Sleep is important to the brain—and research has repeatedly linked dementia, including Alzheimer’s. Apparently, this applies not only to sleep through the night, but to afternoon naps too—as a new study shows.
What is the relation of restful sleep during the day to Alzheimer’s? A lot, as American researchers are now able to show. Napping during the day is clearly not the only indication that a person may already have Alzheimer’s disease. It also signals earlier in the disease that the risk of getting this type is increased. Madness prepared.
How did the studies go?
The study was conducted by a research team from Harvard and the University of San Francisco. Their study was based on data from 1,401 seniors who had been part of the Rush Memory and Aging Project at the Rush Alzheimer’s Disease Center in Chicago for 14 years.1 The mean age of the group of participants was 81 years and about 75 percent were female. At the start of the study, 75.7 percent of the seniors had no cognitive impairment. 19.5 percent already had mild cognitive impairment, while 4.1 percent were Alzheimer’s patients.
As part of the project, subjects wore trackers that recorded their movement. Long periods of inactivity between 9 a.m. and 7 p.m. were counted as a nap. The tracker was used by seniors for 14 days at a time and recorded data round the clock during this period. In addition, study participants underwent a series of neurological tests once a year to assess their cognitive abilities.
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Alzheimer’s patients blink six times more
In fact, data from the long-term study led to some interesting insights into the link between naps and Alzheimer’s. It turned out that the duration of the nap plays a role. Individuals in the trial who had a healthy start and showed no cognitive decline during the study period increased daily naps by an average of eleven minutes per year. So it represents a “normal” adjustment to old age.
Those who developed mild cognitive impairment during the study period had twice the rate of increase, for a total of 24 minutes per day. The test subjects’ sleep duration increased rapidly after a diagnosis of Alzheimer’s: their daily naps increased by 68 minutes.2
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Sleeping more than an hour a day increases risk of Alzheimer’s by 40 percent
But the researchers discovered even more. Namely, the link between napping and Alzheimer’s also appears to exist in the other direction. So clearly long naps are not just an indicator that someone may be suffering from Alzheimer’s disease. It also indicates an increased risk of disease in people who are still healthy.
The scientists compared data from subjects who developed Alzheimer’s within six years with data from subjects who remained mentally healthy. It was noted that study participants who slept more than an hour a day had a 40 percent higher risk of developing this form of dementia than those whose daily naps were less than an hour. In addition to sleep duration, frequency also plays a role. People who nap every day have a 40 percent higher risk of developing Alzheimer’s than those who don’t close their eyes to take a nap every day.
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Could there be a change of mind behind this?
The present study cannot provide an explanation for the results. Nor does it prove that relation is causal. So, sleeping longer during the day leads to Alzheimer’s or vice versa, that Alzheimer’s – and in what way – is to blame when naps become more frequent and last longer.
But researchers believe a previous 2019 study suggests a reason why daytime sleepiness and Alzheimer’s are related. This study compared the brains of deceased people with and without Alzheimer’s. The latter contained, among other things, fewer wakefulness neurons in three areas of the brain.3
Yu Leng, co-led study authors, said, “It is plausible that the association we observed between excessive daytime naps at baseline and increased risk of Alzheimer’s disease during follow-up may reflect the effects of Alzheimer’s pathology in preclinical stages.” can represent.” Professor in the UCSF Department of Psychiatry and Behavioral Sciences.
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conclusion
While it cannot (yet) be said with certainty that naps cause mental decline and thus Alzheimer’s, the researchers consider the results of the study to be highly remarkable. According to Leng, the study shows for the first time that naps during the day and Alzheimer’s “appear to drive interpersonal changes in a bidirectional manner”. Furthermore, the data collected indicate that extended blinking may be a recognizable warning sign. “It will be very interesting to investigate in future studies whether afternoon naps can help slow age-related cognitive decline,” says Leng.
sources say
- 1. Leng Y, Li P, Gao L et al. (2022). Daytime naps and Alzheimer’s dementia: a possible bidirectional relationship, Alzheimer’s and Dementia.
- 2. Leigh, S (2022). Extended napping may signal dementia in seniors. University of CaliforniaA San Francisco.
- 3. Oh, J., Aser, R. A., Ehrenburg, A. J. et al. (2019). Profound degeneration of wake neurons in Alzheimer’s disease. Alzheimer’s and Dementia.
