If you or a loved one lives with sleep apnea, you’re probably familiar with feeling groggy in the morning and having some trouble concentrating during the day. You know that sleep apnea can cause symptoms like these the next day, but you might also ponder if your sleep apnea could raise your risk for future, more serious cognitive problems like dementia. (The term “cognitive” refers to how your brain thinks, learns, remembers, and understands things.)

Health experts have suspected that untreated sleep apnea may lead to cognitive decline for a long time. After all, sleep apnea deprives your brain of the oxygen it needs to function. Researchers are finally discovering the true connections between sleep apnea and mild cognitive impairment (MCI), which can be a precursor to Alzheimer’s disease and other forms of dementia.

Here, we explore those connections and discuss sleep apnea treatments that might help protect your memory.

How Sleep Apnea Affects the Brain

When you have sleep apnea, you periodically stop breathing at night while sleeping. Even though your brain activates a reflex to wake you up and restart your breathing, you may not even notice yourself awakening. But the reflex interrupts your sleep cycle nonetheless, which prevents restful sleep.

This process, happening night after night, can lead to sleep apnea symptoms and observable changes in the brain.

Amyloid Plaques

Researchers have discovered a brain change that happens in both Alzheimer’s disease and sleep apnea — the development of amyloid plaques. Beta-amyloid is a protein fragment in the fatty, insulating layer surrounding neurons (nerve cells).

Long known as a key sign of Alzheimer’s disease, amyloid plaques are misfolded beta-amyloid proteins that build up between brain cells and disrupt their communication. In a healthy brain, beta-amyloid is regularly cleared so it doesn’t build up.

Not only are amyloid plaques seen in people with Alzheimer’s disease and obstructive sleep apnea (OSA), but they also spread in the same way. In people with Alzheimer’s disease and people with OSA, researchers found that amyloid plaques started showing up in the brain near the hippocampus, which is an area involved in memory. The plaques eventually spread into the hippocampus before spreading to other areas of the brain.

Low Oxygen During REM Sleep

Hypoxemia, or low oxygen levels, can damage blood vessels in the brain in people with OSA. When it comes to memory and cognition (thinking), hypoxemia is especially damaging during a sleep stage called rapid eye movement (REM) sleep.

During REM sleep, which is normally when you dream, your brain stores and organizes memories. When REM sleep is interrupted or prevented by hypoxemia in OSA, your brain’s entire memory system doesn’t get the maintenance it needs.

Health experts have found that even people with mild apnea-hypopnea index scores, which measure sleep apnea severity, have brain changes linked to low oxygen during REM sleep. More specifically, low oxygen during REM sleep can cause thinning in an area of the brain that often shows changes in early Alzheimer’s disease called the entorhinal cortex.

Sleep Deprivation

If you’re living with any type of severe sleep apnea, your breathing can stop 30 or more times per hour at night. This adds up and prevents a good night’s sleep. Even if you don’t remember repeatedly waking up, you’re still not getting the quality sleep you need to think clearly during the day.

Health experts aren’t yet sure if sleep deprivation links sleep apnea and dementia, but they know it can shorten your attention span and harm your short-term memory.

Cognitive Symptoms of Sleep Apnea

Even if sleep apnea never leads to long-term memory problems, it’s clear that unmanaged sleep apnea can affect how your brain works on a day-to-day basis. In fact, cognitive symptoms of OSA can look a lot like early symptoms of dementia.

Both sleep apnea and dementia can cause:

• Trouble concentrating
• Short-term memory problems and forgetfulness
• Trouble planning
• Trouble staying organized
• Sleepiness during the day
• Mood changes

Between 10 percent and 15 percent of people with sleep apnea experience long-term or permanent symptoms like memory loss, even with sleep apnea treatment.

Why Sleep Is Important for Memory

Deep sleep, including REM sleep, allows your brain to process memories and retain information.

Poor sleep affects three key brain processes involved in memory and learning:

• Acquisition — Receiving and storing new information you’ve learned
• Consolidation — Organizing information and memories by making connections
• Recall — Accessing and using the information and memories you’ve stored when you need them

Acquisition and recall are most affected by a lack of sleep in people with sleep apnea. This is why you might experience trouble concentrating or short-term memory problems during the day. It’s important to note that you can’t “make up” for lost sleep — if you stay up all night, you’ll have trouble remembering anything you learned the previous day, even if you sleep extra hours the next night.

Sleep is also an opportunity for your brain to rest, heal, and clear out excessive proteins like beta-amyloids. Parts of the brain involved in memory and information storage, like the frontal and parietal lobes, stay active while you sleep, which means they’re especially vulnerable to brain changes like amyloid plaques and vascular damage from hypoxemia.

Treating Sleep Apnea To Reduce Dementia Risk

Although evidence points to sleep apnea being a dementia risk factor, managing your sleep apnea could help prevent long-term memory problems like dementia. In many cases, shorter-term memory problems start to improve around three months after treatment begins.

Treatment With Continuous Positive Airway Pressure

Continuous positive airway pressure (CPAP) is typically the go-to treatment for sleep apnea. It involves a machine with a motor and a face mask that delivers continuous air pressure into your airway. This holds your airway open at night to prevent it from collapsing, which is what happens in people with OSA.

Research on amyloid plaques in people with OSA showed that treatment with CPAP didn’t reduce the number of amyloid plaques in participants’ brains. However, other research found that people who managed their sleep apnea with CPAP were diagnosed with memory and thinking problems 10 years later than people with untreated sleep apnea. This suggests that CPAP therapy may delay the onset of MCI and dementia.

Other Sleep Apnea Treatments

For some people, CPAP isn’t the most suitable way to manage sleep apnea. They might find a CPAP machine to be too loud, or the mask may be too uncomfortable or easy to unconsciously take off at night.

In any case, if CPAP isn’t right for you, your doctor can help you manage sleep apnea in other ways with CPAP alternatives:

• Oral appliances — These are custom mouthpieces that hold your airway open at night.
• Neuromuscular electrical stimulation (NMES) — These implantable devices stimulate muscles in your airway to prevent airway collapse.
• Changes in sleep position — Sleeping on your side instead of your back might improve nighttime breathing
• Managing underlying conditions — Conditions like obesity and hypertension (high blood pressure) can increase your sleep apnea risk.
• Surgery — When other treatments don’t improve sleep apnea, jaw surgery or nasal surgery may be recommended to help open your airway.

Talk to Your Doctor

If you’re concerned about memory problems related to sleep apnea or your overall dementia risk, talk to your doctor. They can recommend treatments and lifestyle changes for your sleep apnea type that will help prevent dangerous pauses in breathing while you sleep that increase your risk for long-term memory problems like dementia.

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On MySleepApneaTeam, people share their experiences with sleep apnea, get advice, and find support from others who understand.

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