'Vicious Cycle' Involves Napping, Alzheimer's

Older adults who suddenly find themselves napping longer and more frequently during the day might want to have their brains checked. That's according to researchers at Brigham and Women's Hospital who explored a link between excessive daytime napping and Alzheimer's disease. They analyzed the duration and frequency of naps among more than 1,400 individuals aged 74 to 88 who wore a sleep tracking device for two weeks annually over 14 years and found those "who napped at least once a day or more than an hour a day were 40% more likely to develop Alzheimer's than those who did not nap daily or napped less than an hour a day," CNN reports.

Researchers aren't prepared to say that napping causes cognitive aging. But "more excessive (longer or more frequent) daytime napping was correlated with worse cognition a year later, and conversely, worse cognition was correlated with more excessive naps a year later," according to the study published Thursday in Alzheimer's & Dementia. Co-senior author Peng Li calls this a "vicious cycle." "Our results not only suggest that excessive daytime napping may signal an elevated risk of Alzheimer's dementia, but they also show that faster yearly increase in daytime napping may be a sign of deteriorating or unfavored clinical progression of the disease," Li tells the Harvard Gazette.

There was a broad shift toward longer and more frequent naps as the participants aged. But those diagnosed with mild cognitive impairment saw their nap time double over the study period, while those diagnosed with Alzheimer’s saw their nap time triple, per CNN. "Our study calls for a closer attention to 24-hour sleep patterns—not only nighttime sleep but also daytime sleep—for health monitoring in older adults," Li tells the outlet. The study accounted for dementia risk factors, including nighttime sleep duration. An ongoing clinic trial is testing whether treating sleep problems before people show signs of cognitive impairment can delay or stop the buildup of amyloid plaques in the brain. (Previous studies have suggested a link as well.)