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A new study published in the British Journal of Sports Medicine has revealed that high cardiorespiratory fitness (CRF) is associated with improved cognitive performance and a significantly lower risk of dementia, even in individuals with a genetic predisposition to the condition. The findings underline the potential of physical fitness as a protective factor against cognitive decline.
CRF, a measure of the circulatory and respiratory systems’ ability to deliver oxygen to muscles during exercise, naturally declines with age, accelerating significantly after the age of 70. Lower CRF levels have been linked to an increased risk of cardiovascular events and mortality. This study highlights the additional link between CRF and brain health.
Study Design and Key Findings
The researchers analyzed data from 61,214 dementia-free participants aged 39–70 years enrolled in the UK Biobank study between 2009 and 2010. The participants underwent a six-minute submaximal exercise test to estimate CRF, completed neuropsychological tests to assess cognitive function, and had their genetic risk for dementia assessed using a polygenic risk score for Alzheimer’s disease. They were followed for up to 12 years.
During the follow-up period, 553 participants (0.9%) were diagnosed with dementia. Analysis revealed that participants with high CRF scores had better cognitive function and were less likely to develop dementia compared to those with low CRF. Specifically:
- The incidence rate ratio (IRR) for dementia was 0.6 for individuals with high CRF.
- Dementia onset was delayed by an average of 1.48 years in high-CRF individuals.
- Among those with moderate to high genetic risk for Alzheimer’s disease, high CRF reduced dementia risk by 35%.
Implications for Prevention
The study’s authors suggest that enhancing CRF through regular physical activity may be an effective strategy for preventing dementia, even among individuals genetically predisposed to the condition. They propose further research into how CRF influences brain health and its mechanisms of interaction with genetic risk factors.
Limitations and Future Directions
As an observational study, the findings cannot establish causality. The authors also acknowledge potential limitations, including an underestimation of dementia cases due to the generally healthier UK Biobank participant pool and reliance on registry data. Additionally, the submaximal exercise test used may be less accurate than maximal testing, and changes in CRF over time were not assessed.
Despite these limitations, the study underscores the importance of physical fitness for cognitive health. “Our study shows that higher CRF is associated with better cognitive function and decreased dementia risk,” the researchers wrote. “Enhancing CRF could be a strategy for the prevention of dementia, even among people with a high genetic predisposition for Alzheimer’s disease.”
Conclusion
With dementia rates expected to rise globally, the findings offer hope for mitigating cognitive decline through lifestyle interventions. Promoting fitness and understanding its role in brain health could be pivotal in addressing this growing public health challenge.
For more details, refer to the study: Association of cardiorespiratory fitness with dementia risk across different levels of genetic predisposition: a large community-based longitudinal study (DOI: 10.1136/bjsports-2023-108048).
