Summary
Pulmonary rehabilitation (PR) programs improve exercise capacity in patients with chronic obstructive pulmonary disease (COPD) and interstitial lung disease (ILD), but few studies compare results between both pathologies. It is not yet obvious whether gains in 6-min walk distance (6MWD) accomplished by patients with ILD are comparable to those with COPD, because existing studies have yielded conflicting results. There are studies that reported simi- lar improvement in exercise tolerance and quality of life in patients with COPD and non-obstructive lung disease. However, the duration of benefit may be shorter lived than that seen after PR among patients with COPD. Also, the type and severity of ILD may also influence outcomes of PR. A recent systematic review and meta-analysis on the impact of pulmonary rehabilitation in patients with idiopathic pulmonary fibrosis showed a growing body of evidence of its benefit in exercise tolerance and quality of life. The aim of our study was to evaluate the effect of PR on exercise capacity using 6-min walk test (6MWT) within and between COPD and ILD patients.

Relevance
This study shows that functional exercise capacity, physiological heart rate response to exercise training, dyspnea and muscle fatigue have similar improvements in COPD and ILD patients; this shows the benefits of PR in both diseases and supports some published literature. This is the first comparison of PR results in these diseases according to the same level of dyspnea, with results supporting the use of pulmonary rehabilitation with comparable benefits across distinct chronic respiratory diseases.