Frequent Daytime Napping Linked to Increased Dementia Risk in Older Adults, Study Finds
A decade-long study by Johns Hopkins researchers suggests daily rest habits may be an indicator of cognitive decline.
Frequent daytime napping among older adults may be associated with a significantly higher risk of developing dementia, according to new research published in The Journal of Gerontology: Medical Sciences. The study, conducted by researchers from the Johns Hopkins Bloomberg School of Public Health, tracked nearly 1,000 adults aged 65 and older who did not exhibit any signs of memory or thinking problems at the study's outset in 2013.
Over the course of a decade, the researchers observed that daily rest patterns, including nap frequency, duration, and whether naps were unintentional, appeared to be linked to long-term brain health. The findings indicated that participants who napped frequently, defined as napping most days or every day, had a 48% increased risk of developing dementia compared to those who rarely or never napped.
The nature of the naps also seemed to play a role. Seniors who fell asleep unintentionally during the day experienced a 39% higher risk. Additionally, shorter naps, specifically those lasting 30 minutes or less, were associated with a 40% increased risk of dementia, even after researchers adjusted for other health factors.
Researchers emphasized that examining daytime napping habits provides a more comprehensive view of overall health than solely assessing nighttime sleep quality or duration. "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," stated study authors Adam Spira, Ph.D., and Kening Jiang, Ph.D.
These associations persisted even after accounting for nighttime sleep length, daytime drowsiness, and indicators of sleep apnea. The study authors noted, "This study provides important longitudinal evidence that frequent and unintentional daytime napping were associated with a higher risk of developing dementia among older adults."
While the researchers acknowledge that daytime resting does not necessarily cause brain changes, they suggest that altered napping patterns could serve as an early warning sign of underlying cognitive decline. Brain regions responsible for regulating wakefulness may begin to deteriorate in the early stages of dementia, potentially leading to increased daytime fatigue. To further investigate this, the team re-analyzed the data, excluding participants who developed dementia within the first five years of the study. The link between frequent, unintentional naps and dementia remained strong, suggesting that changes in napping habits can manifest years before a formal diagnosis.
The researchers cautioned that this was an observational study and has limitations. "We did not directly intervene on participants’ napping behaviors to examine whether changing these behaviors would affect their dementia risk," Spira and Jiang explained. "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."
The findings suggest that monitoring daytime napping patterns in older adults could be beneficial, particularly if naps become more frequent or occur unintentionally, according to the researchers. This research underscores the complex relationship between sleep, daily habits, and cognitive health in aging populations.