Dizziness, blackness, and fainting after standing up from a squatting position may be postural hypotension. Postural hypotension is manifested as a change in position, such as from sitting to upright position, or from lying to sitting or upright position, the patient can suddenly experience a drop in blood pressure, causing transient cerebral hypoperfusion and inadequate cerebral blood supply, which is clinically classified as inadequate blood supply to the internal carotid artery system and the vertebral basilar artery system. In the case of insufficient blood supply to the internal carotid artery system, the patient may experience a transient blackening in front of the eyes when the ophthalmic artery, a branch of the internal carotid artery, is impaired. In the case of insufficient blood supply to the vertebrobasilar system, the patient mainly presents with dizziness, nausea, vomiting, and can develop balance disorders and ataxia. If the patient has balance disorders, fainting can occur, and some patients may also have difficulty swallowing and choking on water. If the patient has a history of postural hypotension, the patient must move slowly when changing position.