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 explainsthe link between exercise and endothelium and seems to demonstrate how regular training upregulateseNOS 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, erythrocytesexpress 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 NOmetabolites (NOx), that persisted four weeks after interruption of training [8]. A similar trend was alsofound after a 12-week physical training [9]. Other authors noted instead that at baseline the NOx levelwas higher in sedentary young subjects compared to the older ones while this difference was not presentbetween younger and older athletes; this difference was eliminated in sedentary subjects by physicaltraining [2].Now we evaluated the NOx level before and after a cardio-pulmonary test in unprofessional athleteswho practised different kinds of sports, in comparison with sedentary controls (SC).