An Overview of Exercise-Induced Bronchospasm (EIB)

Exercise-induced bronchospasm (EIB) is a condition in which the bronchi and bronchioles—the airways of the lungs—respond to physical exertion by constricting (narrowing). This sets off wheezing, a feeling of tightness in the chest, and other symptoms that tend to resolve soon after the activity is over. EIB is diagnosed with several of the same tests used to determine the cause of other types of respiratory problems. The condition is common among elite level athletes and affect from 5% to 20% of the population. If you are among those found to have EIB, you will not have to give up your workouts: The condition can be managed with medication and other measures.

Exercise-Induced Bronchospasm Symptoms

Constriction of the airways during an episode of EIB typically causes some or all of the following symptoms:

• Coughing
• Difficulty breathing
• Wheezing (a distinct breathing noise that indicates distress and is also common in asthma)
• Fatigue and decreased athletic performance
• Chest tightness

Causes

The pathophysiology of exercise-induced bronchospasm is not fully understood. One theory is the increase in breathing rate that occurs during exercise and the fact that during physical exertion many people tend to breathe through their mouths cause the air that reaches the lungs to be drier than usual. (Inhaling through the nose moisturizes the air.)

The drier and often colder air then sets in motion a series of reactions that lead to the release of inflammatory chemicals such as histamine and interleukins.

Other factors that increase the risk of EIB include the type of exercise you participate in; swimming and long-distance running, for example, are high risk. Underlying conditions such as asthma, eczema, or allergic rhinitis are associated with exercise-induced bronchspasm as well.

Diagnosis

Exercise-induced brochospasm typically is diagnosed with any of several tests:

• Exercise challenge testing, which will begin with a basic test called spirometry while you're at rest to determine a baseline measurement of your breathing. You then will participate in some form of activity for six to 10 minutes—often on a treadmill—after which another spirometry measurement will be taken and compared to the first one.
• Surrogate provocation testing: This test involves inhaling a specific substance, usually histamine, mannitol, or methacholine, to see if it triggers bronchoconstriction. You may also be asked to breathe in very dry air containing 5% carbon dioxide or hypertonic saline.
• Forced expiratory volume: Some doctors use forced expiratory volume (FEV) testing before (to determine a baseline) and after exercise, although thi approach to diagnosing EIUB us bit regarded as very accurate.

Treatment

A diagnosis of exercise-induced bronchospasm does not mean you will need to stop working out or engaging in the physical activities you enjoy. In fact, cardio exercise in particular actually may help to improve your condition. Your doctor will be able to choose from a variety of treatment options that will allow you to stay active without triggering your EIB.

Non-Pharmacologic Treatments

When exercising in cold dry weather it is helpful to wear a loose-fitting scarf or mask over your mouth and nose to humidify and warm the air you're breathing. If you are a swimmer it may reduce your symptoms to use a pool with a low concentration of chloramines since these chemicals are known to exacerbate symptoms of EIB.

Warming up before exercise may be beneficial, although there isn't definitive evidence this is the case.

If you have pollen allergies it may be beneficial to workout indoors on days when pollen counts in your area are high. A low-salt diet that is high in antioxidants may also help to reduce the symptoms of EIB.

Medications

The most commonly used medications to treat EIB are in a class of drugs known as short-acting beta-agonists. These include inhaled albuterol and levalbuterol. These medications are inhaled using a device called a spacer usually 15 to 20 minutes before exercise. Accurate instruction on using the inhaler/spacer is very important for effective relief of symptoms.

Albuterol is commonly prescribed, usually well-tolerated, and allowed by many athletic organizations. However, side effects may occur and include increased heart rate and anxiety. Tolerance to the medication and decreased effectiveness can occur with long term use.

Other medications sometimes used include formoterol, cromolyn sodium or terbutaline. These medications may not be allowed by some athletic associations.

Managing Underlying Conditions

If, in addition to EIB, you also have allergies, asthma, or both, managing these underlying conditions will be an important part of controlling symptoms of EIB.

People with underlying asthma should not avoid exercise and may benefit from using albuterol or a similar medication five to15 minutes before exercise.

Additionally, long term medications to control asthma are frequently used and may include: leukotriene antagonists such as Singulair (montelukast), or inhaled glucocorticoids such as beclomethasone or fluticasone. These medications may not be allowed or may be required to be "declared" by athletic associations.

If you have underlying allergies you may need to control your symptoms using medications such as antihistamines (diphenhydramine, cetirizine, loratadine, fexofenadine), or nasal sprays such as fluticasone, or mometasone.

Immunotherapy (allergy shots) may also be an option for treating underlying allergies. Working with a doctor who specializes in treating allergies, called an immunologist, can help you decide on the best treatment options for you and help you to get your allergies under control.