Vasovagal Syncope

What is Vasovagal Syncope?

Vasovagal syncope is another term for fainting. An episode happens when the body overreacts to a trigger, such as a heightened level of emotional stress or something like the sight of blood. This type of fainting can be experienced even if you are otherwise healthy and heart disease is not present.

Triggers cause your blood pressure and heart rate to suddenly drop, and that results in a reduction of the blood flow to the brain. When this occurs, you lose consciousness briefly.

What are the Symptoms of Vasovagal Syncope?

Prior to fainting, you might experience the following symptoms:

  • Lightheadedness
  • Pale skin
  • Nausea
  • Yawning
  • Tunnel or blurred vision
  • Feeling warm
  • A clammy and cold sweat
  • Heaviness in the legs

The people around you may notice that you exhibit abnormal or jerky movements, a weak and slow pulse, and dilated pupils.

Vasovagal Syncope Causes

Vasovagal syncope is caused by a malfunction in the nervous system””the part that controls blood pressure and heart rate. Essentially, it’s your body overreacting to a certain trigger, such as extreme emotional distress or the sight of blood. Your blood pressure and heart rate drop, which reduces blood flow to your brain, and as a result, you collapse.

Some common triggers that may incite an episode of vasovagal syncope include seeing blood, exposure to heat, prolonged exertion, having blood drawn, standing for too long, fearing bodily injury, skipping meals, and straining (such as during a bowel movement). Older adults may have different triggers from younger ones, such as coughing, swallowing, urinating and having a bowel movement.

How is Vasovagal Syncope Treated?

Following a episode, recovery typically starts within under a minute. Avoid standing up too soon, as that could increase your risk of fainting again. It is best to wait 30 minutes before standing up.

Most of the time, vasovagal syncope is harmless, so you will not need any treatment. However, it is possible to injure yourself during a fainting episode, so injuries would need to be treated. Also, your doctor might decide to perform some tests in order to rule out any serious conditions that could cause fainting, such as a heart disorder.

Vasovagal Syncope Prevention

Vasovagal syncope cannot be completely prevented. However, if you already have it, there are steps you can take to prevent having an episode or fainting spell. For instance, dehydration may cause a vasovagal syncope episode; therefore, it’s important to remain hydrated by drinking plenty of water.

Before some people experience the actual vasovagal syncope episode itself, they experience something called a “prodome,” which is a warning that you’re going to have an episode. Pay attention to the signs you have right before your loss of consciousness. This will alert you in the future that you’re about to have an episode and you can try to prevent it from happening by lying down and elevating your legs once you notice the signs, or “prodome.” These signs could include lightheadedness, visual disturbances, buzzing in the ears, nausea, and/or sweating.

If you have frequent episodes, pay attention to the days of the week that you usually have them. Some people have vasovagal episodes on certain days or weeks. Keeping track of these dates may help you avoid a potential episode.

Last Reviewed:
October 11, 2016
Last Updated:
June 14, 2018