Physical activity prevents nitrosative stress in elderly people

Sedentary aging is associated with an increased susceptibility to free radical-induced tissue damage. One of the most important groups of free radicals is represented by reactive nitrogen species (RNS), responsible for the so-called nitrosative stress. It has been shown that physical activity is able to induce up-regulation of antioxidant systems contributing to prevent oxidative and nitrosative stress. The aim of the present study was to cross-sectionally assess whether regular intense aerobic physical activity in elderly people is associated with increased antioxidant defences against nitrosative stress. Thirty male athletes (21-76 years; VO2max 48.4±6.7 ml/kg/min) and thirty matched sedentary controls (20-72 years; VO2max 27.2±5.1 ml/kg/min) were studied. Each group was divided into a younger (<30 years) and an older (>60 years) subgroup. Plasma free radicals antioxidant capacity against peroynitrite was evaluated as Total Oxyradical Scavenging Capacity (TOSC) units. Plasma TOSC values against peroxynitrite radicals (22.05±1.6 vs 16.8±1.5 units/ml, P<0.001) was higher in athletes. Amongst sedentary subjects, the younger subgroup had higher plasma TOSC values than the older subgroup (18.4±0.5 vs 15.4±1.2 units/ml, P<0.01). Amongst athletes, the older subgroup did not show significantly difference in plasma TOSC values compared to younger subgroup (21.2±1.2 and 23.4±1.1 units/ml, ns). In athletes TOSC values was related to VO2max (r=0.36; P<0.05). These results suggest that regular physical activity is associated with increased antioxidant defences against nitrosative stress in elderly athletes.