Exercise capacity as a pulmonary rehabilitation outcome

Disabled patients with chronic respiratory disease and peripheral skeletal muscle disorders have limitations in their exercise capacity, which may be improved after specific training in a pulmonary rehabilitation (PR) program. Individual assessment of exercise capacity by clinically available exercise tests represents an important patient-centered outcome that should be embedded in the rehabilitation process. These measurements include laboratory (treadmill and/or cycle ergometer) and field (walking) tests. The cardiopulmonary exercise test, both performed with incremental (incremental-load test) or predetermined (constant-load or endurance test) loading, is an excellent means to describe the profile of an individual's maximal exercise capacity and to record its change after PR. Among the variety of field-based tests, 6-min walking and shuttle walking are 2 simple tests widely used during PR. These tests are inexpensive and provide information on an individual's functional abilities: the 6-min walking test has been shown to provide level of disability and functional status, whereas the shuttle walking test has been shown to be more suitable to detect change of physical performance following PR. Overall, several available physiologically targeted tests are useful to measure the patient's tolerance to exercise, and many are even sensitive to change once intervention has taken place. In particular, endurance modality tests seem to provide better measurement of changes after PR than incremental exercise tests.