Fainting: Vagal Reaction

Fainting (syncope) is a temporary loss of consciousness. It’s also called passing out. It occurs when blood flow to the brain is reduced. Your healthcare provider believes that your fainting was because of a vagal reaction. This is usually not a sign of serious disease.

A vagal reaction causes your pulse to slow down or the blood vessels to expand. This causes your blood pressure to fall. Less blood to your brain if you are standing or sitting. That results in dizziness, near-fainting, or fainting. Lying down and raising (elevating) your feet often stops the reaction.

Fainting can occur during sudden fear, severe pain, emotional stress, overexertion, overheating. Hunger, nausea or vomiting, prolonged standing, or standing up after sitting or lying for a long time can also cause it.

Home care

Follow these steps when caring for yourself at home:

  • Get plenty of rest. Go back to your normal activities as soon as you are feeling back to normal.

  • Stay hydrated and avoid skipping meals.

  • If you feel lightheaded or dizzy, lie down right away and elevate your legs.

Follow-up care

Follow up with your healthcare provider, or as advised.

Call 911

Call 911 if any of the following occur:

  • Another fainting spell that’s not explained by the common causes listed above

  • Pain in your chest, arm, neck, jaw, back, or abdomen

  • Shortness of breath

  • Severe headache or seizure

  • Your heart beats very rapidly, very slowly, or irregularly (palpitations)

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