Excessive daytime napping may signify an increased risk of Dementia, according to a recent cohort study of older persons.

Researchers at Brigham and Women’s Hospital discovered a bidirectional link between daytime napping and cognitive aging: excessive daytime napping predicted a higher future risk of Alzheimer’s disease, and an Alzheimer’s diagnosis accelerated the increase in daytime napping as people age. 

Excessive Sleeping And Frequent Napping Could Be A Symptom Of Dementia

The team’s findings were published in Alzheimer’s & Dementia: The Alzheimer’s Association Journal.

The effects of daytime napping on cognition in older persons have shown mixed findings. While some studies have found that daytime naps improve acute cognitive function, mood, and alertness, others have found that they have negative effects on cognitive performance.

Nonetheless, Brigham researchers noted that all previous Alzheimer’s disease studies only measured napping in a participant once, and the majority of them were subjective and questionnaire-based.

The current study looked at two hypotheses: (1) people nap longer and/or more frequently as they become older, and the changes occur even quicker as Alzheimer’s progresses; and (2) those who nap too much during the day have a higher chance of acquiring Alzheimer’s.

Rush Alzheimer’s Disease Center and the University of California, San Francisco collaborated on the research. The researchers used data from the Rush Memory and Aging Project (MAP), a prospective cohort study that is still underway.

Actical, a watch-like gadget, was given to over 1,000 people, with an average age of 81, to wear on their non-dominant wrist for up to 14 days. The researchers used a previously established sleep scoring system that took wrist activity counts into account to identify sleep periods. The nap length and frequency were calculated when napping episodes were detected.

Longer and more frequent daytime naps were found to be a risk factor for Alzheimer’s disease in cognitively normal older men and women, regardless of recognized dementia risk variables such as age and nocturnal sleep length and fragmentation. Furthermore, as the disease advanced, yearly increases in napping length and frequency accelerated, particularly after the clinical manifestation of Alzheimer’s. The authors conclude that the connection between daytime napping and cognition is a “vicious loop.”