Abstract
In 26 asthmatic children, a quantitative exercise test was carried out 44 times using a cycloergometer (12.6kpm/kg, for 6 minutes). The objective of the test was to observe the refractory period of exercise-induced bronchospasm (EIB). The children took this exercise test twice in each trial, at 1, 2, 3 and 24hr intervals. Differences in room temperature, humidity and atmospheric pressure as well as levels of exercise performance weve negligible throuout the trials. Under these conditions the pulmonary function levels just before the first and second exercise were nealy equal. When the exercise was given at intervals of 1, 3 and 24 hours, the levels of maximal-percent fall after the second exercise were almost the same as those in the fist test. In the case of the 2 hour intervale test, however, a significant suppression of EIB after the second exercise was observed, and also the recovery rate in pulmonary function was significantly higher than those in the cases of the other intervals. From these result, we concluded that the interval in the present exercise test should be 3 or more hours long when EIB was used for estimating the effects of asthmatic drugs. In addition we concluded that biochemical studies within about 3 hours after the exercise would be necessary for elucidating the mechanism of EIB.
