May is Asthma and Allergy Awareness Month, as well as National Physical Fitness and Sports Month, so the focus on Exercise-Induced Asthma is timely. Exercise-induced asthma (EIA) is characterized by airflow obstruction and triggered by vigorous or prolonged physical activity. People with chronic asthma can develop symptoms whenever they are exposed to a "trigger" of the asthma, such as a virus, pollen, dust, or cigarette smoke. EIA is common; about 80-90% of people who have chronic asthma have EIA. In addition, 35-40% percent of people with seasonal allergies also have EIA, with symptoms that worsen during the spring and fall. EIA affects 12-15% of the total population.
In exercise-induced asthma, the muscle bands around the airways are sensitive to these changes in temperature and humidity of the inhaled air and react by contracting (or spasming), which narrows the airway. The symptoms, which generally begin within five to 20 minutes after the start of physical activity, or 5-10 minutes after brief exercise has stopped, include:
- Coughing
- Tightness in the chest
- Wheezing
- Unusual fatigue while exercising
- Feeling short of breath while exercising
Other factors that can influence the degree of symptoms with exercise are the presence of pollens and pollutants in the air and upper respiratory infections.
A person may have exercise as his or her only asthma trigger, or it may be one of many triggers. These symptoms usually occur during or shortly after exercise. When they are properly treated, most people with exercise-induced asthma can play sports like anyone else. In fact, more than 10% of Olympic athletes have exercise-induced asthma that they have learned to control. "In many cases, the diagnosis of EIA can be determined from a formal pulmonary function test (PFT) prior to and after exercise."
EIA seems to be more prevalent in some winter or cold-weather sports. Some studies have demonstrated rates as high as 35% or even 50% in competitive-caliber figure skaters, ice hockey players, and cross-country skiers.
The problem in EIA occurs distal to the glottis, in the lower airway. Bronchoconstriction is involved that is distinguishable from laryngospasm, which can occur in other exercise-related conditions. One such example is with the condition known as vocal cord dysfunction. In this condition, there is paradoxical narrowing of the vocal cords during inspiration, resulting in stridor, often misconstrued as audible wheezing. Normally, the vocal cords open with inspiration.
EIA usually affects individuals who participate in sports that include an aerobic component.
Glenn VanOtteren, MD, Pulmonologist with mmpc, states, “Inhaled medications taken prior to exercise can control and prevent exercise-induced asthma symptoms. The preferred medications are the short-acting beta2 agonist inhalers (albuterol, pirbuterol); taken 15-20 minutes before exercise, these medications can prevent
the airways from spasm and can provide control of exercise-induced asthma for as long as 4 to 6 hours.”
If these measures fail to control exercise-induced asthma symptoms, your physician may determine that you need daily therapy to control the underlying inflammatory process that results in unstable airways.
In addition to medications, a warm-up phase before exertion and a cool-down period afterward can help prevent exercise-induced asthma. “Exercise should be limited during high pollen days (if allergic) or when temperatures are extremely low and air pollution levels are high. The presence of viral upper respiratory infections can also increase symptoms, so you should restrict exercise if you have such an infection,” says Dr. VanOtteren.
For people with EIA, some activities are better tolerated than others. Activities that involve short, intermittent periods of exertion, such as volleyball, gymnastics, baseball, walking, and wrestling are
generally well-tolerated. Activities that involve long periods of exertion (soccer, distance running, basketball, and field hockey), as well as cold weather sports (ice hockey, cross-country skiing, ice skating), may be less well-tolerated. However, many people with asthma are able to fully participate in these activities. Swimming, which is a strong endurance sport, is generally well-tolerated by asthmatics because it is usually performed in a warm, moist air environment. It is also an excellent activity for maintaining physical fitness.
Source: WebMD
Source: E-Medicine
