Blacking out, also referred to as fainting or syncope, is caused by a lack of blood flow to the brain. People who experience this condition often wake up right after falling over, states About.com.
Managing this condition is achieved by letting the victim rest in a supine position. However, it is important to discover the cause of the episode, says About.com. Most fainting episodes are triggered by the vagus nerve which connects the digestive system to the brain and manages blood flow to the gut. When food is consumed, the vagus nerve pulls blood from other body tissues such as the brain and sends it to the stomach and intestines. Sometimes the vagus never pulls to much blood from the vain, which results in fainting.
Other things that trigger the vagus nerve into working harder include bearing down to have a bowel movement, vomiting or a drop in blood pressure. People that are prone to syncope commonly begin fainting around the age of 13 and it occurs for the rest of their lives, according to About.com. First, the victim feels a flush, then feels suddenly weak and loses consciousness. It is also common for the person to go limp and break out in a cold sweat.