The Impact of Different Exercise Intensities on Vasodilation and Shear Rate Patterns in Children.

Abstract

Purpose: The effect of exercise intensity on vasodilator function is poorly understood in children. The authors compared the acute effect of high-intensity interval exercise (HIIE) with moderate-intensity steady-state exercise (MISS) on postexercise vasodilation and shear patterns in 7- to 12- year-old children. Methods: Superficial femoral artery diameter, shear rates, and flow-mediated dilation were measured pre, immediately following (post), and 1 hour after (post60) HIIE (six 1-min sprints at 90% peak power [Wmax], with 1-min recovery) and MISS (15\xa0min at 44% Wmax). Results: Baseline superficial femoral artery diameter increased similarly following both HIIE (pre 4.23 [0.41]\xa0mm, post 4.73 [0.56]\xa0mm) and MISS (pre 4.28 [0.56]\xa0mm, post 4.59 [0.64]\xa0mm), returning to preexercise values post60. Blood flow and antegrade shear rate were increased post HIIE and MISS, but to a greater extent, post HIIE (P\u2009<\u2009.05). Retrograde shear rate was attenuated post both exercise conditions and remained post60 (P\u2009<\u2009.001). There was a decline in flow-mediated dilation postexercise (HIIE Δ -2.9%; MISS Δ -2.4%), which was no longer apparent when corrected for baseline diameter. Conclusion: Acute bouts of external work-matched HIIE or MISS exert a similar impact on shear-mediated conduit artery vasodilation and flow-mediated dilation in children, and this is reversed 1 hour after exercise.