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.

Methodology

• Participants: 2,000 adults aged approximately 79
• Duration: 3 years
• Data Collection: Participants wore heart monitors for 12 days to assess the strength of their circadian rhythms—the body's internal clock that regulates various functions like hormone release, digestion, and body temperature.

Key Findings

• Total Cases: 176 participants developed dementia.
• Group Comparison:
• Strong Rhythms: 31 out of 728 developed dementia.
• Weaker Rhythms: 106 out of 727 developed dementia.
• Risk Factor: Those with weaker rhythms had nearly two and a half times the risk of developing dementia, even after accounting for factors like age, blood pressure, and heart disease.

Possible Mechanisms

• Disruptions in circadian rhythms may affect body processes like inflammation and sleep.
• Potential increase in the buildup of amyloid plaques in the brain, which are linked to dementia.
• Reduced brain's ability to clear these plaques.

Future Research Directions

• Interventions: Light therapy or lifestyle changes to strengthen circadian rhythms.
• Activity Levels: Only 7% of people most active in the morning developed dementia, compared to 10% of those whose activity peaked later in the afternoon.

Conclusion

Staying active earlier in the day might also be beneficial in lowering dementia risk.