[Exercise test in the asthmatic patient. Study of 75 patients].

Frequency of exercise-induced asthma has been studied in 75 unselected asthmatic patients (adults and children) by measuring the forced expiratory volume at one second (FEV1) and the vital capacity (VC) before and after a treadmill exercise, continued until heart rate was at least equal to 80 p.cent-85 p.cent of maximum heart rate. In 19 subjects (25 p.cent), a more than 20 p.cent decrease from control value of FEV1 was recorded ten minutes after exercise ended. Exercise-induced bronchial obstruction was relieved by a beta adrenergic bronchodilator aerosol inhalation. In the group of 19 subjects having exercise-induced asthma, a significant positive correlation was found between pre-exercise FEV1 values and post-exercise FEV1 decreases. In the whole group of 75 subjects exercise-induced asthma was related to the severity of asthma and not to other clinical or physical characteristics of the subjects. From the data of other authors it appears that frequency of exercise-induced asthma is variable. The reasons of those differences are discussed.