The reasons why patients do not get dizzy when lying down and get up are postural hypotension and otoliths, as follows: First, postural hypotension: postural hypotension means that the patient’s blood pressure is normal when lying down, but after standing up the blood pressure can be reduced by more than 20 mmHg. If the patient gets up too fast, it will lead to a transient lack of blood supply to the brain, so the phenomenon of dizziness will occur, and it is recommended that the patient should get up more slowly. Second, otolithiasis: attention should be paid to exclude whether there is benign paroxysmal positional vertigo, also known as BPPV. BPPV, also called otolithiasis, is caused by the detachment of calcium carbonate particles inside the three semicircular canals, and when changing the position, the calcium carbonate particles stimulate the semicircular canals, leading to the phenomenon of vertigo. You need to go to the ENT department of a hospital to get treatment for reset and take medication to relieve the symptoms.