Fainting, also called syncope, is a sudden loss of consciousness. It occurs when the blood pressure drops and not enough oxygen reaches the brain. There are times when fainting may look like a seizure.2


Fainting can be caused by many things. Many patients have a medical condition they may or may not know about that affects the nervous system or heart. You may also have a condition that affects blood flow through your body and causes your blood pressure to drop when you change positions (for example, going from lying down to standing).2

Risk Factors

While some causes of unexplained fainting are harmless, others may be serious. Heart-related causes, including abnormal heart rhythms, are among the most serious causes of fainting. Also, if you do not have any warning signs before you faint, you may fall unexpectedly and be injured.


  1. Morag R, Brenner B. Syncope. Medscape. April 16, 2014. Accessed November 10, 2015. http://emedicine.medscape.com/article/811669-overview#a5
  2. Cleveland Clinic Website. https://my.clevelandclinic.org/services/heart/disorders/syncope. Accessed November 11, 2015.