Suddenly stand up dizziness may be caused by anemia, postural hypotension, cervical spondylosis and other reasons. 1. Anemia: It means that the hemoglobin content in blood is lower than the normal physiological value. When anemia occurs, the effective circulating blood volume of the body will be reduced, the heart ejection of blood is insufficient, so that the blood supply to the brain is insufficient, dizziness, headache, pallor and other symptoms, dizziness will be more obvious when there is a change in position from squatting to standing and other symptoms. 2. Postural hypotension: also known as upright hypotension, is a manifestation of a significant drop in blood pressure that occurs when getting up quickly. Clinical manifestations such as dizziness and unsteadiness can occur. 3. Cervical spondylosis: a clinical syndrome caused by degenerative changes in the cervical spine, due to the protruding intervertebral discs compressing the arteries supplying blood to the brain to make the cerebral blood supply insufficient, and dizziness and headache appear, and dizziness can be more obvious after standing up suddenly after a long period of sitting. It is recommended to try to move slowly when getting up, and if the symptoms worsen, you can go to the hospital for examination to understand the cause of the disease.