Treating obstructive sleep apnea (OSA) goes beyond improving sleep quality.
“Obstructive sleep apnea is not just about snoring or feeling tired — it is very much a brain condition,” says Joanna Fong-Isariyawongse, MD, a sleep neurologist with UPMC Neurology and an associate professor of neurology at the University of Pittsburgh in Pennsylvania.
Untreated OSA can have a negative effect on memory, learning, and cognitive functions, creating short- and long-term consequences.
“The reassuring news is that sleep apnea is a treatable condition, and treating it may protect long-term brain health,” Dr. Fong-Isariyawongse says.
OSA is a common type of
sleep apnea, a disorder that causes your breathing to pause or get shallow while you sleep. It happens when the muscles in the back of your throat relax, causing your airway to close and oxygen levels to drop. This forces your brain to wake you up to restart breathing, sometimes 30 times or more per hour.
While you may not remember waking, these interruptions disrupt deep sleep, causing widespread and lasting effects on the brain.
“Night after night, the brain is forced into survival mode instead of recovery mode,” Fong-Isariyawongse says. “Over time, this leads to real and measurable changes.”
These changes include structural damage. Compared with people who don’t have OSA, people with OSA have a smaller hippocampus. That's the brain structure responsible for memory and learning. They also have a smaller precuneus, a brain region involved in memory and self-awareness. These size differences may make it harder to form new memories and recall information.
But OSA doesn’t just shrink specific brain regions. It also damages the connections between them, reducing their coordination and communication.
People with severe OSA, or more than 30 sleep interruptions per hour, have significantly more damage to their white matter, the connective nerve fibers in the brain.
This damage may show up as bright spots on MRI scans and can raise your risk of dementia and stroke.
Executive function — your brain’s control center that helps with planning, organizing, managing emotions, and making good decisions — is particularly vulnerable to OSA, Fong-Isariyawongse says.
“OSA is often associated with memory impairment and reduced concentration,” says Kevin Postol, DDS, who specializes in oral treatments for sleep apnea in Twin Oaks, Missouri, and is president of the American Academy of Dental Sleep Medicine. “This can have a dramatic impact on executive functioning and [can] make focusing or getting work done difficult.”
We sometimes call this “brain fog.” It can come from not getting enough quality sleep, which can cause neuroinflammation that prevents brain cells from connecting properly.
“This helps explain why people often say they feel foggy, slower, or not quite themselves,” Fong-Isariyawongse says.
It also may make you more prone to accidents. People with OSA have a 17 percent higher risk of being involved in an auto accident and may be twice as likely to have an accident at work than people who do not have OSA.
Being tired during the day from untreated OSA can add up: People with OSA are 2 ½
times more likely to lose their job involuntarily as well.
Treating OSA can bring immediate benefits for your brain. While improvements don’t always happen overnight, most people notice better daytime alertness, sharper thinking, and stronger long-term memory within the first few weeks of using continuous positive airway pressure (CPAP) therapy, Fong-Isariyawongse says. CPAP is the most common
OSA treatment.
In one to three months, CPAP treatment also may boost your:
While most studies focus on CPAP, other OSA treatments — including oral appliances, weight loss medications, nerve stimulation, and surgery — may also provide cognitive benefits.
Oral appliances or mouth guards, which pull your lower jaw forward or hold your tongue in place, can improve thinking speed and alertness in those with mild-to-moderate sleep apnea, Fong-Isariyawongse says.
The U.S. Food and Drug Administration (FDA) also approved the weight-loss medication tirzepatide (Zepbound) to treat moderate-to-severe OSA, alongside exercise and diet changes. It works indirectly by cutting down your appetite, slowing digestion, and helping you lose weight. These effects can reduce your risk of OSA and help you maintain your cognitive health.
The dual
glucagon-like peptide-1 receptor (GLP-1) and glucose-dependent insulinotropic polypeptide receptor (GIP) agonist can cut as many as 29 sleep interruptions per hour and may improve sleep quality.
“Weight loss, including through medications or surgery, often improves sleep apnea severity, though many patients still need additional treatment,” Fong-Isariyawongse says.
Surgical treatments for more-advanced cases of OSA, including implanted nerve stimulation devices and airway clearance surgery, also can lessen daytime sleepiness and its cognitive effects, she says.
OSA doesn’t just cause short-term fogginess. Without treatment, it can also speed up cognitive decline, Fong-Isariyawongse says.
People with untreated OSA are 12 percent more likely to develop any type of
dementia and have a 29 percent greater risk of developing vascular dementia, the result of reduced blood flow to your brain.
“Sleep is when the brain clears out toxic waste products. When sleep is repeatedly interrupted, those waste products, including proteins linked to Alzheimer’s (disease), can build up faster,” Fong-Isariyawongse says.
If you already have a neurodegenerative brain condition such as Alzheimer’s, you may be especially vulnerable to the long-term effects of OSA. The hippocampus in people with OSA may be significantly smaller than in people with cognitive problems but no OSA.
OSA also can have a long-term effect on sleep itself. Sleep is restorative, in that it helps you restore and strengthen memory and thinking skills. But if your OSA is untreated for years, your sleep patterns are not as helpful to your brain. That can make it harder to maintain clear thinking and memory over time.
Spotting the symptoms of OSA early and starting treatment boosts your chances of protecting your brain long-term, Fong-Isariyawongse says. The longer OSA causes oxygen deprivation and sleep disruption, she says, the harder it is to reverse some changes to your brain.
Improvement timelines vary. Some happen quickly, she says, but the most significant gains in memory, attention, and executive function typically happen after 6 to 12 months of consistent treatment.
“Brain activity patterns also begin to normalize, which suggests real recovery is happening,” Fong-Isariyawongse says.
CPAP therapy has the strongest evidence of improving brain health. People who have used CPAP for more than 20 years may get rid of the added dementia risk that typically comes with OSA.
“While more long-term research is still needed, the direction of the evidence is reassuring,” Fong-Isariyawongse says. “The key message is that treating sleep apnea in any effective way is better than leaving it untreated.”
Sticking to your OSA treatment is key for it to work. About half of people prescribed CPAP therapy drop it after two years, for example.
But those who continue it as their doctor recommends may not only see cognitive improvements; they may also lower their risk of heart issues and other complications.
In addition to OSA treatment, you can help protect your brain health with the following habits:
- Stay engaged. If you don’t regularly challenge your brain, it will lose connections and be less capable of resisting damage. “Learning a new skill, taking a different walking route, or even hiking a new trail forces the brain to build new connections,” Fong-Isariyawongse says. Socializing with friends and having conversations also helps you stay sharp.
- Exercise regularly. Moving your body daily — even if only for 10 minutes — can help protect your brain from decline. “Regular physical activity increases blood flow to the brain and has been shown to increase brain volume and strengthen connections between brain cells,” Fong-Isariyawongse says.
- Get enough sleep. “Consistent, good-quality sleep gives the brain time to repair and clear waste products,” Fong-Isariyawongse says. Most adults should aim for seven to nine hours per night.
- Eat a healthy diet. Certain nutrients can have brain-protective effects. Vitamin E, B vitamins, and omega-3 fatty acids in particular may help improve or maintain brain function. Focus on eating green, leafy vegetables, fatty fish, nuts, eggs, whole grains, berries, and plant oils — all of which deliver these brain-boosting nutrients.
- Limit alcohol and avoid smoking. Drinking lots of alcohol and smoking can worsen OSA and, by extension, brain function, Fong-Isariyawongse says.
- Obstructive sleep apnea (OSA) can interfere with how your brain restores memory and thinking skills. Without treatment, it raises the risk of both short- and long-term cognitive problems.
- Risks of untreated OSA include brain fog, slower thinking, and higher risks of accidents and job-related problems. Longer-term issues include an increased risk of dementia.
- After starting OSA treatment, you may notice improvements to your alertness, memory, mood, and sleep.
- In addition to getting OSA treatment, aim to exercise regularly, get enough sleep, and follow a healthy diet to help boost your cognitive health.
