Does Poor Sleep Cause Dementia?

By Temma Ehrenfeld @temmaehrenfeld
April 19, 2021

Poor sleep increases your risk of dementia. Here’s why, and how you can improve your sleep hygiene and maintain your brain health.

Not to give you another worry to lose sleep over, but there’s even more reason now to see what you can do to improve your rest.

In a large meta-analysis, when researchers pooled data from 51 studies around the world covering more than 2,800 volunteers, the team found that having sleep issues dramatically increased your chance of developing dementia. Lack of sleep also increased your chance of dying within five years.


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What are the signs of poor sleep?

Just to be clear: it is normal to go to bed and wake up earlier when you’re older. With age, you tend to sleep less and take longer to fall asleep.

But it’s a matter of degree. In the study, researchers found that if you lie awake for a half hour or more before you fall asleep, your chance of dementia was 45 percent higher than for people who fall asleep quickly. People who slept five or fewer hours a night typically were twice as likely to develop dementia as people who slept seven to eight. If participants had sleep apnea, their risk went up, too.

Sleeping more than 8 hours routinely also may mean you’re at greater risk of cognitive decline decades later, according to a study of more than 2,300 Finnish twins.

In other research, scientists have developed a way to assess your chance of dementia through electroencephalogram, or EEG, measurements while you sleep. A higher Brain Age Index shows deviation from normal brain aging, which could be a sign of cognitive decline caused by dementia.

What’s the connection to dementia?

Sleep deprivation increases the levels of amyloid-beta in your brain. The protein eventually clumps into what’s called amyloid plaques. Just one night of sleep loss causes an increase of the protein, which is a waste product. The plaques are one tell-tale sign of Alzheimer's disease, although not all dementia patients have them. Those who do tend to have more sleep issues.

Once you have dementia, you’re at risk of certain sleep disorders, including restless legs syndrome and a tendency to act out your dreams. People with dementia may shout, grab, and jump during the night while dreaming.

What can you do to improve your sleep?

  • Maintain a regular schedule. Create a soothing bedtime routine that doesn’t involve light from electronic screens. Take a bath, read print material, listen to music on headphones, pray or talk to a loved one.
  • Don’t nap more than once a day. Limit naps to a half hour.
  • Exercise, as long as you stop well before an hour before bedtime.
  • Get natural sunlight during the day, or use a sunlamp.
  • Stay away from caffeine, alcohol, and nicotine at night.


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April 19, 2021

Reviewed By:  

Janet O’Dell, RN