RT Journal Article SR Electronic T1 Relation of Exercise Capacity With Lung Volumes Before and After 6-Minute Walk Test in Subjects With COPD JF Respiratory Care FD American Association for Respiratory Care SP 1687 OP 1695 DO 10.4187/respcare.03082 VO 59 IS 11 A1 Thomas Wibmer A1 Stefan Rüdiger A1 Cornelia Kropf-Sanchen A1 Kathrin M Stoiber A1 Wolfgang Rottbauer A1 Christian Schumann YR 2014 UL http://rc.rcjournal.com/content/59/11/1687.abstract AB INTRODUCTION: There is growing evidence that exercise-induced variation in lung volumes is an important source of ventilatory limitation and is linked to exercise intolerance in COPD. The aim of this study was to compare the correlations of walk distance and lung volumes measured before and after a 6-min walk test (6MWT) in subjects with COPD. METHODS: Forty-five subjects with stable COPD (mean pre-bronchodilator FEV1: 47 ± 18% predicted) underwent a 6MWT. Body plethysmography was performed immediately pre- and post-6MWT. RESULTS: Correlations were generally stronger between 6-min walk distance and post-6MWT lung volumes than between 6-min walk distance and pre-6MWT lung volumes, except for FEV1. These differences in Pearson correlation coefficients were significant for residual volume expressed as percent of total lung capacity (−0.67 vs −0.58, P = .043), percent of predicted residual volume expressed as percent of total lung capacity (−0.68 vs −0.59, P = .026), inspiratory vital capacity (0.65 vs 0.54, P = .019), percent of predicted inspiratory vital capacity (0.49 vs 0.38, P = .037), and percent of predicted functional residual capacity (−0.62 vs −0.47, P = .023). CONCLUSIONS: In subjects with stable COPD, lung volumes measured immediately after 6MWT are more closely related to exercise limitation than baseline lung volumes measured before 6MWT, except for FEV1. Therefore, pulmonary function testing immediately after exercise should be included in future studies on COPD for the assessment of exercise-induced ventilatory constraints to physical performance that cannot be adequately assessed from baseline pulmonary function testing at rest.