1. Inactivity: Prolonged bed rest or immobility can lead to disuse atrophy. 2. Chronic Illness: Conditions like cancer, COPD, and heart failure can contribute. 3. Neurological Disorders: Diseases such as ALS or multiple sclerosis can lead to muscle wasting. 4. Malnutrition: Lack of essential nutrients can impair muscle health. 5. Aging: Sarcopenia, the age-related loss of muscle mass, is common in elderly patients.