Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: TUESDAY, July 13, 1993 TAG: 9309030377
SECTION: EXTRA PAGE: 6 EDITION: METRO
SOURCE: Jane Brody
DATELINE: LENGTH: Long
Exercise-induced asthma is extremely common, affecting more than 80 percent of people with ordinary asthma, 30 to 40 percent of those with allergic rhinitis (``hay fever'') and 9 percent of people without asthma or allergies who develop asthmatic symptoms only when they exercise.
r= The condition can affect males and females of all ages, races and levels of fitness. Various studies have shown that 3 to 11 percent of elite athletes have exercise-induced asthma.
For example, tests among 597 members of the 1984 U.S. Olympic Team showed that 67 of them, or 11 percent, had asthma or exercise-induced asthma; still, these 67 athletes brought home 41 medals. They were able to compete so successfully by keeping themselves in tiptop physical condition and because their asthmatic condition was effectively treated with airway-opening drugs before competition.
Dr. Donald Mahler, a pulmonologist at Dartmouth-Hitchcock Medical Center in Lebanon, N.H., estimates that 12 to 15 percent of Americans are likely to develop one or more asthmatic symptoms either during vigorous activity or, more typically, within 15 minutes after exercising.
These symptoms, which typically last 20 to 30 minutes, may include a feeling of tightness in the chest, shortness of breath, wheezing and coughing.
Those whose only noticeable symptom is a post-exercise cough often do not realize they have asthma, even though their ability to move air in and out of their lungs may be reduced by as much as 85 percent following exercise.
Others in whom the condition goes undiagnosed do not know that their symptoms are abnormal, and assume that everyone has trouble breathing after a vigorous workout.
Young children can also have unrecognized exercise-induced asthma. Instead of complaining about their breathing difficulties, they sometimes quietly retreat into sedentary activities after finding they cannot keep up with their peers during vigorous exercise.
Writing in the journal Medicine and Science in Sports and Exercise, Mahler urged a careful medical workup for anyone who experiences exercise-related symptoms that resemble asthma, including just a cough. Like ordinary asthma, under certain conditions exercise-induced asthma can become life-threatening.
The journal Emergency Medicine states that exercise-induced asthma should be suspected in any child who seems to avoid physical activity for no apparent reason.
Although the precise causes of exercise-induced asthma are not known, experts believe the symptoms are induced by the drying and cooling effects of air that moves rapidly in and out of the respiratory tract. Symptoms are usually worse during outdoor exercise in winter and in activities that create a wind effect, like running, cycling and skating. Mouth breathing, which is necessary during a vigorous aerobic workout, reduces the warming of air that ordinarily occurs in the nasal passages.
Vigorous distance running is the most likely of common activities to set off asthmatic symptoms. Cycling, skiing (both downhill and cross-country), speed skating, rollerblading, sledding and water-skiing may cause problems for many people. Short bouts (5 to 10 minutes) of very intense exercise can also be troublesome, although shorter track and field events are often all right.
Stop-and-go activities like football, baseball and even tennis are much less likely to produce asthmatic symptoms. Workouts on indoor equipment like a stationary bike, treadmill or ski machine are usually easier to handle than the same activities done outdoors.
Least likely to cause trouble are water-based activities like swimming and aquatic aerobics in an indoor pool because the inhaled air is warm and saturated with water.
Medication and measures to reduce exposure to triggering factors can enable almost any person with exercise-induced asthma to achieve and maintain physical fitness and participate in sports activities. In fact, achieving fitness is one way to reduce the likelihood that asthmatic symptoms will interfere with physical activity.
In addition to cold air, another factor that increases the chances of an asthmatic attack during or after exercise is exposure to allergy triggers like air pollution, cigarette smoke, dust and high pollen counts. Thus, when smog blankets your area or the pollen count is high, it may be best to exercise indoors. When the air is chilly, wearing a scarf over the nose and mouth or a face mask can help warm the incoming air and reduce heat loss from the lungs.
Before a vigorous workout or sports competition, Mahler and other experts strongly recommend a 15-minute exercise warmup followed by a 15-minute rest period.
After the warmup, about half of people prone to exercise-induced asthma become less likely to be affected by the very same exercise for about two hours. Another approach is to ``run through'' the symptoms that start 5 or 10 minutes into the exercise because they will often then subside.
Use of bronchodilating drugs is often essential to the comfortable and safe pursuit of vigorous activities by those with exercise-induced asthma. Treatment must be individualized, since what works for one person may not work for another.
The first line of therapy is an aerosol containing a beta-adrenergic agonist: albuterol, bitolterol, metaproterenol, pirbuterol or terbutaline. The inhalant should always be used just before the activity and, if necessary, during the activity if breathing problems develop. Those who depend on inhalers should always have them on hand during exercise.
If this treatment is ineffective, it can be combined with another inhaled drug, cromolyn sodium. Used one to 20 minutes before exercise, Mahler said, cromolyn can inhibit the constriction of airways induced by exercise.
Other possible treatments are theophylline, antihistamines, inhaled steroids and cough suppressants.
But the doctor warned against over-the-counter drugs that contain epinephrine or ephedrine, which can overstimulate the heart of someone with exercise-induced asthma.
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