Exercise-induced Bronchoconstriction Diagnostics: Impact of a Repeated Exercise Challenge Test

Abstract

OBJECTIVE:The aim of the study was to evaluate whether a repeated exercise challenge test requires reconsideration of the final exercise-induced bronchoconstriction diagnosis due to a difference in test results, and if so, whether the difference is associated with exercise intensity.

METHOD: A total of 20 referred subjects with symptoms strongly suggesting exerciseinduced bronchoconstriction performed two exercise challenge tests on a treadmill. The exercise protocol of the repeated test was adjusted. Forced expiratory volume in 1 second was measured before and at 1, 3, 6, 10, and 15 minutes after exercise. Ventilation and heart rate were measured during exercise.

RESULTS: The exercise intensity was not significantly different between the two tests, yet five subjects tested positive in both tests. Ten subjects tested negative in both tests. Three subjects tested positive in the first test only, while two subjects tested positive in the second test only.

CONCLUSION: Our study showed a 25% divergence in the diagnostic results of two consecutive exercise challenge tests on subjects with symptoms strongly suggesting exerciseinduced bronchoconstriction. The difference in the test results was not explained by a difference in the exercise intensity.

Keywords: exercise challenge test, exercise-induced bronchoconstriction, forced expiratory volume in one second