Sleep apnea is a serious disorder that occurs when people's throats close off and they stop breathing during sleep. People who suffer from sleep apnea get an urgent message from the brain that they must wake up and take a breath. This can happen multiple times every hour, disrupting the sleep cycles. Snoring or sudden awakenings with a sensation of gasping or choking are common symptoms of sleep apnea. Other symptoms include morning headaches, dry mouth and excessive daytime sleepiness. Very effective treatments are available, but many sleep apnea sufferers don't realize that they have the disorder.