Sleep apnea occurs when a person's breathing often is blocked or partly blocked during sleep. It can be mild, moderate, or severe, based on the number of times each hour that breathing stops (apnea) or slows (hypopnea).

The two main types of sleep apnea are:

Obstructive sleep apnea (OSA), which is the result of blocked airflow during sleep, such as from narrowed airways. Other things, such as obesity, often contribute to obstructive sleep apnea.

Central sleep apnea, which results from a problem with how the brain signals the breathing muscles. This type of apnea can occur with conditions such as heart failure, brain tumors, brain infections, and stroke.

A child or adult who has sleep apnea may snore loudly and have restless sleep with difficulty breathing. He or she may wake up with a headache. Or the person may be very tired throughout the day.

Sleep apnea may improve with changes in sleep habits, such as not sleeping on your back. Sleep apnea is usually treated first with a continuous positive air pressure (CPAP) device that improves breathing during sleep. Sometimes other devices are used to help breathing during sleep, and sometimes surgery may help.