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JAMA Patient Page
September 8, 2004


JAMA. 2004;292(10):1260. doi:10.1001/jama.292.10.1260

Fainting, also known by the medical term syncope, is the temporary loss of consciousness, often accompanied by falling down or a strong urge to lie down, followed by spontaneous recovery. The most common reason for fainting is a temporary decrease in blood flow to the brain. Except for the risk of physical injury from falling, fainting itself is often not a serious health problem. However, sometimes fainting can be a sign of a serious underlying disorder, so determining the cause is important. The September 8, 2004, issue of JAMA includes an article about fainting after exercise.

Causes of syncope

  • Emotional stress

  • Drop in blood pressure due to change in position or blood loss

  • Heat or dehydration

  • Arrhythmias (abnormal heart rhythms)

  • Heart abnormalities

  • An oversensitive region in an artery in the neck called the carotid artery

  • Blood clots in the lung

Common symptoms just before syncope

  • Warmth

  • Nausea

  • Field of vision either whites out or blacks out

  • Dizziness, lightheadedness

  • Sweaty palms

Diagnosing causes of syncope

A physical examination and a careful history of what happens just before and during fainting are very important in determining the cause. Individuals who faint often should be tested for abnormal heart rhythms using an electrocardiogram (ECG), a machine that records the electrical impulses of the heart. They generally should also be evaluated with an echocardiogram (ultrasound of the heart) to see if there are abnormalities in the heart muscle or valves. In some cases, other tests may be performed, such as a Holter monitor (a 24-hour recording of the heart rhythm) or a tilt test, in which blood pressure and heart rate are measured while the person is lying down on a table and again after the patient stands up or the table is tilted upright.


Treatment for fainting depends on its underlying cause. If no serious cause is found, the only interventions that may be necessary are avoiding situations that lead to fainting and protection from injury from falling. If a more serious cause is found, treatment is directed at the responsible condition.

For more information

Inform yourself

To find this and other JAMA Patient Pages, go to the Patient Page link on JAMA's Web site at http://www.jama.com. A Patient Page on electrocardiograms was published in the April 23, 2003, issue.

Sources: National Heart, Lung, and Blood Institute; National Institute of Neurological Disorders and Stroke; American Heart Association; Centers for Disease Control and Prevention

The JAMA Patient Page is a public service of JAMA. The information and recommendations appearing on this page are appropriate in most instances, but they are not a substitute for medical diagnosis. For specific information concerning your personal medical condition, JAMA suggests that you consult your physician. This page may be photocopied noncommercially by physicians and other health care professionals to share with patients. Any other print or online reproduction is subject to AMA approval. To purchase bulk reprints, call 718/946-7424.