Fainting 

Introduction  

Reduced blood flow to the brain can make you feel odd, sweaty and dizzy 

Who is affected by fainting?

Fainting is very common, affecting up to 4 in 10 people at least once during their lifetime.

Most people experience their first episode of fainting before the age of 40. If your first episode occurs after 40, it may be a sign of a serious underlying problem.

Neurally mediated syncope is the most common type of fainting. It often occurs for the first time during the teenage years and affects girls more than boys.

Fainting is a sudden, temporary loss of consciousness that usually results in a fall.

Healthcare professionals often use the term "syncope" when referring to fainting, because it distinguishes fainting from other causes of temporary unconsciousness, such as seizures (fits) or concussion

In most cases, when a person faints, they'll regain consciousness within a minute or two. However, less common types of fainting can be medical emergencies.

Dial 999 to request an ambulance if a person who has fainted doesn't regain consciousness within two minutes.

What causes a faint?

To function properly, the brain relies on oxygen that's carried in the blood. Fainting can occur when the blood flow to the brain is reduced.

Your body usually corrects reduced blood flow to the brain quickly, but it can make you feel odd, sweaty and dizzy. If it lasts long enough, you may faint.

Read more about the symptoms of fainting.

There are various reasons for a reduction in blood flow to the brain, but it's usually related to a temporary malfunction in the autonomic nervous system. This is the part of your nervous system that regulates the body's automatic functions, including heartbeat and blood pressure. This type of fainting is called "neurally mediated syncope".

Neurally mediated syncope can be triggered by emotional stress, pain or prolonged standing. It can also be caused by physical processes such as coughing, sneezing or laughing.

Read more about the causes of fainting.

What to do if you or someone else faints

If you feel you're about to faint, lie down, preferably in a position where your head is low and your legs are raised. This will encourage blood flow to your brain.

If it's not possible to lie down, sit with your head between your knees. If you think someone is about to faint, you should help them to lie down or sit with their head between their knees.

If a person faints and doesn't regain consciousness within one or two minutes, put them into the recovery position.

To do this:

  • place them on their side so they're supported by one leg and one arm
  • open their airway by tilting their head back and lifting their chin
  • monitor their breathing and pulse continuously

You should then dial 999, ask for an ambulance and stay with the person until medical help arrives.

Treatment for fainting

In most cases, a person will return to normal within a few minutes of fainting, and no further treatment will be needed.

If a person experiences repeated episodes of fainting, it's important for a healthcare professional to investigate the cause.

Read more about the diagnosis of fainting.

Treatment for fainting will depend on the type you're experiencing. In many cases of neurally mediated syncope, no further treatment is needed.

If you've had a fainting episode, advice to deal with possible future fainting episodes includes:

  • avoiding triggers – such as hot and crowded environments, or emotional stress
  • spotting the warning signs – such as feeling lightheaded
  • lying down to increase blood flow to the brain

Read more about how fainting is treated

Page last reviewed: 04/11/2014

Next review due: 04/11/2016

Ratings

How helpful is this page?

Average rating

Based on 239 ratings

All ratings

Add your rating

Comments

The 1 comments posted are personal views. Any information they give has not been checked and may not be accurate.

Januka Rai said on 31 May 2011

once when i started to skip food as i was on diet, i fainted one time in the morning at 3 or 4 am and i was unconsious, didnt know anything what was going around. I saw everything black and feel very dizzy so i got fainted. It was really horrible and i fell down on the flood but my grandad picked me up and woke me up thank god. But i culdnt open my eyes so he took me to bed and i slept. So, we must always eat healthy food to keep our flow of blood and oxygen to all parts of our body and brain. Thank you

Report this content as offensive or unsuitable

Falls

Older people are particularly at risk of falling because they often have long-term health conditions and can be unsteady on their feet

Emergency services

Read about A&E departments and other emergency services available in the NHS, such as minor injury units or emergency contraception