- A new study published in Neurology indicates that sleep apnea and a lack of deep sleep are associated with poorer brain health.
- Findings from the research suggest that people who spend less time in deep sleep are more likely to have brain biomarkers associated with a heightened risk of stroke, Alzheimer’s disease, and cognitive decline.
- Sleep apnea is a chronic sleep disorder that can also increase other health risks, including cardiovascular disease and hypertension.
The sleep disorder sleep apnea is often — but not always — hallmarked by snoring, a nuisance for bed partners.
However, it’s more than a pesky, inconvenient problem.
Now, a new study is associating sleep apnea with poorer brain health, too.
The research, published Wednesday in the online issue of Neurology, the medical journal of the American Academy of Neurology, involved looking at sleep factors and biomarkers of brain health.
Researchers suggested that individuals with sleep apnea who spend less time in deep sleep are more likely to have brain biomarkers associated with a heightened risk of stroke, Alzheimer’s disease, and cognitive decline.
“These biomarkers are sensitive signs of early cerebrovascular disease,” said study author Diego Z. Carvalho, MD, MS, of the Mayo Clinic in Rochester, Minnesota, and a member of the American Academy of Neurology in a media release. “Finding that severe sleep apnea and a reduction in slow-wave sleep are associated with these biomarkers is important since there is no treatment for these changes in the brain, so we need to find ways to prevent them from happening or getting worse.”
One sleep expert believes studies like this one are critical to raising awareness about brain health, sleep apnea, and ways people can reduce their risk for adverse outcomes (and developing the condition in the first place).
“Your family history of Alzheimer’s and your genes do not define your destiny for brain aging,” says David Merrill, MD, Ph.D., an adult and geriatric psychiatrist and director of the Pacific Neuroscience Institute’s Pacific Brain Health Center in Santa Monica, Calif. “Studying the brain effects of lifestyle factors demonstrates that what we do matters and really makes a difference in how successfully we age.”
But the study does have its limitations.
The study included 140 people with an average age of 73. Every participant had obstructive sleep apnea but did not have dementia before the study.
The pool was split fairly evenly between people with mild (34%), moderate (32%), and severe (34%) sleep apnea.
Each participant had undergone a brain scan and overnight sleep study in a lab. The latter looked at the duration people spent in “deep sleep” (also known as non-REM stage 3 or slow-wave sleep).
Why? Because time spent in this stage is a good indication of sleep quality.
None of the participants developed dementia during the study. However, researchers’ findings do suggest declining brain health.
For every 10-point decrease in deep sleep a person experiences, white matter hyperintensities increased.
These increases were the equivalent of being 2.3 years older. So, a person whose slow-wave sleep decreased by 20 percentage points had the white matter hyperintensity amounts of a person 4.6 years older.
Further, each 10-point decrease in slow-wave sleep lowered axonal integrity equal “similar to the effect of being three years older.” The more severe a person’s sleep apnea was, the higher volume of white matter hyperintensity and lower axonal integrity their brains had.
That might feel like a ton of jargon.
Put more simply:
“Lack of slow-wave sleep, in this case, due to sleep interruption from sleep apnea, results in effectively, a mild form of brain damage, or at least aging, by about two years for every 10% loss of slow-wave sleep,” says Alex Dimitriu, MD, who is double board-certified psychiatry and sleep medicine and founded Menlo Park Psychiatry & Sleep Medicine. “This is consistent with the theory that the brain needs slow-wave sleep to clean itself up and prepare for the next day.”
However, correlation doesn’t necessarily equate to causation.
Researchers were able to indicate an association between these sleep disturbances and brain changes. They cannot say whether this association causes the alterations or vice versa.
Dimitriu says loud snoring is a common symptom of sleep apnea. But not everyone who snores has sleep apnea. People with sleep apnea experience pauses in breathing.
“The brain panics and wakes up to restore normal breathing,” Dimitriu says.
The drawback? Constant sleep fragmentation.
“People with sleep apnea sometimes wake several times in the night, often to use the bathroom,” Dimitriu says. “Others may sleep through it but snore or have gaps in their breathing. People with sleep apnea will often feel sleepy during the day, have a tendency to doze off, or drink too much coffee.”
Dimitriu says that risk factors for sleep apnea include being overweight and having a small jaw. Nasal congestion and allergies can exacerbate the issue.
Diagnosis is critical.
“Assessing the quality of your sleep is important because getting adequate oxygen to the brain throughout the night results in a healthier brain,” says Merrill. “This can be done in collaboration with your doctor in a sleep lab or even at home with a home sleep apnea test.”
There are steps people can take to reduce sleep apnea risks, and people who have been diagnosed with the conditions have treatment options.
Harneet Walia, MD, the director of sleep medicine and continuous improvement at Miami Cardiac & Vascular Institute, shared some ways to prevent or treat sleep apnea such as lifestyle modifications that include:
- Weight loss. “Diet and exercise can help. Talk to your provider if you are struggling,” Walia says.
- Sleep posture. “Avoid sleeping on the back, as sometimes people may experience sleep apnea when lying on their back,” Walia says.
- Treating nasal congestion, such as with allergy medications.
Should a person be diagnosed with sleep apnea, Walia says the mainstay treatment is a Continuous Positive Airway Pressure (CPAP) device, which delivers air pressure to keep airway passage open, reducing or eliminating snoring and sleep apnea risks.
“Surgical interventions, such as hypoglossal nerve stimulation, [are possible] for patients who are intolerant to CPAP therapy and who have moderate to severe obstructive sleep apnea,” says Walia.
Whether you have sleep apnea or not, experts share that sleep quality is important for your overall well-being.
- Maintain a regular sleep/wake schedule seven days per week. Yes, even on weekends. “If my patients share that they have a lot of variability in their schedules, I often tell them to start off by waking up every day at the same time,” Walia says. “This serves as an anchor point for maintaining the regularity of the schedule.”
- Set screens aside. “Avoiding electronics in the nighttime, especially closer to bedtime, is key because the blue light emitted from those devices could suppress melatonin…thereby potentially disrupting sleep,” Walia says.
- Do something “uninteresting.” Don’t toss and turn, trying to fall asleep. “If you’re unable to sleep within 20 minutes of laying down, then leave the bedroom and do something uninteresting, coming back only when sleepy,” Walia says. “The idea is to train the mind to sleep, not to lie down and think about stuff.”
- Avoid naps. “It is key to avoid taking naps close to bedtime,” Walia says. “If someone must take a nap, it should only last 20 minutes and should be done during the earlier part of the day so they can fall asleep at bedtime.”
- Maintain an environment that promotes good sleep. “Design your sleep environment to establish the best conditions for sound sleep,” Walia says. “Your bedroom should be comfortably cool and free from any noise or light that can disturb your sleep.”
If you have difficulty sleeping, this new study may give you one more reason to worry (and perhaps lose sleep). But Merrill advises against feeling discouraged.
“Poor sleep quality is associated with worse brain health, but that doesn’t mean you need to lose hope,” Merrill says.
Changes and discussions with your healthcare provider can help you course-correct.