Frequent Daytime Napping Linked to Higher Dementia Risk in Older Adults

Older adults who nap most days, or who doze off without meaning to, are more likely to develop dementia than those who rarely nap, according to a study by researchers at the Johns Hopkins Bloomberg School of Public Health that drew wide attention this week.

The research, published in The Journals of Gerontology, Series A, followed 995 Medicare beneficiaries aged 65 and older who were free of dementia when the study began. Using data from the National Health and Aging Trends Study, a long-running survey of older Americans on Medicare, the team tracked participants from 2013 to 2023. During that time, about 42 percent developed possible or probable dementia.

Compared with people who rarely or never napped, those who napped most days or every day had about a 48 percent higher risk of dementia after the researchers accounted for other factors. People whose naps were unintentional had about a 39 percent higher risk, and those whose naps lasted 30 minutes or less had about a 40 percent higher risk, according to the paper and a HealthDay report on it. The links held after the researchers adjusted for nighttime sleep habits.

Some of the other comparisons were weaker. Napping only occasionally, napping on purpose and taking naps longer than half an hour were not significantly tied to higher risk once all factors were considered, the paper shows. The authors described their subgroup analyses by age, sex and sleep problems as exploratory.

The most important caveat is the direction of cause. The study is observational, so it shows an association, not proof that napping harms the brain. The relationship may run the other way: the earliest stages of dementia can damage brain regions that keep people awake during the day, leading to more naps years before memory problems are diagnosed. Adam Spira, the study’s senior author and a professor in the Bloomberg School’s mental health department, told HealthDay that more frequent napping could be a marker of brain changes rather than their cause.

That possibility is part of what makes the finding useful. Kening Jiang, the lead author, said in a news release that monitoring napping could serve as an early and accessible marker. The authors wrote that napping might also turn out to be a modifiable risk factor, but only if further research supports that idea, and they called for larger and longer studies.

For older adults, the practical advice from the findings is modest. A short nap is not a diagnosis. But a noticeable change, such as a parent who begins falling asleep during the day without intending to, may be worth mentioning at the next doctor’s visit.