Fainting (Syncope)

Overview

Fainting, also called syncope (sin-ko-pee), is a sudden, temporary loss of consciousness caused by a drop in blood flow to the brain. It usually happens quickly and lasts only a few seconds to a couple of minutes. You may feel lightheaded or dizzy just before fainting, and then you wake up on your own.

Yes, fainting is very common. About one in three people will faint at some point.

Fainting can affect anyone, but it is more common in teenagers and young adults, especially during emotional stress or standing for long periods. Older adults may faint due to changes in blood pressure or heart conditions.

Symptoms

Common symptoms

• Feeling lightheaded or dizzy
• Nausea or feeling queasy
• Sweating or feeling clammy
• Blurred or tunnel vision
• Hearing a ringing sound or feeling 'far away'
• Sudden weakness or a sense that you are about to pass out

Symptoms in children

• May faint during a growth spurt or after standing for a long time
• Often triggered by pain, fear, or emotional upset
• May seem pale and feel cold just before fainting

Symptoms in older adults

• May faint without warning or with only brief dizziness
• Can happen when getting up too quickly from sitting or lying down
• May be linked to certain medicines or underlying heart problems

Causes

Main causes

• Vasovagal syncope (most common) – triggered by emotional stress, pain, fear, or standing for too long
• Orthostatic hypotension – a sudden drop in blood pressure when standing up too quickly
• Heart-related syncope – due to an irregular heartbeat (arrhythmia) or heart valve problems
• Situational syncope – fainting after coughing, urinating, or having a bowel movement
• Medication side effects – some drugs can lower blood pressure or cause dehydration

Risk factors

• Being dehydrated or overheated
• Standing for long periods, especially in hot or crowded places
• Stress, anxiety, or intense emotions
• Having a heart condition, such as an arrhythmia or heart failure
• Taking medicines that affect blood pressure or blood flow
• Having low blood sugar or anaemia

When to see a doctor

See a doctor urgently if:

• If you faint and have chest pain, shortness of breath, or a very fast or irregular heartbeat
• If you faint and are pregnant or over 65
• If you faint while lying down (not just standing or sitting)
• If you have a known heart condition

Book a routine appointment if:

• If you faint for no clear reason or it happens more than once
• If you feel dizzy or lightheaded often but haven't actually fainted
• If you are worried about your fainting episodes

Diagnosis

Your doctor will ask about what happened before, during, and after the faint. They will also review your medical history and perform a physical exam, including checking your blood pressure lying down and standing up.

Tests that may be done

• Electrocardiogram (ECG) – to check your heart's rhythm
• Blood pressure monitoring – supine and standing measurements
• Blood tests – to check for anaemia, dehydration, or other issues
• Tilt table test – where you are strapped to a table that tilts to see how your body responds to position changes
• Holter monitor – a portable ECG worn for 24 hours or longer to capture heart activity during daily life

What to expect at your appointment

Your doctor will try to find out what triggered the faint. In many cases, no serious cause is found, and you will be reassured. If a heart problem is suspected, you may be referred to a cardiologist for further testing.

Treatment

Treatment for fainting depends on the cause. Often, simple lifestyle changes and avoiding triggers are enough. If a heart condition is found, your doctor will treat that underlying issue.

Self-care at home

• When you feel faint, lie down with your legs raised above your heart level, or sit and put your head between your knees.
• Stay hydrated by drinking plenty of water throughout the day.
• Avoid standing for long periods – take breaks and move around.
• If you feel dizzy when standing up, get up slowly.
• Learn your personal triggers (like stress, heat, or hunger) and try to avoid them.

Medical treatments

If fainting is due to a heart rhythm problem, treatment may include medicines to control the heart rate or rhythm. In some cases, a device like a pacemaker might be recommended. Your doctor will discuss the best options for your situation. For vasovagal syncope, medicines or salt tablets may sometimes be used to help maintain blood pressure.

When is surgery considered?

Surgery is rarely needed for fainting itself. If the cause is a heart valve problem or a structural heart issue, surgery on the heart may be necessary, but this is uncommon.

Living with this condition

Most people who faint occasionally can live a normal life. Pay attention to your body's warning signs and act quickly when you feel faint. Keep a note of your fainting episodes – what you were doing, how you felt, and how long it lasted – to share with your doctor.

Lifestyle tips

• Drink enough water to keep your urine pale yellow.
• Eat regular meals to avoid low blood sugar.
• If you drink alcohol, do so in moderation and with food.
• Avoid hot baths or saunas if you are prone to fainting.
• If you have a job that involves standing or driving, talk to your doctor about safety precautions.

Diet and exercise

A balanced diet with enough salt (unless you have high blood pressure) can help maintain blood pressure. Regular, moderate exercise can improve circulation and reduce the risk of fainting. Ask your doctor about exercises that are safe for you.

Mental health and emotional wellbeing

Fainting can be frightening and may cause anxiety about having another episode. It is normal to feel worried, but try not to let it stop you from doing your usual activities. If anxiety is affecting your life, speak to your doctor or a mental health professional.

Prevention

You can reduce your risk of fainting by avoiding your triggers. For most people, staying hydrated, moving slowly, and managing stress are effective. If you have a heart condition, following your treatment plan is important.

Complications

If left untreated

• Injury from falling (such as fractures or head trauma)
• If fainting is due to an undiagnosed heart problem, untreated it could lead to more serious events such as a serious arrhythmia or cardiac arrest

Long-term outlook

For most people, fainting is a one-time event or a rare occurrence that does not cause long-term problems. When the cause is found and treated properly, the outlook is excellent. Even when fainting is linked to a heart condition, modern treatments are very effective at managing it and allowing you to lead a full, active life.

Find support

International organisations

• British Heart Foundation ↗
• American Heart Association ↗

Local organisations

• NHS – Fainting information ↗ · UK

Helplines

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