Many people think of Alzheimer’s disease as a memory disorder. The first signs that come to mind are forgetting names, getting lost, or having trouble performing familiar tasks.
But scientists are increasingly discovering that changes in sleep may occur long before severe memory problems appear.
Researchers at the University of Kentucky’s Sanders-Brown Center on Aging recently published two studies that provide new clues about the connection between sleep and Alzheimer’s disease.
Their findings, published in the journals SLEEP and Alzheimer’s & Dementia, suggest that sleep disturbances may not simply happen because of Alzheimer’s disease. Instead, poor sleep may actively influence changes occurring inside the brain.
Scientists have long known that people with Alzheimer’s disease often experience sleep problems. They may have trouble falling asleep, wake frequently during the night, or feel sleepy during the day. Their body clocks can also become disrupted, making it difficult to maintain regular sleeping and waking patterns.
Researchers now believe these changes may begin years before dementia becomes obvious. This possibility has important implications because it suggests that improving sleep could become part of future strategies to protect brain health.
In one of the new studies, researchers investigated the effects of dim light at night. This type of exposure is very common in modern life. People frequently use smartphones in bed, watch television late at night, or sleep in rooms affected by outside lighting.
The body relies on darkness to maintain its natural sleep-wake cycle. When light is present at night, the brain may become confused about whether it should remain awake or prepare for sleep.
The researchers found that nighttime light exposure disrupted normal daily rhythms. Activity patterns became less stable and more fragmented. In Alzheimer’s disease models, dim light also slightly increased amyloid accumulation in the brain.
Amyloid is a protein that can clump together and form plaques, one of the main features of Alzheimer’s disease. Although the increase was modest, the findings suggest that environmental factors such as nighttime lighting may influence brain processes related to the disease.
The researchers also observed changes in microglia, which are specialized immune cells that help maintain brain health. When these cells become excessively activated, they can contribute to inflammation.
The second study explored whether inflammation itself might contribute to sleep disturbances. The researchers followed sleep and biological rhythms over time and discovered that disruptions appeared during midlife, before major memory problems emerged.
This finding is particularly important because it suggests that sleep changes may be among the earliest detectable signs of disease development.
The scientists then tested an experimental compound called MW151, which reduces excessive inflammatory signaling in the brain. Treatment improved sleep quality and helped restore healthier daily rhythms. Surprisingly, these improvements occurred without reducing amyloid levels.
The results indicate that inflammation may independently contribute to poor sleep in Alzheimer’s disease. In other words, sleep disruption cannot be explained entirely by the presence of amyloid plaques.
The studies add to a growing body of evidence suggesting that sleep and circadian rhythms play a fundamental role in brain aging. They also highlight the possibility that interventions aimed at improving sleep may have benefits that extend beyond simply helping people feel rested.
The researchers caution that these findings are still in the early stages and do not yet provide direct clinical recommendations. More studies involving people are needed before scientists know whether targeting sleep and inflammation can slow or prevent Alzheimer’s disease.
Nevertheless, the findings support practical sleep habits that are already recommended for overall health. Maintaining regular bedtimes, limiting screen exposure before sleep, reducing unnecessary light at night, and creating a sleep-friendly environment are simple steps that may help support healthy biological rhythms.
The research also changes the way scientists think about Alzheimer’s disease. Instead of viewing poor sleep as only a consequence of dementia, researchers increasingly see sleep as an active part of the disease process itself.
As scientists continue to unravel these connections, protecting sleep may become an important piece of maintaining brain health and reducing the burden of Alzheimer’s disease in aging populations.
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Source: University of Kentucky.
