Currently, the reference test in assessing functional capacity in COPD patients during pulmonary rehabilitation is the six-Minute Walking Test (6MWT). However, the realization of the 6MWT requires a 30m-long corridor, according to the American Thoracic Society Guidelines. Lack of sufficient space can prevent the realization of 6MWT, especially for private practitioner pulmonologists, and also in hospitals. The six-minute stepper test (ST6) which can be performed in a normal room, should be an interesting alternative.