 The first visit will be used to review the inclusion criteria and to obtain consent. A spirometry will be obtained. Patient on tiotropium or glycopyrronium will be switched to open label ipratropium see allowed medication. Visit 2 will include pulmonary function testing including spirometry, lung volumes and diffusion capacity measurements. A maximal incremental shuttle walking test, the COPD assessment test CAT and the MRC scale will be also be completed. Patients will then be familiarized with the 3-min constant rate shuttle walking test. During Visit 3, patients will perform two 3-min constant rate shuttle walking test which will serve to determine dyspnea at baseline. The investigators will aim for a dyspnea Borg Score 3, the rationale being that it is important to obtain a significant dyspnea signal considering that the objective of the study is to evaluate the efficacy of bronchodilation to improve dyspnea. Patients in whom it will not be possible to achieve this level of dyspnea at the end of the 3- min constant rate shuttle walking test will be excluded for further study participation. 