The symptoms of dizziness and vertigo that occur when lying down are caused by positional vertigo. Positional vertigo is caused by the sensitivity of the vestibular system to gravitational stimulation and has the following three conditions: 1. Spontaneous degeneration of the ellipsoidal sac of the inner ear, where the otolith is dislodged and enters the semicircular canal, and the patient will experience vertigo, nausea and vomiting when changing position, lasting about 20 seconds. 2. Vestibular migraine can present positional vertigo when the patient changes position and experiences 5 minutes to 72 hours of Dizziness and vertigo, usually with a history of migraine, are more common in women.3. The vertebrobasilar artery is severely narrowed and occluded, and the blood flow through it at this time can seriously affect the blood supply to the cerebellum and brain stem parts, thus causing the blood supply to the brain tissue to be in an unstable state, or even infarction, which can cause the symptoms of dizziness and vertigo. In addition, patients suffering from anemia can also cause this symptom, which is caused by anemia that easily affects the blood supply and oxygen supply function of the brain.