The most common cause of fainting
What Is Vasovagal Syncope?
Vasovagal syncope is a type of fainting (temporary loss of consciousness) caused by a sudden drop in heart rate and blood pressure, leading to reduced blood flow to the brain. It is the most common form of syncope, often triggered by certain situations such as stress, standing for long periods, or pain.
While vasovagal syncope is usually benign, it can sometimes indicate an underlying heart rhythm issue or lead to injury from falls.
Common Triggers
Vasovagal syncope can be triggered by:
- Emotional stress or anxiety
- Pain or fear
- Standing or sitting in one position for too long
- Dehydration or overheating
- Straining, e.g. during bowel movements or urination
Symptoms Before Fainting
People often experience warning signs just before an episode, including:
- Lightheadedness or dizziness
- Nausea
- Blurred vision or tunnel vision
- Sweating
- Pale skin
- Ringing in the ears
- Feeling warm or suddenly weak
These symptoms usually appear seconds to minutes before fainting, giving a chance to lie down and possibly prevent loss of consciousness.
Is It Dangerous?
On its own, vasovagal syncope is not dangerous, however:
- It can cause injury from a fall
- Recurrent episodes may affect daily life or confidence
- In rare cases, it may be confused with a more serious heart condition
It is therefore important to rule out other causes of fainting, especially if episodes are frequent, occur without warning, or happen during exercise.
Diagnosis
A cardiologist may recommend:
- Electrocardiogram (ECG) – to check heart rhythm
- Holter monitor or event recorder – for episodes happening over time
- Tilt table test – to reproduce symptoms by monitoring your response to changes in position
- Echocardiogram– to rule out other causes
- Blood tests – to rule out other causes
Treatment and Management
Most cases of vasovagal syncope can be managed with simple measures:
Lifestyle Adjustments
- Stay well hydrated
- Avoid prolonged standing or hot environments
- Learn to recognise early warning signs
- Cross your legs or tense muscles to maintain blood pressure when symptoms start
- Increase salt intake (if recommended by your doctor)
Medications
In some cases, medication may be prescribed if lifestyle changes are not enough.
Pacemaker
In some cases, if fainting is due to a significant drop in heart rate and does not respond to other treatments, a pacemaker may be considered.
When to See a Specialist
You should see a cardiologist if:
- Fainting occurs frequently or without warning
- Episodes happen during exercise
- You have a known heart condition
- There is a family history of sudden cardiac death
While vasovagal syncope is common and often harmless, it’s important to make sure it is not a sign of something more serious.