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Fainting Symptoms

Signs and Symptoms of Fainting Before, During and After

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Updated April 08, 2014

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

Fainting (syncope) is a sudden loss of consciousness from a lack of blood flow to the brain. Victims usually wake up quickly after collapsing. Although fainting is defined as a sudden loss of consciousness, the moments leading up to actually passing out will probably have several signs and symptoms that the victim is about to faint.

Signs and Symptoms that You're About to Faint

Before fainting, a victim can exhibit or feel all or some of these signs and symptoms, depending on the cause of the fainting:

In cases of fainting caused by stimulation of the vagus nerve (the most common type of fainting), victims might have cramps or an urge to have a bowel movement right before they pass out.

How Fainting Looks

In cartoons, fainting is always done by falling over stiff as a board and landing either flat on your face or back. In movies, the classic melodramatic faint was with a gasp, a hand to the forehead and collapsing into the arms of the nearest male heartthrob.

In real life, fainting ranges from subtle to violent. As the brain stops getting enough blood flow to stay conscious, it stops sending out signals to the muscle cells. The muscles lose their tone and the body just collapses into whatever heap gravity pulls it to.

Occasionally, that sudden exit of blood from the brain leads to a little nervous impulse -- kind of like static through a phone line. It may result in a bit of a tremble or shake. Sometimes it looks like a shudder; sometimes it looks like a seizure (albeit very short). When I was growing up I lived in the country where we had telephone lines strung across poles at the sides of the roads. When a car would hit a pole and knock the lines down, the phone would sometimes ring -- just for a second. It's very similar in the nervous system.

Ever felt an involuntary jerk in your arms or legs just as you fall asleep? That is called a myoclonic contraction, and it's exactly the same type of twitch some fainting victims get.

While a myoclonic contraction is not a seizure, true seizures can also cause a sudden loss of consciousness. However, the symptoms of a seizure are different. So is the treatment of seizures.

Symptoms After Fainting

Once you go from vertical to horizontal, blood starts flowing back into the brain and you begin to wake up. It can be quick or it can take a while; everybody's different.

Here are some of the more common symptoms that can occur after fainting:

  • Sweating stops
  • Color begins to return
  • Rapid pulse or "racing heart"
  • Loss of bowel or bladder control (incontinence)

Fainting Overview

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