Vasovagal syncope is the medical name for the condition where individuals faint due to a bodily overreaction to certain triggers. Two of the most common triggers are extreme emotional distress or the sight of blood. When a patient is exposed to the trigger, their blood pressure and heart rate suddenly drop. This causes a reduction in blood flow to the brain, which then leads to a brief loss of consciousness. In most cases, vasovagal syncope is harmless and doesn't require treatment. However, some patients may injure themselves when they faint. A patient's doctor might also recommend further testing to rule out cardiovascular disorders and other more serious conditions that cause fainting.