Table of ContentsView AllTable of ContentsSymptomsWhat to DoCausesRisk FactorsWhen to See a ProviderDiagnosisTreatmentPrevention
Table of ContentsView All
View All
Table of Contents
Symptoms
What to Do
Causes
Risk Factors
When to See a Provider
Diagnosis
Treatment
Prevention
You won’t die from vasovagal syncope on its own.However, the suddenness of the reaction and temporary loss of consciousness that follows can lead to dangerous falls and injuries.
Vasovagal syncope suddenly develops when your body reacts so strongly to a trigger—like seeing blood or being scared—that youfaint. Your heart rate and blood pressure plummet, but the heart doesn’t stop.
An episode of fainting from vasovagal syncope usually only lasts seconds to minutes. For example, fainting while sitting in a chair while having your blood taken could be an episode of vasovagal syncope.
Verywell / Brooke Pelczynski
Symptoms of Vasovagal Syncope
Fainting from a vasovagal response can be sudden and unexpected. However, you may have warning signs a few seconds or minutes before a fainting episode.
The signs leading up to fainting are called theprodromeof syncope, or pre-syncope. The symptoms that come on after you regain consciousness are calledpostdromalsymptoms.
Prodromal Symptoms
Prodromal symptoms of syncope can include:
The time between when prodromal symptoms come on and when you actually pass out can last for a few seconds.
Vasovagal Episode Symptoms
Episodes of vasovagal syncope have several key symptoms and features that make them different from other causes of fainting:
Postdromal Symptoms
After an episode of vasovagal syncope, many people will feel nauseous, dizzy, and very tired. These symptoms can last anywhere from minutes to hours.
You are at risk of fainting again until these symptoms go away. You will need to avoid driving, climbing ladders, or doing anything that would be dangerous for you or others around you should you pass out.
You should also be aware of thewarning signsof another fainting episode and take steps to try to prevent it.
If you think you might faint from vasovagal syncope, there are some steps you can take to stay safe.
Stay calm but know that you don’t have long to keep a fainting spell from happening—maybe five to 10 seconds.
If you faint because you have vasovagal syncope, there are a few things you can do to take care of yourself after it happens:
First Aid for FaintingIf you think you may have gotten hurt when you fell, do not move. Call for help if you are able, and wait for emergency responders to arrive. You should also call 9-1-1.If another person faints, you may need to call 9-1-1 and providefirst aid: Make sure the person has an open airway and is breathing. Loosen tight clothing around the neck. Raise the person’s feet so they are higher than the heart. Keep the person lying down for at least 10 to 15 minutes.
First Aid for Fainting
If you think you may have gotten hurt when you fell, do not move. Call for help if you are able, and wait for emergency responders to arrive. You should also call 9-1-1.If another person faints, you may need to call 9-1-1 and providefirst aid: Make sure the person has an open airway and is breathing. Loosen tight clothing around the neck. Raise the person’s feet so they are higher than the heart. Keep the person lying down for at least 10 to 15 minutes.
If you think you may have gotten hurt when you fell, do not move. Call for help if you are able, and wait for emergency responders to arrive. You should also call 9-1-1.
If another person faints, you may need to call 9-1-1 and providefirst aid: Make sure the person has an open airway and is breathing. Loosen tight clothing around the neck. Raise the person’s feet so they are higher than the heart. Keep the person lying down for at least 10 to 15 minutes.
What Triggers Vasovagal Syncope?
Vasovagal syncope happens when something triggers thevasovagal reflex, which causes blood vessels to widen (dilate) suddenly. Dilation of the blood vessels causes a lot of the blood in the body to pool in the legs.
Vasovagal syncope is a reflex syncope, meaning it’s a response to a stimulus, including physical and psychological stress. Common triggers of vasovagal syncope include:
There’s a strong link between vasovagal syncope andanxiety, and it can have a cyclical effect. Strong feelings of stress and anxiety can be a trigger for syncope, and repeated fainting spells can raise anxiety levels and lead to mental health conditions like depression.
Who’s at Risk for Vasovagal Syncope?
The reflex that causes vasovagal syncope can affect anyone and fainting spells are common. However, some people are more at risk of fainting from vasovagal syncope than others.
When to See a Healthcare Provider
It’s a good idea to contact your healthcare provider after you’ve fainted unexpectedly—especially if you’ve never fainted before.
If you’ve been diagnosed with vasovagal syncope, call your provider if you are pregnant or have recurrent episodes of fainting. If you have heart problems, syncope could be a warning sign of something more serious.
Get medical attention right away if you have other symptoms before you faint, such as:
How Is Vasovagal Syncope Diagnosed?
To diagnose vasovagal syncope, your healthcare provider will review your symptoms, medical history, andfamily history. You’ll also be asked about the events leading up to your fainting episode.
In addition, your provider might want to do these common tests:
Your provider may want to do imaging tests like an X-ray, MRI, or CT scan if they want to check a specific part of your body more closely, like your chest or head, though these tests are less commonly used to diagnose fainting.
The results of these tests help your provider rule out other, sometimes more seriouscauses of fainting:
How Is Vasovagal Syncope Treated?
People who have a single, one-time episode of vasovagal syncope generally do not need any medical treatment.If you have recurrent fainting episodes, you should talk to your provider.
Fainting episodes can come at inconvenient, impractical, and unsafe times. While vasovagal syncope is not life-threatening, the consequences of fainting can be. For example, falls can cause serious injuries, and fainting behind the wheel could lead to a car accident.
Treatment for vasovagal syncope usually includes a combination of strategies like medication and exercise.
Medications
Certain medications can help regulate blood pressure and heart rate and may help people with vasovagal syncope, including:
Exercises
Examples of exercises that may help prevent fainting from vasovagal syncope include:
Apacemaker(a device that regulates the heartbeat) used to be suggested for people with vasovagal syncope, but research has shown it is not helpful.
If you have recurrent syncope, ask your healthcare provider before starting a fitness plan. You may need to havestress testingand other exams to determine how much exercise you can do safely.
How Can You Prevent Vasovagal Syncope?
The best thing you can do to prevent fainting is to avoid your triggers—for example,excessive heat, stress, dehydration, pain, and prolonged standing.
If you have low blood pressure, consider talking to your provider about whether increasing your salt intake could help you avoid fainting episodes.
Summary
See a healthcare provider if you had an episode of fainting, especially if it’s your first time or you have multiple episodes. Your provider can run tests to rule out other causes of fainting, some of which can be serious.
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