Exercise-induced asthma. Physiologic and clinical considerations.

This article discusses the physiologic and clinical aspects of exercise-induced asthma. Alterations in heat and water exchange in the respiratory tract appear to be important in initiating exercise-induced asthma, which can be reproduced by isocapneic hyperventilation with cold dry air. These pulmonary responses are also closely related to the level of non-specific airways hyperreactivity. Proposed mechanisms by which airways cooling and drying produce bronchospasm are reviewed and therapeutic approaches are discussed.