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.
Contents of this article:
Here are some key points about fainting. More detail and supporting information is in the main article.
- The scientific term for fainting is syncope.
- Fainting is usually caused by a lack of oxygen in the brain.
- Every case of fainting should be treated as a medical emergency until the cause is known.
- In Victorian England, women would faint to appear fashionably frail.
- Symptoms can include blurred vision and confusion.
- There are a different types of fainting, one of which is orthostatic hypotension.
- Potential causes of fainting include dehydration, alcohol and diabetes.
- Treatment of fainting depends on the causes of the condition.
What is syncope?
Fainting can sometimes be a sign of a more serious illness, or nothing to worry about at all.
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, and even death.
Near-syncope vs syncope
- Pre- or near-syncope (a pre- or near-syncoptic episode) - this is when the person can remember events during the loss of consciousness, such as dizziness, blurred vision, muscle weakness, as well as the fall before hitting their head and losing consciousness.
- Syncope (a syncoptic episode) - this is when the individual may remember the feelings of dizziness and loss of vision, but not the fall.
Symptoms of syncopeThe hallmark sign is evident to anyone around - the patient passes out, faints, suddenly loses consciousness.
The following signs and symptoms may precede a fainting episode:
- A feeling of heaviness in the legs
- Blurred vision
- Feeling warm or hot
- Lightheadedness, dizziness, a floating feeling
- The individual may be falling over
- The patient may be slumping
- The person may be unusually pale
- There may be a drop in blood pressure
- There may be a weak pulse.
On the next page, we look at the causes of fainting.