(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.