Sleep problems might be related to cognitive decline—here's what you can do.

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Older adults who have sleep issues have nearly a 30% increased risk of developing dementia, according to a new meta-analysis.

The research, which was published in the Journal of Neurology, Neurosurgery, & Psychiatry, analyzed data on 51 studies of middle-aged and older people in North America, Europe, and East Asia to see if there was a link between sleep issues and mental health over time.

The researchers discovered that a slew of common sleep problems were linked to a higher risk of developing dementia. People with insomnia (a sleep disorder that’s marked by difficulty falling asleep or staying asleep) had a 27% increased risk of developing dementia. Those who had sleep inadequacy, which is defined by not getting enough sleep, were 25% more likely to develop dementia. People who had sleep inefficiency, i.e. they spent too much time awake in bed, had a 24% higher risk of dementia. And those with sleep apnea, a potentially serious sleep disorder where breathing stops and starts at night, had a 29% higher risk of memory loss.

While this sounds surprising, the concept that poor sleep could lead to dementia actually isn’t a new idea. “We’ve suspected this for a long period of time,” board-certified sleep medicine researcher W. Christopher Winter, MD, of Charlottesville Neurology and Sleep Medicine and author of The Sleep Solution: Why Your Sleep Is Broken and How to Fix It, tells Health.

What is dementia, exactly?

Dementia is a term that’s used to describe the loss of cognitive functioning, such as thinking, remembering, and reasoning, as well as behavioral abilities to the point where it interferes with someone’s daily life and activities, according to the National Institute on Aging (NIA). There are different forms of dementia, including Alzheimer’s disease, Lewy body dementia, frontotemporal disorders, and vascular dementia. People with dementia can develop issues with memory, language skills, visual perception, problem solving, self-management, and the ability to focus and pay attention.

Dementia is more common as people age, but it’s not a normal part of getting older, the NIA says.

Why might sleep issues be linked to dementia?

The study didn’t explore this, but lead study author Wei Xu, MD, PhD, a professor of neurology at China’s Qingdao University, has a few theories. Sleep problems might cause inflammation in the brain that can eventually lead to dementia, he tells Health. It also might reduce the efficiency of the brain’s metabolism, like the brain’s ability to transfer waste through its glymphatic system, which could lead to a loss of neural cells, he says. Sleep problems also may lead to the atrophy (or shrinkage) of important areas of the brain, like the hippocampus, which regulates motivation, emotion, learning, and memory, explains Dr. Xu.

There are a lot of different mechanisms that might be behind the link but, overall, it comes down to poor sleep being bad for your health. “Unhealthy bodies lead to unhealthy brains,” says Amit Sachdev, MD, associate medical director for the department of neurology and ophthalmology at Michigan State University.

So can getting better sleep lower your risk of dementia?

It’s hard to say for sure, but Dr. Xu recommends doing the following to improve your sleep, and possibly lower your risk of dementia:

  • Try to get better quality sleep.
  • Don’t sleep for too long or too short period of time. Everyone has different sleep needs, but the National Sleep Foundation recommends that adults between 25 and 64 get 7 to 9 hours of sleep a night, and adults 65 and over score 7 to 8 hours each night.
  • Nap for less than an hour.
  • Try to regulate your sleep patterns to avoid being sleepy during the day—in other words, go to bed and wake up at roughly the same times each day.
  • If you’re diagnosed with a condition like sleep apnea, get treated for it.

Of course, there are many factors that can lower your risk of developing dementia, and sleep management may only be one.

“Three domains are of critical importance: Keeping a healthy lifestyle, controlling your vascular risk factors, and maintaining a balanced mood,” says Dr. Xu. Experts haven’t figured out the exact recipe for preventing dementia, but living a healthier lifestyle and getting a better night’s sleep can’t hurt.

“Better health prevents many ailments, including dementia,” says Dr. Sachdev. “Better sleep is an important feature of health. While dementia is complicated, the decision to sleep better is simple.”

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