Effect of Oral Astaxanthin Formula on Pulmonary Rehabilitation in Patients With COPD

Inclusion Criteria: * Patients who met the GOLD diagnostic criteria for stage II-IV COPD * Patients who met the indications for pulmonary rehabilitation training: mMRC score * 3 or self-reported decline in physical function. Exclusion Criteria: * Hypoxemia (resting partial pressure of oxygen \< 60mmHg or oxygen saturation \< 88%) or patients requiring continuous oxygen therapy or with any contraindications to exercise testing (refer to the American Society of Thoracic Surgeons/American College of Chest Physicians exercise testing guidelines). * Using oral glucocorticoids * Long-term oxygen therapy * Participated in a supervised exercise program within the past 12 months * History of other pulmonary diseases, including pneumoconiosis, bronchiectasis, tuberculosis, primary pulmonary hypertension, pulmonary embolism, interstitial lung disease * Skeletal, neuromuscular, cardiovascular, or metabolic disorders that limit the participant's ability to exercise actively or that involve muscle activity, such as cancer, diabetes, muscle weakness, etc.