What is fainting?
Fainting (known medically as ‘Syncope’) is a transient loss of consciousness with a resultant loss of postural tone caused by a temporary interruption of blood flow to the brain. It must be differentiated from other causes of transient loss of consciousness such as epileptic seizure and causes of sudden collapse such as vertigo.
Fainting can be due to a simple physiological cause or can indicate a more serious underlying disease. The most common innocuous cause of syncope is the vasovagal (or common) faint.
The brain requires a continuous supply of oxygen to maintain its function and particularly to preserve consciousness. Cerebral circulation is maintained by the action of the heart producing a pressure (blood pressure) to drive the flow. In addition to a steady regular output of blood a continuous return flow to the heart is needed to sustain blood pressure. Any condition that interferes with either the action of the heart or the return circulation can result in reduced cardiac output with consequent fall in cerebral circulation and loss of consciousness.
