It is acute and reversible airway narrowing that occurs during, and also frequently after, exercise. Exercise-induced bronchospasm occurs commonly in people with and without asthma. In people with a known history of asthma, exercise is one of the most common triggers of bronchospasm and affects 50-80% of asthmatics.(1) In the general population without asthma or atopy, the prevalence of exercise-induced bronchospasm is approximately 10%.(2) The prevalence of exercise-induced bronchospasm is even higher in competitive athletes, as prevalence rates in this group are as high as 50%.
Uncontrolled gastroesophageal reflux disease can also cause problems with symptoms during exercise. Gastroesophageal reflux disease occurs more frequently during exercise than at rest, and can be a cause of chest pain or abdominal pain during exertion. Studies have found that increased intensity of exercise can result in increased reflux in both trained athletes and untrained people.
Palpitations, skipped beats, dizziness, or syncope may suggest cardiac arrhythmias or cardiomyopathies; however there was no history of this in the case and the electrocardiogram was normal.
One disorder than can be particularly difficult to differentiate from exercise-induced bronchospasm is vocal cord dysfunction. Vocal cord dysfunction is characterized by variable, extrathoracic airflow obstruction caused by paradoxical adduction of the vocal cords during respiration. Vocal cord dysfunction may present with throat tightness, hoarse voice, or inspiratory stridor on physical exam. Common triggers of vocal-cord dysfunction include exercise, stress, gastroesophageal reflux, post-nasal drip, and strong odors or fumes. A suspicion of vocal cord dysfunction may be raised if there is flattening of the inspiratory limb of the flow-volume loop during spirometry or if a patient with presumed exercise-induced bronchospasm is not responding to medical therapy.