Dizziness starts at 5~6 p.m., which may be caused by brain fatigue, elevated blood pressure, cervical spondylosis and other factors. 1. Brain fatigue: If the patient is engaged in intense mental labor, after the heavy work in the morning and afternoon, it may lead to overuse of the brain, and the brain is extremely tired, so dizziness may occur at 5~6 pm. 2. Elevated blood pressure: 5-6 p.m. is the second peak of blood pressure in a day. Increased blood pressure during this time may cause dizziness. 3. Cervical spondylosis: If the patient has been sitting and standing for a long time for work and study, improper sitting posture, sedentary, etc. may lead to cervical spondylosis, and when the herniated cervical disc compresses the vertebral artery and causes insufficient blood supply, dizziness may occur at 5~6 pm. There are many reasons why dizziness starts at 5~6pm. It is recommended that patients pay attention to rest, avoid sitting improperly and sedentary at work. If dizziness often starts at 5~6pm, it is recommended that patients consult a doctor in time so as to avoid delaying their condition.