Exercise Asthma
Most asthmatics have increased asthma symptoms with exercise. Asthma most often involves inflammation of the airways, which can influence constriction of smooth muscles around the airways, causing symptoms of asthma. Triggers of asthma symptoms can include exposure to allergens, cold and dry air, exercise, stress, irritants, acid reflux and viral infections.However, only a small percentage of people, however, have true exercise-induced asthma (which is known medically as exercise-induced bronchoconstriction). The strictest definition of exercise-induced asthma is asthma that is only worsened by exercise and not other triggers. The way that exercise causes worsening of asthma symptoms is similar for exercise induced asthma as it is with other forms of asthma worsened by exercise.
Exercise results in cooling and drying of the airways, which leads to constriction of smooth muscle around the airways, causing worsening of asthma symptoms. The amount of exercise required to trigger symptoms in asthmatics varies from person to person, although the more vigorous the exercise, the more severe the symptoms. Asthma symptoms usually get the worst as soon as airway re-warming occurs, such as when exercise stops.
Diagnosis of Exercise-Induced Asthma
The diagnosis of exercise-induced asthma is usually made when a person experiences worsening asthma symptoms during exercise. However, this may simply mean that the person has asthma worsened by exercise rather than true exercise-induced asthma. If a person only has asthma symptoms brought on by exercise, then an exercise challenge can be performed. Shortly after an exercise challenge of a specific duration and intensity, a person’s spirometry values (lung function) will fall 15-20% if that person has exercise-induced asthma.Prevention of Exercise-Induced Asthma
Exercise-induced asthma may be prevented with exercising indoors away from cold, dry air. Certain activities performed in warm, humid environments (such as indoor swimming) may also help prevent symptoms. Exercising outdoors or in cold, dry air would be expected to worsen exercise-induced asthma symptoms.Symptoms may also be minimized with drinking lots of fluids (staying hydrated), and performing appropriate warm-up activities prior to a full workout. Good control of nasal allergies would also help to control exercise-induced asthma symptoms.
Treatment of Exercise-Induced Asthma
Symptoms of exercise-induced asthma can be rapidly treated with albuterol or similar rescue medication. If no medication is available, symptoms will usually resolve without treatment over about 15 to 30 minutes once exercise has stopped.Exercise-induced asthma can be prevented in a number of ways. The most drug-free way is for a person to experience a mild asthma attack as a result of an exercise warm-up activity. For about 40 minutes after this, a person can exercise without causing additional asthma symptoms. This is called the refractory period, and is taken advantage of by many professional and Olympic athletes who may not be able to use typical asthma medications due to certain rules and regulations.
Exercise-induced asthma can be prevented simply by using a rescue inhaler, such as albuterol, approximately 10 to 15 minutes before exercise. If the exercise is especially strenuous or prolonged, albuterol may need to be re-taken every 2 to 4 hours as needed. Montelukast (Singulair) has also been shown to be helpful in preventing exercise-induced asthma, even if it is taken at least 2 hours before the exercise is started. Cromolyn (Intal), another inhaled asthma medication, can be used 10 to 15 minutes before exercise, with or without albuterol, and can be helpful in some cases of severe exercise-induced asthma.
Often, asthma that worsens with exercise is a sign of uncontrolled asthma. In these cases, asthma that worsens with exercise should be treated with a controller therapy, such as an inhaled steroid, and inhaled steroid/long-acting beta-agonist combination (such as Advair), or other controller medicine. Long-acting beta-agonists, such as salmeterol (Serevent) or formoterol (Foradil), were used by themselves in the past for exercise-induced asthma. However, since then we know that these medicines stop working after about a month, and could potentially cause worsening asthma if a person has more than just exercise-induced asthma.
Learn more about determining if your asthma is controlled.
Sources:
Nish, A. Staying Fit with Exercise-Induced Asthma. Allergy and Asthma Advocate. Summer 2008. American Academy of Allergy, Asthma and Immunology Website. Accessed July 28, 2008.
McFadden ER, Jr. Exercise Induced Airway Narrowing. In: Adkinson NF, Yunginger JW, Busse WW, et al, eds. Middleton’s Allergy Principles and Practice. 6th edition. Philadelphia: Mosby Publishing; 2003:1323-1332.
Carlsen KH et al. Treatment of exercise-induced asthma, respiratory
and allergic disorders in sports and the relationship to doping:
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DISCLAIMER: The information contained in this site is for educational purposes only, and should not be used as a substitute for personal care by a licensed physician. Please see your physician for diagnosis and treatment of any concerning symptoms or medical condition.
