Study finds physical activity boosts brain health and cuts dementia risk

Staying physically fit can significantly lower the risk of developing dementia and delay its onset by nearly 18 months, according to new research highlighting the critical role of exercise in boosting brain health. The findings offer hope, even for those genetically predisposed to dementia, revealing that maintaining a high level of fitness can reduce their risk by up to 35%.

The study, published in the British Journal of Sports Medicine, underscores the importance of physical fitness across a lifetime as a key strategy to lower the likelihood of developing dementia. It found that individuals with the highest levels of cardiorespiratory fitness (CRF)—a measure of the body’s ability to deliver oxygen to muscles during exercise—had better cognitive function and a lower risk of dementia compared to those with lower fitness levels.

Study Details

The research analysed data from 61,214 participants aged 39 to 70 who joined the UK Biobank study between 2009 and 2010. At the time of enrolment, none of the participants had been diagnosed with dementia. Over a follow-up period of up to 12 years, the researchers monitored their health outcomes.

To assess their physical fitness, participants completed a six-minute stationary bike test, measuring their CRF levels. Cognitive function was evaluated through neuropsychological tests, and genetic predisposition to dementia was calculated using a polygenic test for Alzheimer’s disease risk.

The study’s authors wrote, “Our study shows that higher CRF is associated with better cognitive function and decreased dementia risk. Moreover, high CRF may buffer the impact of genetic risk of all dementia by 35%.”

The researchers also noted that individuals with high CRF experienced a delay in dementia onset of approximately 1.48 years. The study was led by Professor Weili Wu from the Ageing Research Centre at the Karolinska Institute in Stockholm, Sweden.

Implications for Dementia Prevention

The findings provide further evidence supporting the role of a healthy lifestyle in reducing dementia risk. Organisations dedicated to dementia care emphasised the study’s importance in showing how physical activity can be a protective factor against cognitive decline.

“This research emphasises that exercise is an important part of maintaining a healthy lifestyle and could reduce the risk of developing dementia later in life,” said Dr Richard Oakley, Associate Director of Research and Innovation at the Alzheimer’s Society. “What is particularly promising about this study is that exercise also appears to reduce dementia risk in people who have a higher genetic risk of developing Alzheimer’s disease.”

The Lancet Commission on dementia, in its July report, identified physical inactivity as one of 14 modifiable risk factors for dementia. Other factors include hearing loss, low levels of education, air pollution, social isolation, and depression.

Dr Jacqui Hanley, Head of Research at Alzheimer’s Research UK, commented, “This new research highlights how good cardiorespiratory fitness, a key measure of overall physical health, could help lower the risk of developing dementia in the future. However, it is important to note that we don’t know if there is a direct link between cardiorespiratory fitness and reduced dementia risk. More research is needed to find out exactly how it affects the brain.”

Observational Nature of the Study

The researchers emphasised that their findings were observational and do not definitively establish a causal relationship between higher CRF and reduced dementia risk. Nevertheless, they suggest that improving cardiorespiratory fitness could be a viable strategy for preventing dementia, even in individuals with a high genetic predisposition for Alzheimer’s disease.

“Enhancing CRF could be a strategy for the prevention of dementia,” the authors concluded, adding weight to the growing body of evidence that physical activity plays a critical role in supporting cognitive health.

Call to Action

Dementia charities and health experts encourage people to adopt a proactive approach to reducing their dementia risk by incorporating regular exercise into their lives, avoiding smoking, limiting alcohol intake, and maintaining overall physical and mental health.

This study provides yet another compelling reason to make fitness a priority—not just for physical well-being but also for preserving cognitive health in the years to come.