The Influence of Exercise and Insulin Resistance on Biomarkers of Endothelial Dysfunction

Abstract

Insulin resistance is associated with endothelial dysfunction, contributing to the pathogenesis of atherosclerosis and ultimately cardiovascular disease. While exercise can help in the prevention and treatment of insulin resistance, it is not clear if exercise induced improvements in insulin resistance translate to parallel improvements in endothelial function. PURPOSE: To determine whether the insulin sensitizing effects of acute and habitual exercise are associated with improvements in biomarkers of endothelial dysfunction in overweight adults. METHODS: 23 overweight-to-mildly obese adults (BMI: 27-34 kg/m²) were recruited for this study, including 11 regular exercisers (“EX”; 2.5h exercise/week) and a well-matched cohort of 12 non-exercisers (“Non-EX”; no planned physical activity). Matsuda Composite Index of Whole Body Insulin Sensitivity (ISI) using an oral glucose tolerance test, and biomarkers of endothelial dysfunction (E-selectin, P-selectin, intracellular adhesion molecule, (ICAM-1), vascular adhesion molecule (VCAM-1), plasminogen activator inhibitor-1 (PAI-1), and von Willebrand factor (vWF-1)) were measured the morning before (Day 1) and after (Day 2) a single session of exercise. RESULTS: On Day 1 ISI was significantly greater in EX vs. Non-EX (3.13±0.26 vs. 2.29±0.20; P=0.03), with no differences in biomarkers of endothelial dysfunction between groups. However, ISI on Day 1 was significantly correlated with concentrations of E-selectin (r = 0.18, P<0.05), VCAM-1 (r = 0.22, P=0.03), and PAI-1 (r = 0.19, P=0.04) for all subjects. A single session of exercise improved ISI in Non-EX (2.29±0.20 vs. 2.78±0.31; P=0.03), but not EX. The increased ISI in Non-EX was accompanied by a significant reduction in E-selectin (22±2.9 vs. 18±2.6 ng/mL; P=0.005). Remaining biomarkers of endothelial dysfunction were unchanged after acute exercise in both groups. CONCLUSIONS: We found significant correlations between measures of insulin sensitivity and biomarkers of endothelial dysfunction among overweight adults. Additionally, the insulin sensitizing effects of a single session of exercise was accompanied by a reduction in E-Selectin, a biomarker of endothelial dysfunction.