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department of Medicine

Section of pulmonary and critical care medicine

Research - Asthma in the Athlete

 

Recently, the Division of Pulmonary and Critical Care Medicine and the Department of Sports Medicine at Temple University Hospital joined together to explore the problem of asthma in the athlete.

 

During the last two years, we have evaluated the prevalence and impact of asthma in high school football players in the Delaware Valley area. This investigation has led to a greater understanding of this problem and has identified certain adolescents who are at risk for asthma while playing high school football.

 

It was found that up to 10% of 240 football players tested in Philadelphia demonstrated exercise-induced bronchospasm (EIB). A past history of wheezing and living in poverty areas were independent risks for the development of bronchospasm after exercise.

 

When pretreated with an inhaled bronchodilator, such as albuterol, by metered-dose inhaler, the bronchospastic condition was substantially improved, if not eliminated.

 

The use of a peak expiratory flow meter was found to be helpful in identifying high school athletes who were at risk for EIB. Simply by comparing airflow before and following a one mile run and recognizing a fall in peak expiratory flow of 15%, we were able to predict those athletes who would develop EIB. The use of albuterol not only improved their asthmatic condition, but by identifying these football players, their athletic performance was enhanced.

 

During the last ten years we have learned a great deal about EIB. We know that when this condition is properly identified it can be avoided with simple medication regimes as well as warm up and cool down exercises. EIB affects a large segment of the population. Approximately 90% of asthmatics experience EIB, with many stating that exercise is a major precipitant of their asthma. Additionally, nearly 40% of patients who have allergic rhinitis experience EIB.

 

In the general population who are not diagnosed as asthmatic and who do not have upper airway allergies, the incidence of EIB is much lower, ranging between 3% and 10%. However, in high risk groups (e.g., athletes who have a history of previous wheezing but not yet diagnosed as having asthma) the incidence might approach 20%. This condition seems to be more bothersome for children than adults.

 

EIB typically follows exercise in the cool-down period. Its clinical manifestations are protean: coughing and chest congestion are often noted (certain athletes experience an inability to take a deep breath); chest tightness; lightheadedness with minimal respiratory symptoms; or just a failure to perform at a level that they are used to. Therefore, it is important to realize that this common problem does exist, its clinical manifestations are often difficult to equate with asthma, and a high index of suspicion is paramount in making a diagnosis.

 

The etiology of EIB is likely multifactorial and remains poorly understood. Obviously, if the airways are inflamed, the cool, dry condition that occurs during enhanced ventilation is likely to further enhance inflammation of the airways. However, certain athletes with EIB have very little recognized airway inflammation. Patients with chronic asthma have ongoing airway inflammation; however, patients with isolated EIB may have little to no inflammation present.

 

Although most patients recover from EIB within one hour, late asthmatic responses can occur 3 to 9 hours after exercise. This late asthmatic reaction, which is uncommon, often occurs in children who have severe early reactions. It has also been shown that repeated exercise challenges during the refractory period may still reduce airflow, but less so than the initial EIB experience.

 

Factors which influence the severity of EIB include certain ambient air conditions (e.g., cold, dry air, and environmental pollutants), the duration, type and intensity of exercise, overall asthma control, the presence of upper or lower respiratory tract infection, poor physical condition, intensity of exercise, overall asthma control, the presence of upper or lower respiratory tract infection, poor physical condition, and the time since the last episode of EIB occurred.The activity performed may also influence EIB. Activities such as running and cycling , which require high levels of metabolism and are near maximum levels of aerobic capacity, are most likely to cause EIB. Furthermore, running and cycling are often done in cold weather, which enhances the likelihood of post exercise asthma. On the other hand, exercise at a level below aerobic capacity, especially in a warm humid environment, has a lower propensity for EIB.

 

The diagnosis of EIB combines classic historical symptoms with response to empiric preventive therapy. However, an exercise challenge test documenting a significant decrease in airflow and reversal of bronchoconstriction with albuterol can be a helpful diagnostic tool. Furthermore, a methacholine challenge test demonstrating enhanced airways hyperreactivity also supports the diagnosis of EIB.

 

We believe that it is helpful to teach the patient how to use a peak expiratory flow meter, and perform pre-and post-exercise PEF measurement. If a 15% fall in airflow occurs which is minimized or eliminated with albuterol pretreatment before exercise, the diagnosis can be made. A standard exercise challenge in the laboratory is less sensitive than a methacholine challenge in diagnosing hyperreactivity and EIB. However, field studies using peak expiratory flow meters might be more valuable than doing challenge testing at a hospital or medical office.

 

The goal of EIB treatment is to allow patients to participate fully in their athletic activities without respiratory distress. This should allow EIB patients to achieve maximal exercise performance and perhaps realize their full potential to play sports. Management should begin with enhanced reconditioning. Short exercise bursts during a warmup have been shown to decrease EIB. This simple maneuver takes advantage of the refractory period and decreases the frequency and severity of bronchospastic episodes. Exercising in a warm humid environment can be helpful and certainly pharmacological therapy has its place.

 

The use of a short acting beta agonist such as albuterol (2 or 3 puffs, 15 to 20 minutes prior to exercise) has been shown to be helpful in controlling EIB. If multiple exercise events are going to occur within a 10 to 12 hour period of time, it may be helpful to use salmeterol before the initial exercise. Often this eliminates the need for recurrent administrations of a short-acting beta agonist such as albuterol.

 

Agents such as cromolyn and nedocromil sodium, when administered approximately one hour prior to exercise, might enhance the efficacy of albuterol pretreatment in controlling difficult EIB. In our opinion, there is little role for the prophylactic administration of corticosteroids or oral theophylline. In select individuals, the use of these medications may be helpful, but the principal role of corticosteroid therapy and oral theophylline is to control chronic persistent asthma. By controlling chronic persistent asthma, EIB often becomes better controlled.

 

Gilbert D'Alonzo, DO
David Kukafka, MD