February 11, 2026
Poor sleep has been linked to an increased risk of developing Alzheimer’s disease and other forms of dementia. A new study underscores just how important sound sleep may be for the aging brain. It found that about one in eight cases of dementia may be related to the bedtime tossing and turning of insomnia that keeps so many of us awake at night.
For the study, researchers in Boston reviewed medical records from 5,899 men and women aged 65 and older who were part of the National Health and Aging Trends Study, a long-running study of older Americans. Nearly 30 percent reported having symptoms of insomnia, including having difficulty falling asleep or staying asleep through the night. About 6.6 percent had Alzheimer’s disease or other forms of dementia.
The researchers also analyzed data from several large-scale studies linking insomnia with dementia risk and calculated that about one in eight cases of dementia in the study population were tied to poor sleep. The proportion of dementia cases tied to insomnia was highest among women in their late 60s and men in their early 70s.
“Approximately 13 percent of dementia cases, almost half a million cases, among U.S. older adults may be attributable to insomnia,” the authors noted. “Addressing insomnia could be a promising target for dementia prevention efforts in aging populations.”
The findings, reported in the Journals of Gerontology: Series A, show only an association between insomnia and dementia risk and cannot prove cause and effect. But they add to growing evidence that sleep has a strong impact on the risk for dementia, comparable to the effects of hearing loss or high blood pressure.
Many studies in large numbers of people suggest that over time, sleeping fewer or more hours than the recommended seven to eight hours a night may play a role in dementia onset. Scientists believe that deep sleep may help to cleanse the brain, ridding the brain of toxins that can damage healthy brain cells. Poor sleep may also elevate levels of body-wide inflammation, which can have a corrosive effect on the brain.
The findings are especially concerning given the prevalence of insomnia, particularly in older men and women. While many people turn to sleeping pills, these drugs do not fully induce deep sleep and may have long-term serious side effects.
Sleep experts generally recommend psychological approaches like cognitive behavioral therapy, or CBT, as a first-line treatment for insomnia. CBT teaches people to challenge negative or stressful thoughts at bedtime with positive thoughts that induce relaxation. Before going to bed, think of soothing images or try meditation to help clear your head of anxious thoughts.
Other measures to promote sounder sleep include avoiding coffee or other stimulants after 3 in the afternoon and avoiding alcohol in the evenings; they can disrupt our natural sleep cycles. The light emitted by electronic screens, including phones and e-readers, can cause similar disruptions, so avoid exposure close to bedtime.
Try to keep a consistent bedtime schedule and maintain the bed as a sanctuary for sleep. If you do find yourself tossing and turning to get to sleep or waking in the middle of the night for more than 20 minutes, get out of bed and try a relaxing activity like reading a book or listening to soothing music.
Until researchers find more effective treatments or a cure for Alzheimer’s, getting better quality sleep may be one more way to help slow the onset of dementia as the years advance.
By ALZinfo.org, The Alzheimer’s Information Site. Reviewed by Eric Schmidt, Ph.D. Fisher Center for Alzheimer’s Research Foundation at The Rockefeller University
Source: Yuqian Lin, MS; Fei Wu, MS; Yuhan Wu, MS; et al: “Quantifying the Population-Level Impact of Insomnia on Dementia Among Older Adults in the United States.” The Journals of Gerontology: Series A, December 27, 2025
