What Stage of Sleep Does Sleep Apnea Occur?

Updated March 16, 2020

Getting a good night’s sleep is important for maintaining your health and a healthy lifestyle. However, there are many factors that can compromise the quality of your sleep, which can, in turn, affect your health and overall quality of life.

One such issue that can hinder the quality of sleep a person receives is sleep apnea. Sleep apnea is a sleeping disorder that causes a person to have pauses in their breathing or moments of shallow breathing. This means that people who suffer from sleep apnea stop breathing repeatedly during their sleep and if left untreated it may even occur hundreds of times a night. This can be extremely dangerous, as it means that the brain, as well as the rest of the body, might not receive enough oxygen.

The pauses in breath caused by sleep apnea can last from a few seconds to a few minutes and can happen many times a night. Generally, this can be identified by loud snoring and even choking or snorting when the breathing returns. This sleep disorder disturbs normal sleep, and this means that those who suffer from it will experience sleepiness, fatigue and an overall feeling of tiredness during the day.

Different Forms of Sleep Apnea

There are two different forms of sleep apnea, these are known as obstructive sleep apnea (OSA) and central sleep apnea. There are certain differences between these two different types of sleep apnea that make their treatments and symptoms different. Let’s take a deeper look at the two different forms of sleep apnea.

Obstructive Sleep Apnea (OSA)

Obstructive sleep apnea occurs when there is a blockage of some sort which disrupts the airflow and affects the breathing. OSA is the most common form of sleep apnea. It generally occurs due to the soft tissues collapsing in the back of the throat during sleep. The muscles of the human body generally relax during sleep. Especially within the throat, the air passage is comprised of soft collapsible walls of tissue which can become an obstacle preventing air from passing and thus stopping the breathing of the person.

Mild or occasional obstructive sleep apnea can occur due to conditions such as upper respiratory infections, this may be considered less critical, however, if you suffer from chronic or severe sleep apnea then it requires proper treatment in order to prevent serious issues such as low blood oxygen, sleep deprivation, and other issues that might occur.

Central Sleep Apnea

Central sleep apnea occurs when regular unconscious breathing just stops. Unlike obstructive sleep apnea the airway is not blocked but there is disruption or instability in the respiratory control center and the brain is unable to send singles to the muscles to breathe.

The brain’s respiratory control centers are imbalanced, which means that the carbon dioxide levels in the blood which are monitored by a neurological feedback mechanism do not respond fast enough to maintain a consistent rate of respiration. The breathing system cycles between apnea and hyper apnea, where breathing happens at a faster rate to compensate for the pauses in breathing.

During periods of central sleep apnea, the sleeper stops breathing and then starts again, there is no effort made to breathe, there are no chest movements or struggles to breathe. This is dangerous as extended periods of not breathing can lead to many complications such as not enough oxygen reaching the brain and the rest of the body.

Stages of Sleep

There are two major different stages of sleep which are known as REM sleep and non-REM sleep. REM stands for rapid eye movement, which means that our eyes move very quickly in different directions. This rapid movement of the eyes does not happen in non-REM sleep. REM sleep is the deeper form of sleep and when dreams occur, in this stage the brain looks similar to the way it would when you are awake.

Due to the fact that REM sleep is the deeper form of sleep the muscles are more relaxed. Although sleep apnea can occur during any stage of sleep, it most often occurs during the REM stages of sleep and it is typically worse during that stage. This is because especially the muscles in the upper airway are further relaxed naturally during the REM stage of sleep. It is due to this fact that many individuals only suffer from sleep apnea in REM sleep.

Stages of Non-REM Sleep

Prior to reaching the deeper stage of REM sleep, an individual passes through three different non-REM sleep stages. Depending on the severity of sleep apnea, it can occur during these stages of sleep as well.

Stage 1: The first stage of non-REM sleep occurs when your eyes are closed, and it is very easy to wake you up. You are just drifting off and generally lasts for about five to ten minutes. Sleep apnea is unlikely to start at this stage as the body is not completely relaxed and the muscle tone is still partially there.

Stage 2: The second stage starts when you are in light sleep. There are certain features of this stage that make it distinct. In this stage, your body’s temperature starts to drop and your heart rate slows down. Your body starts to prepare for a deeper sleep.

Stage 3: This is the final stage of sleep and is the deepest stage of sleep. It is hardest to wake you up from this sleep and if you do wake up you feel disoriented for a few minutes. This is the restorative sleeping state where the body repairs its tissues, regrows bones, and strengthens the immune system. After this when the REM sleep starts. This is the stage after REM sleep. This is also very likely to evoke sleep apnea as the body is in a very deep slumber and muscles are very relaxed.


Overall sleep apnea has two different forms and if untreated it can be quite dangerous to the health of a person. Although sleep apnea can occur in any stage of sleep it is most likely to occur during the deeper stages of sleep which includes REM sleep. Hopefully, this article was able to shed some light on sleep apnea and the stages of sleep it occurs in.