EPO and chronic obstructive pulmonary disease: The intervention will have the following secondary objectives: (1) to establish the behavior of HIF-1α at rest and in acute response to physical exercise, (2) to determine the response of VEGF and EPO after the physical training program and its correlation with HIF-1α, (3) to identify the correlation between the expression of HIF-1α and the changes in exercise capacity in patients with COPD living at high altitude after the 8-WVP, (4) to determine the effects of the physical exercise program on fitness and the quality of life of people with COPD.