Behaviour of nitric oxide metabolites in unprofessional athletes before and after a cardiopulmonary test

Physical training causes an increase in nitric oxide (NO) production [2, 3, 8, 9] and this datum explains the link between exercise and endothelium and seems to demonstrate how regular training upregulates eNOS expression, although it is not sure if this upregulation is due to shear stress or metabolic factors [3]. However, it must be underlined that besides to be directly influenced by exogenous NO, erythrocytes express a functional NOS [5, 6, 11, 13] that raises the circulation NO pool. The literature data describe that an 8-week exercise training induced an increase in plasma levels of NO metabolites (NOx), that persisted four weeks after interruption of training [8]. A similar trend was also found after a 12-week physical training [9]. Other authors noted instead that at baseline the NOx level was higher in sedentary young subjects compared to the older ones while this difference was not present between younger and older athletes; this difference was eliminated in sedentary subjects by physical training [2]. Now we evaluated the NOx level before and after a cardio-pulmonary test in unprofessional athletes who practised different kinds of sports, in comparison with sedentary controls (SC).