Plasma antioxidant activity and cutaneous microvascular endothelial function in athletes and sedentary controls

Aging is associated with endothelial dysfunction in both conduit arteries and peripheral microcirculation. Furthermore, aging is associated with an increased susceptibility to free radical mediated tissue damage. The aim of this study was to assess the relationship between age, regular aerobic-endurance training, plasma antioxidant activity and microcirculatory skin blood flow in healthy individuals. Thirty-six male athletes (range: 22-74 years; VO2max 54.3 +/- 5.2 ml/kg/min) and 36 age-sex-matched sedentary controls (range: 20-75 years; VO2max 34.2 +/- 3.4 ml/kg/min) were studied. Each group was divided into a younger (60 years) subgroup. Hand and foot baseline and stimulated skin blood flow (SBF) was measured by laser-Doppler flowmetry. Plasma free radicals antioxidant capacity against both peroxyl and hydroxyl radicals was also evaluated as Total Oxyradical Scavenging Capacity (TOSC) units. Baseline SBFs were not significantly different between athletes and sedentary groups, while plasma TOSC values against peroxyl radicals (18.4 +/- 3.1 vs. 13.8.0 +/- 3.4 units/ml, P < 0.001) and hydroxyl radicals (8.7 +/- 2.5 vs 4.9 +/- 2.3 units/ml, P