Fainting

The medical term for fainting is syncope. Fainting is a sudden loss of consciousness, usually temporary and typically caused by a lack of oxygen in the brain. The brain oxygen deprivation has many possible causes, including hypotension (low blood pressure).

The following words or phrasal expressions also mean to faint: to pass out, to black out, to fall unconscious, to fall in a faint. The verbs to come to and to come round mean to recover consciousness.

Sometimes syncope may be just that - a fainting episode with no medical importance. On some occasions, however, it may be caused by a serious illness, condition or disorder. Every case of fainting should be treated as a medical emergency until the cause is known and signs and symptoms have been treated. Anybody who has recurring fainting episodes should contact their doctor.

If oxygen levels are below 16% at atmospheric pressure most people faint due to hypoxia. If oxygen levels fall below 11% individuals may die by suffocation. The amount of oxygen in the air depends on its partial pressure - inhaling pressurized gas while scuba diving which is below 16% oxygen does not cause hypoxia (because the air is pressurized).

Syncope due to hypoxia may also be caused by malfunctioning lungs, problems with blood circulation, or carbon monoxide poisoning. Some people faint at the sight of blood, or when receiving an injection or seeing somebody having one.

In Victorian England (19th Century) fainting in women was a commonplace stereotype, as well as modern portrayals of that period. Some believe that the respiratory effects of tight corsets worn at the time may have been a contributory factor. However, during Victorian times aristocratic women were encouraged to display a feminine frailty by fainting at dramatic moments.

Children sometimes play a game (fainting game) in which they deliberately restrict blood flow to the brain in order to trigger syncope - this is dangerous and may cause brain damage,...