A recent study has identified a potential link between frequent, unintentional napping in older adults and an increased risk of developing dementia. The research, published in the Journal of Gerontology: Medical Sciences, followed nearly 1,000 adults aged 65 and older for a decade, all of whom were free of dementia at the study's outset.
Participants self-reported their napping habits, specifying frequency, duration, and whether they napped intentionally or unintentionally. Researchers defined unintentional napping as falling asleep without meaning to, such as dozing off while reading.
According to the findings, individuals who napped daily or almost daily had a 48% higher risk of dementia compared to those who rarely or never napped. Naps lasting less than 30 minutes were associated with a 40% increased risk, while unintentional naps showed a 39% higher risk.
However, the study's authors emphasized that napping itself may not cause dementia. "More frequent napping could be a marker of changes in the brain, rather than a cause of brain changes that lead to dementia," said Adam Spira, the study's senior author, in a press release.
Experts also clarified that this research does not suggest that stopping afternoon naps will lower dementia risk. Dr. Heather Elizabeth Whitson, director of the Duke Center for the Study of Aging and Human Development, who was not affiliated with the research, noted that the study cannot conclude whether interrupting napping behavior would be protective.
Other researchers pointed out that previous studies have yielded mixed results on the link between sleep and dementia. The study also acknowledged limitations, including the potential for self-reported data to be subject to memory errors.
Sleep and dementia are known to be interconnected in complex ways. Poor nighttime sleep has been linked to dementia, but this relationship is often bidirectional: neurodegenerative changes can disrupt sleep, and disrupted sleep may also be a risk factor for dementia. Sleep is believed to play a crucial role in brain health, including the clearance of toxins and natural repair processes.
Despite these findings, the study does not indicate that all napping is detrimental. Planned naps, particularly after a night of disturbed sleep, can be beneficial. Whitson suggested that unintentional, short naps appear to be the most concerning aspect of the findings, while intentional, longer naps did not show similar negative associations.
One expert suggested that naps around 45 minutes might be optimal for cycling through different sleep stages, but flexibility is advised, especially if a nap is taken due to a specific event like a late night. Culturally ingrained practices like siestas were also deemed unlikely to be problematic if they are a norm within a community.
Falling asleep unintentionally during the day is not considered a normal part of aging. The study noted that a significant portion of older adults do not experience unintentional daytime sleepiness. If unintentional napping is occurring, it is recommended to consult a doctor, as it could signal underlying conditions such as obstructive sleep apnea, in addition to potential links with dementia.
Whitson added that receiving a dementia diagnosis today is different than in the past, with advancements in therapies and ongoing research. Knowing one's health status allows for timely planning of treatments and interventions for safety and well-being.