Exercise-induced asthma (EIA) occurs in people who experience asthma symptoms during or after exercise. Although people with asthma may experience symptoms when they exercise, those with EIA are generally symptom-free when they are not exercising. In some cases, asthma may be triggered by a combination of factors that includes exercise.
People with EIA frequently give up physical activity. However, the condition is very rarely dangerous, and it should not prevent anyone from exercising as long as they take prescribed medications and closely follow their physician’s guidelines.
Many elite athletes have EIA and continue to excel at their chosen sports. Asthma in general is more often seen among Olympic athletes than in the population, according to the American Academy of Allergy, Asthma and Immunology. However, some sports may be better than others. For instance, swimming is considered to be a great exercise choice for people with EIA, but cross-country skiing may not be a good choice.
About exercise-induced asthma
Exercise-induced asthma (EIA) is a condition that affects people during vigorous activity, particularly in cold and dry conditions. People with EIA are unusually sensitive to changes in air temperature and humidity, and can find their breathing severely impaired within five to 20 minutes of beginning activity.
Most asthmatics experience asthma symptoms during exercise. However, for some individuals, exercise is the sole trigger that causes asthma symptoms. Children are more likely to experience symptoms related to EIA than adults.
Exactly why EIA occurs is unknown. Some experts believe that rapid breathing during exercise prevents air from being properly warmed as it enters the airway. Normally, most of the air a person breathes in enters through the nose, where it is warmed and moistened to 80 to 90 percent humidity before proceeding to the lungs.
However, during exercise, air tends to enter through the mouth, where air is warmed to just 60 to 70 percent humidity. As the cooler air enters the bronchial tubes, it causes the airways to swell (bronchospasm) and secrete excess mucus. This, combined with a contraction of the airway muscles, narrows the passageway. In addition, EIA may be caused by water loss around the cells of the bronchial lining during rapid breathing. As the tissue dries out, mast cells release the chemicals that trigger inflammation and asthma symptoms.
Potential causes of exercise-induced asthma
The triggers responsible for exercise-induced asthma differ from person to person. Typically, though, it is most likely to occur during prolonged, intense exercise in a cool, dry environment.
Allergens and pollutants inhaled during exercise often trigger symptoms. If pollen is known to trigger asthma in a person, then exercising on a grassy field is likely to put that individual at risk for an attack.
Those exercising on a busy street might find that excess air pollution triggers symptoms. Recent studies have shown that air pollution can have a significant effect on a person’s lungs. Specifically, research suggests that certain pollutants can trigger bronchoconstriction (tightening in the airways) in sensitive individuals, making it more difficult to breathe. Depending on the area, exercising outside may bring a person into contact with air pollutants and increase the chance of bronchoconstriction or an asthma attack.
In addition, pollutants can trigger bronchospasm. They can also make a person more sensitive to another trigger that would not cause a reaction alone, or might cause a smaller reaction alone.
In some individuals, it appears that foods eaten several hours prior to exercise can increase the likelihood of an attack. A condition called exercise-induced anaphylaxis tends to occur when a person eats certain foods, and subsequently exercises in hot, humid conditions. Intensity of exercise also may be a factor in triggering this condition. Foods that can provoke a life-threatening reaction include:
- Egg whites
Cold air alone can be enough to trigger EIA. For this reason, people with the disorder must be careful when exercising outdoors during the winter months.
Signs/symptoms of exercise-induced asthma
Those with exercise-induced asthma (EIA) may notice symptoms within five to 20 minutes of beginning activity. Symptoms often grow worse once exercise is complete, before gradually improving after 10 to 20 minutes of rest. Symptoms may not appear until a person is finished exercising. Sometimes, several hours pass before symptoms occur.
EIA symptoms include:
- Shortness of breath
- Breathing difficulty
- Chest pain or tightness
- Excessive fatigue during exercise
In rare instances, a person may experience exercise-induced anaphylaxis, a potentially life-threatening allergic reaction that requires emergency medical treatment. Symptoms of anaphylaxis include:
- Severe itching of the eyes and face
- Feeling anxious
- Palpitations (an awareness of a strong, fast, irregular, abnormal or “galloping” heartbeat)
- Slurred speech, tongue swelling and inability to swallow
- Swelling of the throat
- Rapid or weak pulse
- Red or swelling skin
- Angioedema (swelling on the lips, eyelids, throat and tongue)
- Nausea or vomiting
- Bluish tint to skin (cyanosis), including lips or nail beds
- High-pitched breathing sounds
- Nasal congestion
- Breathing difficulty
- Collapse or loss of consciousness
- Loss of bladder control
- Cardiac arrest
- Respiratory arrest
Parents need to watch for more subtle signs of EIA in their children. If a child appears reluctant to participate in activities or maintains that they are “not athletic,” this may mask fears related to undiagnosed EIA.
Diagnosis methods for exercise-induced asthma
A physician will need to examine and test a patient before arriving at a diagnosis of exercise-induced asthma. In addition to asking questions about the patient’s medical history and asthma-related symptoms, a series of tests is likely. Many of these tests are used to diagnose all forms of asthma, and include:
- Pulmonary function test. Measures how much air the lungs can hold and how quickly it is exhaled.
- Bronchoprovocation test. Involves inducing a minor asthma attack to diagnose asthma when symptoms are not present. Most bronchoprovocation tests use histamine or methacholine but may include specific agents, such as food additives or environmental allergens.
- Spirometry. Measures how much air a person blows out in a specific period of time, and how forcefully it is blown. It can reveal the extent of airway obstruction present, and how much of the obstruction is reversible.
- Pulse oximetry. Measures the amount of oxygen in a person’s bloodstream using a probe placed on a fingertip.
- Chest x-ray. Produces an image of the chest using low doses of radiation. This test can be useful in detecting air trapped in the lungs. It may also be used to rule out other conditions and diseases known to cause symptoms similar to asthma.
- Allergy skin testing. Identifies a specific allergen that might be triggering asthma attacks. While allergies are a separate condition from asthma, allergic reactions often trigger attacks in asthmatics. A small amount of the allergen is introduced to the skin (through a prick, scratch, patch or injection), and a hive will indicate that an allergy to the substance is present. It is not 100 percent accurate, but can be an effective tool in diagnosing allergy triggers.
- Allergy blood tests. Measures the amount of specific immunoglobulin E (IgE) produced to an individual allergen in a sample of blood. The most commonly used blood test for allergy related conditions is the radioallergosorbent test (RAST). This test looks for the presence of allergy-specific IgE in the bloodstream. During an allergic reaction, the body produces IgE antibodies to protect against what it mistakenly perceives to be a dangerous substance. The level of IgE correlates to the sensitivity a patient has to the allergen.
Because of the nature of EIA, a physician also may test the patient’s breathing during exercise. During these tests, a patient will use a treadmill or stationary bike. The patient’s breathing will be tested at rest, after six to eight minutes of exercise and then at regular intervals. The last test will come at least 30 minutes after the patient has finished activity. By examining the results, a physician can determine how exercise affects the patient’s breathing ability.
Even when exercise-induced asthma is suspected, a physician will want to rule out other potentially more serious conditions before proceeding with treatment. For example, shortness of breath during exercise could be related to an underlying heart condition, poor athletic conditioning or pulmonary problems rather than asthma. In such cases, a physician may want to perform an echocardiogram to rule out potential heart ailments or other conditions. Also known simply as an “echo,” an echocardiogram is a common diagnostic test that uses sound waves to create pictures of the heart and its vessels.
Treatment options for exercise-induced asthma
There is no way to cure exercise-induced asthma. Those who have the condition will have it for the rest of their lives. However, certain medications can help individuals to participate in physical activities while managing the symptoms of the disorder.
Using certain medications as a pre-treatment to exercise can reduce the likelihood of suffering symptoms of EIA. These include:
- Inhaled short-acting bronchodilators. A physician may instruct a patient to take two puffs of this medication 15 to 30 minutes prior to exercise. Such medications often can prevent the airways from contracting for as long as four to six hours.
- Long-acting bronchodilators. In some cases, a physician may prescribe a medication to provide 12–hour control of symptoms. However, it is important that patients carry a short–acting bronchodilator in case symptoms suddenly appear.
- Inhaled corticosteroids or leukotriene modifiers. These long–term control therapies are intended to reduce airway responsiveness to the triggers of an allergic reaction.
Prevention of exercise-induced asthma
Asthma should not prevent a person from getting proper exercise. The benefits of regular physical activity generally outweigh the risks associated with exercise-induced asthma (EIA) so long as the exercise is planned according to a physician’s strict guidelines.
All asthmatics should have an asthma action plan to provide the necessary guidelines in case of an asthma attack. When the patient is a child, copies of the plan should be provided to the child’s physical education teacher and coaches.
Many world-class athletes compete despite having EIA. In addition, a physically fit individual has increased resistance to asthma attacks. To keep EIA under control, a physician may recommend the following steps:
- Use an inhaled beta-agonist medication 15 to 30 minutes before beginning physical activity (if advised to do so by a physician). Always carry this medication during exercise to treat a flare-up.
- Plan a long warm-up period before and cool-down period after exercise. Between 30 to 60 minutes is ideal, but follow your physician’s recommendations.
- Choose appropriate forms of exercise. Asthmatics with well-controlled conditions can enjoy almost any sport. However, some are particularly recommended. For example, swimming is ideal for those susceptible to EIA because breathing the warm, humid air from a body of water keeps the airways from cooling and drying.
Sports that combine short bursts of activity with periods of rest – such as baseball, tennis, volleyball and sprinting – are better than outdoor endurance sports such as soccer, basketball, ice hockey, cross-country skiing and long-distance running.
- Breathe through the nose while exercising. This warms and humidifies the air before it is inhaled.
- When inhaling through the mouth, pucker or purse the lips, as during whistling or when blowing out a candle. Keeping the lips pursed warms and humidifies the air before it reaches the airways.
- Wear a mask or scarf over your face. This warms cold air before it is inhaled.
- Avoid training where the air is polluted, such as heavy traffic areas.
- Avoid training in dry or cool weather whenever possible. Cold-weather sports such as hockey, cross-country skiing and ice skating also may trigger symptoms.
- Avoid training where pollens are high, such as in forests or grass fields.
- Drink plenty of fluids.
- Choose short-duration interval training activities. This consists of repeated cycles of several minutes of training, followed by several minutes of rest. Running for longer than six consecutive minutes is known to trigger asthma attacks in some people.
- Refrain from exercising with a cold, the flu, bronchitis or any other respiratory tract infection.
- Stop exercising if symptoms arise and do not return to the activity until the symptoms subside.
Questions for your doctor
Preparing questions in advance can help patients to have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctors the following questions about exercise-induced asthma:
- Do my symptoms suggest exercise-induced asthma?
- Is there testing to confirm I have exercise-induced asthma? If so, which ones will you use to diagnose me?
- Is this condition dangerous? What risks does it pose to my overall health?
- What are my treatment options?
- Am I likely to have an asthma attack every time I exercise?
- Will medications allow me to safely participate in sports and other physical activities?
- Are certain sports better choices than others? What activities do you recommend for me?
- Are there certain environments I should avoid while exercising? Is it better for me to exercise indoors or outdoors?
- Would I benefit from limiting the time I spend exercising?
- Under what circumstances should I seek emergency medical treatment for exercise-induced asthma?
- Are my children likely to develop this condition as well?