Napping throughout the day, especially for long periods of time, can be an indication of the presence of Alzheimer’s disease.
A team of scientists from the University of California, San Francisco concluded in a recent survey that prolonged naps are linked to an increased likelihood of developing mild cognitive impairment or Alzheimer’s disease.
according to The Guardianscientists suggest it’s likely that taking naps too often could be an early warning sign, rather than causing mental decline.
“Maybe a sign of accelerated agingsaid Yue Leng, professor of psychiatry at American University. “The main sign of decline is that if you’re not taking a nap and you notice that you’re starting to get more sleepy during the day, that could be a sign of declining cognitive health.”
The team analyzed data from a group of more than 1,000 volunteers, aged 81 on average, over several years. Participants wore a watch-like device to track mobility for up to 14 days, with each period of prolonged inactivity from 9 a.m. to 7 p.m. interpreted as a nap.
The volunteers also underwent tests to assess cognition each year. At baseline, 76% of participants had no cognitive impairment, 20% had mild cognitive impairment, and 4% had Alzheimer’s disease.
For participants who did not develop cognitive impairment, the daily daytime nap increased by an average of 11 minutes per year.
THE rate of increase doubled after a diagnosis of mild cognitive impairment for a total of 24 minutes and almost tripled for a total of 68 minutes after an Alzheimer’s diagnosis.
In total, the volunteers who slept more than an hour a day had a 40% higher risk of developing Alzheimer’s disease than those who slept less than an hour a day.
Furthermore, participants who slept at least once a day had a 40% higher risk of developing Alzheimer’s disease than those who slept less than once a day.
Although insomnia and poor quality sleep patterns at night are common in people with dementia, this study found that “the association between long naps and dementia remained after a sleep adjustment”. “This suggests that the role of the daytime nap is important on its own,” Leng said.
Yet, it’s important to point out that there is neither “sufficient evidence” nor “any obvious biological mechanism” to trace a causal relationship that “it is the nap itself that causes cognitive aging.” It’s just “a sign” of the existence of dementia or Alzheimer’s disease.
O scientific article was recently published in Alzheimer’s and dementia.