Exercise intensity and the protection from postprandial vascular dysfunction in adolescents

Abstract

BACKGROUND: Acute exercise transiently improves endothelial function, and protects the vasculature from the deleterious effects of a high fat meal (HFM). We sought to identify whether this response is dependent on exercise intensity in adolescents. METHODS: Twenty adolescents (10 male, 14.3 ± 0.3 y) completed three 1-day trials: 1) rest (CON); 2) 8x1 min cycling at 90% peak power with 75s recovery (high-intensity interval exercise; HIIE); 3) cycling at 90% of the gas exchange threshold (moderate-intensity exercise; MIE) one hour before consuming a HFM (1.50 g∙kg(-1) fat). Macrovascular and microvascular endothelial function were assessed before and immediately after exercise, and three hours after the HFM by flow mediated dilation (FMD) and laser Doppler imaging (peak reactive hyperaemia; PRH). RESULTS: FMD and PRH increased one hour after HIIE (P<0.001, ES=1.20 and P=0.048, ES=0.56) but were unchanged after MIE. FMD and PRH were attenuated three hours after the HFM in CON (P<0.001, ES=1.78 and P=0.02, ES=0.59). FMD remained greater three hours after the HFM in HIIE compared to MIE (P<0.001, ES=1.47) and CON (P<0.001, ES=2.54), and in MIE compared to CON (P<0.001, ES=1.40). Compared to CON, PRH was greater three hours after the HFM in HIIE (P=0.02, ES=0.71) and MIE (P=0.02, ES=0.84), with no differences between HIIE and MIE (P=0.72, ES=0.16). Plasma [triacylglycerol] and [total antioxidant status] were not different between trials. CONCLUSIONS: Exercise intensity plays an important role in protecting the vasculature from the deleterious effects of a HFM. Performing HIIE may provide superior vascular benefits than MIE in adolescent groups.