Sleep Apnea is a serious sleep disorder that can be life threatening and at times fatal. People with sleep apnea often fall asleep normally; however, once asleep their ability to breathe is blocked. Usually this inability to breathe is caused by the muscles in the throat relaxing too much and collapsing into the airway. The body then sends a signal to the brain that breathing has temporarily been blocked. This causes the person to wake up and start breathing again.