A Lack of Sleep in Middle Age Can Increase the Risk of Dementia

Experts say the brain goes through a cleansing process while you’re asleep. Westend61/Getty Images

Researchers say getting adequate sleep in your 50s and 60s can lower your risk for dementia later in life.In their study, research…

Experts say the brain goes through a cleansing process while you're asleep. Westend61/Getty Images
  • Researchers say getting adequate sleep in your 50s and 60s can lower your risk for dementia later in life.
  • In their study, researchers reported that people who got 6 hours or less sleep per night were 30 percent more likely to develop dementia.
  • Experts say the final hours of sleep are crucial — that's when the brain goes through a cleaning-up process.

Go ahead, get that extra hour of sleep. Your brain may thank you later.

New research suggests that people not getting enough sleep in their 50s and 60s may be increasing their chances of developing dementia later in life.

The study, published last week in the journal Nature Communications, followed nearly 8,000 people in Great Britain for about 25 years, beginning when they were about 50 years old.

The subjects who reported averaging 6 hours or less sleep a night were 30 percent more likely to develop dementia than those who regularly averaged 7 hours or more of sleep per night.

Doctors say that even an extra hour of sleep can make a difference when it comes to the brain getting its necessary internal work done.

“We’ve discovered that sleep and memory consolidation are related,” Dr. Abhinav Singh, the facility director of the Indiana Sleep Center, told Healthline. “It is during different sleep stages and their cycling that new memories and information are processed, the excess and negative memories are removed, and the archiving of contextual memories take place.

“Emotional memory processing also takes place during our sleep cycles,” Singh said. “The last two hours of sleep are rich with REM sleep, and more evidence is coming that this is an important phase of sleep that helps us with memory consolidation and emotional memory. And if you deprive yourself of these last two hours, you are going to impair that process.”

How the brain cleanses itself

The brain takes the time in the final hours of sleep to literally take out the trash and clean up, Dr. Chelsie Rohrscheib, a neuroscientist and sleep specialist at sleep technology company Tatch, told Healthline.

“Our brain and body undergo many essential biological functions that only occur during sleep, including clearance of toxic waste products that build up in the brain,” Rohrscheib said. “The accumulation of a specific type of brain waste called beta-amyloid is thought to be the primary cause of Alzheimer’s disease.

“Most of the removal of beta-amyloid occurs during the deepest stages of sleep,” Rohrscheib said. “When sleep is restricted to less than seven hours, the brain has less time to clear beta-amyloid away, leading to toxic levels of accumulation and raising the risk of developing Alzheimer’s.”

Cause and effect

Opinions differ over whether the lack of sleep in people in their 50s and 60s could be a symptom of other underlying conditions leading to dementia.

“This study does not establish a causal relationship between dementia and short sleep duration,” Dr. Zeeshan Khan, the medical director for the Institute for Sleep Medicine at Deborah Heart and Lung Center in New Jersey, told Healthline. “It simply makes an association between the two. Insufficient sleep may be an early sign or risk factor for dementia.”

The study factored in other causes believed to lead to dementia, including smoking, alcohol consumption, exercise, body mass, education level, conditions such as diabetes, and mental illness. There were no noteworthy differences found by gender.

The effect of sleep on overall health is something that hasn’t necessarily been studied extensively until recently. Some doctors say it doesn’t help that in some cultures, work time is frequently valued over devoting equal time to sleep.

“Some countries and cultures, for example the U.S.A. and Japan, prioritize work and accomplishments over getting sufficient sleep,” Rohrscheib said. “For many years, sleeping less than 7 hours was seen as a badge of honor. Within recent decades, science has demonstrated the long-term damage sleep loss does to the brain and body, but unfortunately, it will take time for cultural norms to shift in a positive direction.”

How to sleep well

Rohrscheib said people should aim for a consistent schedule of 7 to 9 hours of sleep per night.

Bedrooms should be cool, comfortable, dark, and quiet.

She said pre-sleep relaxing routines should start an hour before bed and people should avoid light-emitting devices.

Caffeine should be avoided for 8 hours before bedtime and stress factors need to be dealt with before hitting the sack.

Dr. Kate Burke, a senior medical advisor at PatientsLikeMe, said new research suggests four or five healthy lifestyle factors can reduce the risk of dementia by 60 percent, compared to adopting none or only one.

Exercise, formal education, and cognitive stimulation may reduce dementia risk as does avoiding smoking and alcohol.