Older adults who napped most days had a 48% higher risk of dementia over 10 years, and the researchers think the nap may be an early warning sign

Many older adults take a nap most afternoons and think nothing of it. Researchers at the Johns Hopkins Bloomberg School of Public Health looked at whether those naps say anything about the brain. They followed 995 Medicare beneficiaries aged 65 and older who were free of dementia in 2013, recording how often they napped, whether they meant to, and for how long. The team then tracked who developed dementia over the next ten years.

People who napped most days or every day had a 48% higher risk of developing dementia than those who rarely or never napped. Falling asleep without meaning to, nodding off rather than choosing to lie down, was linked to a 39% higher risk. Naps of 30 minutes or less were also linked to higher risk.

Occasional naps and planned naps showed no link with dementia. The pattern held after the researchers accounted for age, health conditions, how long people slept at night, daytime sleepiness and the risk of sleep apnea.

“Monitoring napping behaviors could serve as an early and accessible marker to help identify older adults at higher risk for dementia and guide targeted interventions for dementia prevention,” lead author Kening Jiang said in a statement.

The direction of the link is the big open question, and the researchers say it probably runs both ways. Napping during the day may reduce the drive to sleep at night and disrupt nighttime sleep, itself a dementia risk factor. But dementia can also damage the brain regions that keep people awake, years before memory problems appear. A 2022 study in Alzheimer’s & Dementia that tracked older adults with wrist monitors found that daytime napping increased as dementia developed, and that more napping also predicted later decline, pointing to a two-way relationship.

Night-time sleep matters too. An earlier analysis of the same national study found that older adults who slept five hours or less a night had about twice the risk of dementia.

The data come from the National Health and Aging Trends Study, a nationally representative survey of Medicare beneficiaries that has interviewed participants every year since 2011. Napping habits were reported in a sleep module in 2013, and dementia was identified through yearly assessments up to 2023.

The second finding is that shorter is not automatically safer. Many people assume a quick 20-minute nap is the healthy kind, but in this study, naps of 30 minutes or less were linked to higher dementia risk, which fits the idea that frequent nodding off may be a signal rather than the problem itself.

For older adults and their families, the practical point is about change. A new habit of falling asleep during the day without meaning to is worth mentioning to a doctor, along with how well the person sleeps at night, since sleep apnea and other treatable problems can cause daytime sleepiness. Dementia risk is shaped by many factors, including some that differ between women and men.

There are limits to what this shows. Napping was self-reported once, in 2013, and people may misjudge their own naps. With fewer than 1,000 participants, some estimates are imprecise, and the study cannot show whether napping contributes to dementia or simply reflects changes already underway.

Source

Jiang K, Gross AL, Wu CT, et al. “Napping characteristics and incident dementia: results from the National Health and Aging Trends Study.” The Journals of Gerontology: Series A, 2026.
DOI: 10.1093/gerona/glag208

Also cited

Li P, Gao L, Yu L, et al. “Daytime napping and Alzheimer’s dementia: A potential bidirectional relationship.” Alzheimer’s & Dementia, 2023.
DOI: 10.1002/alz.12636

Robbins R, Quan SF, et al. “Examining sleep deficiency and disturbance and their risk for incident dementia and all-cause mortality in older adults across 5 years in the United States.” Aging, 2021.
DOI: 10.18632/aging.202591