Body Clock Weakness Tied to Higher Dementia Risk in Seniors

Researchers have uncovered a surprising link between a person's internal body clock and their risk of developing dementia. The study, which wrapped up in December 2025, tracked over 2, 000 adults, all around 79 years old and initially free of dementia, for three years. To gather data, participants wore heart monitors for 12 days, allowing scientists to assess the strength of their circadian rhythms—the body's internal clock that regulates various functions like hormone release, digestion, and body temperature. The findings were striking. Out of the participants, 176 developed dementia. When divided into three groups based on the strength of their circadian rhythms, a clear pattern emerged. Only 31 out of 728 people with strong rhythms developed dementia, while 106 out of 727 with weaker rhythms were diagnosed. Even after accounting for factors like age, blood pressure, and heart disease, those with weaker rhythms were found to have nearly two and a half times the risk of developing dementia.So, what's the connection? Experts believe that disruptions in circadian rhythms might mess with body processes like inflammation and sleep. This could potentially increase the buildup of amyloid plaques in the brain, which are linked to dementia, or reduce the brain's ability to clear these plaques. Wendy Wang, one of the study authors, suggests that future research should explore whether interventions like light therapy or lifestyle changes could help lower dementia risk by strengthening circadian rhythms. Interestingly, the study also found that activity levels during the day played a role. Only 7% of people who were most active in the morning developed dementia, compared to 10% of those whose activity peaked later in the afternoon. This suggests that staying active earlier in the day might also be beneficial.