Dizziness and lethargy may be related to physiological factors, or may be caused by high blood pressure, cerebral arteriosclerosis and other reasons. 1. Physiological factors: if the recent mental stress, psychological burden, mental tension, anxiety, coupled with insufficient sleep, the brain can not get enough rest, easy to cause brain dysfunction, may cause dizziness, lethargy, can also be accompanied by a lack of energy, mental lethargy and other symptoms. 2. Hypertension: when the blood pressure fluctuates and rises, the pressure in the cerebral blood vessels increases significantly, and the brain is stimulated by the stronger pressure, it may show dizziness and drowsiness, and may be accompanied by headache, nausea and other symptoms. 3. Cerebral arteriosclerosis: due to the thickening and hardening of the walls of the blood vessels in the brain, resulting in narrowing of the lumen, leading to poor blood circulation, resulting in insufficient blood supply to the brain tissues, oxygen supply, which may cause dizziness, drowsiness, may also be accompanied by headaches, fatigue and other symptoms. Dizziness and lethargy may also be caused by other reasons, if the symptoms do not get better, it is recommended to consult a doctor as soon as possible to clarify the cause of the disease, and standardized diagnosis and treatment under the guidance of a professional physician.