Not Getting Enough Deep Sleep Could Raise Risk of Dementia

2 min read

Oct. 31, 2023 -- People who don’t get enough deep sleep could face a higher risk of developing dementia later in life, researchers say in a new study.

“We found that aging was associated with a decline in the amount of the deepest stages of sleep, known as slow wave sleep,” said Matthew P. Pase, senior author of the study published in the journal JAMA Neurology, in an email to CNN. Pase is an associate professor of psychology and neurology at Monash University in Australia. “We then found that persons with greater declines in slow wave sleep over time had a higher risk of getting dementia over the next 17 years of follow-up.”

During slow wave sleep, the body removes unwanted material from the brain, including beta-amyloid protein, a hallmark sign of Alzheimer’s disease, CNN reported.

Deep sleep is the third sleep stage, and is thought to be the most restorative, Richard Isaacson, MD, of the Institute for Neurodegenerative Diseases in Florida, told CNN. He did not work on the study.

Researchers examined 346 people who were, on average, 69 years old and had participated in a federal program identifying cardiovascular risk. Participants had completed two overnight sleep studies beginning in the 1990s.

Within 17 years of completing the sleep studies, 52 participants had dementia. 

“Each percentage decrease in slow-wave sleep per year was linked with a 27% increased risk of developing dementia and a 32% higher risk of Alzheimer’s disease dementia,” CNN reported. “The rate of slow-wave sleep loss accelerated from age 60, peaked from ages 75 to 80, and slowed afterward.”

Isaacson said the study shows how sleep quality can affect cognitive decline and dementia. 

“It’s important to not only pay attention to the total amount a person is sleeping each night, but also monitor sleep quality as best as possible,” he said.

Show Sources

JAMA Neurology: “Association Between Slow-Wave Sleep Loss and Incident Dementia.”

CNN: “Getting less slow-wave sleep as you age may increase your risk of dementia, study finds.”

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