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A new study has found evidence linking excessive napping with an increased risk of developing Alzheimer's disease. A team of researchers poured over 14 years of data from more than 1,400 people between the ages of 74 and 88 collected by the Rush Memory and Aging Project.
The study, which was published in the medical journal Alzheimer's and Dementia: The Journal of the Alzheimer's Association, found that elderly adults who nap for at least one hour every day are 40% more likely to develop signs of dementia than those who nap for less than an hour.
"We found the association between excessive daytime napping and dementia remained after adjusting for nighttime quantity and quality of sleep," said co-senior author Dr. Yue Leng, an assistant professor of psychiatry at the University of California, San Francisco.
Leng explained that the increased sleep created a "vicious cycle" in which more sleep led to an increased risk of dementia, which causes people to sleep more.
"The vicious cycle we observed between daytime sleep and Alzheimer's disease offers a basis for better understanding the role of sleep in the development and progression of Alzheimer's disease in older adults," lead researcher Peng Li said, according to the Harvard Gazette.
The researchers hope their study will spur more investigations into the daytime sleep patterns of elderly adults.
"Our hope is to draw more attention to daytime sleep patterns and the importance of patients noting if their sleep schedule is changing over time," said co-senior author Kun Hu of the Medical Biodynamics Program in the Brigham's Division of Sleep and Circadian Disorders. "Sleep changes are critical in shaping the internal changes in the brain related to the circadian clocks, cognitive decline, and the risk of dementia."