Inclusion Criteria:  Subjects who voluntarily agree to participate in the study; Subjects with moderate-grade Chronic Obstructive Pulmonary Disease (COPD) (GOLD 2-50% ≤ FEV1 <80% of predicted) according to GOLD criteria; Subjects undergoing treatment with oxygen therapy and non-smokers; Ex-smokers Outpatients and inpatients  Exclusion Criteria:  Refusal of Informed Consent Severe cognitive impairment, detected by administration of the Mini Mental Status Examination Test (MMSE) Pregnancy Patients with oncological or psychiatric pathologies Main immunodepression