Circadian Rhythm Changes in Dementia
Your body has an internal clock called the circadian rhythm. It helps control when you sleep, wake up, eat, and feel active. This clock follows a roughly 24-hour cycle and gets signals from light, darkness, and daily routines. In people with dementia, this clock often gets out of sync. These changes can start early in the disease and make daily life harder.
Studies show that weaker and more fragmented circadian rhythms link to a higher risk of dementia. A strong rhythm means your body stays on track with sleep and activity, even if schedules change. But a weak one makes it easy for light shifts or seasons to throw things off. People with these weak rhythms often move their sleep times around more. Activity that peaks later in the day, instead of morning or early afternoon, also raises the risk. This mismatch happens when the body clock does not line up with daytime light or evening dark.
In Alzheimer’s disease, a common type of dementia, these rhythm problems show up in clear ways. Patients often have restless nights, little sleep, and more naps during the day. This starts years before memory loss gets bad. Caregivers notice it early. Later, sundowning happens, where confusion worsens in the late afternoon or evening.
Why does this matter? Disrupted rhythms may change body processes like inflammation. They can mess with sleep and lead to buildup of amyloid plaques in the brain. These plaques link to dementia. In mouse studies, Alzheimer’s scrambled the rhythms in brain cells that clear plaques. Hundreds of genes lost their normal timing for tasks like fighting inflammation or removing waste. This turns orderly brain work into chaos.
Aging plays a role too. As people get older, the circadian rhythm responds less to light or activity. This makes it key to stick to regular schedules. Daytime sleepiness or new napping habits, even after enough night sleep, signal risks. Brain areas for wakefulness and sleep get hit early in dementia.
Researchers measured rest-activity patterns in large groups. They found those with the weakest rhythms faced higher dementia odds. The work came out in late 2025. Experts like Wendy Wang from UT Southwestern note these shifts happen with age and may speed up brain diseases. More studies look at fixes like light therapy or routine changes to help lower risks.
Sources
https://www.news-medical.net/news/20260104/Weaker-and-fragmented-circadian-rhythms-linked-to-higher-dementia-risk.aspx
https://timesofindia.indiatimes.com/life-style/health-fitness/health-news/how-your-body-clock-can-influence-your-risk-of-dementia/articleshow/126334892.cms
https://medicine.washu.edu/news/alzheimers-disrupts-circadian-rhythms-of-plaque-clearing-brain-cells/
https://www.boomermagazine.com/sleep-and-dementia-connection/
https://www.neurology.org/doi/10.1212/WNL.0000000000214513
https://www.healthbanks.com/PatientPortal/MyPractice.aspx?UAID=%7BDF0DAC52-E107-4CEB-A3C2-C9020F35D7A8%7D&TabID=%7BX%7D&ArticleID=1767096939094
