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Fainting Facts: Understanding the Causes, Symptoms and Treatments

Fainting Facts

Anyone who’s ever fainted knows how alarming it can be to suddenly pass out. Luckily, fainting – the medical term for which is syncope – is nearly always harmless, though some people are more prone to it than others.

Fainting is a brief loss of consciousness followed by a quick recovery. It’s difficult to put a precise figure on how many people have been affected by fainting, as most don’t get any medical help for it if it happens just the once or very occasionally. However, it’s common at all ages and affects up to four in 10 people at least once in their lives (i).

What happens when you faint?

Your brain needs oxygen delivered in the blood to function properly. But if you have a sudden drop in blood pressure or heart rate, your blood vessels dilate and your blood pools in your extremities. This can be a result of a temporary problem with the part of your nervous system that regulates your body’s automatic functions (the autonomic nervous system).

However, it also means there’s less blood flowing to your brain. And when your brain doesn’t get the oxygen-rich blood it needs – even for a brief period – it can make you lose consciousness.

Though in many cases the cause of fainting isn’t clear there are several things that can make your autonomic nervous system stop working properly temporarily, including:

  • Pain

  • Emotional stress

  • Seeing something unpleasant or frightening

  • Heat

  • Standing for too long

  • Laughing

  • Coughing

  • Sneezing

  • Straining during a bowel movement

  • Physical exertion (especially in hot temperatures)

  • Taking drugs or drinking alcohol

  • Taking certain types of medication (blood pressure drugs, for instance)

  • Drinking too much caffeine

  • Not drinking enough water (dehydration)

Some people get warnings before they faint. You may, for instance, start to feel dizzy, light-headed and nauseated, and you could break out in a sudden cold, clammy sweat and turn pale. Some also find they can’t stop yawning before a faint, or that their breathing becomes faster and deeper.

Other possible warning signs include confusion, ringing in your ears and blurred vision (or spots in front of your eyes).

Conditions that can cause fainting

Fainting isn’t usually a sign of anything serious if you have your first fainting spell before you reach the age of 40 (i). Indeed, the most common type of faint – called a neurally mediated syncope – usually happens for the first time during the teenage years, affecting more girls than boys.

If you faint for the first time after 40, however, it’s more likely to be caused by an underlying health problem. Recurring fainting spells – at any age – can also be a sign that something’s not quite right.

Here are some of the conditions that can make you faint:

Panic attacks

Panic attacks are very common and are often a symptom of anxiety. They can cause a range of symptoms, including the feeling that you’re going to faint. This may happen because in a panic attack you start breathing faster or more deeply than normal (in other words, you start to hyperventilate). Hyperventilating means you take in too much oxygen and get rid of too much carbon dioxide too quickly. But when your blood levels of carbon dioxide become too low the blood vessels that supply the brain become constricted, and not enough blood gets to the brain.

Low blood pressure

Abnormally low blood pressure – or hypotension – can cause dizziness and fainting, especially when it drops suddenly (as a result of shock, for instance). Some people are also affected by low blood pressure when they stand up from a sitting position or after lying down. This is called orthostatic hypotension or postural hypotension, and it’s more common in older people and those who’ve been confined to bed for a long time because of an illness.

There are several things that can cause orthostatic hypotension, one of which is dehydration. Being dehydrated means you have less fluid in your blood, and that makes your blood pressure lower. Uncontrolled diabetes can also lead to dehydration as it can make you urinate frequently, which can leave your blood fluid levels too low.

Some types of medication – such as medicines for high blood pressure and depression – can trigger orthostatic hypotension too, as can certain neurological conditions such as Parkinson’s disease. Discover more on how to maintain a healthy blood pressure in our guide.


Red blood cells and haemoglobin are essential parts of the blood because they transport oxygen from your lungs to all the other parts of your body. But if you have anaemia you’ll have fewer red blood cells or less haemoglobin than normal, which means your brain may not be getting the amount of oxygen it needs (ii).

Heart problems

Having a heart condition may also interrupt the supply of blood to your brain, causing a type of fainting called cardiac syncope. For instance, a condition called arrhythmia – which is when you have an abnormal heart rhythm – can make you feel faint as well as cause dizziness, breathlessness and chest pain.

A slow heart rate can also make you feel woozy because your brain isn’t getting enough blood – this can happen when your heart beats fewer than 40 beats per minute. However, this is a rare condition and is often treated by having a pacemaker fitted.

Other heart and blood vessel problems that can affect blood flow to the brain include problems with the sinus node – an area of your heart that helps it to beat – a blood clot in the lungs, a problem with the electrical impulses that control your heart muscle (heart block), structural problems with the muscles of the heart (cardiomyopathy), and having narrowed or blocked blood vessels to the heart (coronary heart disease).

Reflex anoxic seizures

This is a type of fainting that mostly affects young children. It happens when the heart stops beating for up to 30 seconds. While reflex anoxic seizures can be very alarming, according to the NHS they aren’t dangerous (iii), and affected children usually grow out of them by the time they reach their fifth birthday.

Chronic lung disease

People with lung conditions such as chronic obstructive pulmonary disease (COPD) may also experience feelings of dizziness and fainting due to low blood oxygen levels caused by poor breathing.

Should you see your GP?

Most cases of fainting aren’t harmful, but a few can be more serious. See your GP if you’ve fainted and…

  • You’ve never fainted before (especially if you’re 40 or older)

  • You faint frequently

  • You have diabetes

  • You’re pregnant

  • You have heart disease

  • You had chest pains or a fast or irregular heartbeat before you fainted

  • You took longer than a few minutes to come around after fainting

  • You hurt yourself when you fell over


What to do if you feel faint

If you’ve fainted before you may recognise the warning signs that it might happen again. Here’s what to do if you feel you’re going to faint:

  1. Sit down straight away. Then if possible lie down and raise your feet above the level of your heart with some pillows or some clothing. This helps get your blood flowing to your heart, and then your brain. If you feel nauseated, turn onto your side in case you vomit.

  2. If it’s impossible to lie down, try to put your head between your knees, as this may help increase the blood flow to your brain.

  3. If you do faint, don’t get up as soon as you come around. Try to stay lying down for at least 10 minutes, and when you get up, do so very slowly.


There are also things you can do whenever you’re in situations that have led to you fainting in the past. For instance, if standing for too long makes you feel faint, try moving up onto your toes and back down again. This keeps your leg muscles working and sending blood back up to your heart.

Another good tip is to tense your major muscles – the legs, abdomen and buttocks, for instance – if you think you’re starting to feel faint. Called a physical counterpressure manoeuvre, this can stop you from fainting by increasing your blood pressure temporarily.

If being in a hot or crowded environment tends to make you feel faint, try to avoid it if at all possible. If you can’t avoid it, try wearing compression stockings, as they can help prevent blood pooling in your legs.

Having something salty to eat or drink such as a couple of crackers or a sports drink could also help you feel better, as the salt will raise your blood pressure briefly and make a sudden drop less likely.

It’s also a good idea to drink plenty of fluids to prevent dehydration. This is particularly important whenever the weather’s hot, when you’ve been exercising of if you’ve had a bout of diarrhoea or vomiting.

Breathing deeply may also be helpful: breathe in for a count of four through the nose, then breathe out for a count of eight through the mouth.

How to help someone who feels faint

Even if you’re not affected by fainting yourself it may be useful to know what you should do if someone else feels they’re about to pass out. St John Ambulance advises the following (iv):

  • If someone’s feeling faint, tell them to lie down.

  • Kneel down next to them and raise their legs, supporting their ankles on your shoulders to help blood flow back to the brain. Watch their face for signs that they’re recovering.

  • Make sure they have plenty of fresh air – ask bystanders to move away and give them room, and if you’re inside ask someone to open a window.

  • Reassure them and help them to sit up slowly when they’re ready.

If someone around you has already fainted and is lying on the floor, try to position them on their back. Check their airways and if they’re breathing normally try to raise their legs above heart level while loosening any constrictive clothing such as collars or belts. Make sure they don’t get up again too quickly when they come around, or they could faint again (encourage them to wait for at least 10 minutes before getting up). If possible, give them something cool to drink.

However, if someone faints and isn’t breathing, call 999 for an ambulance immediately.

Natural support for fainting

Years ago, people used smelling salts to bring someone who fainted back to consciousness. You can still buy smelling salts, but you could also use an open bottle of lavender, rosemary or peppermint essential oil, placing it under their nose. Smelling one of these essential oils could also be helpful if you start feeling faint.

Acupressure practitioners recommend applying pressure to a point called governor vessel 26 (GV26) to revive someone who has fainted or to stop a faint before it happens. Find it in the middle of the two ridges that run between the nose and the lips, about half way up, and press with your little finger.

Taking a tummy-friendly iron supplement may be useful for those who faint or feel lightheaded because they have iron-deficiency anaemia, with studies confirming that some people who faint may be low in iron (vi). You could also try eating more iron-rich foods, such as red meat, seaweed, pumpkin seeds, spinach and other green vegetables.

Meanwhile, if you’re low in iron there’s a chance your diet may be lacking one or more other essential nutrients. Taking a good-quality multivitamin and mineral supplement may be an effective insurance policy, especially if your diet isn’t always as healthy as it should be.

While experiencing frequent fainting can be disruptive to everyday life, these simple steps should help to make it a little easier.  For more advice on how to support your body through a range of health conditions, visit our health library.

Disclaimer: The information presented by Nature's Best is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. Self-treatment is not recommended for life-threatening conditions that require medical treatment under a doctor's care. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications.



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  6. , , Low iron storage in children and adolescents with neurally mediated syncope. J Pediatr. ;153(1):40-4. Available online:

  7. , Reduced Iron Stores and Its Effect on Vasovagal Syncope (Simple Faint). J Pediatr. ;153(1):9-11.Available online:


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Our Author - Christine Morgan


Christine Morgan has been a freelance health and wellbeing journalist for almost 20 years, having written for numerous publications including the Daily Mirror, S Magazine, Top Sante, Healthy, Woman & Home, Zest, Allergy, Healthy Times and Pregnancy & Birth; she has also edited several titles such as Women’ Health, Shine’s Real Health & Beauty and All About Health.

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