Metabolic And Vascular Responses Acutely Affected By Meal Consumption And Exercise

Abstract

Lifestyle strongly regulates vascular and metabolic function, with physical activity eliciting acute, short- and long-term effects. We examined risk factor changes after a single exercise session in sedentary people. PURPOSE: To determine how glucose control, arterial elasticity and inflammatory markers respond to a single bout of moderate intensity exercise performed the day before or immediately prior to a standardized mixed meal. METHODS: Participants (5M/6F) were young (26 y±1), normal BMI (22.7 ± 0.3), untrained (VO2peak 25 ± 1 ml/kg/min), but generally healthy. The test meal (670 kcal, 45/40/15% energy as CHO/fat/pro) was consumed on 3 separate mornings. One trial (no-exercise) was after refraining from moderate-to-vigorous activity for ≥3 days. On the other 2 trials, a 45-min exercise bout at 75% HRmax was performed either 17-hr (prior afternoon) or 1-hr (same morning) before the meal. RESULTS: Post-meal energy expenditure increased (24% above baseline at 1-hr) and fuel oxidation shifted toward CHO but there were no differences between trials. Fasting glucose (83±1 mg/dl) and insulin (6.1±0.8 μIU/ml) were similar among trials, but 3-hr post-meal AUC's were reduced by 9 & 19% (p<0.05), respectively, on the acute exercise trial. Small artery elasticity, measured by diastolic pulsewave contour analysis, was reduced 18-20% from 1-3 hours (p < 0.01) after the meal on the no-exercise trial. This post-meal decline was prevented on both exercise trials, demonstrating both acute and residual benefits of exercise. In contrast, large artery elasticity was not significantly affected by the meal or exercise. After prior-day exercise, fasting SBP (110±1 mmHg) and DBP (61±1) were reduced (p < 0.05) by 3 and 2 mmHg, respectively. These effects may be mediated in part by changes in inflammatory markers like ICAM-1 and VCAM-1, which were reduced 5-6% (p<0.03) by prior-day exercise, C-reactive protein (40% lower after acute exercise) and visfatin (7% lower after acute and prior day exercise). Other putative cyto-/adipokines (IL6, HMW adiponectin, e-selectin) were unchanged. CONCLUSION: These results demonstrate that exercise has positive benefits on metabolic and vascular outcomes in untrained young people that begin to accrue after a single moderate exercise session. Supported by NIH Grant P20 DKRR024215