The causes of fainting are as follows: 1. Hypoglycemia, for patients with transient hypoglycemia will appear dizziness and sudden collapse, accompanied by palpitations, panic, profuse sweating, hand tremors and other obvious symptoms. 2. For patients with hypotension, especially for patients with postural hypotension, dizziness accompanied by sudden collapse will occur after moving from the prone position to the standing position or from the squatting position to the upright position. 3. In some patients with acute cerebrovascular insufficiency, such as those with vertebral basilar artery insufficiency and internal carotid artery system insufficiency, dizziness and sudden collapse may occur due to transient cerebrovascular stenosis and spasm. 4. Some female patients may also have neurogenic hypotension, or plant nerve dysfunction that leads to fainting.