Weakness of the legs in the elderly does not mean that they will not live a long life, and it usually does not cause patients to live a long life as long as they are not suffering from advanced cancer, acute illnesses, critical illnesses, and so on. Leg weakness in the elderly may be related to degenerative changes in the bones and muscles of the lower limbs. Some diseases may also cause leg weakness in the elderly, such as lumbar disc herniation, lower extremity venous thrombosis, cirrhosis, cerebral infarction, heart failure, renal insufficiency, and malignant tumors, etc. Whether or not it will affect life expectancy needs to be judged according to the specific disease: 1. Lower extremity muscle degeneration: older people with the increase in age, lower extremity muscles may undergo degeneration, the lower extremity loses the support of the muscles, the leg will appear weak. If the symptoms are mild, early intervention, generally does not affect the life expectancy; if the symptoms are serious, and even lead to the patient can not walk, may have a certain impact on the life expectancy; 2, lumbar disc herniation: may make the elderly lower limb nerve root damage, resulting in weakening of the lower limb muscle strength, leg weakness, usually accompanied by hip and leg pain, numbness and other symptoms. At this time, it needs to be treated by drugs, physical therapy, surgery and other treatments, which can improve the symptoms and generally do not affect the life expectancy; 3. Lower extremity venous thrombosis: mostly seen in long-term bedridden elderly people, which can lead to the lower extremity blood supply is affected, resulting in the elderly leg swelling, numbness, weakness, pain, and the legs may be different thicknesses. At this time can be treated by surgery, but also auxiliary drugs to improve circulation, can relieve the symptoms, less impact on life; 4, cirrhosis: cirrhosis of the elderly portal vein pressure increases, colloid osmotic pressure decreases, the albumin reduces, can cause lower limb edema, weakness, there is also a certain impact on life. At this time should be actively treated by drugs, surgery and other means, can improve the quality of survival of the elderly, prolong the survival time; 5, heart failure: the elderly chronic heart failure usually affects the ability to move, heart failure is serious when the lower limbs do not circulate well, affecting the muscle function leads to the elderly leg weakness, mostly accompanied by chest tightness, shortness of breath, dyspnea and other conditions, if not treated in time, it may be life expectancy has a certain impact; 6, Renal insufficiency: when the old man suffers from chronic kidney disease or other diseases, resulting in impaired renal function, electrolyte disorders can occur, and leg weakness occurs, usually accompanied by urinary changes such as polyuria or oliguria, and if there are serious complications such as renal failure, it may affect life expectancy, and even endanger life; 7. Malignant tumors: malignant bone tumors, such as osteoblastoma, osteosarcoma and other bone tumors occurring in the lower limbs or other parts of the body. malignant tumors occurring in the bone metastasis, may lead to muscle involvement, so that the elderly appear the symptoms of weakness of the affected side of the leg, at this time may affect the life expectancy, need to seek timely medical treatment for surgical treatment, radiotherapy, endocrine therapy, etc., usually can prolong the life and improve the quality of patient’s survival.