Fainting is a brief loss of consciousness that usually happens because blood flow to the brain temporarily falls.
Many fainting episodes are not caused by a serious medical problem, but a collapse should never simply be ignored. A person may faint because they are too hot, dehydrated, hungry, in pain or emotionally distressed, but fainting can also be associated with low blood pressure, heart problems, diabetes, seizures or other medical conditions.
This guide explains how to recognise fainting, what to do if someone feels faint, how to respond if they lose consciousness, when to call 999 and when further medical assessment is needed.
Fainting, sometimes called syncope, is a temporary loss of consciousness caused by a short reduction in blood flow to the brain.
A typical faint is brief. The person may feel unwell beforehand, collapse, then regain consciousness within a short period.
According to NHS guidance, someone who has fainted will usually wake within around 30 seconds. If they cannot be woken within one minute, this should be treated as an emergency.
There are many possible causes of fainting.
Common triggers can include:
Sometimes the reason is obvious, but fainting can also happen without a clear trigger. NHS guidance advises seeing a GP after a faint so the possible cause can be assessed.
A person may have warning symptoms shortly before losing consciousness.
These can include:
If someone recognises these symptoms early, helping them into a safe position may prevent a fall and reduce the risk of injury.
If someone says they feel as though they are about to faint, act before they collapse.
NHS guidance recommends:
If they are standing and cannot immediately lie down, crossing the legs, rocking on the toes or clenching the fists may also help while a safer position is found.
| Step | What to do | Why it matters |
|---|---|---|
| 1. Make sure the area is safe | Check for traffic, machinery, electricity, sharp objects or another hazard before approaching. | The casualty may have collapsed because of an environmental danger, and you should not become another casualty. |
| 2. Check responsiveness | Speak loudly, ask if they are OK and gently shake their shoulders. | This helps determine whether they are responding normally. |
| 3. Check breathing | If they do not respond, open the airway and check whether they are breathing normally. | An unresponsive person who is not breathing normally may be in cardiac arrest rather than simply fainting. |
| 4. If breathing normally, lie them flat | Place them on their back and raise their legs if appropriate. | This can help improve blood flow back towards the brain. |
| 5. Monitor recovery | Stay with them and watch their breathing and level of response. | A normal faint should usually resolve quickly. |
| 6. Help them sit up slowly | Once fully recovered, allow them to sit up gradually rather than standing immediately. | Standing too quickly can cause another faint. |
A typical faint should be brief.
NHS guidance says the person will usually wake within around 30 seconds.
Call 999 or 112 if they cannot be woken within one minute.
Do not continue assuming that prolonged unconsciousness is simply a faint. There may be another medical emergency.
Call 999 or 112 if the person:
These situations can indicate something more serious than an ordinary faint and require urgent medical assessment.
For more help deciding which NHS service is appropriate, see our When to Call 999 vs 111 vs GP guide.
If someone has collapsed, is unresponsive and is not breathing normally, do not treat the situation as an ordinary faint.
Call 999 or 112 immediately, obtain an AED if one is available and begin CPR.
Occasional irregular gasps are not normal breathing and can occur during cardiac arrest.
See our CPR Explained for Adults, Children & Babies and AED & Defibrillators Explained guides for further information.
If a person remains unresponsive but is breathing normally, their airway must be protected while emergency help is arranged.
Call 999 if they have not recovered promptly.
Where appropriate, place them in the recovery position and continue monitoring their breathing.
See our Recovery Position Explained guide for step-by-step information.
Yes, where appropriate.
NHS and St John Ambulance guidance both recommend lying a person who has fainted on their back and raising their legs.
This can help blood return towards the brain.
However, do not force the legs into this position if:
The casualty's safety and any injuries caused by the fall should also be considered.
Pregnancy changes how someone who feels faint should be positioned.
NHS guidance says that if a person who has fainted is pregnant, especially if they are more than 28 weeks pregnant, it is better to place them on their side rather than flat on their back.
This is because the weight of the uterus can reduce blood return to the heart when lying flat later in pregnancy.
If the person does not recover quickly, has abdominal pain, bleeding or another concerning symptom, seek urgent medical advice.
Do not give food or drink while someone is unconscious or not fully alert.
Once they have completely recovered, are sitting safely and can swallow normally, drinking some water may be appropriate, particularly if heat or dehydration contributed to the faint.
If low blood glucose is suspected in someone with diabetes, the situation should be managed according to their usual hypo plan once they are conscious and able to swallow safely.
See our First Aid for Diabetic Emergencies guide for further information.
No.
Allow the person to recover gradually.
Once they are fully responsive:
Standing too quickly can cause another drop in blood pressure and a second collapse.
Fainting is one possible cause of temporary unconsciousness, but not every unconscious person has fainted.
| Typical faint | Potentially more serious unconsciousness |
|---|---|
| Usually lasts only a short time. | May continue beyond one minute or worsen. |
| The person normally recovers fully. | The person may remain confused, drowsy or unable to respond normally. |
| May follow heat, standing, hunger, dehydration, pain or emotional stress. | May be caused by head injury, seizure, stroke, cardiac arrest, poisoning or another emergency. |
| Normal breathing is present. | Breathing may be abnormal or absent in a life-threatening emergency. |
If you are unsure why someone is unconscious, assess their response, airway and breathing rather than assuming they have simply fainted.
See our First Aid for an Unconscious Person guide for more information.
A seizure and a faint can sometimes be confused, particularly because brief movements may occasionally occur around a collapse.
A seizure may involve:
NHS guidance advises calling 999 if someone faints and is shaking or jerking as though having a seizure.
Do not restrain someone who is having a seizure and do not put anything in their mouth.
See our First Aid for Seizures guide for detailed information.
Fainting and medical shock are different conditions.
A simple faint happens because blood flow to the brain temporarily falls and the person usually recovers quickly.
Medical shock is a life-threatening failure of circulation caused by serious injury or illness and does not normally resolve simply because the person lies down.
Shock may follow:
See our First Aid for Shock guide for the important differences.
Low blood glucose can cause dizziness, weakness, confusion and eventually loss of consciousness, particularly in someone who has diabetes.
A diabetic emergency should not automatically be described as an ordinary faint.
Look for clues such as:
If the person is fully conscious and able to swallow safely, help them follow their usual hypo treatment plan.
If they become unconscious, give nothing by mouth and call 999.
Yes.
Hot environments can contribute to fainting, particularly when combined with dehydration or prolonged standing.
A person who feels faint because of heat should be moved to a cooler environment where possible and allowed to rest.
However, fainting can also occur with more serious heat illness.
If the person is confused, has very hot skin, has a seizure or does not recover normally, consider heatstroke and call 999.
See our First Aid for Heat Exhaustion & Heatstroke guide for further information.
Fainting associated with chest pain or an abnormal heartbeat can indicate a potentially serious heart problem.
Call 999 if someone faints and has:
See our First Aid for Chest Pain & Suspected Heart Attack guide.
Fainting during exercise is different from feeling faint after standing in a hot room or missing a meal.
NHS guidance specifically says to call 999 if someone faints while exercising.
This is because collapse during physical exertion can sometimes be associated with a serious heart or circulation problem.
Stop the activity, assess responsiveness and breathing, and seek emergency help.
A typical vasovagal faint often happens while someone is standing or after they change position.
Fainting while already lying down is less typical.
NHS guidance therefore lists fainting while lying down as a reason to call 999.
Do not simply wait for repeated episodes to happen before seeking help.
The collapse itself can cause injury, particularly if someone falls onto a hard floor, furniture or another object.
After a faint, check for:
NHS guidance advises calling 999 if someone seriously injured themselves before or after fainting.
For further guidance, see our First Aid for Minor Head Injuries and First Aid for Fractures & Dislocations guides.
Yes.
NHS guidance recommends seeing a GP if you have fainted.
Most fainting episodes are not caused by something serious, but medical assessment can help identify why the episode happened and whether further tests are necessary.
Repeated fainting should not simply be accepted as normal.
Repeated fainting can affect driving safety.
NHS guidance says that people who faint regularly may need to tell the Driver and Vehicle Licensing Agency (DVLA), depending on the circumstances.
You must not drive if your GP has referred you to a specialist and you are waiting for assessment where the relevant driving restrictions apply.
For individual driving requirements, check current GOV.UK and DVLA guidance.
Someone can faint in any workplace, but the consequences vary depending on where the collapse happens.
A faint beside an office desk may cause a minor fall. The same event while:
can create additional risks.
Workplace first aiders should therefore make the area safe, assess the casualty and consider injuries caused by the collapse as well as the faint itself.
Children and teenagers can faint, particularly because of heat, dehydration, prolonged standing, pain or emotional stress.
The same basic first aid principles apply:
Call 999 if the child cannot be woken within one minute, has abnormal breathing, has a seizure, is seriously injured or has other emergency warning signs.
Common mistakes include:
Fainting itself usually does not require equipment from a first aid kit.
The most important actions are correct positioning, monitoring and recognising when emergency help is needed.
A first aid kit may still be useful if the person has injured themselves during the fall, for example by sustaining a cut or graze.
You can view our range of first aid kits for home, workplace, travel and general emergency preparedness.
| Situation | What to do |
|---|---|
| Feels faint | Help them lie down with their legs raised. If this is not possible, sit them down with their head lowered. |
| Has fainted but is breathing normally | Lie them on their back, raise the legs where appropriate and monitor recovery. |
| Pregnant | Especially after 28 weeks, position them on their side rather than flat on their back. |
| Not awake within 1 minute | Call 999. |
| Not breathing normally | Call 999, obtain an AED and begin CPR. |
| Chest pain, palpitations, seizure or serious injury | Call 999. |
| Fainted during exercise or while lying down | Call 999. |
| Recovered normally | Help them sit up slowly and arrange GP assessment to establish the possible cause. |
The NHS provides current guidance on the causes and symptoms of fainting, what to do if someone feels faint or has collapsed, and when emergency medical help is required.
You can read the NHS guidance on fainting. St John Ambulance also provides clinically reviewed first aid guidance for fainting.
Explore our most popular first aid kits for home, car, travel, family trips, camping, workplace and everyday emergencies.
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