Constricted Airways Can Find Relief
Thu, 27 Oct. 2011 - 3:32 p.m. MT
Credit: ARA Staff - American Running Association
Exercise-induced bronchoconstriction (EIB) affects a broad spectrum of the active population, and with pollen season in full force and effect, it helps to look closer at what many outdoor enthusiasts may be suffering from, and to examine what it takes to alleviate it.
EIB, which has also sometimes been known as exercise-induced asthma (EIA), is a condition in which physical exercise triggers an acute narrowing of the airways. During bronchoconstriction, the smooth muscle that surrounds the airways in the lungs contracts or tightens, narrowing the airways and blocking the flow of air. In the case of EIB, bronchoconstriction is thought to be caused by the loss of heat, water, or both from the lungs as ventilation is increased during exercise. Typically, EIB starts after several minutes of physical activity and reaches its peak five to 10 minutes after exercise. The symptoms usually resolve spontaneously, at least to some degree, within about an hour.
EIB sufferers have airways that are more sensitive than normal airways to environmental triggers such as cold or dry air. As you exercise strenuously, the air you breathe in through your mouth reaches the lower airways without passing through the warming, humidifying, and filtering effect of the nose. Depending on the temperature or quality of the air during exercise, bronchoconstriction may then occur. Other triggers present in the air, including pollution, allergens, or other irritants may aggravate EIB.
EIB is a condition most often found in people with asthma, a chronic disease in which the air passages in the lungs are very sensitive and can become inflamed and swollen. Once exercise-induced bronchoconstriction occurs in a person with asthma, the airways begin to swell and secrete mucus, both of which further obstruct the airways, making it difficult for the person to breathe. It’s important for patients with asthma to discuss their desired activity levels with their physician and develop an asthma management strategy.
Symptoms of EIB vary from person to person. The following list of common symptoms may be experienced shortly after exercise begins or within five to 20 minutes after activity ceases. The symptoms usually diminish within an hour, but they may last longer.
The most common symptoms are:
Chest tightness or pain Shortness of breath Wheezing Coughing Extreme fatigue Gastrointestinal discomfort Sore throat
The diagnosis of EIB is usually based on a detailed history of symptoms. A careful physical examination should also be performed, although in most cases it will be normal due to the episodic nature of EIB. The exam is important, however, to rule out any other potential causes. The most objective measure of EIB is a pulmonary function test, such as an FEV1 measurement. This stands for “Forced Expiratory Volume in the first second,” and is coupled with an appropriate exercise challenge.
With the right treatment, most people with EIB can enjoy regular exercise. EIB management attempts to prevent or at least reduce the symptoms so patients can exercise without any serious limitations. The key to successfully treating patients with EIB is pre-treatment—by taking medication two hours prior to exercise, the potential bronchoconstriction can usually be simply and effectively blocked. Asthma sufferers should always bring an inhaler along for workouts, as pre-treatment medicines are not effective for acute asthma attacks. Patients should always warm up before exercise and cool down afterward in an effort to minimize the risk of attack with non-pharmacological strategies as well.
(The Merck Manual of Medical Information, 2d. ed., 2003, Merck Research Laboratories, Whitehouse Station, NJ, 1907 pp.; http://www.merck.com/newsroom/press_releases/product/2007_0425.html)
(RUNNING & FITNEWS® April / May 2007 • Volume 25, Number 3)