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What is Fainting?

Tricia Christensen
Tricia Christensen
Tricia Christensen
Tricia Christensen

Fainting is a generally brief and unexpected loss of consciousness that may be caused by a variety of factors. Sometimes loss of consciousness does not indicate severe problems, and other times it may suggest certain dangerous physiological factors.

Often people describe initial fainting symptoms as feeling hot, possibly hearing a rushing sound, feeling dizzy, and seeing spots. These symptoms if quickly addressed may help a person remain conscious. Usually it is recommended that people lie on the floor with the feet elevated slightly.

Emotional stress may cause fainting.
Emotional stress may cause fainting.

In some cases, fainting simply occurs too quickly to stop. Before a person knows it, they may simply wake up on the floor a few seconds after having lost consciousness. This can be disorienting, since the person’s memory of how they got on the floor may be affected and it may be hard to understand what just happened.

There are many causes of fainting, which makes identifying cause difficult at times. Some common causes are extreme emotional stress, too little food or drink resulting in low blood sugar or dehydration, normally low blood pressure, excessive physical activity, straining with a bowel movement then standing up quickly, or simply standing up too quickly. Medical causes may include arrhythmias, heart attack, stroke, severe injury, or conditions like narrowing of the aortic valve.

Not consuming enough food may cause fainting.
Not consuming enough food may cause fainting.

Fainting is broken into several groups often defined by cause, and is often called “syncope.” Vasovagal syncope tends to occur when blood pressure or heart rate lower significantly. Some people tend to have vasovagal reactions to stress, as from seeing blood, getting hurt, or seeing someone else get hurt. This type of episode, when vasovagal syndrome is known, is usually not dangerous.

Excessive physical activity may cause fainting.
Excessive physical activity may cause fainting.

Pressure, externally on the nerves surrounding the carotid arteries can lead to carotid sinus syncope. Some people have very sensitive nerve endings around their carotid arteries, which may cause even a small amount of pressure to result in a loss of consciousness.

In some cases, fainting can occur directly after using the bathroom. When the condition occurs after someone urinates it is called micturition syncope. Other forms have been linked to excessive coughing, or even excessive laughing. In most of these cases, the blood pressure quickly and momentarily drops, causing loss of consciousness.

Drinking water can help prevent fainting from dehydration.
Drinking water can help prevent fainting from dehydration.

Sometimes fainting can indicate a serious condition like stroke or heart attack. If consciousness is not restored in a few seconds, then one should alert a physician immediately. This is particularly the case if the person has seemed unduly upset prior to the loss of consciousness, is elderly, or has a known cardiac condition.

Tricia Christensen
Tricia Christensen

Tricia has a Literature degree from Sonoma State University and has been a frequent WiseGEEK contributor for many years. She is especially passionate about reading and writing, although her other interests include medicine, art, film, history, politics, ethics, and religion. Tricia lives in Northern California and is currently working on her first novel.

Learn more...
Tricia Christensen
Tricia Christensen

Tricia has a Literature degree from Sonoma State University and has been a frequent WiseGEEK contributor for many years. She is especially passionate about reading and writing, although her other interests include medicine, art, film, history, politics, ethics, and religion. Tricia lives in Northern California and is currently working on her first novel.

Learn more...

Discussion Comments

anon6027

Can you faint because of locking your knees while standing for an extensive period of time? Does this decrease blood flow to the brain enough to cause a person to faint?

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    • Emotional stress may cause fainting.
      By: chatmali
      Emotional stress may cause fainting.
    • Not consuming enough food may cause fainting.
      By: photophonie
      Not consuming enough food may cause fainting.
    • Excessive physical activity may cause fainting.
      By: Igor Mojzes
      Excessive physical activity may cause fainting.
    • Drinking water can help prevent fainting from dehydration.
      By: Aaron Amat
      Drinking water can help prevent fainting from dehydration.
    • Low blood pressure may can fainting to occur.
      By: Jürgen Fälchle
      Low blood pressure may can fainting to occur.
    • Fainting can result from feeling too crowded.
      By: Ints Vikmanis
      Fainting can result from feeling too crowded.
    • Grief might cause fainting.
      By: Lisa F. Young
      Grief might cause fainting.
    • Excessive stress can cause fatigue and fainting.
      By: Ambrose
      Excessive stress can cause fatigue and fainting.
    • Excessive exercise without proper nutrition can cause fainting.
      By: Helder Almeida
      Excessive exercise without proper nutrition can cause fainting.