Drowsy head always want to sleep, may be related to physiological factors, may also be due to neurasthenia, insufficient blood supply to the brain and other reasons. 1. Physiological factors: if the recent overthinking, excessive brain fatigue, too much psychological stress, emotional tension, anxiety, poor sleep, can lead to drowsiness and sleep, but also accompanied by inattention, poor mental state and other manifestations. 2. Neurasthenia: the disease is a functional disease, can lead to the patient’s brain easily fatigue, the spirit is easily excited, often patients with combined sleep disorders, long-term sleep disorders, may cause drowsiness, always want to sleep feeling, may also be accompanied by memory loss, temperamental performance. 3. Insufficient cerebral blood supply: commonly found in patients with hyperlipidemia and cerebral atherosclerosis, due to high blood viscosity and narrowing of blood vessel lumen, resulting in insufficient blood supply and oxygen supply to the brain, which may cause dizziness and drowsiness and be accompanied by headache, weakness and other symptoms. Drowsiness and sleepiness may also be caused by other reasons, through supplemental sleep, reasonable rest, if the symptoms continue to fail to improve, it is recommended to seek medical treatment as soon as possible, under the guidance of a professional physician to clarify the cause of the disease, standardized diagnosis and treatment.