Understanding ‘exercise-induced asthma’ in kids

Although this winter has been relatively mild so far, at least on the East Coast, cold weather is inevitably going to come. When it does, how will this affect your ability to exercise? Does exercising in cold weather pose difficulties for you? Does it cause you to have wheezing, or cough, or shortness of breath? Many of our young elementary school and high school students are involved in a variety of sports activities in the winter time. What is the best way to get through the cold months?

Exercise-induced bronchoconstriction (EIB) or "exercise-induced asthma" is a well-established condition with strict diagnostic criteria.The diagnosis is established by changes in lung function which are provoked by exercise, and is not based on symptoms. The condition involves acute narrowing of the airway occurring as a result of exercise.

EIB is more commonly known as "exercise-induced asthma," but I refer to it as EIB because it can occur in asthmatics and non-asthmatic individuals. However, asthmatics, who already may have a propensity for airway obstruction, are more prone to EIB. EIB is a particularly important issue in children and young adults because it is this group of individuals who are the most active in individual and team sports.

While EIB can occur at any time of the year, the effects of cold-dry air magnify the problem. The mechanisms responsible for causing airway obstruction with exercise are not completely known, but it is believed that it may be due to a combination of chemicals released into the airways that can lead to inflammation, and the activation of sensory nerves leading to the production of excessive amounts of mucous.

It has been observed that EIB has a higher incidence in Nordic skiers and competitive swimmers. These are both high ventilation sports, as are other common causes such as soccer or running. The higher rate of ventilation in these sports causes drying of the inhaled air, which is a key factor in EIB. Other environmental triggers that may increase the likelihood of developing EIB in various sports include exposure to high allergen or airborne particulate levels, high ozone environments, trichloramines in indoor swimming pools, and high-emission pollutants in ice rinks.

There are a number of exercise challenges tests available to identify those individuals who may have EIB. These tests are usually done in an allergist or pulmonologist office, or in a hospital pulmonary laboratory. Patients are given a spirometry (lung function) test and then asked to exercise to achieve a high level of ventilation. The spirometry test is repeated to see if there is a drop in lung function. Certain criteria specific to the test must be met in order to make the diagnosis.

The treatment of EIB involves several measures. Firstly, the implementation of a warm up and cool down period often helps to mitigate the airway obstruction of EIB. The type of regimen for warm up is very specific and you should ask an allergy specialist or a physician knowledgeable about EIB how to do this. For many athletes, the prophylactic use of short acting bronchodilators such as albuterol five to 20 minutes before exercise allows the participant to fully engage in their sport of choice. Of course, if there is underlying asthma, then the asthma must be optimally controlled with the use of standard asthma medications, which may include inhaled corticosteroids, or inhaled corticosteroid/ long acting bronchodilator combination medications. Another medication useful in the treatment of EIB is montelukast, an inhibitor of an inflammatory mediator known as leukotriene. There is poor evidence that the use of devices to warm the inhaled air, or dietary changes provide any benefit to individuals with EIB.

For young athletes who engage in competitive sports, they should realize that certain medications may be banned, as determined by the International Olympic Committee and the World Anti-Doping Agency. Short acting bronchodilators are permitted, as are some of the long acting bronchodilators. Inhaled steroids are permitted. Other medications may require a therapeutic use exemption (TUE). The list of permitted medications is published yearly, but it is always a good idea to fully disclose the use of any medications and consult the regulatory agencies if you have any questions about the use of medications in competitive sports.

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