Sleep apnea is categorized into three types: obstructive, central, and mixed sleep apnea.

Obstructive sleep apnea occurs when a person’s tongue and throat muscles become too relaxed during sleep, temporarily causing breathing to stop until low oxygen level jolts the sleeper awake to normalize his or blood oxygen level.

This momentary cessation of breathing can occur, for some people, hundreds of times a night.

Central sleep apnea occurs when your brain doesn’t send proper signals to the muscles, and erroneously tells them to stop breathing.

Sometimes people can develop a combination of obstructive and central sleep apnea — which is called mixed sleep apnea.

People with congestive heart failure, hypothyroid disease, kidney failure, brain damage from stroke or other factors, or neurological ailments such as Alzheimer’s and Parkinson’s disease are at particular risk for central sleep apnea.

In addition, alcohol use and/or the use of sedative medications such as sleeping pills, antidepressants, or other drugs can result in central sleep apnea — which can be fatal if respiratory arrest (breathing stoppage) occurs.

The most common risk factors for sleep apnea include older age, male gender, family history of the condition, obesity, large neck circumference, smoking, and nasal congestion.