There are two reasons for dizziness once lying down, as follows: 1, blood pressure fluctuation: sudden increase in blood pressure during lying down, the head is sensitive to blood pressure, causing dizziness symptoms; 2, otoliths: also called benign paroxysmal positional vertigo, there will be dizziness once lying down, if the patient lies dizzy towards the right side, try to avoid lying towards the right side, avoid violent head movements, head and body should be turned together to avoid another attack. Benign paroxysmal positional vertigo should be reset, and the manual reset should be operated by a professional doctor in a regular hospital. Usually, we should pay attention to the regularity of life and avoid bad habits, such as tiredness, staying up late, poor rest and little exercise during the day, all of which can cause otoliths or benign paroxysmal positional vertigo attacks, so we must develop a healthy lifestyle.