Incidence of exercise-induced asthma in children.

The incidence of exercise-induced asthma (EIA) was studied in 134 asthmatic, 102 nonasthmatic atopic, and 56 nonatopic children. Pulmonary function tests measuring forced vital capacity (FVC) and one-second forced expiratory volume (FEV1) were performed on each child prior to and serially for 20 minutes following free running exercise. The incidence of the EIA among the asthmatic and atopic nonasthmatic children was 63% and 41% respectively, and 7% among control subjects. Airway function was studied prior to and after a standardized free running exercise test. Forty-one percent of the nonasthmatic and 63% ofthe asthmatic atopic children had a significant decrease in airway function as compared to 5% of the nonallergic subjects.