Deconditioning of exercise-induced asthma

The majority of asthmatic children develop a significant degree of bronchospasm after a moderate amount of exercise. Etiology of this phenomenon has remained unknown. Pulmonary function tests, measurements of blood gases, and immunological assessments have been essentially normal. This study was designed to investigate the role of conditioning process in the development of exercise-induced bronchospasm (EIB). Fifty asthmatic children, between the ages of 8 and 15, were subjected to a standardized test of exercise. Thirty-six of the children who developed EIB were divided into an experimental and a control group. The experimental procedure was designed as a classical extinction procedure in which the conditioned stimulus (exercise) was presented without the occurrence of conditioned response of EIB. Only the experimental group received isoproterenol inhalation before the exercise to prevent the occurrence of EIB, while the control groups received plain air in a similar manner. The experimental group showed a significant improvement after the extinction procedure. A 6 month follow-up indicated that the majority of the children in the experimental group maintained the gains that were acquired during the experimental procedure.