General
Feeling faint
Feeling light-headed and as though you might pass out, or briefly losing consciousness.
Education and reference only. This explains the common causes of feeling faint and the warning signs that need urgent help, in plain language — it is not a diagnosis or a substitute for advice from a clinician. If you feel very unwell or are worried, seek medical help.
Quick answer
What is feeling faint?
Feeling faint means feeling light-headed, woozy or as though you are about to pass out, and a faint or blackout is a brief loss of consciousness from which you quickly recover. The most common cause is a temporary drop in blood reaching the brain, for example on standing quickly, after a fright, or when too hot.
- Get urgent help: Fainting during exercise or while lying down, or with chest pain or palpitations – a possible heart cause needing urgent assessment. Fainting with a slow recovery, confusion, or a fit.
- Self-care: If you feel faint, sit or lie down straight away and, if you can, raise your legs to help blood return to your brain; this often stops a faint coming on.
About feeling faint
Feeling faint means feeling light-headed, woozy or as though you are about to pass out, and a faint or blackout is a brief loss of consciousness from which you quickly recover. The most common cause is a temporary drop in blood reaching the brain, for example on standing quickly, after a fright, or when too hot. Most faints are harmless. Some patterns, though, point to a heart or other cause that needs assessment, particularly fainting during exercise, while lying down, or with chest pain or palpitations. Noting what you were doing, any warning symptoms, and how quickly you recovered helps tell a simple faint from one that needs checking.
When to get help
Call 999 or go to A&E if feeling faint comes with any of these warning signs:
- Fainting during exercise or while lying down, or with chest pain or palpitations – a possible heart cause needing urgent assessment.
- Fainting with a slow recovery, confusion, or a fit.
- A faint that follows a head injury.
- Fainting in pregnancy.
When to see a doctor
See a doctor if you faint for the first time, faint more than once, or feel faint often without an obvious reason such as standing up too quickly. It is important to be assessed if fainting comes with palpitations, breathlessness or chest discomfort, or if there is a family history of heart problems or sudden death. Persistent light-headedness that affects your daily life, or that comes with tiredness and looking pale, is also worth getting checked.
Not sure how urgent it is? It is always OK to call NHS 111 for advice, day or night.
What can cause it
Common causes of feeling faint
Feeling faint has many possible causes. Each links to a full, plain-language guide to that condition — what it is, how it's treated and when to seek help.
What helps
Self-care and what you can do
If you feel faint, sit or lie down straight away and, if you can, raise your legs to help blood return to your brain; this often stops a faint coming on. Stand up slowly, especially after lying or sitting, and keep well hydrated, particularly in hot weather. Eating regularly and not skipping meals helps avoid light-headedness, and learning your own warning signs, such as feeling hot, sweaty or seeing spots, lets you act early. If you have fainted, let yourself recover fully before getting up, and avoid driving or operating machinery until you know the cause.
Answers
Feeling faint: frequently asked questions
When does fainting need urgent assessment?
See someone urgently if you faint during exercise or while lying down, or alongside chest pain or palpitations, as these can point to a heart cause. Fainting with slow recovery, confusion, a fit, after a head injury, or in pregnancy also needs prompt medical attention.
Why do people faint?
Most faints happen because of a brief drop in blood reaching the brain, for example on standing quickly, after a fright, or when too hot. These simple faints are usually harmless, but fainting linked to the heart or that happens repeatedly should be checked.
What should I do if I feel like I am going to faint?
Sit or lie down straight away and raise your legs if you can, which helps blood return to your brain and may stop the faint. Stand up slowly afterwards, stay hydrated, and recover fully before getting up or driving.
Can anaemia make me feel faint?
Yes. With too few healthy red blood cells, less oxygen reaches the brain, which can cause dizziness, faintness, tiredness and looking pale. If you have these symptoms, a clinician can check for anaemia and look into the cause.
Sources
Where this is drawn from
- NICE CKS: Blackouts and syncope.
- British Heart Foundation.
Related symptoms
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