Apnea literally means cessation of breath. If you have sleep apnea, your breath can become very shallow or you may even stop breathing while you are asleep. Obstructive sleep apnea is a condition in which the flow of air pauses or decreases during breathing while you are asleep because the airway has become narrowed, blocked, or floppy. Several types of sleep apnea exist, but the most common type is obstructive sleep apnea, which occurs when your throat muscles intermittently relax and block your airway during sleep. The most noticeable sign of obstructive sleep apnea is snoring. Sleep apnoea is associated with being overweight, and other risk factors.