Many people, when using the toilet or sitting or squatting for a long time, will suddenly stand up and experience transient dizziness or even blackness, or even blinding. For the entire human body, both the blood pressure in the brain and the upper and lower extremities have a balancing effect, and the blood pressure level should be kept stable. After standing up suddenly, because of low blood pressure and position change, there will be a transient shortage of blood supply to the brain, and the shortage of blood supply to the brain will produce transient dizziness, blackness and blinding, and even fall. With the change of body position, people have their own blood pressure regulation function to keep the intracerebral pressure in balance. However, at a certain age, or for some special reasons, the regulation of maintaining the brain pressure balance may be affected or decreased. In particular, the elderly because of the imbalance of the nervous system regulation, or decline in function, can cause postural changes, cerebral blood pressure regulation is insufficient, all of a sudden there will be dizziness, not only after a long squat stand up dizziness. If you get up quickly and your body position changes slightly, you may experience dizziness, darkness, or even loss of consciousness. Sometimes dizziness is so severe in older people that they need to go to the hospital or even undergo medication.