Patients feel dizzy when they stand up from squatting: 1. The most common factor is called upright hypotension, also known as postural hypotension, which is a manifestation of abnormal blood pressure self-regulation. It is especially common in the elderly population, and patients will suffer from poor blood pressure adjustment after standing up quickly, resulting in dizziness, blackout, fainting, and other uncomfortable symptoms; 2. Patients will also suffer from this condition when their blood volume is insufficient, such as dehydration caused by high temperature heat stroke in summer, acute gastroenteritis, or bleeding, burns, or adrenal cortical insufficiency; 3. Adverse reactions to medications, and if the patient takes a large amount of cerebral vasodilators, diuretics, and prolonged periods of time. 3, the adverse reaction of drugs, if the patient takes a lot of cerebral vasodilators, diuretics, long-term use of antihypertensive drugs or antidepressants, there will also be this symptom; 4, the homeostatic regulation of the internal environment is weakened, for example, the patient is in the chronic cardiac insufficiency, there will also be the above clinical manifestations.