Bronchial Responsiveness and Lung Function in a Cohort of College Students of Medical Technology V. Spirometric Response in Exercise- Induced Asthma

Abstract

Abstract To determine the prevalence of exercise- induced asthma (EIA) among Chinese young asthmatics, 16 male and female college students, 19 to 25 yr of age, with a past history of bronchial asthma took part in this study. All of them had increased bronchial responsiveness as assessed by methacholine challenge. Additional samples of 14 normal healthy adults of similar age served as the control group. Exercise tolerance tests were conducted on each subject with a cycle ergometer, and forced expiratory spirograms were recorded just before and 10 minutes after the tests. A fall in forced expiratory volume in 1s(FEV1) and /or peak expiratory flow rate (PEFR) of at least 10% was considered positive for EIA. Our data show that the prevalence of EIA in these asthmatic students was 56.3%(9/16). None of the normal subjects demonstrated a decrease in expiratory flow after stopping exercise. In positive EIA responders, the mean reduction in FEV1 and PEFR post- exercise were 530 ±165 ml and 3.6 ± 1.2 L/s, respectively. A prominent decrease in FEV1/ forced vital capacity (FVC) was also found following cycle ergometry. On the contrary, no significant changes in these flow parameters were demonstrated in asthmatic subjects who did not have EIA. We conclude that EIA is commonly, but not necessarily present in Chinese young asthmatics. positive for EIA. Our data show that the prevalence of EIA