Syncope fainting or passing out (1652)

Key points below

Fainting or passing out

What is syncope?

Syncope is better known as fainting or passing out. It is a loss of consciousness and muscle tone. Syncope is caused by a sudden decrease in blood flow to the head. It is often triggered by growth spurts and puberty. Most children stop fainting as they get older.

What are the symptoms?

Children who faint often feel dizzy or lightheaded. They may have a spinning feeling called vertigo. Many children:

What are the causes?

Neurocardiogenic (or Vasovagal) syncope. This is the most common cause of fainting in a child. It is not harmful. 

Your child may faint when the heart rate slows down or the blood vessels enlarge. This type can be caused by:

Orthostatic hypotension. This is another common cause of fainting. It is not harmful. Blood collects in the legs and causes low blood pressure, which slows down blood flow to the head. It usually happens when a child:

Heart problems. This is not common. It can be caused by an abnormal heart rhythm or a problem with the heart’s structure. 
Other causes of syncope are head injuries, seizures, pain, breath holding, and low blood sugar.

How is it diagnosed?

The healthcare provider will do an exam. You and your child will be asked about symptoms. These details are important to help find the cause. Other tests that may be done include:

How can fainting be prevented?

If your child feels dizzy:

Have your child:


Call your child’s doctor, nurse, or clinic if you have any questions or concerns or if your child:

  • Faints during exercise or with activity.
  • Has special health care needs that were not covered in this sheet.