Fainting is a loss of consciousness that happens quickly and sometimes without warning. A person is usually alert again in a short amount of time.
Fainting happens when there is a decrease in blood flow to the brain. There are many health problems that can cause fainting.
Some things that can trigger fainting are:
These health problems may also cause fainting:
Things that may increase the risk of fainting are:
Fainting is a sudden loss of consciousness that resolves in a short amount of time. Before this happens, a person may feel:
Call your doctor if you are having periods of fainting. This is important if you:
Call for emergency medical services right away if you have:
The doctor will ask about your symptoms and health history. You will also be asked what you were doing when this symptom happened. A physical exam will be done. This is often enough to make the diagnosis. More tests may need to be done. The tests that are done depend on what the doctor believes may be the cause.
If there is an underlying cause, it will need to be treated. Treatment may not be needed for a person who only fainted once.
Some underlying health problems cause people to faint. They will need to be treated.
People who feel as though they may faint can lower the risk with movements that promote blood flow to the brain, such as:
American Heart Association
Family Doctor—American Academy of Family Physicians
Brignole M, Moya A, et al. 2018 ESC Guidelines for the diagnosis and management of syncope. Eur Heart J. 2018 Jun 1;39(21):1883-1948.
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Fainting. Family Doctor—American Academy of Family Physicians website. Available at: http://familydoctor.org/familydoctor/en/diseases-conditions/fainting.html. Updated December 6, 2017. Accessed April 9, 2020.
Syncope—approach to the patient. EBSCO DynaMed website. Available at:https://www.dynamed.com/approach-to/syncope-approach-to-the-patient. Updated July 9, 2019. Accessed April 9, 2020.
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Last reviewed February 2020 by EBSCO Medical Review Board Rimas Lukas, MD Last Updated: 4/9/2020