The acute effect of exercise intensity on vascular function in adolescents
Medicine and Science in Sports and Exercise
American College of Sports Medicine
© 2015 American College of Sports Medicine
Reason for embargo
Introduction: Impairments in vascular function are present in asymptomatic youths with risk factors for cardiovascular disease. Exercise can promote vascular health in youth, but the effect of exercise intensity and the time course in response to acute exercise are unknown. Methods: Twenty adolescents (10 male, 14.1 ± 0.3 y) on separate days, and in a counter-balanced order: 1) cycled at 90% of the gas exchange threshold (moderate-intensity exercise; MIE); 2) completed 8x1 min cycling at 90% peak power with 75 s recovery (high-intensity interval exercise; HIIE). The duration of MIE (25.8 ± 2.1 min) was work-matched to HIIE (23.0 min). Macro- and micro-vascular function were assessed before, immediately post, and 1 and 2 hours after exercise by flow mediated dilation (FMD) and laser Doppler imaging (total reactive hyperaemia). Results: FMD was attenuated immediately after HIIE (P<0.001, ES=1.20) but not MIE (P=0.28, ES=0.26). Compared to pre-exercise, FMD was elevated 1 and 2 hours after HIIE (P<0.001, ES=1.33 and P<0.001, ES=1.36) but unchanged in MIE (P=0.67, ES=0.10 and P=0.72, ES=0.08). Changes in FMD were unrelated to shear or baseline arterial diameter. Compared to pre-exercise, total reactive hyperaemia was always greater after MIE (P<0.02, ES>0.60 for all) and HIIE (P<0.001, ES>1.18 for all). Total reactive hyperaemia was greater in HIIE compared to MIE immediately after (P=0.03, ES=0.67) and 1 hour after (P=0.01, ES=0.62) exercise, with a trend to be greater 2 hours after (P=0.06, ES=0.45). Conclusion: Exercise intensity is positively associated with macro- and micro-vascular function 1 and 2 hours after exercise. Performing HIIE may provide superior vascular benefits than MIE in adolescents.
This is a non-final version of an article published in final form in Medicine and Science in Sports and Exercise.
Medicine and Science in Sports and Exercise, 2015