Response of nose and bronchi to exercise in asthma and rhinitis: similarities and differences.

The response of asthmatic patients to exercise differs from that of healthy subjects, and the mechanisms responsible for the exercise-induced bronchoconstriction in the former group remain uncertain. The severity of bronchospasm may be related to water loss from the respiratory tree, but there are conflicting explanations for this. The response of the nose to exercise, in healthy subjects or in patients with asthma and rhinitis, has been the subject of few investigations, but a recent study found that the nose responds in a different fashion to the bronchi in patients with rhinitis and asthma. The bronchial tree responds by narrowing, while the nose becomes more patent. There is evidence that the bronchi are the main sites of airway narrowing in exercise-induced bronchoconstriction, while there can also be simultaneous tracheal dilatation. In addition, it now appears that the nasal response to exercise in all subjects parallels that of the trachea. In total, the results suggest that different mechanisms are responsible for regulating the patency of the upper and lower airways.