"The groundwork of all happiness is health." - Leigh Hunt

Too little deep sleep can increase the chance of dementia

Oct. 31, 2023 — People who don't get enough deep sleep could also be at higher risk of developing dementia later in life, researchers say in a new study.

“We found that aging is associated with a decline in deep sleep phases known as slow-wave sleep,” Matthew P. Pase, senior creator of the study published within the journal JAMA Neurology, said in an email CNN. Pase is an associate professor of psychology and neurology at Monash University in Australia. “We then found that individuals with a greater decline in slow-wave sleep over time had a higher risk of developing dementia over the next 17 years of follow-up.”

During deep sleep, the body removes unwanted substances from the brain, including beta-amyloid protein, a trademark sign of Alzheimer's disease, CNN reported.

Deep sleep is the third phase of sleep and is taken into account probably the most restful, said Dr. Richard Isaacson of the Institute for Neurodegenerative Diseases in Florida told CNN. He didn't work on the study.

Researchers studied 346 people, on average 69 years old, who had participated in a federal program to discover cardiovascular risks. Participants had accomplished two overnight sleep studies starting within the Nineties.

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

“Each percentage decrease in deep sleep per year was associated with a 27% increased risk of developing dementia and a 32% increased risk of Alzheimer's dementia,” CNN reported. “The rate of slow sleep loss accelerated starting at age 60, peaked at age 75 to 80, and slowed thereafter.”

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

“It's important to pay attention not only to how much total sleep a person gets per night, but also to monitor sleep quality as best as possible,” he said.