A common daytime habit among many older adults could increase their risk of developing dementia, a new study suggests.
Researchers at Johns Hopkins University said daytime naps, particularly their frequency, intention and duration, influenced the risk of developing dementia.
However, experts stressed that the findings were observational and do not establish that napping directly causes dementia. The study was published online in Gerontology journals: medical sciences on October 5.
These findings follow previous research in the field, some of which indicated that sleepiness was associated with an abnormal accumulation of dementia-associated proteins in the brains of otherwise healthy adults, said Dr. Andrew Varga, a sleep neurologist and neuroscientist at the Icahn School of Medicine at Mount Sinai. News week.
Daytime napping influenced dementia risk
Researchers looked at clinical data from nearly 1,000 U.S. Medicare users who were at least 65 years old and did not have dementia when the study began in 2013. They followed the participants for up to 10 years.
They found that those who nap frequently, meaning almost every day or every day, had a 48% higher risk of developing dementia than those who rarely or never nap.
The researchers said this was the case even after taking into account several demographic factors, such as health conditions and nighttime sleep characteristics.
Involuntary napping, meaning falling asleep without wanting to, was also associated with a 39% higher risk of developing dementia.
They also identified that nap duration also had an impact. Sleeping during the day for 30 minutes or less was associated with a 40% higher risk.
A “two-way” association
The scientists noted that the association may have a “bidirectional” character, meaning that cognitive decline may cause more frequent intentional and unintentional napping, as well as napping potentially increasing disease risk.
Varga said that as amyloid and tau proteins — which are associated with the development of dementia — “begin to accumulate and neurons begin to malfunction or die, some of the first neurons affected are those that control the regulation of sleep and wakefulness as well as the circadian rhythm.
“This means that periods of sleep may occur during the day at inappropriate times,” he said.
However, while the researchers followed some participants who did not have dementia at the start of the study for 10 years, they said the results seem to suggest that napping habits may have an influence on the development of dementia, and not just be a reflection of the disease.
How might napping affect dementia risk?
Regarding how napping might affect dementia risk, Adam Spira, the study author and professor of mental health at Johns Hopkins University, said: News week it is possible that daytime napping could affect nighttime sleep.
“This is important because nighttime sleep disturbances are linked to brain changes associated with dementia, such as the accumulation of proteins like beta-amyloid and increased neuroinflammation,” he said.
He added, in particular, that “naps can reduce the ‘homeostatic sleep drive,’ the body’s natural drive toward sleep that builds up throughout the day, potentially disrupting nighttime sleep.”
Lack of sleep and sleep apnea “have been shown to increase the risk of dementia, with proposed mechanisms including increased production of amyloid and tau (the bad proteins that accumulate in Alzheimer’s disease), decreased clearance of amyloid and tau from the brain, increased inflammation, and impaired immune function,” Varga said.
Dr Omonigho Bubu, director of the Aging Research in Sleep Equity and Dementia Prevention program at New York University, said: News week that daytime napping may also reflect “underlying sleep disturbances, excessive daytime sleepiness, or early neurodegenerative changes already affecting brain systems that regulate sleep and wakefulness.”
“In this sense, napping may be either a contributing factor or a warning sign, or both,” he said.
What the results mean
Kening Jiang, first author of the study and a postdoctoral researcher at Johns Hopkins University, said News week the findings suggest that daytime napping “could be an important potential risk factor for dementia” and “highlight the importance of considering daytime napping, in addition to nighttime sleep, as napping behaviors may help identify older adults at higher risk of dementia and inform dementia prevention strategies.” »
“However, whether daytime naps cause dementia has not yet been established, and further research is needed to understand whether this is a causal relationship,” he said.
Varga said it’s important to note that “not all naps are bad, and they have documented benefits,” but it becomes a concern when “naps are a response to either insufficient nighttime sleep or sleep of sufficient duration but interrupted by a disorder.”
Bubu said the findings suggest that “daytime sleep behaviors should not be neglected in older adults.” He added that “the key message is not that all naps are harmful, but that changes in nap habits deserve attention.”
Reference
Kening Jiang, Alden L Gross, Catriona Tingsea Wu, Junxin Li, Halima Amjad, Emerson M Wickwire, Jennifer S Albrecht, Atul Malhotra, Chien-Yu (Irene) Tseng, Marc Kaizi-Lutu, Chunyu Liu, Christopher N Kaufmann, Adam P Spira, (2026) Nap characteristics and incident dementia: results from the National Health and Aging Trends Study, The gerontology journals: series A. https://doi.org/10.1093/gerona/glag208
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Contact Newsweek editors about this story: Kara Dolman And Paul Donnelley.
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