Patients who get dizzy when they stand up usually experience dizziness due to the following factors: 1. Postural hypotension, where some patients maintain a normal but low blood pressure level while sitting or lying down, and suddenly stand up to cause insufficient blood return, which can also lead to dizziness and headache. 2. Acute cerebrovascular insufficiency of blood supply, which can also lead to dizziness when standing up, such as transient cerebrovascular ischemic attack (TIA), because the circulating blood supply to the cerebral vessels is insufficient, there will be dizziness due to ischemia of the cerebral vessels when standing up. 3, people with reduced heart function because the heart’s blood supply capacity is insufficient and oxygen supply capacity is reduced, when the body position changes, the heart does not play a sufficient role in supplying oxygen and supplying circulation, so dizziness will occur when standing up.