Causes of fainting include severe or emotional trauma, a drop in blood pressure, low blood sugar, dehydration, and seizures. Other causes include hyperventilation, drug or alcohol consumption, standing up too fast, and physical exertion in the heat, claims Healthline.
Fainting is a collapse and sudden loss of consciousness that occurs due to decreased blood flow to the brain. Fainting accounts for 3 percent of emergency visits and 6 percent of hospital stays, claims WebMD.
The most common types of fainting are vasovagal, carotid sinus syncope and situational syncope, says Healthline. Vasovagal is the most common type, typically occurring in kids and young adults, according to WebMD.