Exercise-induced bronchospasm: epidemiology, pathophysiology, and therapy.

Exercise induced bronchospasm (EIB) is a common clinical problem seen in most individuals with chronic asthma and in nearly half the allergic population. Bronchospasm is typically present 5-15 min after cessation of activity, with spontaneous resolution usually occurring within 20-60 min. The stimulus for EIB is apparently a combination of airway cooling and drying, which results in pulmonary mast cell mediator release. Bronchospasm is generally more severe if there is greater baseline bronchial hyperreactivity or higher intensity of exercise. The treatment of choice for EIB is preexercise administration of a beta-adrenergic agonist. Other useful therapies may include cromolyn, theophylline, calcium channel blockers, anticholinergics, and antihistamines. The crucial step for clinicians caring for these patients is making the diagnosis of EIB. The condition responds well to therapy, and treatment may allow for greater enjoyment of activity and enhanced athletic performance.