Inclusion Criteria:  Hospitalized COPD patients GOLD (3 and 4) in stable phase after an acute exacerbation. Written informed consent is required for participation.  Exclusion Criteria:  Acute respiratory failure with clinical instability or respiratory acidosis defined by pH<7.35 Severe acute physical illness that does not allow the subject to participate in a clinical trial Unable to give consent Language, cognitive, or other impairments that may prevent independent completion of questionnaires