A recent study published in the journal “Alzheimer’s & Dementia” provides insights into the relationship between sleep duration and Alzheimer’s disease.
Researchers found that people who sleep an average of more than 8.5 hours per night have higher levels of a biomarker called p-tau181 in their blood. This suggests that long sleep duration may be one of the earliest signs of neurodegenerative brain changes, writes postimees.ee.
Study
The study analyzed health data from 2410 people. The average age of participants was 70 years. Slightly more than half of the participants were women. To get the most comprehensive picture of the relationship between sleep and biomarkers, the study included both healthy individuals and those with mild cognitive impairment, dementia, or a history of stroke.
Participants were asked about their usual night’s sleep duration. Blood samples were also taken to examine Alzheimer’s disease-related biomarkers – substances that can indicate brain changes.
When analyzing the results, researchers also considered other factors that could influence sleep and brain health. These included age, sex, kidney function, depression, sleep apnea, and genetic predisposition to Alzheimer’s disease.
Results
Most study participants (61%) slept between six and nine hours per night. Another 24% slept up to six hours, and 15% slept longer than nine hours.
According to “Medical News Today”, those who slept longer than nine hours were generally older, more often suffered from depression, used antidepressants, and more frequently had dementia.
Although the levels of all studied biomarkers tended to increase with longer sleep duration, a statistically significant association was found only with the p-tau181 biomarker. Researchers identified the following patterns:
Read more Romania condemns Russia: three Russian drones shot down in Romania in three days
- People who slept between 6 and 9 hours had the lowest p-tau181 biomarker level.
- People who slept more than 8.5 hours had a higher level of this biomarker than those who slept 6–9 hours.
- People who slept at least 10 hours had the highest p-tau181 biomarker level.
- People who slept up to 6 hours also had a slightly higher biomarker level than those who slept 6–9 hours.
Is long sleep a cause or a consequence of the disease?
Neurologist Dr. Steven Allder commented that while this study does not prove that sleep disturbances cause Alzheimer’s disease, they may be an early sign of the disease.
He also emphasized that sleep duration alone does not indicate its quality. A person spending nine or ten hours in bed may actually be sleeping very fragmentedly and constantly waking up at night, even without realizing it. Since deep sleep is important for the brain’s cleansing from metabolic waste, fragmented sleep can disrupt these processes.
According to S. Allder, many dementia specialists believe that changes in sleep rather reflect changes already occurring in the brain, rather than causing them. People may start sleeping longer even before the first memory impairments appear and not notice it themselves.
To determine whether long sleep is a risk factor for Alzheimer’s disease or an early sign of it, long-term studies are needed to monitor the sleep of healthy individuals and Alzheimer’s disease-related biomarkers over many years.
Development of Dementia
The development of dementia is influenced by many factors, including genetics, vascular health, lifestyle, and natural aging. Sleep is just one part of this complex picture.
To maintain good brain health in the long term, experts recommend:
Read more In Rokiškis district – burial of the remains of 15 partisans and their relatives killed by Soviets
- getting enough sleep;
- exercising regularly;
- taking care of cardiovascular health;
- keeping the brain active, for example, by reading, solving puzzles, or learning new things.
