What is Exercise-Induced Asthma (EIA)?

Patients who have asthma have narrowing of the airways causing them to have difficulty moving air out of the lungs. Chronic asthma is an inflammatory disorder. Most patients with chronic asthma will have a flare when they exercise. Other individuals appear to have a flare of asthma only when they exercise and do not otherwise have chronic asthma.

What are the symptoms and triggers?

If you have exercise-induced asthma, you may experience breathing difficulty within 5-20 minutes after exercise. Symptoms may include wheezing, chest tightness, coughing and chest pain. Other EIA symptoms include prolonged shortness of breath, often beginning 5-10 minutes after brief exercise.

Patients with EIA have airways that are overly sensitive to sudden changes in temperature and humidity, especially when breathing colder, drier air. During strenuous activity, people tend to breathe through their mouths, allowing the cold, dry air to reach the lower airways without passing through the warming, humidifying effect of the nose. With mouth breathing - also common in patients with colds, sinusitis and allergic rhinitis ("hay fever") - air is moistened to only 60-70% relative humidity, while nose-breathing warms and saturates air to about 80 to 90% humidity before it reaches the lungs.

In addition to mouth-breathing, air pollutants, high pollen counts, and viral respiratory tract infections can also increase the severity of wheezing with exercise.

* Diagnosis
To confirm a diagnosis of EIA, a physician:

1. Obtains a patient history.
2. Performs a breathing test when the patient is at rest to ensure that
    the patient does not have chronic asthma.
3. Often may perform a breathing test after exercise.

Measurement can be done in a medical facility or "on the field." In the office setting, a patient exercises for six to eight minutes using a treadmill or cycle to create enough exertion to maintain a heart rate at 80-90% of the age-related maximal predicted value. The patient breathes into a breathing machine called a spirometer, which processes the patient's ability to breathe out, or expire air. This test is performed before exercise and at various intervals from two to 30 minutes after exercise stops. A decrease of at least 12-15% in the volume of air blown out (as compared to the starting value) by the patient in one second (termed the forced expiratory value in one second, or FEV 1) indicates possible EIA.
On the field, expiratory airflow can be evaluated before and after a six- to eight-minute "free run" or after participation in a sport or activity that usually induces respiratory symptoms. Airflow is again measured for 30 minutes after exercise ends. Although a portable spirometer can be used, physicians often recommend a small, relatively inexpensive peak flow meter to demonstrate the characteristic post-exercise decrease in expiratory airflow. In this case a 15-20% decrease is required for the test to be considered positive for EIA.

*Recommended activities

Although the type and duration of recommended activity varies with each individual, some activities are better for those with EIA. Swimming is often considered the sport of choice for asthmatics and those with a tendency toward bronchospasm because of its many positive factors: a warm, humid atmosphere, year-round availability, toning of upper body muscles, and the way the horizontal position may help mobilize mucus from the bottom of the lungs. Walking, leisure biking, hiking and free downhill skiing are also activities less likely to trigger EIA. In cold weather, wearing a scarf or surgical mask over the mouth and nose can decrease symptoms by warming inhaled air.
Team sports that require short bursts of energy, such as baseball, football, wrestling, golfing, gymnastics, short-term track and field events or surfing are less likely to trigger asthma than sports requiring continuous activity such as soccer, basketball, field hockey or long-distance running. Cold weather activities such as cross-country skiing and ice hockey are also more likely to aggravate airways. However, many asthmatics have found that with proper training and medical treatment, they are able to excel as runners or even basketball players.

Sports that are less likely to trigger EIA:

• Swimming
  
• Walking
  
• Leisure biking
  
• Hiking
  
• Free downhill skiing
  
• Team sports that require short bursts of energy , including:
  
  o Baseball
  o Football
  o Wrestling
  o Golfing
  o Gymnastics
  o Short-distance track and field events
  

• Soccer
  
• Basketball
  
• Field hockey
  
• Long-distance running
  
• Cross-country skiing
  
• Hockey
  

How can EIA be treated?

If you think you have exercise-induced asthma, you should be seen by a physician to make the proper diagnosis. For the majority of patients, a short-acting beta2-agonist inhaled 5 to 30 minutes before exercise (preferably as close to the start of exercise as possible) will ease attacks. Also you should warm up for 6-10 minutes before you begin your full exercise program. When appropriate, you may also be directed by your physician to use long-term controller medications (for example, an inhaled steroid or a type of drug called a leukotriene modifier). Many of the same drugs that are used to treat asthma are used to treat exercise-induced asthma.

What are some of the myths of EIA?

• If you have EIA, you cannot participate in sports.
  
• You can't become an elite athlete if you have EIA.
  
• Only people who have chronic asthma have EIA.
  

These ideas are simply not true. Exercise is good for people with EIA, as long at they take proper precautions. Because cold and dry conditions often worsen asthma, cross-country skiing is probably not a good choice of exercise. However, swimming is an excellent sport for people with EIA. Many elite athletes, including Olympic champions, have a history of asthma. About 4-7% of the population is reported to have asthma and most have EIA. Moreover, additional groups of people have EIA who do not otherwise have chronic asthma.

Does exercise commonly cause death in patients with EIA?

No. Death is extremely rare in this setting. Although some very high profile athletes have been reported to die after an asthma attack this is extremely uncommon and should not dissuade anyone from participating in sports. What type of doctor should I see if I have EIA?
Allergist/immunologists are knowledgeable and effective in diagnosing and managing this condition. Allergists are very skilled at evaluating triggers for asthma including exercise and other substances in the air. However, in difficult to diagnose cases, a multi-disciplinary approach may be needed. This includes the care by a pulmonologist, an otolaryngologist (ENT), and an allergist/immunologist.