Vasovagal syncope

Overview

Vasovagal syncope (pronounced vay-zoh-VAY-gul SIN-ko-pee) is a common cause of fainting. It happens when your body overreacts to a trigger, like the sight of blood or strong emotion, causing a sudden drop in heart rate and blood pressure. This reduces blood flow to your brain, and you briefly lose consciousness. It is usually not dangerous and you recover quickly.

Yes, vasovagal syncope is very common. Many people will faint at least once in their lifetime, and vasovagal syncope is the cause in up to half of all fainting episodes.

It can affect people of all ages, but it is most common in teenagers and young adults. It tends to run in families.

Symptoms

Common symptoms

• Feeling lightheaded or dizzy
• Nausea or queasiness
• Sweating
• Blurred vision or seeing spots
• Feeling warm or flushed
• Weakness
• Ringing in the ears
• Yawning or sighing
• A brief loss of consciousness (fainting) that usually lasts less than a minute

Symptoms in children

• Children may feel sick or complain of a stomachache before fainting
• They might look pale or clammy
• Fainting can occur during a tantrum, when scared, or after standing for a long time

Symptoms in older adults

• Older adults may have less typical warning signs
• They might experience confusion or memory loss after fainting
• There is a higher risk of injury from falling during a fainting episode

Causes

Main causes

• A strong emotional reaction, such as fear, anxiety, or the sight of blood or needles
• Physical triggers like intense pain, heat, or dehydration
• Prolonged standing, especially in a hot or crowded place
• Straining during a bowel movement or urination (called 'situational syncope')
• Coughing or swallowing very hot or cold foods

Risk factors

• Being young (teenagers and young adults are more prone)
• A family history of fainting
• Dehydration or not eating enough
• Fatigue or lack of sleep
• Emotional stress or anxiety

When to see a doctor

See a doctor urgently if:

• If you faint more than once in a short period
• If you have any symptoms listed under 'emergency'
• If you are over 40 and faint without a clear trigger

Book a routine appointment if:

• If this is your first fainting episode
• If you are concerned about the fainting and want to rule out other causes
• If the fainting happens in situations where it could be dangerous (e.g., driving, using machinery)

Diagnosis

Doctors diagnose vasovagal syncope by talking with you about your fainting episodes and triggers, and by doing some simple tests to rule out other causes.

Tests that may be done

• A physical exam and listening to your heart
• Blood pressure and heart rate measurements while lying down, sitting, and standing
• An electrocardiogram (ECG/EKG) to check your heart's rhythm
• A tilt-table test, where you lie on a table that tilts up to see if fainting can be provoked

What to expect at your appointment

Diagnosis is usually straightforward. Most people do not need many tests. Your doctor will ask you about your symptoms and triggers. The tilt-table test is not always needed but can help confirm the diagnosis if it is unclear.

Treatment

Treatment for vasovagal syncope focuses on avoiding triggers and learning how to prevent or manage fainting episodes. Most people do not need medication. The goal is to improve blood flow to your brain when you feel symptoms starting.

Self-care at home

• When you feel symptoms like dizziness or nausea, lie down immediately with your legs elevated above heart level. If you cannot lie down, sit and put your head between your knees.
• Cross your arms or legs and tense your muscles (called 'applied muscle tension') to help raise your blood pressure.
• Drink plenty of water to stay hydrated.
• Eat regularly and avoid skipping meals.
• If you know a trigger (like the sight of blood), tell the person who is with you so they can help you sit or lie down.

Medical treatments

In rare cases where fainting happens often and affects quality of life, a doctor may recommend medications that help control blood pressure or prevent the drop in heart rate. These are never first-line treatments and should only be used under close medical supervision. No specific drug names are given here.

When is surgery considered?

Surgery is not used for vasovagal syncope. It is not a heart problem that requires a procedure.

Living with this condition

Most people with vasovagal syncope live normal lives without major changes. It is helpful to know your triggers and take steps to avoid them. If you feel faint, remember to lie down or sit with your head down. It is also a good idea to tell close friends, family, or coworkers what to do if you faint.

Lifestyle tips

• Stay well-hydrated by drinking water throughout the day.
• Avoid alcohol, which can lower blood pressure.
• Get up slowly from sitting or lying down to prevent dizziness.
• Wear compression stockings if your doctor recommends them to help blood flow.
• Avoid hot, crowded environments when possible.

Diet and exercise

Eating small, frequent meals can help prevent blood pressure drops after eating. A balanced diet with enough salt may be suggested (ask your doctor, especially if you have high blood pressure). Regular exercise improves circulation and can help reduce fainting episodes, but avoid exercising in extreme heat or dehydration.

Mental health and emotional wellbeing

Vasovagal syncope can be frightening and may cause anxiety about fainting again. Some people avoid certain activities or places. It is normal to feel this way. Talking to a healthcare provider or a counsellor can help you manage these fears.

Prevention

You can often prevent episodes by avoiding known triggers and by doing the self-care actions described above, such as lying down at the first sign of symptoms. Staying hydrated and eating regularly also helps.

Screening programmes

Routine screening is not needed for vasovagal syncope. If you have frequent fainting, your doctor may suggest monitoring with a heart rate or blood pressure check.

Complications

If left untreated

• Injury from falling during a faint, such as bruises, cuts, or fractures
• Concussion if you hit your head when falling
• Anxiety or fear of fainting again
• Rarely, fainting while driving or operating machinery could cause an accident

Long-term outlook

The outlook for vasovagal syncope is excellent. It is not a sign of a serious health problem in most cases. Episodes often become less frequent over time. With simple precautions, people can continue all their usual activities.

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