What happens when you faint?

What happens when you faint? - You were watching the news on CNN recently, when the anchor Poppy Harlow collapsed during a live? She spoke in a graphic on the screen at the time, over a period of 10 seconds or more, his speech was halting and paste - and then there was silence.

With the schema in the approval rate of President Obama is on the screen, the issue moved to a commercial.

After a brief stuffed CNN colleague, Ms. Harlow, who is pregnant, has reappeared and assured his audience that was fine.

She explained that she was a little hot, fainted briefly, and now it felt good. She closed the show and quickly informed his doctor. Soon after, she tweeted that she and her baby were fine. The video series was widely distributed. It is not every day that you can see (or hear) someone low on live television. But have you ever wondered exactly what is fainting?

Fainting is not just one thing

As the term is commonly used, fainting is a sudden and temporary loss of consciousness. The medical term is "syncope" which comes from "syncope" Greek meaning "contraction" or "cut". 

It is an appropriate term because syncope occurs due to a sudden reduction of blood flow to the brain. Syncope is common: nearly a third of people report having at least one episode of loss of consciousness during his lifetime. 

But while "fading" is commonly used to describe people in good health low may be due to a number of conditions, ranging from harmless to life threatening.

Some of the most common causes of fainting include:

    * Vasovagal syncope. The name of the report refers to increased activity of the vagus nerve which signals the heart to slow down and blood vessels ("vasopressin") to open. This combination of effects results in a drop in blood pressure and too little blood flow to the brain.

The sight of blood or emotional or physical stress are common triggers of this condition. Straining during defecation or even strong cough can also cause vasovagal syncope. And therefore can a hot or a sense of panic or claustrophobia.

   * Abnormal heart rhythm. If the heart rate is significantly slower or faster, blood pressure and fainting can fall may follow. Among the many triggers an abnormal heart rhythm are heart disease itself, certain medications, or an overactive thyroid gland.

    * Orthostatic hypotension. This term means a drop in blood pressure that develops during the movement of the supine to standing or sitting. Dehydration, medication or drugs (including alcohol) and blood loss are common culprits underlying. The condition also becomes more common with age.

There are many other causes of fainting, such as blood sugar or seizures. But in many cases you can not find the cause. 

Although nearly 75% of people who do not have anything serious vanish as the cause, it is important to have controls to ensure that you are in that 75%. And even when he did not find anything serious, many people get injured if they fall when they lose consciousness.

People who lost consciousness and occupations involving passengers or heavy machinery operation may be recommended to restrict activities that could themselves or others at risk if they are still missing. 

Pregnancy is another condition that can make it more likely fainting. Blood vessels tend to dilate during pregnancy and blood pressure is usually on the low side. Not much to drop enough to cause fainting blood pressure.

When fainting is fashionable 

In some circumstances, fainting in a specific signal - "fade" or "fail" - has become a cultural expectation. For example, it was common for aristocratic women of Victorian England for a low particularly dramatic moment.

Examples abound of "hysterical fainting" where a lot of people close to each other begins to fail due to a common illness or exposure to a toxin or even a curse. And then there is the game we played in the gentle district intentionally: we breathe deeply and rapidly for some time and then hold our breath and push. It has never worked for me - which is fortunate, because it can be dangerous.

The bottom line 

The circumstances of the disappearance of Poppy Harlow - a warm atmosphere under the studio lights, pregnancy and stressful job - seem more than enough to trigger an episode of fainting. But it was the right thing to be checked by your doctor. In fact, perhaps the only surprise of fainting - including recent event Poppy Harlow in the air - is that this does not happen more often. 
By: Robert Shmerling, M.D.