What is Fainting and why do people Faint?
Written by Glenn Rosenberg   
Thursday, 15 October 2009
Fainting is a temporary loss of consciousness and muscle tone. It is caused by not having enough blood flow to the brain.
What is going on in the body?

When there is not enough blood flow to the brain, passing out protects the brain from damage. People who faint generally lose muscle tone and fall to the ground. When someone is lying on the ground, the blood being pumped out of the heart doesn't have to fight gravity to get to the brain. Those who faint have a relaxed body, which uses less energy. This also makes it easier for the heart to pump blood to the brain.
What are the causes and risks of the condition?

The cause of fainting may be minor or it may be life-threatening. Often, no cause can be found. The following diseases and conditions may cause fainting:
- anemia, or a low red blood cell count
- arrhythmias, or irregular heartbeats
- carotid stenosis, which is narrowing of the arteries supplying the brain
- congestive heart failure, a condition in which a weakened heart fails to pump enough blood to body organs
- hypoglycemia, which is a low blood sugar that occurs most often in people with diabetes
- low oxygen in the blood from any cause
- orthostatic hypotension, or low blood pressure that is caused by standing up too quickly
- pulmonary embolus, which is a blood clot in the arteries supplying the lungs

Additional factors that can cause fainting are as follows:
- dehydration
- extreme fatigue
- low blood pressure as a side effect of medications for high blood pressure
- marked fear
- pain, such as an acute injury
- prolonged or severe coughing
- side effects of certain medications, such as sedatives
- straining to urinate or have a bowel movement
- stressful events

There may be other causes as well. In some cases, no cause is found.

What are the treatments for the condition?

First aid for a person who has fainted includes the following steps:
- Check for signs of circulation, such as normal breathing, coughing, or movement in response to stimulation.
- Contact the emergency medical system immediately if these signs are absent.
- Start cardiopulmonary resuscitation or CPR if the person stops breathing.

If the person has signs of circulation, he or she has probably fainted. The individual should be left on the ground and both legs should be elevated. This helps improve blood flow to the brain. The person should remain lying down for at least 10 minutes, even if he or she wakes up. After that, he or she should get up slowly and sit in a chair for a few minutes. The person should have help when trying to stand up. Someone who gets up too fast and without help may faint again.

Most of the time, no further treatment is needed for fainting. If the person faints repeatedly or has other symptoms, more treatment may be needed. Following are some of the common treatments:
- blood transfusions for anemia
- fluids for dehydration
- medications for arrhythmias
- medications to raise the blood pressure
- oxygen
- stopping medications that are causing low blood pressure

What are the side effects of the treatments?

All medications have possible side effects. These may include allergic reactions, stomach upset, and headaches. Surgery carries a risk of bleeding, infection, and allergic reactions to anesthesia. Blood transfusions may cause allergic reactions or infections.
What happens after treatment for the condition?

Those who have simple fainting usually need no further monitoring or treatment. Those who have heart disease may need ongoing treatment for many years. Most people are able to return to normal activities after treatment. Those with frequent fainting may need to avoid certain activities, such as climbing ladders or driving.