Encyclopedia: Fainting
Fainting, frequently called syncope , is a sudden, and generally momentary, loss of consciousness, or blacking out caused by the Central Ischaemic Response, because of a lack of sufficient blood and oxygen in the brain. The first symptoms a person feels before fainting are dizziness; a dimming of vision, or brownout; tinnitus; and feeling hot. Moments later, the person's vision turns black, and he or she drops to the floor...