Exercise-induced asthma
Encyclopedia
Exercise-induced asthma, or E.I.A., is a medical condition
characterized by shortness of breath induced by sustained aerobic exercise. It shares many features with other types of asthma
, and responds to some typical asthma medications, but does not appear to be caused by the same inflammatory reaction as the other types.
. Constriction of these vessels then follows, worsening the degree of obstruction to airflow. This sequence generates symptoms similar to those seen in other forms of asthma, but occurs without the inflammatory changes that underlie them.
and/or coughing, with an elevated respiratory rate
and wheezing, which may be audible even without a stethoscope
. Examination will usually reveal the wheezing and a prolonged expiratory phase. In the occasional severe attack, altered level of consciousness and cyanosis
due to depressed oxygenation
of the blood
may occur. Severe attacks are often the result of someone with both allergic and exercise-induced asthma exercising in a high-allergen environment (e.g. walking uphill alongside slowly moving traffic at dusk), and can be fatal.
In most cases, a relative "refractory period" follows resolution of an attack. During this approximately one hour period, resumption of exercise will likely produce either none or mild symptoms. Curiously as well, some 6–10 hours after the initial attack, a rebound attack with milder symptoms often develops without precipitating exertion.
Some athletes take advantage of the refractory period by precipitating an attack by "warming up," and then timing their competition such that it occurs during the refractory period. Step-wise training works in a similar fashion. An athlete warms up in stages of increasing intensity, using the refractory period generated by each stage to get up to a full workload.
The most common medication approach is to use a beta agonist about twenty minutes before exercise. Some physicians prescribe inhaled anti-inflammatory mists such as corticosteroids or leukotriene antagonist
s, and mast cell stabilizer
s have also proven effective. A randomized crossover study
compared oral montelukast
with inhaled salmeterol
, both given two hours before exercise. Both drugs had similar benefit but montelukast
lasted 24 hours.
, Amy Van Dyken
, and Nancy Hogshead, Olympic track star Jackie Joyner-Kersee
, baseball Hall of Famer Catfish Hunter
, and American football player Jerome Bettis
are among the many who have done so.
According to International Olympic Committee
statistics, during most of Olympic Games
in last 20 years from 1/3 to 2/3 of athletes claimed to have asthma. Some medical experts tie such inordinate rates of reported asthma with athletes' desire to use complex medication to help them achieve better results.
Apart from sportsmen, school children are one of the major groups suffering from EIA as exercise programs and sports activities form a big part of most schools. Proactive schools usually set special EIA-friendly guidelines for EIA students so that they can be included in mainstream student exercise programs without feeling left out.
Disease
A disease is an abnormal condition affecting the body of an organism. It is often construed to be a medical condition associated with specific symptoms and signs. It may be caused by external factors, such as infectious disease, or it may be caused by internal dysfunctions, such as autoimmune...
characterized by shortness of breath induced by sustained aerobic exercise. It shares many features with other types of asthma
Asthma
Asthma is the common chronic inflammatory disease of the airways characterized by variable and recurring symptoms, reversible airflow obstruction, and bronchospasm. Symptoms include wheezing, coughing, chest tightness, and shortness of breath...
, and responds to some typical asthma medications, but does not appear to be caused by the same inflammatory reaction as the other types.
Etiology
While the potential triggering events for E.I.A. are well delineated, the underlying pathogenesis is poorly understood. It usually occurs after at least several minutes of vigorous, "aerobic" activity, which demands that normal nasal breathing be supplemented by mouth-breathing. The resultant inhalation of air that has not been warmed and humidified by the nasal passages seems to generate increased blood flow to the linings of the bronchial tree, resulting in edemaEdema
Edema or oedema ; both words from the Greek , oídēma "swelling"), formerly known as dropsy or hydropsy, is an abnormal accumulation of fluid beneath the skin or in one or more cavities of the body that produces swelling...
. Constriction of these vessels then follows, worsening the degree of obstruction to airflow. This sequence generates symptoms similar to those seen in other forms of asthma, but occurs without the inflammatory changes that underlie them.
Signs and symptoms
During an attack, the E.I.A. victim will likely be short of breathDyspnea
Dyspnea , shortness of breath , or air hunger, is the subjective symptom of breathlessness.It is a normal symptom of heavy exertion but becomes pathological if it occurs in unexpected situations...
and/or coughing, with an elevated respiratory rate
Tachypnea
Tachypnea means rapid breathing. Any rate between 12-20 breaths per minute is normal. Tachypnea is a respiration rate greater than 20 breaths per minute. - Distinction from other breathing terms :...
and wheezing, which may be audible even without a stethoscope
Stethoscope
The stethoscope is an acoustic medical device for auscultation, or listening to the internal sounds of an animal body. It is often used to listen to lung and heart sounds. It is also used to listen to intestines and blood flow in arteries and veins...
. Examination will usually reveal the wheezing and a prolonged expiratory phase. In the occasional severe attack, altered level of consciousness and cyanosis
Cyanosis
Cyanosis is the appearance of a blue or purple coloration of the skin or mucous membranes due to the tissues near the skin surface being low on oxygen. The onset of cyanosis is 2.5 g/dL of deoxyhemoglobin. The bluish color is more readily apparent in those with high hemoglobin counts than it is...
due to depressed oxygenation
Oxygenation (medical)
Oxygenation occurs when oxygen molecules enter the tissues of the body. For example, blood is oxygenated in the lungs, where oxygen molecules travel from the air and into the blood...
of the blood
Blood
Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....
may occur. Severe attacks are often the result of someone with both allergic and exercise-induced asthma exercising in a high-allergen environment (e.g. walking uphill alongside slowly moving traffic at dusk), and can be fatal.
In most cases, a relative "refractory period" follows resolution of an attack. During this approximately one hour period, resumption of exercise will likely produce either none or mild symptoms. Curiously as well, some 6–10 hours after the initial attack, a rebound attack with milder symptoms often develops without precipitating exertion.
Treatment
As with any asthma, the best treatment is avoidance, when possible, of conditions predisposing to attacks. In athletes who wish to continue their sport or do so at times in adverse conditions, preventive measures that can be taken include altered training techniques and medications.Some athletes take advantage of the refractory period by precipitating an attack by "warming up," and then timing their competition such that it occurs during the refractory period. Step-wise training works in a similar fashion. An athlete warms up in stages of increasing intensity, using the refractory period generated by each stage to get up to a full workload.
The most common medication approach is to use a beta agonist about twenty minutes before exercise. Some physicians prescribe inhaled anti-inflammatory mists such as corticosteroids or leukotriene antagonist
Leukotriene antagonist
A leukotriene antagonist is a drug that inhibits leukotrienes, which are fatty compounds produced by the immune system that cause inflammation in asthma and bronchitis, and constrict airways....
s, and mast cell stabilizer
Mast cell stabilizer
Mast cell stabilizers are cromone medications used to prevent or control certain allergic disorders. They block a calcium channel essential for mast cell degranulation, stabilizing the cell and thereby preventing the release of histamine and related mediators. One suspected pharmacodynamic...
s have also proven effective. A randomized crossover study
Crossover study
A crossover study is a longitudinal study in which subjects receive a sequence of different treatments . While crossover studies can be observational studies, many important crossover studies are controlled experiments, which are discussed in this article...
compared oral montelukast
Montelukast
Montelukast is a leukotriene receptor antagonist used for the maintenance treatment of asthma and to relieve symptoms of seasonal allergies. It is usually administered orally...
with inhaled salmeterol
Salmeterol
Salmeterol is a long-acting beta2-adrenergic receptor agonist drug that is currently prescribed for the treatment of asthma and chronic obstructive pulmonary disease. It is currently available as a dry powder inhaler that releases a powdered form of the drug...
, both given two hours before exercise. Both drugs had similar benefit but montelukast
Montelukast
Montelukast is a leukotriene receptor antagonist used for the maintenance treatment of asthma and to relieve symptoms of seasonal allergies. It is usually administered orally...
lasted 24 hours.
Prognosis
As evidenced by the many professional athletes who have overcome E.I.A. using some combination of the above treatments, the prognosis is usually very good. Olympic swimmers Tom DolanTom Dolan
Tom Dolan is a swimmer from the United States, who won a gold medal and silver medal at the 2000 Summer Olympics and a gold medal at the 1996 Summer Olympics...
, Amy Van Dyken
Amy Van Dyken
Amy Van Dyken is an American swimmer who has six career Olympic gold medals. Four of these gold medals came in the 1996 Summer Olympics, making her the first American woman to accomplish such a feat and the most successful athlete at the 1996 Summer Olympics...
, and Nancy Hogshead, Olympic track star Jackie Joyner-Kersee
Jackie Joyner-Kersee
Jacqueline "Jackie" Joyner-Kersee is a retired American athlete, ranked among the all-time greatest athletes in the women's heptathlon as well as in the women's long jump. She won three gold, one silver, and two bronze Olympic medals, in those four different events...
, baseball Hall of Famer Catfish Hunter
Catfish Hunter
James Augustus "Catfish" Hunter , was a Major League Baseball right-handed pitcher. During a 15-year baseball career, he pitched from 1965-1979 for both the Oakland Athletics and the New York Yankees...
, and American football player Jerome Bettis
Jerome Bettis
Jerome Abram "The Bus" Bettis is a retired American football halfback who played for the NFL's Los Angeles/St. Louis Rams and Pittsburgh Steelers. Bettis is considered one of the best big backs ever because his footwork and power, and is currently fifth on the National Football League's all-time...
are among the many who have done so.
According to International Olympic Committee
International Olympic Committee
The International Olympic Committee is an international corporation based in Lausanne, Switzerland, created by Pierre de Coubertin on 23 June 1894 with Demetrios Vikelas as its first president...
statistics, during most of Olympic Games
Olympic Games
The Olympic Games is a major international event featuring summer and winter sports, in which thousands of athletes participate in a variety of competitions. The Olympic Games have come to be regarded as the world’s foremost sports competition where more than 200 nations participate...
in last 20 years from 1/3 to 2/3 of athletes claimed to have asthma. Some medical experts tie such inordinate rates of reported asthma with athletes' desire to use complex medication to help them achieve better results.
Apart from sportsmen, school children are one of the major groups suffering from EIA as exercise programs and sports activities form a big part of most schools. Proactive schools usually set special EIA-friendly guidelines for EIA students so that they can be included in mainstream student exercise programs without feeling left out.