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Central Sleep Apnea (CSA) and Excessive Daytime Sleepiness

Excessive daytime sleepiness (EDS) is a potential symptom of sleep apnea. This blog will focus specifically on how daytime sleepiness impacts people with Central Sleep Apnea (CSA).

Anyone who experiences any kind of sleep apnea understands how daytime sleepiness can impact a person’s life. It goes beyond just feeling tired. Extreme daytime sleepiness can be debilitating. It can affect every part of a person’s life, from relationships to work performance. It can be a significant safety risk, as well. One study found people with excessive daytime sleepiness were 2.5 times more likely to suffer an accident at work.1

older man sleeping on the wheel of a car

The first step in dealing with excessive daytime sleepiness is to learn more about what may be causing it.

What is Central Sleep Apnea?

Most people are familiar with Obstructive Sleep Apnea (OSA). For people with OSA, the throat can collapse and block the airway during sleep. When that happens, the oxygen (O2) level in the blood drops, and the carbon dioxide (CO2) level rises. Sensors throughout the body alert the brain that there is a problem. The brain responds by waking the sleeper up so they will begin to breathe again.

However, OSA is just one of several kinds of apneas. Central sleep is another type of sleep apnea. For people with CSA, the signals from the brain to the breathing muscles are interrupted or irregular.2 The irregular breathing pattern leads to decreased oxygen and increased carbon dioxide in the blood. Eventually the brain senses this change and “remembers” to breathe. However, the interruptions in breathing and drops in oxygen levels can lead to poor sleep and other health risks.

One of the key symptoms of central sleep apnea is excessive daytime sleepiness. The key word is excessive. Everyone feels sleepy sometimes during the day. Not every drowsy feeling falls into the category of excessive daytime sleepiness, however.

stick figure asleep at desk

What is Excessive Daytime Sleepiness?

Excessive daytime sleepiness is what doctors call hypersomnia. It is different from just feeling tired.

People with hypersomnia:

  • Can nap during the day and still feel sleepy
  • Can fall asleep doing any task, even driving a car or eating
  • Can still sleep a lot at night and be tired in the day

There are key signs of excessive sleepiness to watch for, such as:

  • Chronic brain fog makes it difficult to think
    clearly and concentrate
  • Problems making decisions
  • Poor short-term memory
  • Lack of productivity
  • Nodding off

It is hard to be subjective about something as vague as the level of sleepiness. That’s why healthcare professionals often recommend a method of self-evaluation called the Epworth Sleepiness Scale (ESS).

What is the Epworth Sleepiness Scale?

The ESS is a self-evaluation survey that can help measure levels of sleepiness.3

It lists scenarios, and the tester determines the chance they may fall asleep using this scale:

Epworth sleep graphic

Although the test is still somewhat subjective, it gives testers a way to gauge their level of sleepiness. This test is for all kinds of sleep apnea and also for narcolepsy. Someone who scores higher than 11 on the ESS is likely experiencing excessive daytime sleepiness.3

What is the Multiple Sleep Latency Test (MSLT)?

The MSLT, which is sometimes called a daytime nap study, is a more objective survey of excessive daytime sleepiness. It measures how fast someone falls asleep in a quiet area during the day.

A board-certified sleep medicine physician conducts the MSLT. It is a full-day test that consists of five scheduled naps separated by two-hour breaks. During each nap, the subject lies quietly on a bed and tries to go to sleep. If they succeed, a staff member wakes them after 15 minutes. If they fail to fall asleep in 20 minutes, the test ends.4

During the nap, a series of sensors measure whether the person actually falls asleep and the various stages of sleep reached, such as REM. The MSLT is a clinical diagnostic test for excessive sleepiness. The ESS is a selfevaluation.

What are the Other Signs of Central Sleep Apnea?

Excessive daytime sleepiness is one of the key symptoms of CSA but not the only one. Other indicators include waking up frequently during the night or segmented sleep. Repeated pauses in breathing during sleep can disrupt sleep. Sometimes, these pauses may even cause the sleeper wakes up suddenly. Even if the sleeper doesn’t full wake up, breathing issues can make it hard to get restful sleep.

graphic of AHI 48.3

The Apnea-Hypopnea Index (AHI) measures the severity of sleep apnea based on the number of times someone stops breathing per hour during sleep:5

  • Up to four times a night is normal
  • Between 5-15 is mild sleep apnea
  • Between 15-30 is moderate sleep apnea
  • Anything greater than 30 is severe sleep apnea

Someone with severe sleep apnea could wake up 30 times or more an hour each night. That’s why someone who has CSA can feel sleepy all the time regardless of the amount of perceived sleep they get. In this case, its like someone tapping you on the shoulder all night long, telling you to “wake up and breathe”… completely exhausting!

Other signs of this sleep-related disorder include:

  • Morning headaches
  • Shortness of breath
  • Chest pain at night
  • Low tolerance for exercise

Snoring is typically associated with OSA, but it can happen with CSA, as well.6

How Central Sleep Apnea and Excessive Daytime Sleepiness Impact Health

The constant sleep-wake cycle takes a toll on a person mentally and physically. Sleep is a necessary part of good health. The brain uses this time to form new neural pathways that allow you to learn and remember. Studies indicate that children who do not get enough sleep have trouble at school with both learning and socialization. They may even feel angry and act out impulsively.7

People who are sleep deficient because of CSA experience brain-related side effects such as poor memory, trouble with decision-making, and problem-solving. They may struggle to control their emotions and cope with stress, as well. This all occurs because the brain didn’t have the chance to prepare for the new day.6

Central sleep apnea, when left untreated, can have serious consequences. People experiencing extreme daytime sleepiness should consider getting evaluated for central sleep apnea or obstructive sleep apnea.