Sleep apnea is a breathing disorder characterized by brief interruptions of breathing during sleep.
The lack of deep, restorative sleep often leads to early morning headaches and excessive daytime sleepiness. It has been estimated that as many as 18 million Americans have sleep apnea. Sleep apnea seems to run in some families, suggesting a possible genetic basis. Recent research suggests that there may be a link between breathing problems during sleep and heart disease. The only way to find out for sure is to study a large group of mostly healthy people.