Inclusion Criteria:

• Age 18 to 65 years.
• Diagnosis of systemic lupus erythematosus according to the 2019 European Alliance of Associations for Rheumatology/American College of Rheumatology classification criteria.
• Stable, non-organ-threatening systemic lupus erythematosus, defined as a Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) score of 6 or less at screening, with no active renal or central nervous system involvement.
• Stable background lupus therapy, defined as no initiation of a new disease-modifying antirheumatic drug or biologic therapy and no change in the dose of immunosuppressive therapy within 8 weeks before enrollment.
• Persistent fatigue and/or muscle pain, with a PROMIS Fatigue T-score of 55 or greater.
• Stable prednisone dose, or equivalent glucocorticoid dose, of 5 mg per day or less for at least 12 weeks before enrollment.
• Able to safely participate in a moderate-intensity exercise program.
• Able and willing to provide informed consent.
• Able and willing to comply with the home-based exercise protocol and study procedures.

Exclusion Criteria:

• Prednisone dose greater than 5 mg per day, or receipt of a glucocorticoid burst within 8 weeks before enrollment.
• Pregnancy.
• Severe anemia, defined as hemoglobin less than 10 g/dL.
• Uncontrolled hypothyroidism.
• Severe systemic lupus erythematosus disease activity, defined as a SLEDAI-2K score greater than 8.
• End-stage kidney disease requiring renal replacement therapy or estimated glomerular filtration rate less than 30 mL/min/1.73 m².
• Uncontrolled hypertension, defined as blood pressure greater than 160/100 mmHg.
• Decompensated heart failure.
• Unstable pulmonary disease.
• Neurologic condition that limits exercise performance.
• Uncontrolled diabetes mellitus.
• Severe osteoarthritis that limits safe participation in the exercise intervention.
• Overlap autoimmune disease, including inflammatory myopathy, mixed connective tissue disease, or systemic sclerosis.
• History of solid-organ or bone marrow transplantation.
• Any contraindication to magnetic resonance imaging.
• Inability to fit safely on the magnetic resonance imaging scanner bed.
• Myocardial infarction or cerebrovascular event within the previous 3 months.
• Serious hemorrhage, including cerebral hemorrhage, within the previous 12 months.
• Acute infectious illness within 1 month before enrollment.
• Inability to provide informed consent.
• Inability to adhere to the home-based exercise protocol.
• Current participation in a structured exercise program.