Jan. 5, 2005

ACC Sports Sciences Main Page

John M. MacKnight, M.D.
University of Virginia Sports Medicine

Exercise-induced bronchospasm (EIB) is a common condition affecting athletes of all ages and levels. It is found in approximately 10 percent of school children, 17 percent of winter Olympians, and 35 percent of figure skaters and hockey players. It is important to distinguish exercise induced asthma (EIA), in which a patient has asthma at rest that is then made worse by exercise, from exercise induced bronchospasm (EIB) where athletes have normal lung function at rest but develop asthmatic symptoms in the setting of physical exertion. Untreated EIB can significantly impair training and result in loss of performance quality; therefore, an understanding of this common malady and the appropriate use of medical attention are essential to feeling well and competing at the highest level.

Typical symptoms of EIB include wheezing, coughing (particularly AFTER activity), shortness of breath, chest tightness, poor exercise tolerance, and dizziness or lightheadedness. These will generally arise 6-10 minutes into high-level exercise, but up to 50 percent of sufferers may develop symptoms much later, sometimes even after their training activities are completed. Rapid onset of activity from rest or aggressively pushing up one's training length and intensity (a bit too fast) may unmask a tendency toward EIB. Cold and dry air are common triggers to EIB (as discussed below) and a higher incidence is seen in athletes with histories of allergies and chronic sinus problems.

Given those factors, swimming and diving should provide a more favorable environment for EIB sufferers with warm, moist air to help protect their airways. Nevertheless, these athletes are not immune to the problem as evidenced by the high number of Olympic caliber swimmers who are medication-dependent for management of their EIB. Some suggest that the high chemical setting, particularly chlorine, may trigger asthma even if other factors are more favorable.

There are 3 prevailing theories with respect to the triggering mechanism for EIB:
1. "Hyperosmolarity theory" - water loss in the airways with intense training sets off a cascade of reactions which narrow the airway and create wheezing
2. "Airway re-warming theory" - hyperventilation with intense training cools the airway surfaces; upon re-warming, a variety of chemicals are released by the body which cause airway narrowing
3. "Heat exchange theory" - cold air creates spasm and nerve irritation in the airways, causing them to constrict

A formal diagnosis can be obtained in a variety of ways utilizing a number of breathing tests (pulmonary function tests) from very simple to very complex. The major issue is to show that the efficiency of blowing air out/forcibly exhaling decreases with exercise as compared to rest.

"EIB is a highly treatable condition and need not rob you of athletic performance."

If this is the case, a diagnosis of EIB is made. In many cases, experienced sports medicine physicians can presumptively diagnose athletes with EIB simply based on their history and description of symptoms. Office or poolside assessments can be made with a peak flow meter which measures how much air can be quickly exhaled. Formal pulmonary function tests, with or without provocative measures to cause wheezing, are rarely necessary in the athletic population.

Treatment centers around two major issues: environmental/training control and the use of medications. Whenever feasible, athletes should have their training environment altered to minimize the tendency to trigger asthmatic responses. This includes water temperature, chemical content, air temperature, pollen or other allergen avoidance, and modifying the training program to avoid rapid changes in training duration or intensity. Each of these features can make a substantial difference in the behavior of an athlete's asthma. If all of the environmental factors have been addressed and the athlete is still symptomatic, medication use on a consistent basis is appropriate to ensure full lung function and maximal performance.

The most common medication for EIB is ALBUTEROL (also known by the trade names VENTOLIN or PROVENTIL). Albuterol is a bronchodilator (airway opener) which is generally inhaled 15-20 minutes prior to an anticipated sports activity. Used this way, it provides a up to four hours of protective effect from the tendency to develop airway narrowing with exercise. This is a highly effective method of treatment for most athletes with EIB.

In cases with continued wheezing, the addition of another medication is appropriate. Most commonly this second agent is from a class of medications called leukotriene antagonists which block some of the problematic chemical reactions that occur with EIB. The leukotriene antagonist most highly touted for its use in EIB is MONTELUKAST (trade name- SINGULAIR). This once a day pill provides the convenience of consistent asthma prevention regardless of the timing of training or competition.

Many athletes prefer to have the medication in their system ahead of time as it helps them feel comfortable that asthma symptoms are not likely to interfere with their activities. Agents from this family can also be combined with albuterol if necessary. Seek the advice of your physician regarding the right combination of therapy for you. There are many combinations of therapy that can be prescribed. EIB is a highly treatable condition and need not rob you of athletic performance. EIB medications are safe, are not addictive, and have few if any side effects in most athletes.

One unique property of EIB is that of the "refractory period." This phenomenon can be used as an additional means of managing EIB or may actually take the place of medications in some circumstances. When EIB is triggered, a number of chemicals which create inflammation in the airways are released. However, there is a finite amount of each of these chemicals produced and stored at any one point in time. If an athlete exerts themselves heavily enough to produce wheezing, these chemicals are released in large amounts to the point of depleting the available supply.

Thus, if an athlete rests for a short time (typically 15-20 minutes) and allows the asthmatic symptoms to subside, they can then re-exert as heavily as they would like and they will not re-develop wheezing because most of the causative chemicals have already been released and used. This can be a valuable part of a consistent management approach (as I have done with several athletes at UVA) or as a performance saving technique should the athlete be caught unexpectedly without their medication.

If you or someone you know is suffering with what sounds like EIB, here are some helpful thoughts to getting you back on your game:
1. Many, many active individuals explain away their symptoms and never pursue a medical evaluation. If you've experienced some or all of the symptoms noted above, you likely have EIB and you need to get it checked out by your primary care or sports medicine physician. You are potentially robbing yourself of performance.
2. Follow your physician's recommendations with respect to medications. They're very safe and very effective, so don't sell yourself and your performance short- use them!
3. Knowing how to live with EIB is the key to great management. Don't expect to go full throttle right off the bat on a cold day but warm up and let your body get accustomed to the air and your expected level of activity. Being reasonable and realistic with your body helps to prevent failure.

EIB is an extremely common medical condition in active individuals. Always be aware of the presenting features and see your medical professional right away if you have concerns about it. Asthma is to be respected but not feared. A thoughtful approach to its management should always ensure safe and productive exercise performance.

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