The following measures were taken to describe the sample at baseline: spirometry, lung volumes, diffusing capacity of the lung for carbon monoxide (DLco), Charlson Comorbidity Index, body mass index (BMI), fat-free mass as measured by dual energy X-ray absorptiometry, peak work rate obtained from a symptom-limited incremental cycle ergometry test, and self-reported time spent in physical exercise each week prior to enrolling in this study.