Inclusion Criteria:  Men or women 40 years of age or older;  Diagnosed with COPD according to the 2018 Global Initiative for Lung Disease (GOLD) criteria:  Smoking intoxication greater than or equal to 10 pack-years Bronchial obstruction on spirometry with a FEV1 to FVC ratio post-bronchodilator < 70%. Available measurement of lean body mass by bioelectrical impedancemetry performed as part of routine care; Insured under the French social security system; Informed consent signed by the participant and the investigator (at the latest on the day of inclusion and before any examination required by the research).  The patients included will be sarcopenic and non-sarcopenic (equal numbers in each group, patients categorized according to the result of dexametry), and will be matched on sex and age (± 5 years).  Exclusion Criteria:  Other concomitant respiratory pathology (e.g., asthma); Acute exacerbation of COPD or acute intercurrent condition (e.g. infection) ongoing or resolved within the last 48 hours Current systemic corticosteroid therapy; Contraindication to muscle biopsy: acquired or innate hemostasis disorders, anticoagulant therapy or double anti-platelet aggregation; contraindication to lidocaine: known hypersensitivity, patients with recurrent porphyrias; Presence of a concomitant muscular pathology, innate (e.g. genetic myopathy) or acquired (e.g. myositis); Progressive bronchopulmonary cancer; Pregnant or breast-feeding woman; Patient undergoing respiratory rehabilitation; Refusal to participate in the study.  Exclusion criteria between V1 and V2:  Disorders of hemostasis detected on the blood sample; Pregnancy in progress.