Exercise-induced asthma, also known as exercise-induced bronchoconstriction, occurs when the tubes responsible for transporting air into and out of the lungs narrow during exercise, causing asthmalike symptoms. Anywhere from 40 to 90 percent of all children with asthma are affected by exercise-induced asthma, but with proper treatment, they can still live active lives.
Symptoms
Children with exercise-induced asthma tend to experience symptoms five to 10 minutes after they start exercising. These symptoms tend to peak roughly five to 10 minutes after the child has stopped exercising and can persist for over an hour. Symptoms include wheezing, tightness or pain in the chest, coughing and shortness of breath. Children with exercise-induced asthma may be easily winded and unable to run for more than a few minutes without stopping. While shortness of breath and fatigue are normal after physical activity, symptoms of exercise-induced asthma tend to be more severe and take longer to subside.
Triggers
Choosing physical activities that do not trigger symptoms is key to managing exercise-induced asthma. Walking, biking, hiking, golfing, swimming and team sports that require short bursts of energy are less likely to trigger symptoms. Cold-weather activities and endurance sports will often make symptoms worse, since children with exercise-induced asthma tend to have lungs that are overly sensitive to changes in temperate and humidity. Other factors that can trigger or intensify symptoms include stale air, dry air, air pollution, pollen, respiratory infections, chemicals and being out of shape.
Medications
A short-acting bronchodilator administered five to 30 minutes before physical activity may prevent exercise-induced asthma symptoms from developing, though the effects only last two to three hours. Children also seem to respond well to anti-inflammatory medications when used before physical activity. When used in conjunction with a long-acting bronchodilator, anti-inflammatory medications seem to prevent symptoms from developing for several hours. Children with chronic asthma may find that they need an inhaled steroid to manage their symptoms. A class of drugs known as leukotriene antagonists may also help suppress exercise-induced asthma symptoms.
Prevention
Children with exercise-induced asthma do not need to avoid exercise. A slow warm-up lasting 15 minutes or so before strenuous exercise can sometimes stave off symptoms. Limiting strenuous exercise when allergens are present or when the child is suffering from a respiratory infection can also reduce the intensity and frequency of symptoms.
Diagnosis
When diagnosing a child with exercise-induced asthma, a doctor will typically take a detailed history of the child's asthma and allergy symptoms and triggers. Once a history has been taken and a physical exam has been performed, the doctor may decide to administer a series of breathing tests to determine how well the lungs are functioning. These can include a spirometry, an exercise test, a peak flow measurement, a nitric oxide test or the methacholine challenge, in which the child inhales a small amount of a substance called methacholine to see if it triggers symptoms. Most of these tests are relatively simple and can be done in the office.
