(HealthDay News) -- Fainting occurs when you temporarily lose consciousness because of a sudden drop in blood flow to the brain.

The U.S. National Library of Medicine mentions these possible causes of fainting:

  • Straining to produce a bowel movement.
  • Having a prolonged bout of coughing.
  • Standing in one spot for an extended period.
  • Standing up too quickly from lying down.
  • Having extreme pain or fear.
  • Bleeding heavily.
  • Suffering significant dehydration.
  • Having a rapid drop in blood pressure.
  • Taking certain medications, or abusing drugs or alcohol.
  • Hyperventilating.
  • Having low blood sugar.