- Exercise-induced asthma
Infobox_Disease
Name = PAGENAME
Caption =
DiseasesDB = 31728
ICD10 =
ICD9 = ICD9|493.81
ICDO =
OMIM =
MedlinePlus =
eMedicineSubj = sports
eMedicineTopic = 155
MeshID = D001250Exercise-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.Fact|date=March 2007Etiology
While the potential triggering events for E.I.A. are well delineated, the underlying pathogenesis is poorly understood.Fact|date=March 2007 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
edema . 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.Fact|date=March 2007igns and symptoms
During an attack, the E.I.A. victim will likely be short of breath and/or
coughing , with an elevated respiratory rate andwheezing , which may be audible even without astethoscope . 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 environmentFact|date=March 2007 (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.Fact|date=March 2007 Curiously as well, some 6-10 hours after the initial attack, a rebound attack with milder symptoms often develops without precipitating exertion.Fact|date=March 2007
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, and/or do so at times in adverse conditions, preventive measures, including altered training techniques and medications, can be taken.
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.Fact|date=March 2007 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.Fact|date=March 2007
The most common medication approach is to use a
beta agonist about twenty minutes before exercise.Fact|date=March 2007 Some physicians prescribe inhaled anti-inflammatory mists such ascorticosteroids orleukotriene antagonist s, andmast cell stabilizer s have also proven effective.Fact|date=March 2007 A randomizedcrossover study compared oralmontelukast with inhaledsalmeterol , both given two hours before exercise. Both drugs had similar benefit butmontelukast lasted 24 hours.cite journal |author=Philip G, Pearlman DS, Villarán C, "et al" |title=Single-dose montelukast or salmeterol as protection against exercise-induced bronchoconstriction |journal=Chest |volume=132 |issue=3 |pages=875–83 |year=2007 |pmid=17573489 |doi=10.1378/chest.07-0550]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 Dolan ,Amy Van Dyken , andNancy Hogshead , Olympic track starJackie Joyner-Kersee , baseball Hall of FamerCatfish Hunter , and American football playerJerome Bettis are among the many who have done so.At the same time, it should be noted that according to
International Olympic Committee statistics, during most ofOlympic Games in last 20 years from 1/3 to 2/3 of athletes claimed to have asthma.Fact|date=March 2007 Some medical experts tie such inordinate rates of reported asthma with athletes' desire to use complex medication to help them achieve better results.Fact|date=March 2007References
External links
*cite web |url= http://www.aaaai.org/patients/publicedmat/tips/exerciseinducedasthma.stm|title= Tips to Remember: Exercise-induced asthma|accessdate= 2007-04-12|publisher=
American Academy of Allergy, Asthma, and Immunology |
*cite web |url= http://www.nationaljewish.org/disease-info/diseases/asthma/living/healthy/exercise.aspx|title= Exercise-Induced Asthma|accessdate= 2007-04-12|year= 2002|month= July|publisher=National Jewish Medical and Research Center
* [http://www.atsdr.cdc.gov/HEC/CSEM/asthma/ Case Studies in Environmental Medicine (CSEM): Environmental Triggers of Asthma] – Agency for Toxic Substances and Disease Registry, U.S. Department of Health and Human Services.
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