How long older people sleep may affect their brain health, according to a study published Monday in the journal JAMA Neurology.
Sleep disturbances are common at the end of life, the study authors wrote, and are associated with changes in Cognitive function – the mental capacity to learn, think, reason, solve problems, make decisions, remember and pay attention.
Age-related changes in sleep have also been linked to first signs Alzheimer’s disease, depression and heart disease, the authors therefore investigated possible associations between self-reported sleep duration, demographic and lifestyle factors, subjective and objective cognitive function, and participants’ beta-amyloid levels.
People in the study who reported a short sleep duration – defined in the study as six hours or less – had elevated levels of beta-amyloid, which “dramatically increases” the risk of dementia, said said the study’s lead author, Joe Winer, postdoctoral researcher. at Stanford University in California, by email.
This was in comparison to participants who reported normal sleep duration, which the study authors defined as seven to eight hours of sleep per night.
Seniors with insufficient sleep also scored moderately to significantly lower on tests commonly used on the elderly to assess cognitive abilities, including orientation, attention, memory, language, and visual skills. -spatial; and identify mild dementia.
Sleeping too much was also associated with poorer executive function, but these people did not have high levels of beta-amyloid. Participants who reported a long sleep duration (nine hours or more) scored slightly worse on the number symbol substitution test than those who reported normal sleep duration. For more than a century, this the test evaluated associative learning skills by observing the candidates’ ability to correctly match symbols to numbers according to a key on the page within 90 to 120 seconds.
“The main point to remember is that it’s important to maintain healthy sleep late in life,” Winer said via email. “In addition, people who sleep too little and people who sleep too much had higher symptoms (body mass index and) more depressive.” The results suggest that short and long sleep could involve different underlying disease processes, Winer added.
BETA AMYLOIDDE 101
Beta-amyloid or amyloid-β is “a protein created during normal brain cell activity, although we are still not sure what its function is,” Winer said.
“Amyloid-β is one of the first detectable markers in the progression of Alzheimer’s disease, said Winer.“ In Alzheimer’s disease, amyloid-β proteins start to build up throughout the brain , sticking together in plates. Amyloid plaques are more likely to appear with age, and many people with amyloid that has accumulated in their brains remain healthy. About 30% of healthy 70-year-olds will have substantial amounts (of) amyloid plaques in their brains. “
When a person has Alzheimer’s disease, the person’s brain cells that collect, process and store information degenerate and die, according to the Alzheimer Association. The “amyloid hypothesis”, one of the main theories about the culprit behind this destruction, suggests that the buildup of the protein could disrupt communication between brain cells, eventually killing them.
Previous research has suggested “that sleep can both help limit the production of amyloid in the brain and support the drainage system that clears it,” said Laura Phipps, communications manager at Alzheimer’s Research UK , who did not participate in the study, by email.
Amyloid-β can start to build up many years before the obvious symptoms of Alzheimer’s disease show up, Phipps added. “This makes it difficult to distinguish between cause and effect when studying sleep problems and Alzheimer’s risk, especially if you only look at the data at one point in time.”
SLEEP, DEPRESSION AND SOCIODEMOGRAPHY
The present study analyzed 4,417 participants with an average age of 71.3 years, mostly white and from the United States, Canada, Australia and Japan.
The short and long sleep groups reported more depressive symptoms than the normal sleep group. Self-reported caffeine consumption was not associated with sleep duration. But the more alcoholic beverages participants drank on a daily basis, the more likely they were to sleep longer.
There were also differences between genders, races and ethnicities: being female and having more years of education were both significantly related to sleeping longer each night. And compared to white participants who reported an average sleep duration of seven hours and nine minutes, Winer said that black or African American participants reported an average sleep duration of 37.9 minutes less. Asian participants reported 27.3 minutes less than White participants, and White Latino or Hispanic participants reported 15 minutes less.
These results suggest that sleep disparities could be associated with disparities in other aspects of life, such as cardiovascular and metabolic health, socio-economic factors, and “racial discrimination and perceived racism” correlated with less. of sleep in previous studies, the authors wrote.
“To better understand the order and direction of causation in these relationships, future research will need to build a picture of how sleep patterns, biological processes, and cognitive skills change over longer periods of time,” said Phipps.
“This new research comes from a large international study of cognitively healthy people, but it relied on participants to report their sleep duration rather than directly measuring it,” she added. “Researchers were unable to assess the quality of sleep or the time spent at different stages of a sleep cycle, each of which may be an important factor in the link between sleep and cognitive health.”
Whether certain cognitive domains are more affected by extreme sleep duration than others also remains controversial, the authors wrote.
Seniors concerned about these findings should consider sleep as important as diet and exercise to their health, Winer said.
“While researchers are still struggling to understand the complex relationship between sleep and our long-term cognitive health, high-quality sleep can be important for many aspects of our health and well-being,” said Phipps. “The best evidence suggests that between seven and nine hours of sleep is optimal for most adults and anyone who thinks their sleep patterns may affect their long-term health should speak to their doctor.”