What Are the Causes of Syncope or Fainting?

By Max. D Gray. Updated: January 24, 2017
What Are the Causes of Syncope or Fainting?

Fainting, syncope or blacking out involves a sudden and temporary loss of consciousness and body movements that can happen at any time. It occurs when the brain is not getting enough oxygen which results in a sense of dizziness and weakness that, subsequently, leads to a partial or total loss of awareness.

So that you know what are the common causes of fainting and to help you identify when someone is at a greater risk of having a blackout, in the following oneHOWTO article you will find out what are the causes of syncope or fainting.

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Fainting occurs when your blood pressure is too low and therefore unable to carry sufficient oxygen to the brain to keep it in full awareness. Losing consciousness can be partial or total, but normally recovery is fast. The person who has fainted returns to back to their normal state within a few minutes.


One of the common cause of fainting is hypoglycemia, commonly called sugar drop. This condition is much more common in diabetics; if they do not control the concentration of sugar in their blood or take too high a dose of their treatment, it can cause them to pass out at any time.

Hypoglycemia can have different symptoms, from partial loss of consciousness to full syncope, but also sweating and shaking. It is very important to know how to prevent hypoglycemia to avoid fainting and the related risks of falling and passing out.


People who have anemia suffer from having a low red blood cell count, which can lead to not enough blood flow reaching the brain. Anemia is therefore one of the main causes of syncope or fainting.

You are also more likely to faint after losing a major amount of blood, for example, due to surgery, injuries or very heavy periods.


Another possible cause of syncope or fainting is from a lack of nutrients, dehydration or sudden changes in blood pressure. Often we experience these problems simultaneously, especially people who suffer from food disorders such as anorexia or bulimia, and that is why fainting is a very frequent occurrence for these people.


During pregnancy, the body experiences a series of changes which may also affect the circulatory system, often causing a drop in blood pressure. For this reason, pregnant people may suffer from blackouts - among other problems - which are preventable by staying well hydrated and avoiding sudden movements such as getting out of bed too quickly.


In addition to those mentioned above, other common causes of syncope or fainting are as follows:

  • Being stuck in a small space in extreme heat, with little ventilation or with too many people.
  • Strong emotions strong and intense overexcitement can lead to a blackout.
  • Extreme pain may cause you to pass out.
  • The fears produced by phobias could also cause you to faint.

This article is merely informative, oneHOWTO does not have the authority to prescribe any medical treatments or create a diagnosis. We invite you to visit your doctor if you have any type of condition or pain.

If you want to read similar articles to What Are the Causes of Syncope or Fainting?, we recommend you visit our Diseases & secondary effects category.

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What Are the Causes of Syncope or Fainting?
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