The Authors studied the modifications in nasal mucociliary clearance times before and after aerobic exertion in athletes. A total of 60 athletes with high-level training (age range 18-37 years) were selected for this study. Persons who smoked or had allergies, nasal sinus phlogosis or tumors, altered nasal cavity morphology (i.e. deviation of the septum and/or hypertrophy of the turbinates), fever or who were taking topic and/or systemic drugs or had previously undergone head and neck surgery were all ruled out of the study. The authors then studied the mucociliary clearance time (MCCT) in these subjects using the saccharin test. This test involves placing a small amount of saccharin on the medial face of the lower turbinate, approximately 1.5 cm from the anterior end and then evaluating the time that elapses before the patient perceives the sweet taste. This test was performed: in 30 subjects one hour prior to and 15 minutes after physical aerobic exertion; in the remaining subjects (controls) the test was performed twice with a 75 minute interval between them. The results showed that the mucociliary clearance time increased after exertion which was, on the average, 11.29 minutes. On the basis of these data, the Authors discuss the likely causes for the detected increase, and correlate it to changes in ventilation and nasal secretion viscosity during physical exercise. According to previous research, these variations are also found in untrained subjects who undergo physical exertion; for this reason, the Authors conclude that nasal clearance is not significantly affected by training.