A groggy head may be related to lack of sleep, or may be caused by neurasthenia, cervical spondylosis, insufficient cerebral blood supply and other reasons. 1. Lack of sleep: If the recent mental stress is too great, poor mood, or excessive late night, resulting in poor sleep quality, sleep time is not sufficient, the brain did not get enough rest, is likely to cause brain dysfunction, it may be manifested in the head drowsiness, can also be accompanied by sleepiness, weakness and other symptoms. 2. Neurasthenia: the disease is usually due to long-term emotional, psychological stress and other reasons leading to long-term sleep disorders, due to long-term sleep disorders, the brain is in a state of fatigue for a long time, it may show drowsiness, but also can be accompanied by memory loss, irritability and other symptoms. 3. Cervical spondylosis: Especially for patients with cervical disc herniation, it is easy to lead to local vascular nerve root compression, causing insufficient blood supply of vertebral basilar artery, which may show dizziness and may be accompanied by neck and shoulder pain, numbness of the upper limbs, weakness and other symptoms. 4. Insufficient cerebral blood supply: Due to the obstacle of cerebral arterial blood circulation, resulting in insufficient blood supply and oxygenation of local brain tissues, it may show dizziness and may be accompanied by headache, drowsiness and other symptoms. Drowsiness may also be related to other factors, and it is recommended to consult a doctor as soon as possible to clarify the cause of the disease and give targeted treatment under the guidance of the doctor.