Exercise Induced Asthma

Why does exercise cause asthma symptoms? It is thought that the intense breathing that takes place during exertion causes water loss from the lungs, which cools the lungs’ moist lining. The drop in temperature begins a process that results in constriction of the muscles around the airways and inflammation within the airways – the ingredients of an asthma attack.

EIA can be difficult to diagnose. Patients who experience chest tightness, wheezing, shortness of breath or cough after exertion most likely have EIA. (But EIA should be explored whenever any symptoms appear regularly with exercise.) Symptoms usually peak 8 to 15 minutes after exercise ends. These signs and symptoms are then usually followed by a so-called “refractory period” of up to three hours during which normal breathing is restored and difficulty in breathing is unlikely. A late phase of symptoms may occur four to six hours later in some patients.

A diagnosis of EIA can be confirmed with an exercise challenge and spirometry testing. Spirometry is a test performed in the doctor’s office that measures the volume of air that can be forced out of the lungs in one second (called the FEV1). First, the patient takes the spirometry test. Then, he or she uses a treadmill or performs some other type of exercise. After that, FEV1 is measured again. FEV1 that drops more than 10-15 percent after exertion indicates that the patient has EIA. Not all doctors have the equipment to conduct this type of testing. Some patients are asked to measure their peak flow rates before and after exercise. Again, a significant decrease in airflow after exercise suggests EIA. Finally, some doctors diagnose EIA by giving the patient a trial of a bronchodilator medication (which relaxes the smooth muscle around the airways) to treat their symptoms. If the bronchodilator relieves the symptoms and if treatment before exercise prevents symptoms, it is likely that the patient has EIA.

An asthma management plan for someone with EIA would likely include some or all of the following treatments:

1. Pre-treat with medication. Short-acting beta agonists (bronchodilators) such as albuterol or levalbuterol, when taken before exercise, can prevent asthma symptoms from occurring and maximize one’s exercise capacity. Bronchodilators may only protect against symptoms during one and a half hours of exercise. Healthcare providers typically advise their patients that they can take another dose after this period, if needed. They may also prescribe a long-acting bronchodilator (LABA), which would prevent symptoms for a longer period of time. (It also needs to be taken further in advance of exercise.) Pre-treatment is usually recommended even if no symptoms are present. (Note: Studies have shown that montelukast sodium, a leukotriene modifier, may reduce the severity of symptoms of EIA and decrease the recovery time for the lungs to achieve their pre-exercise capacity.)
2. Take peak flow measurements before and after exercise. If peak flow measurements before exercise indicate that the asthma is not well controlled, they should either not participate in the activity or participate in a less strenuous way (perhaps playing goalie where less running is involved). Decreased activity should only be a temporary solution. If the person is regularly having trouble exercising, it is a sign that his or her asthma is not controlled. The person should visit the healthcare provider so changes can be made to the treatment plan. With proper asthma management, people should be able to exercise comfortably.
3. Do warm-up and cool-down exercises before and after exertion. This has been shown to help prevent asthma symptoms. If symptoms develop during the warm-up, a quick-relief medication (bronchodilator) should be taken. Once the symptoms have resolved, the warm-up can be started again.
4. Quick-relief medications (bronchodilator) must be available at all times. This means during school (for children) as well as after-school activities. If medications are kept in the nurse’s office, be sure that the office is unlocked and that these are readily available during after-school sports and activities. Medications should also be available to students during field trips or sporting events that are away from the school facility. Students should be taught how and when to use their inhalers and, if school rules permit, they should carry these inhalers with them.
5. Avoid cold, dry air that provokes EIA. If this is not possible, the person should wear a scarf over his or her face during the activities outside in cold weather to warm and humidify the air before it reaches the lungs.

With proper asthma management, most people can play any sport. A small percentage may still have some trouble. These people may want to choose sports that are less likely to provoke asthma symptoms. Sports that require a lot of running with little time for breaks, such as soccer or basketball, are more likely to cause symptoms than a sport, such as baseball, that provides periods of rest. Swimming and other water sports, which take place in warm, humid air, are often the best type of exercise for people with EIA.