increases in CCA stiffness along with increases in hemodynamic pulsatility. The increase in pulsatility may be due to a combination of increased forward wave intensity from increased LV contractility into a smaller vessel (i.e. impaired matching of diameter and flow) coupled with reduced LV suction.