A person’s internal body clock, known as the circadian rhythm, may have far-reaching implications for brain health in later life, according to recent research. These 24-hour biological cycles, which regulate sleep, hormone release, body temperature and heart rate, are increasingly being linked to cognitive well-being and the risk of dementia.
Research led by experts at Loughborough University highlights that a strong, well-maintained circadian rhythm can be protective. A study conducted in 2025 involving over 2,000 participants, with an average age of 79, revealed that individuals with robust daily rhythms experienced almost half the risk of developing dementia compared to those with disrupted cycles. The findings suggest that the timing of sleep and wakefulness is not merely a lifestyle matter but may be a significant determinant of long-term brain health.
Over a three-year follow-up, participants with weaker circadian patterns showed higher rates of cognitive decline. Disruption of these rhythms is often associated with poor sleep quality, a factor long suspected to contribute to both dementia and cardiovascular disease. The study accounted for heart health and blood pressure, common markers linked to sleep disruption, although the effects of sleep apnoea remain complex due to overlapping risk factors such as obesity, diabetes, smoking and alcohol consumption.
The research also emphasises lifestyle interventions. Addressing physical inactivity linked to fatigue from disrupted sleep may offer multiple benefits: reducing obesity, improving sleep quality, supporting neuronal health and potentially lowering dementia risk through interconnected pathways. Maintaining consistent sleep schedules, promoting daily activity and limiting factors that disturb circadian timing could therefore play a pivotal role in preserving cognitive function.
Professor Eef Hogervorst of Loughborough University’s School of Sport, Exercise and Health Sciences notes that recognising and respecting the body’s natural rhythms should become an integral aspect of healthy ageing strategies. “Our internal clock governs more than just sleep,” he explains. “It orchestrates complex physiological processes, and its stability may be key in protecting the brain against age-related decline.”
This research adds to the growing body of evidence that circadian health is a crucial, yet often overlooked, factor in ageing populations. As the global population ages, strategies that maintain strong biological rhythms could offer significant public health benefits, reducing the prevalence and impact of dementia.
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