Fainting is a brief episode of unconsciousness caused by a sudden drop in blood pressure. The most likely cause of this sudden drop will either be some change in the blood vessels or the heartbeat itself.  Blood vessels continually adjust their width to ensure a constant blood pressure. For instance, the vessels constrict (tighten) when we stand up to counteract the effects of gravity. Temporary low blood pressure can be caused by various events that prompt blood vessels to dilate (expand), including extreme heat, emotional distress or pain. The lack of blood to the brain causes loss of consciousness.

Most fainting will pass quickly and won’t be serious. Usually, a fainting episode will only last a few seconds, although it will make the person feel unwell and recovery may take several minutes. If a person doesn’t recover quickly, always seek urgent medical attention.

Symptoms of fainting
The symptoms of a faint include:
-- Dizziness
-- Light-headedness
-- A pale face
-- Perspiration
-- Heightened anxiety and restlessness
-- Nausea
-- Collapse
-- Unconsciousness, for a few seconds
-- Full recovery after a few minutes.

First aid and fainting
First aid treatment for a person who has fainted includes:
Help the person lie down. A person who has fainted in a chair should be helped to the ground.
If the person is unconscious, roll them on their side. Check they are breathing and that they have a pulse.
If possible, elevate the person’s feet above the height of their head.
If the fainting episode was brought on by heat, remove or loosen clothes, and try to cool the person down by wiping them with a wet cloth or fanning them.
Assess the person for any potential injuries if they have fallen.