READ THIS NEXT: Napping at This Time Boosts Your Brain Health, Study Says. Sleep problems have long been associated with Alzheimer’s disease and other forms of dementia. “Many older adults have problems sleeping, but people with dementia often have an even harder time,” explain Mayo Clinic experts. In fact, they explain that sleep disturbances affect up to 25 percent of patients with mild to moderate dementia, and half of patients with severe dementia. These sleep disturbances tend to get worse as dementia progresses in severity, they note. READ THIS NEXT: If You Can’t Do This, You May Be at High Risk of Dementia, New Study Says. According to a 2022 study published in the Journal of the American Geriatrics Society, sleep and dementia are linked in several ways. The researchers behind the study say that certain sleep characteristics may help reveal your dementia risk, even if you’re currently in good cognitive health.ae0fcc31ae342fd3a1346ebb1f342fcb To explore the link between sleep characteristics and dementia, the team collected questionnaire data from 1,982 participants in rural China, all of whom were 60 years or younger and dementia-free at the start of the study. Over the course of the following four years, 97 of those individuals developed dementia. After analyzing the sleep data of those who developed cognitive decline and comparing it to those who did not, the team learned that senior men who spent more than eight hours in bed per night were at 69 percent greater risk of dementia than those who were in bed for between seven and eight hours. The risk was also twice as high for those who went to bed before nine o’clock in the evening, compared to those who went to bed at 10 p.m. or later. The study authors write that there may be multiple reasons that a longer time spent in bed or a consistently earlier bed time could contribute to a higher likelihood of dementia. “Several potential mechanisms may explain the associations of sleep problems with dementia and cognitive decline. Long sleep duration has been associated with global brain atrophy, more white matter hyperintensities, and proinflammatory biomarkers… which may be the pathways linking long sleep duration to dementia,” they theorize. However, it’s important to note that the study did not establish causality, and the researchers admit that the exact reasons for the associations “are unknown.” It’s possible that interrupted or poorer quality nighttime sleep—long associated with dementia—causes daytime sleepiness and earlier bedtimes, as well as longer total time spent in bed. For more health news sent directly to your inbox, sign up for our daily newsletter. Sleep is essential for healthy cognitive function, and getting too little of it has also been shown to increase your likelihood of developing dementia. Studies suggest that getting a minimum of seven hours of quality sleep per night helps to stave off cognitive decline. However, people who get six hours of sleep or less are at significantly heightened risk of dementia and other illnesses—and those getting under five hours per night may be in outright danger. A 2020 study conducted by researchers at Harvard Medical School examined sleep data from 2,800 individuals aged 65 and older and found that those who slept less than five hours per night were twice as likely to develop dementia within five years. They also observed that those individuals were twice as likely to die of any cause within that five year period, compared to those who slept six to eight hours per night. Taken together, these studies all seem to have a common message, despite their seemingly polarized findings: that both quantity and quality of sleep matter greatly when it comes to your cognitive and general health. Speak with your doctor for more information if you believe your sleep is negatively affecting your wellbeing.
