According to a study published on August 30, 2021 in the journal JAMA Neurology, how long older adults sleep affects their brain health.
The study authors wrote that sleep disruption is common in later life and is associated with changes in cognitive function — the mental ability to learn, think, think, problem-solve, make decisions, remember and pay attention.
Because age-related changes in sleep are associated with early symptoms of Alzheimer’s disease, depression, and cardiovascular disease, the authors examined associations between self-reported sleep duration, demographic and lifestyle factors, subjective and objective cognitive functioning, and participant levels. . beta amyloid.
Research shows that too little or too much sleep has different effects on brain health in older adults.
Elevated beta amyloid “significantly increases” the risk of dementia among people who sleep 6 hours or less, said Joe Wiener, a postdoctoral fellow in the study. via e-mail to Stanford University, California.
This was compared to participants who reported normal sleep duration, which the study authors defined as seven to eight hours of sleep per night.
Sleep-deprived older adults performed significantly worse on tests commonly used in older adults to assess cognitive abilities, including orientation, attention, memory, language, and visuospatial abilities; identify mild dementia.
Although excessive sleep was associated with poorer performance, those subjects did not have increased beta amyloid levels. Participants who reported long sleep duration (nine or more hours) scored slightly worse on the Digit Substitution Test than those who reported normal sleep duration. For more than a century, this test has been used to assess associative learning by testing the ability to correctly match letters to numbers according to a button on a page within 90 to 120 seconds.
“The bottom line is that healthy sleep is important later in life,” Wiener said in an email. “In addition, both those who slept too little and those who slept too much had (body mass index and) more depressive symptoms.” The findings suggest that short and long sleep may be associated with different disease processes, Wiener added.
Beta amyloid 101
Beta amyloid, or amyloid-β, is “a protein that is produced during normal brain cell activity, but we still don’t know much about its function,” Wiener said.
“Amyloid-β is one of the first signs of Alzheimer’s disease progression,” Wiener said. “In Alzheimer’s disease, amyloid-β protein begins to accumulate in the brain and become attached to plaques. Amyloid plaques are more likely to form as we age, and many people with amyloid deposits in their brains remain healthy. About 30 percent of healthy 70-year-olds have large amounts of amyloid plaques in their brains. “
According to the Alzheimer’s Association, brain cells in people with Alzheimer’s disease are less able to acquire, process and store information and die. One of the main theories to blame for this damage, the “amyloid hypothesis,” suggests that protein deposits disrupt communication between brain cells, eventually killing them.
Previous research has shown that “sleep can limit amyloid build-up in the brain and support the drainage system that clears it,” said Laura Phipps, head of Alzheimer’s Research UK, who was not involved in the study. by email.
Phipps added that amyloid-β begins to accumulate years before Alzheimer’s symptoms appear. “This makes it difficult to distinguish between cause and effect when studying sleep problems and Alzheimer’s risk, especially if you only look at data from one point in time.”
Sleep, depression, and socio-demographics
The current study analyzed 4,417 participants with an average age of 71.3, mostly white, from the United States, Canada, Australia, and Japan.
Both the short and long sleeper groups reported more depressive symptoms than the normal sleeper group. Self-reported caffeine consumption was unrelated to sleep duration. But the more alcohol participants drank each day, the more likely they were to sleep longer.
There were also differences between gender and race and ethnicity: being female and having more years of education were significantly associated with sleeping longer each night. Weiner said blacks or African-Americans slept an average of 37.9 minutes less than whites, who said they slept an average of seven hours and nine minutes. Asian participants reported 27.3 minutes less than whites, and Latino/Hispanic whites 15 minutes less.
These findings suggest that sleep disparities in cardiovascular and metabolic health, socioeconomic factors, and “racial and racial disparities” are linked to imbalances in other aspects of life. the authors wrote that it shows that
Remaining questions
“To better understand the sequence and direction of causality in these relationships, further research is needed to build a picture of how sleep patterns, biological processes, and cognitive abilities change over time,” Phipps said.
“This new study comes from a large international study of cognitively healthy people, but it relied on participants reporting their sleep duration rather than measuring their sleep duration.
