There are many causes of weakness of limbs, lack of energy and dizziness: 1. If the patient is middle-aged or elderly, there is cerebral arteriosclerosis, cerebral blood supply deficiency or blood is in high fat and high viscosity state, the patient will show symptoms of dizziness, weakness of limbs and lack of energy. The above symptoms persist, and can be improved when the patient takes drugs to activate blood stasis, and can be clarified by doing transcranial Doppler and blood tests. 2. The symptoms of dizziness, weakness of the limbs and lack of energy will also appear when the patient has a cold or fever.