Exercise-Induced Asthma: Effective Prophylaxis

What is the optimal means of preventing exercise-induced bronchospasm in children with asthma?

—— MD

Exercise-induced bronchospasm (also called exercise-induced asthma or exercise-induced bronchoconstriction) occurs in as many as 90% of patients with asthma and in 40% of those with allergic rhinitis. However, about 9% of patients with exercise-induced bronchospasm have no history of asthma or allergy.¹ Bronchospasm generally begins 10 to 15 minutes after the start of exercise and peaks 8 to 15 minutes after the exertion ends. The episode usually concludes about an hour later. Typical symptoms include shortness of breath, cough, chest tightness, and wheezing. In children with severe asthma, even slight exertion may result in symptoms.

The best way to prevent exercise-induced bronchospasm is to have the patient use an inhaled bronchodilator before exercise. Unlike exposure to allergens, exercise does not provoke long-term airflow limitation. Thus, exercise-induced bronchospasm can usually be treated prophylactically. In some children, exercise-induced bronchospasm reflects poorly controlled asthma. Such children will benefit from more aggressive management of their underlying disease. Most asthma medications—both short- and long-acting—will suppress bronchospasm if taken before exercise.

Because children frequently engage in unplanned physical activity, it may be more practical (and thus effective) to give a long-acting agent, such as salmeterol( or formoterol(, at home early in the day than to rely on short-acting drugs that must be taken 15 minutes or so before exercise. Long-acting bronchodilators have been shown to protect against exercise-induced asthma for 9 hours.

—— Henry Milgrom, MD
Director, Ambulatory Pediatric Allergy Program
National Jewish Medical & Research Center
Denver