6533b862fe1ef96bd12c6e9a

RESEARCH PRODUCT

Lipid peroxidation and nitric oxide metabolites in sedentary subjects and sportsmen before and after a cardiopulmonary test.

subject

description

Our aim was to investigate the effects of an exercise test on some indices of oxidative status and endothelial function, in trained and untrained subjects. We examined lipid peroxidation, nitric oxide metabolites (NOx) and their ratio before and after a cardiopulmonary test, using a cycloergometer. We enrolled 60 male subjects who practiced sport unprofessionally, subdivided in two groups (A and B) according to the values of VO2max. Group A included sportsmen with poor or fair aerobic fitness (VO2max 39 ml/Kg/min). The control group included 19 male sedentary subjects. Lipid peroxidation was evaluated by detection of the thiobarbituric acid-reactive substances (TBARS); the NOx were evaluated employing the Griess reagent. At rest, in comparison with sedentary controls, an increase in TBARS, NOx and TBARS/NOx ratio was found in all sportsmen and partially in the two groups. After the cardiopulmonary test, the increase of TBARS and TBARS/NOx ratio was significantly more evident in sedentary controls than in sportsmen. No variation was observed for NOx in any group. These data suggest that sportsmen are protected against the acute oxidative stress induced by an exercise test, and that protection is not strictly dependent on the aerobic fitness. Physical activity is associated with an enhanced oxidative stress, which is implied in the pathophysi- ology of many diseases, including cardiovascular diseases. Nevertheless, people who regularly practice physical activity are generally considered more protected against atherosclerotic vascular diseases. An exercise of sufficient intensity induces a prooxidant/antioxidant imbalance, that can be investigated by means of several indicators. The effects of oxidative stress can be in fact demonstrated in lipids, proteins and nucleic acids; on the other hand, total antioxidant capacity can be evaluated as a whole or in its components, including enzymatic and non-enzymatic systems. In athletes, at rest, some papers reported an increase in lipid peroxidation (LP) in comparison with sedentary controls (4, 26, 43), others observed a LP decrease (10, 18, 39, 55) while others did not find any difference between athletes and controls (19). After an exercise test many authors showed, in comparison with baseline data, a LP increase (1, 2, 34, 46, 47, 57) in controls and in athletes and others found a