Leisure-time Physical Activity And Vascular Endothelial Function In Adolescents

Abstract

Exercise training improves vascular endothelial function in high-risk adolescents. The effect of leisure-time physical activity on endothelial function in healthy adolescents is unknown. PURPOSE: To study the association of leisure-time physical activity and brachial artery endothelial function in adolescents. METHODS: Physical activity habits and brachial artery flow-mediated endothelial function were assessed in 483 13-year-old adolescents participating in an atherosclerosis prevention study (STRIP). Endothelial function was examined with ultrasound and physical activity with a validated self-administered questionnaire. A leisure-time physical activity index (PAI; MET h/wk) was calculated by multiplying weekly mean leisure-time exercise intensity, duration and frequency [mean±SD PAI: boys 31.2±23.0 MET h/wk, girls 24.0±20.9 MET h/wk; P(gender difference)<0.001]. Maximum flow-mediated dilatation (FMDmax; %) and total FMD response [the area under the dilatation curve 40-180 sec after hyperemia (FMDauc; % x s)], were used as measures of endothelial function. RESULTS: In boys, FMDmax and FMDauc were directly associated with PAI in regression analyses adjusted for brachial artery diameter (FMDmax: P=0.020, FMDauc: P=0.0055). The associations remained significant also after further adjustments for BMI, HDL-cholesterol, LDL-cholesterol, triglycerides, hs-C-reactive protein and systolic blood pressure. The similar association was not found in girls. A difference of ∼50 MET h/wk corresponding to ∼10 h of moderate intensity activity weekly between sedentary and active boys was associated with ∼1% unit difference in FMDmax. CONCLUSIONS: Leisure-time physical activity is directly associated with brachial artery FMD responses in 13-year-old boys. This confirms that physical activity beneficially influences endothelial function in healthy male adolescents. Lack of association in girls may be explained by their overall lower physical activity level. Indeed, girls and boys having the same leisure-time physical activity level have an identical FMDmax response. Supported by the Finnish Ministry of Education, the Finnish Cultural Foundation and the Juho Vainio Foundation.