Effect of Acute Exercise on Postprandial Lipemia and Biomarkers of Endothelial Function and Inflammation in Adolescents

Abstract

Elevated postprandial lipemia (PPL) is associated with impaired endothelial function, an increase in adhesion molecule expression and inflammation. Acute exercise reduces PPL in adults. To our knowledge, no studies have reported the effect of acute exercise on PPL in adolescents. PURPOSE: To investigate the effect of an acute bout of exercise (600 kcal) on postprandial changes in triglycerides (TG), glucose, insulin, adhesion molecules (sICAM-1, sVCAM-1) and inflammatory markers (CRP, IL-6, TNF-α, WBC) following a high-fat meal in normal-weight (NW) and overweight (OW) adolescents. METHODS: 10NW(BMI: 20.9±1.7kg.m−2, 15.6±0.7y) and 8 OW(BMI: 28.3±3.6 kg.m−2, 15.9±0.4y) adolescent boys underwent two 6h oral fat tolerance tests (OFTT) separated by 7 d. On the evening prior to each OFTT, subjects rested (CTL) or completed a treadmill walk/run at 70% VO2max until 600 kcal had been expended (EX). Blood samples were obtained at baseline and at 30 min, 1, 2, 4 and 6 h postprandially. Dependent t-tests were used to compare summary postprandial responses and 3-way ANOVA with repeated measures were used to determine changes over the postprandial period. RESULTS: There was an 81. 1±40.7% increase in lipemia following the OFTT in the CTL trial, and a 75.3±21.2% increase in the EX trial, in both groups. Area under the TG vs. time curve was reduced during the EX trial in both groups (8.3±3.1 vs. 6.9±1.6 mmol L-1.6hrinNW, p=.054; 11.3±5.4vs. 8.3±2.3 mmol.L-1.6hr in OW, p=.056). The magnitude of the attenuation did not differ between NW and OW (p=.269). Insulin response to the test meal did not differ between the EX and CTL trials or between NW and OW. Glucose response was lower in both NW and OW groups in the CTL condition (CTL: 24.5±2.9 vs. EX: 28.9±3.2 mmol.L-1, p<0.001). IL-6 increased similarly in NW and OW following the OFTT in both experimental trials (CTL: 1.46±0.49 (0 h) vs. 2.72±1.60 (6 h) pg.ml-1, p=0.001;EX: 1.81±1.03 (0 h) vs. 3.71±2.21 (6 h) pg.ml-1, p=0.002) and was higher during the EX condition than the CTL condition (p=.043). TNF-α was higher in OW than NW (p<.001) but there was no main effect of exercise or the OFTT. WBC number was higher in OW than NW (p=.049), and increased similarly in both groups following the OFTT in both experimental conditions (p<.001). There were no changes in CRP, sVCAM-1 or sICAM-1 following the OFTT and there were no differences between experimental condition or BMI group. CONCLUSION: Acute exercise attenuates postprandial TG response but does not reduce inflammation or alter adhesion molecule expression in NW and OW adolescents. Supported by the Irish Research Council for Science, Engineering and Technology: funded by the National Development Plan.