Effect Of Body Mass Index On Exercise Tolerance In Patient With Stable Chronic Obstructive Pulmonary Disease

Objective:To analyze the effect of body mass index on exercise tolerance in patients with stable chronic obstructive pulmonary disease(COPD).Methods:A total of 131 patients with stable COPD admitted to our hospital from 2016to 2017 were enrolled.According to body mass index(BMI),they were divided into group A(low BMI group,BMI<24 kg/m~2)of 70cases and group B of 61 cases(high BMI group,BMI?24 kg/m~2).The differences in exercise tolerance indexes between the two groups were compared.Exercise tolerance indicators included a six-minute walk test(6MWT),a cardiopulmonary exercise test(total exercise test time,maximum metabolic equivalent),and a modified version of the British Medical Research Council Dyspnea Questionnaire(mMRC questionnaire)score.Results:(1)6MWT test results:the results of 6MWT in group A were(303.6±35.4)m,and the results of 6MWT in group B were(246.3±27.0)m.The difference was statistically significant(t=3.947,P<0.05).There was a negative correlation between BMI and 6MWT results(r=-0.654,P<0.05).(2)Cardiopulmonary exercise test results:The total time of exercise test in group A was longer than that in group B(t=32.211,P<0.05),and the maximum metabolic equivalent was greater than that in group B(t=10.859,P<0.05).The difference was statistically significant.There was a negative correlation between BMI and total exercise time and maximum metabolic equivalent(r=-0.804,-0.547,P<0.05).(3)mMRC questionnaire results:Group A had mild dyspnea in 11 cases,moderate dyspnea in 46 cases,and severe dyspnea in 13 cases.Group B had mild dyspnea in 5 cases,moderate dyspnea in 25 cases,and severe dyspnea in 31cases,the difference between the two groups was statistically significant(?~2=15.327,P<0.05).BMI was positively correlated with the degree of dyspnea(rs=0.737,P<0.05).Conclusion:BMI is closely related to exercise tolerance in patients with stable COPD,and exercise tolerance is lower in those with higher BMI.