What is vasovagal syncope?
Vasovagal syncope is the most common type of fainting. It happens when your heart rate slows down and your blood pressure drops in response to certain triggers. This temporarily reduces blood flow to your brain and causes you to faint.
Vasovagal syncope is usually harmless and is not a sign of a serious medical condition. However, sudden fainting can lead to falls or injury.
This type of fainting occurs when the vagus nerve overreacts. This nerve helps regulate your heart rate and blood vessel tone. When overstimulated, it slows the heart and causes blood vessels to widen, leading to a drop in blood pressure.
Normally, your body automatically keeps blood pressure stable. But when this reflex is disrupted by certain triggers, blood flow to the brain decreases and fainting can occur.
What are the symptoms of vasovagal syncope?
Before fainting, you may experience warning signs such as:
- Pale or yellowish appearance
- Dizziness or lightheadedness
- Tunnel vision (narrowed visual field)
- Nausea
- Feeling hot or breaking into a cold sweat
- Blurred vision
- Ringing in the ears
- Weakness
Sometimes fainting occurs suddenly without any warning symptoms.
Loss of consciousness is usually brief. Most people regain consciousness within seconds to about a minute, though you may feel tired or slightly disoriented afterward.
When to see a doctor?
If you faint for the first time, you should see a doctor. Your physician will want to confirm that the episode is vasovagal syncope and rule out serious heart or neurological conditions.
Seek urgent medical attention if:
- You were injured during fainting
- You have chest pain or irregular heartbeat
- You experience shortness of breath
- The fainting episode lasts several minutes
- You are pregnant
- You notice shaking or jerking movements during fainting
What triggers vasovagal syncope?
Common triggers include:
- Standing for a long time
- Hot environments
- Seeing blood, needles, or injuries
- Blood donation
- Hunger or dehydration
- Severe pain
- Emotional stress or fear
- Severe coughing or sneezing
- Straining during bowel movements
How is vasovagal syncope diagnosed?
Diagnosis starts with a detailed medical history and physical examination. Your doctor will ask what you were doing before fainting and how you felt.
Tests may include:
- ECG (electrocardiogram)
- Echocardiography (heart ultrasound)
- Exercise stress test
- Holter monitoring
- Tilt table test
- Blood tests
The goal is mainly to rule out serious cardiac or neurological causes.
How is vasovagal syncope treated?
Vasovagal syncope often does not require treatment. However, if episodes are frequent or cause injury, several strategies can help.
You should:
- Identify and avoid triggers
- Stay well hydrated
- Increase salt intake if your doctor recommends it
- Exercise regularly
- Avoid prolonged standing
If you feel faint:
- Sit or lie down immediately
- Raise your legs
- Tighten your leg muscles
- Take slow, deep breaths
If lifestyle changes are insufficient, medications may be considered. In rare cases with frequent, resistant episodes, a pacemaker or specialized procedures targeting the vagus nerve (cardioneuroablation) may be discussed.
Is vasovagal syncope dangerous?
Vasovagal syncope is usually benign. The main risk is injury from falling.
Fainting while driving or working in hazardous environments can be dangerous. Recurrent episodes may also reduce quality of life, so medical follow-up is important.
Living with vasovagal syncope
If you have vasovagal syncope:
- Learn to recognize warning signs
- Avoid known triggers
- Drink enough fluids
- Eat regularly
- Be cautious in hot environments
- Consider lying down during blood tests or injections
If you have a history of fainting, follow your doctor’s advice about driving or working in potentially risky situations.
Reference: Vasovagal syncope
