Obesity and inactivity are associated with endothelial dysfunction that may contribute to the development of atherosclerosis. We examined the effects of a short-term lifestyle intervention on circulating biomarkers of endothelial health. Nineteen overweight or obese (mean body mass index (BMI): 28.9 +/- 0.7 kg/m2) men and women underwent 6 weeks of body mass reduction induced by moderate energy restriction (approximately 750 kcal/d; 1 kcal = 4.184 kJ) and aerobic training (approximately 400 kcal/d). Fasting serum samples were collected at baseline and after reduction in body mass (week 6) to assess concentrations of nitrotyrosine (NT), secretory phospholipase A2 (sPLA2), and soluble intracellular adhesion molecule-1 (sICAM-1). Body mass was significantly reduced from 81.3 +/- 2.8 to 77.3 +/- 2.6 kg (p < 0.05). Circulating concentrations of NT and sICAM-1 were significantly reduced with treatment (approximately 25% and approximately 10%, respectively), whereas sPLA2 levels were significantly elevated (approximately 45%). Elevations in sPLA2 were negatively correlated with changes in NT (r = -0.58, p = 0.047); reductions in NT did not correlate significantly with reductions in sICAM-1. It appears that circulating markers of endothelial health are susceptible to short-term exercise interventions with modest reduction in body mass, and such a lifestyle modification may improve endothelial health by reducing protein nitration products and cellular adhesion.