Science and Technology Daily (intern reporter Zhang Jiaxin) Is there a link between cognitive decline and excessive daytime naps (or naps)?

According to an article published today in Alzheimer's Disease and Dementia, the journal of the Alzheimer's Society, a new study from the Rush Alzheimer's Center in the United States suggests that there is a potential connect.

　　The link appears to go both ways, the researchers said.

Longer and more frequent naps were associated with poorer cognitive performance a year later, and those with poorer cognitive ability slept longer and more frequently a year later.

　　Pathology associated with cognitive decline can lead to other functional changes, said co-author Aaron Buchman, MD, a neuroscientist at Rush University Medical Center.

That said, Alzheimer's is not just a pure cognitive impairment, it's actually a multisystem disorder that includes sleep difficulties, movement changes, body composition changes, depressive symptoms, behavioral changes, and more.

　　The researchers followed more than 1,400 patients for up to 14 years.

Participants wore a sensor on their wrist that recorded activity for 10 consecutive days, and underwent annual examinations and cognitive tests.

Any prolonged inactivity between 9am and 7pm is considered a nap.

　　At the start, more than 75 percent of the participants showed no signs of cognitive impairment, 19.5 percent had mild cognitive impairment, and just over 4 percent had Alzheimer's disease.

Among those who did not develop cognitive impairment during follow-up, daily nap time increased by about 11 minutes per year.

Nap times doubled after a diagnosis of mild cognitive impairment and nearly tripled after a diagnosis of Alzheimer's disease.

　　The researchers also compared participants who were cognitively normal but developed Alzheimer's disease at the start of the study with those whose minds remained stable during the study.

They found that older adults who napped more than an hour a day had a 40 percent higher risk of developing Alzheimer's disease.

　　Buchman emphasized that the study does not imply that naps cause Alzheimer's disease or vice versa.

"This is an observational study, so we can't say 'a causes b'." But they unfold at the same time, and the same pathology may have an effect on both.