Vasovagal syncope occurs when you faint because your body overreacts to certain triggers, such as the sight of blood or extreme emotional distress.
The vasovagal syncope trigger causes your heart rate and blood pressure to drop suddenly. That leads to reduced blood flow to your brain, causing you to briefly lose consciousness.
Vasovagal syncope is usually harmless and requires no treatment. But it's possible you may injure yourself during a vasovagal syncope episode. Your doctor may recommend tests to rule out more serious causes of fainting, such as heart disorders.
Symptoms
Before you faint due to vasovagal syncope, you may experience some of the following:
- Pale skin
- Lightheadedness
- Tunnel vision — your field of vision narrows so that you see only what's in front of you
- Nausea
- Feeling warm
- A cold, clammy sweat
- Yawning
- Blurred vision