RESUMO
OBJECTIVE: To explore the exercise capacity of patients with occupational pneumoconiosis with varying degrees of pulmonary dysfunction. METHODS: A total of 488 hospitalized occupational pneumoconiosis patients were selected as study subjects using the judgment sampling method and examined for pulmonary function test and cardiopulmonary exercise test(CPET). Among them, 272 patients with normal lung function were assigned as the control group, and 216 patients with abnormal lung function as the case group. The case group was divided into mild, moderate and severe pulmonary dysfunction subgroups according to the forced expiratory volume in one second/predicted value ratio(FEV_1%pred).RESULTS: The FEV_1%pred, maximal voluntary ventilation(MVV), maximum exercise tidal volume(VT_(max)), breathing reserve(BR), maximal Watt(W_(max)), maximum oxygen uptake(VO_(2max)) and anaerobic threshold(AT) in patients of the case group were lower than that in the control group(all P<0.05). The FEV_1%pred, MVV, VT_(max), W_(max), and VO_(2max) in patients in the 3 subgroups of abnormal lung function were decreased(all P<0.05) compared with the control group. The VO_(2max) and AT decreased in the case group with the increase of the degree of pulmonary dysfunction(P<0.05). The FEV1%pred, MVV, maximal exercise minute ventilation and VT_(max) of the study subjects were positively correlated with VO_(2max) and AT(all P<0.01), but the BR had no correlation with VO_(2max) and AT(all P>0.05). CONCLUSION: The more serious the abnormal degree of pulmonary function in the patients with occupational pneumoconiosis, the more obvious the decline of their exercise ability, showing a dose-effect relationship.