Dementia risk may be linked to seemingly harmless daily habit, new research suggests

Frequent daytime napping among older adults has been linked to a higher risk of developing dementia, according to a study published in The Journal of Gerontology: Medical Sciences.

Researchers from the Johns Hopkins Bloomberg School of Public Health tracked nearly 1,000 adults age 65 and older who showed no signs of memory or thinking problems when the study began in 2013.

A decade later, the researchers found that daily rest habits — like how often people nap, how long they sleep and whether they fall asleep by accident — are linked to long-term brain health.

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The study found that participants who napped frequently, defined as most days or every day, had a 48% higher risk of developing dementia compared to those who rarely or never napped.

Whether the naps were intentional also appeared to play a role. Seniors who fell asleep unintentionally had a 39% higher risk, while shorter naps were also linked to poorer outcomes.

Napping for 30 minutes or less was linked to a 40% increased risk of dementia, even after researchers adjusted for other health factors. For naps longer than 30 minutes, the association was less pronounced after researchers accounted for nighttime sleep patterns.

The research team stressed that looking at daytime napping habits gives a much clearer picture of overall health than looking at nighttime sleep alone.

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"Our study highlights the importance of looking beyond just how long people nap and considering other napping characteristics, such as how frequently they nap and whether their naps are intentional," study authors Adam Spira, Ph.D., a professor at the Bloomberg School, and postdoctoral fellow Kening Jiang, Ph.D., told Fox News Digital.

"This study provides important longitudinal evidence that frequent and unintentional daytime napping were associated with a higher risk of developing dementia among older adults."

The findings held true even after accounting for nighttime sleep length, daytime drowsiness and indicators of sleep apnea.

"Nighttime sleep and daytime napping are closely related," Spira and Jiang went on. "Daytime napping may compensate for poor nighttime sleep, but it may also reduce the drive to sleep at night, potentially contributing to nighttime sleep disturbances, another important potential risk factor for dementia."

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Researchers pointed out that daytime resting does not necessarily cause brain changes. Rather, changing nap habits could be an early warning sign of underlying changes in the brain.

Brain regions that help regulate wakefulness can start to break down in the early stages of dementia, leading to more frequent daytime fatigue, they noted.

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To double-check this, the team re-analyzed the data after removing anyone who developed dementia during the first five years.

The link between frequent, accidental naps and dementia remained just as strong, suggesting that changes in napping habits can show up years before a formal diagnosis.

The researchers emphasized that this was an observational study with limitations.

"We did not directly intervene on participants’ napping behaviors to examine whether changing these behaviors would affect their dementia risk," Spira and Jiang told Fox News Digital.

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"Although we don’t know whether napping causes dementia, our study findings suggest that daytime napping patterns may be useful indicators of future dementia risk," they added.

The findings suggest that daytime napping patterns in older adults may be worth monitoring, particularly when naps become frequent or happen unintentionally, according to the researchers.