Dementia, a condition affecting over 55 million people globally, continues to rise in prevalence, ranking as the seventh leading cause of death worldwide. 

While genetic predispositions, such as the APOE e4 gene, contribute to dementia risk, lifestyle factors like lack of physical activity, uncontrolled diabetes, high blood pressure, hearing loss, and tobacco or alcohol use also play a significant role, according to the Centers for Disease Control and Prevention (CDC).

Emerging evidence suggests that physical activity could be a powerful tool in reducing the risk of cognitive decline, even for those with genetic vulnerabilities.

Physical activity helps individuals maintain their cardiorespiratory fitness, which is crucial for ensuring adequate oxygen supply to muscles during exercise. 

This, in turn, has profound implications for brain health. Claire Sexton, DPhil, senior director of scientific programs and outreach at the Alzheimer’s Association, notes that growing evidence shows modifying certain risk factors and adopting healthy behaviors can significantly reduce the risk of cognitive decline and dementia. She highlights that as many as 40% of dementia cases worldwide may be attributable to modifiable risk factors.

A recent study published in the British Journal of Sports Medicine underscores this perspective. The research demonstrates that older adults, including those carrying the APOE e4 gene, could lower their risk of dementia by improving cardiorespiratory fitness. 

The study found a strong association between higher fitness levels and better cognitive performance in key functions that typically decline with aging.

To investigate this, researchers recruited 648 cognitively healthy participants aged 65 to 80 from Boston, Pittsburgh, and Kansas City. Excluding individuals with diabetes, severe cardiovascular conditions, or those engaging in regular moderate-to-vigorous physical activity, the study assessed participants’ cardiorespiratory fitness through graded treadmill tests. Their VO2max, a measure of maximum oxygen consumption, served as a critical indicator of fitness levels.

 Participants with higher VO2max scores demonstrated superior cognitive abilities in areas such as processing speed, working memory, and episodic memory. This pattern held true across all ages and even among individuals with the APOE e4 gene or on beta-blocker medication.

Ryan Glatt, a brain health coach and director of the FitBrain Program at Pacific Neuroscience Institute, affirmed that the findings align with prior research and reinforce the importance of cardiovascular health for brain aging. He emphasized, however, that the study, being observational, cannot establish causation.

Dr. Clifford Segil, a neurologist at Providence Saint John’s Health Center, elaborated on the physiological mechanisms connecting cardiovascular and brain health. He explained that poor cardiovascular health can lead to strokes and vascular dementia, characterized by cognitive slowing. Enhancing cardiorespiratory fitness may mitigate these risks by improving blood flow, reducing inflammation, and supporting overall brain metabolism. Additionally, mechanisms such as increased cerebral blood flow, reduced oxidative stress, and synaptogenesis—the formation of new neural connections—may contribute to improved cognitive health, though further research is needed to confirm these effects.

Effective strategies to combat the rise in dementia cases are essential. Claire Sexton emphasizes the importance of regular physical exercise, controlling blood pressure, managing diabetes, maintaining healthy sleep patterns, eating nutritious foods, and staying mentally active by learning new skills. She advises individuals to incorporate as many of these habits as possible into their daily lives, stressing that even small changes can make a significant difference.

With dementia cases projected to nearly double by mid-century, prioritizing physical activity and adopting healthier lifestyles are pivotal steps toward preserving brain health. This growing body of evidence underscores that preventive actions, even later in life, can substantially reduce the risk of dementia and protect cognitive function for years to come.