Exercise-induced bronchospasm: the symptoms, diagnosis, and treatment.
Shelby Rush, M.D., FACSM, is a full-time faculty member at Natividad Family Medicine Residency Program in Salinas, CA, and is assistant clinical professor at the University of California, San Francisco Department of Family and Community Medicine. She coordinates the orthopedic and sports medicine curricula at Natividad Medical Center where she has a sports medicine clinic. Dr. Rush completed a fellowship in sports medicine at The Orthopedic Specialty Hospital in Salt Lake City, UT. She is board certified in Sports Medicine and Family Practice. Dr. Rush is a physician for the U.S. Ski & Snowboard Association and a team physician for Hartnell College and North Salinas High School. She also was a member of the medical team for skating events at the 2002 Olympic Games.
Exercise induced bronchospasm (EIB) is a common condition characterized by a transient constriction of airways after 10 to 15 minutes of moderate exercise. The symptoms are chest tightness, cough, wheezing, or shortness of breath. Some people feel so short of breath that they feel they are dying or having a heart attack. It is important for health and exercise personnel to recognize the syndrome of EIB because people affected by this form of asthma, or airway constriction, will often avoid exercise. The post-exercise symptoms are a major disincentive for clients to exercise. With proper recognition, the effects of EIB can be minimized and, in some people, even prevented.
One way to help clients is to question their post-exercise symptoms and perceptions of their exertion. Ask them about the common symptoms of chest tightness, breathlessness, coughing, wheezing, or difficulty catching their breath. These symptoms may occur with any increase in exercise exertion, during exercise or soon after exercise. They most commonly occur shortly after exercise. Some simple questions in the form of a questionnaire administered at intake of new clients can help to identify people with EIB. Once recognized, EIB can be treated and will cease to be an obstacle to exercise. Anyone who has asthma, allergic rhinitis (airborne allergies, like hay fever), or at least one of the symptoms of EIB, should be referred to his or her primary care physician for proper evaluation and treatment.
Exercise-induced bronchospasm is very prevalent. It is present in 10% of athletes. Numerous studies have shown that many athletes are not aware that they have EIB. Additionally, most people with documented asthma and 40% of people with allergic rhinitis experience EIB. If you suspect a client has EIB, in addition to referring them to their primary treating physician, workers in the athletic arena can reassure patients that continuing exercise is safe.
When clients are referred for medical evaluation, they should expect a thorough history and physical examination. Their physician needs to check for previous symptoms of asthma, allergic rhinitis, family history of asthma or allergies, smoking or other drug use, and systemic symptoms. They will examine ear, nose, throat, heart, and lungs and conduct pulmonary function tests. Patients with known asthma or allergic rhinitis can expect a shorter visit, focused upon current symptoms and symptom triggers, with a review of current medications. Older patients who have never been diagnosed with asthma or EIB may need to have a more comprehensive examination, including chest X-ray, electrocardiogram, and treadmill stress test. For those with an uncertain diagnosis, the physician may perform an exercise challenge test. Some medical problems that may mimic EIB are listed in Table 1. Exercise challenges also may be used for clients who do not respond to medical treatment. It also is a useful tool to quantify the severity and responsiveness of people with known EIB.
Health/fitness professionals can help people with EIB. After an athlete is diagnosed with EIB, the next step is to reassure him or her that exercise is safe. Multiple studies have shown that not only is it safe, but with conditioning, clients will have less severe symptoms. Also, with proper warm-up periods, symptoms may be completely prevented (see Table 2). A refractory period, a time when people have resistance to EIB, happens after initial exercise and lasts for several hours. This can be used to the advantage of the athlete to completely prevent all symptoms. Because the severity of the EIB attack is related to the intensity of the exercise, by slowly warming up with 10 minutes of light cardiovascular exercise, they may be able to exercise symptom-free. Gyms can help lessen triggers by providing a warm, relatively humid environment for exercise. Dry, cool air worsens the symptoms of EIB. For athletes who must exercise outdoors in the cold weather, recommend that they cover their nose and mouth to allow proper warming of the air. During the cold weather, exercising in an indoor pool is the best option. Just as athletes with stress fractures can run in deep water to maintain their training and cardiovascular level, so can athletes with EIB during winter months.
The next step is to ensure that athletes use medicines to prevent or control the symptoms of EIB if nonmedical measures do not prevent all symptoms. Some medicines taken before exercise can prevent all symptoms. It also is important to make sure that athletes with allergic rhinitis (hay fever) or asthma get proper medical treatment. Simple antihistamines (anti-allergy medicines) or inhaled steroids (asthma medications) may be enough to control the symptoms of EIB. For most people, these initial steps will only reduce the symptoms and they will need further pharmacologic (medicinal) treatments to control their symptoms.
Some of the pharmacologic treatments are listed in Table 3. The first line of medications includes inhaled bronchodilators or beta agonists. By taking short-acting beta agonists 15 minutes to 1 hour before exercise, athletes can prevent symptoms. Inhibition of EIB with short-acting beta agonists lasts for 4 hours. The long-acting beta agonists last for 12 hours. Salmeterol and formoterol are both approved for prevention of EIB. Salmeterol should be taken 30 to 60 minutes before exercise, and formoterol should be taken 15 minutes before exercise. It is important that professional, college, and Olympic athletes have documentation of their EIB with their respective governing body, and that an exercise professional review the prescribed inhaler to ensure that it is allowed. Most physicians are not aware of the drug restrictions on athletes (see Table 4).
Two other classes of medications are frequently used to prevent EIB. Inhaled mast cell stabilizers cromolyn and nedocromil are the second most prescribed medications. These inhalers are not as effective against EIB as the beta agonists. Like the other inhalers, they must be taken 10 to 20 minutes before exercise. The second class of medication is the antileukotrienes. Leukotriene receptor antagonists zafirlucast (Accolate) and montelukast (Singular) are available in the United States for the treatment of asthma. Both have been shown to protect against EIB when taken 1 hour before exercise. Their effect lasts for 12 hours. Despite multiple studies demonstrating the benefit of the antileukotrienes for the prevention of EIB, they do not have FDA approval for this use. Patients prescribed this class of medication for their asthma or allergic rhinitis should notice a decrease in their EIB. If you note that a client is taking one of these agents, you may recommend taking it at least an hour before exercise. A few studies have demonstrated the antileukotrienes are as effective in preventing EIB as salmeterol, and patients do not develop tolerance as they do with the long-acting beta agonists. Other agents have been used to treat EIB, but they are not as effective as the previously mentioned agents. Some physicians may use them in conjunction with another medication. One new medication that may prove effective is inhaled furosemide, but further investigation is needed to see if initial results are reproducible.
Once proper diagnosis and medical prevention of EIB is established, it is important to stress to the clients the importance of continuing with non-pharmacologic treatments. Remind them to use a brief cardiovascular warm-up period, advise them to cover their nose and mouth with a cloth if they are exercising outdoors in the cold, and make sure they plan to stay hydrated before, during, and after exercise.
Gotshall, R.W. Exercise-induced bronchoconstriction. Drugs
Mahler, D.A. Exercise-induced asthma. Medicine & Science in Sports & Exercise® 25:554-561, 1993.
© 2004 American College of Sports Medicine
Sinha, T., and A.K. David. Recognition and management of exercise-induced bronchospasm. American Family Physician