Is Naptime a Problem?
In another look at sleep, we found an article by Noah Tucker of PhillyVoice called, “Excessive daytime napping linked to increased risk of Alzheimer’s disease in older adults, study finds.” To clarify, these results pertain to long and frequent daytime naps of the elderly. This data comes from Brigham and Women’s Hospital in Boston. The significance of the study can be described by Peng Li, an assistant professor of Medicine at Harvard and the lead author of the study as he said, “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.”
Regarding the specifics behind the study, Tucker noted that there were 1,401 participants between the ages of 74 and 88. Tucker added that these individuals wore a movement tracker for two weeks every year from 2005 to 2020 and that a nap was defined as any lack of movement for an extended period between 9 a.m. and 7 p.m. As a counterpoint/question, it would be interesting to know how precise the movement trackers are because it seems reasonable to assert that many elderly people may go many hours without getting up from a chair or moving significantly.
Tucker described the results by saying that “The participants who napped at least once a day for more than one hour were 40% more likely to develop Alzheimer’s than those who napped less than an hour a day or not at all.” He also noted, “Investigators also discovered that while daily daytime napping increased by about 11 minutes per year on average for adults with no cognitive impairment, those with an Alzheimer's diagnosis napped for an additional 68 minutes per day.” Learning this, while some naptime can be helpful, it may be prudent to be mindful of how much a loved one may be napping in the day and gently suggesting other alternatives if a loved one naps excessively. However, it’s important to stress that Yue Leng, study contributor and professor at the University of California San Francisco shared that while the study established a link between excessive napping and cognitive decline, there is currently not enough evidence to state that excessive napping causes cognitive decline.
Discussing the results, Leng stated, “We found the association between excessive daytime napping and dementia remained after adjusting for nighttime quantity and quality of sleep” and “This suggested that the role of daytime napping is important itself and is independent of nighttime sleep.” Tucker notes two other related studies. The first is noted as having observed that two-hour daily naps raised cognitive impairment risk more than daily naps that are under 30 minutes. The second is a USCF study Tucker describes as having “found that the brains of deceased Alzheimer's patients have fewer wake-promoting neurons than those without the disease. It tied this shortage to the formation of tau tangles – a hallmark of dementia caused by increased enzyme activity that leads proteins to misfolding and clumping.” Lastly, one other study that doesn’t appear to be linked to the article is being conducted by Rush University’s Memory and Aging Project that features data that covers nearly a decade and a half. Tucker calls this the latest study.
Question Answered and Advice
Looking back a question we proposed toward that start of this writing, we were curious how accurate the movement trackers are given that minimal movement may be confused with sleep. Toward the end of Tucker’s article, he includes a few comments from Richard Isaacson, director of the Alzheimer’s Prevention Clinic at Florida Atlantic University. Acknowledging this possible flaw, he has stated, “Further studies are warranted with devices that are validated to detect sleep versus sedentary behavior” and “But at the same time, being sedentary and not moving for long periods of time is a known risk factor for cognitive decline and Alzheimer’s.”
As a parting fact to note, Leng mentioned at “limited increases in daytime sleep are a normal part of aging” and that nighttime sleep quality declines with increased health problems. Researchers have said that caregivers should be mindful of older adults’ daytime naps and that significant increases should be shared with a doctor. Before 3 p.m., Tucker states that naps should be no longer than 15 to 20 minutes to avoid hindering nighttime sleep.