Background: Impairment of vascular endothelial function and increased intima-media thickness (IMT) are important early steps in atherogenesis. Longitudinal data on the effect of physical activity on endothelial function and IMT in healthy adolescents are lacking. We investigated prospectively the association of leisure-time physical activity with endothelial function (brachial artery flow-mediated dilatation; FMD) and aortic IMT in adolescents.
Methods and results: FMD and IMT were measured with ultrasonography at 13 (n=553), 15 (n=531), and 17 (n=494) years of age in adolescents participating in a longitudinal atherosclerosis prevention study (Special Turku Coronary Risk Factor Intervention Project for Children). Mean aortic IMT, maximum FMD, and total FMD response (area under the dilatation curve 40 to 180 seconds after hyperemia) were calculated. Leisure-time physical activity was assessed with a questionnaire, and metabolic equivalent (MET) hours per week of leisure-time physical activity were calculated by multiplying weekly mean exercise intensity, duration, and frequency. Leisure-time physical activity was directly associated with endothelial function (P for maximum FMD=0.0021, P for total FMD response=0.0036) and inversely with IMT (P=0.011) after adjustment for age, sex, body mass index, high-density lipoprotein/total cholesterol, systolic blood pressure, and C-reactive protein and regarding FMD brachial artery diameter. Sedentary adolescents who increased their leisure-time physical activity from <5 to >5 (IMT) or >30 (maximum FMD) MET h/wk between 13 and 17 years of age had an increased maximum FMD (P=0.031) and decreased progression of IMT (P=0.047) compared with adolescents who remained sedentary. IMT progression was attenuated in persistently active adolescents compared with those who became sedentary (P=0.0072).
Conclusions: Physical activity is favorably associated with endothelial function and IMT in adolescents. Importantly, a moderate increase in physical activity is related to decreased progression of IMT. A physically active lifestyle seems to prevent the development of subclinical atherosclerotic vascular changes in healthy adolescents. Clinical Trial Registration- URL: http://www.clinicaltrials.gov. Unique identifier: NCT00223600 (STRIP19902010).