This NHS content is written for people in England. Services, contact routes and treatment arrangements may differ in other countries.
Causes of fainting
There are many reasons why someone might faint.
Causes include:
- standing up too quickly – this could be a sign of low blood pressure
- not eating or drinking enough
- being too hot
- being very upset, angry or in severe pain
- heart problems
- taking drugs or drinking too much alcohol
Symptoms of fainting
Fainting usually happens suddenly. Symptoms can include:
- dizziness
- cold skin and sweating
- feeling warm or hot
- feeling sick
- changes to your vision
See a GP if:
- you have fainted
It’s probably nothing serious, but it’s important to get checked by a GP to find out what might have caused it.
Things you can do to prevent fainting
If you feel like you're about to faint, try to:
- lie down with your legs raised – if you cannot do this, then sit with your head lowered between your knees
- drink some water
- eat something
- take some deep breaths
Call 999 if:
Someone faints and they:
- are not breathing
- cannot be woken up within 1 minute
- have not fully recovered or have difficulty with speech or movement
- have chest pain or a pounding, fluttering or irregular heartbeat (heart palpitations)
- have seriously hurt themselves
- are shaking or jerking because of a seizure or fit
- fainted while exercising
- fainted while lying down
Fainting
Fainting
Fainting
Causes of fainting can include standing up too quickly, not eating or drinking enough and having a heart problem.
Content supplied by the NHS website, refreshed 19 August 2026. View the original NHS article ↗
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