Postural hypotension is called postural hypotension when there is a significant decrease in blood pressure when the patient automatically changes from the prone position to the upright position. The specific criteria are as follows: the subject lies quietly on his back for 10 min then blood pressure and pulse rate are measured once per minute until the two blood pressure values are similar, and the average value is taken as the blood pressure value before the postural change. After that, the subject was allowed to stand up automatically, and the right upper arm was placed at the same level as the heart, and the blood pressure and pulse rate were measured again. The data immediately and every minute thereafter were recorded and compared with that before standing up for a total of 7 min. After standing up, the blood pressure dropped by at least 2.7/1.3 kPa (20/10 mmHg) or the systolic blood pressure dropped to below 10.7 kPa (80 mmHg) and was maintained for more than 2 min. In recent years, people in China have applied the electric flat – upright tilt bed with automatic, timed ECG, blood pressure and pulse rate monitor to diagnose upright hypotension or upright syncope, which is more convenient, safe and accurate. Postural hypotension can be further divided into: ① Reversible postural hypotension: more common. Older people, especially those who are bedridden for a long time, have poor venous return in the lower extremities or the whole body, such as phlebitis, venous structural defects, muscle atrophy, and weakened muscle pump action. If there is also heart attack, heart failure or inadvertent use of strong diuretics, it can prompt an attack of postural hypotension. Methyldopa, guanethidine, etc. affect sympathetic nerve function resulting in the disappearance of reversible small arterial reflexes, and postural hypotension is also likely to occur when the patient changes position. It is characterized by a significant drop in systolic blood pressure, a basic unchanged diastolic blood pressure, and an increased heart rate, and fainting may occur at individual times. It can be corrected after the cause is removed. (2) Irreversible postural hypotension: postural hypotension can occur in some patients with autonomic dysfunction, especially with reduced alpha-adrenergic nerves and reduced release of vasoconstrictor mediators. In addition, shy-Drager’s syndrome is a slow-onset, progressively worsening geriatric disease that manifests as upright hypotension, autonomic dysfunction (e.g., urination, sweating, and sexual dysfunction), and other neurological dysfunctions. The disease is caused by significant degeneration and atrophy of the autonomic nerve center, cerebellum, olivary nucleus of the cerebellum, cerebral bridge, and spinal cord. The prognosis is poor and the death rate is high. In a group of patients followed up for 5 years in China, the death rate reached 44.1%.