There are many causes of weakness in the elderly. These diseases can cause generalized weakness in the elderly, which can be accompanied by sensory impairment and speech impairment. 3. sarcopenia and weakness, sarcopenia, weakness and malnutrition can cause a decrease in muscle volume and muscle strength in the elderly, which is an important cause of weakness and even death. 4. various infections, such as lung infections, urinary tract infections, sepsis, etc., are common causes of weakness in the elderly.