Regular exercise is known to prevent chronic conditions and slow cognitive decline. New research suggests that cardiovascular fitness, the body's ability to deliver oxygen to muscles during exercise, could also play a crucial role in reducing dementia risk.
A recent study found that improved cardiorespiratory fitness is linked to better cognitive performance and a lower risk of dementia, even among those genetically predisposed.
As people age, cardiovascular fitness typically declines by 3% to 6% every decade in their 20s and 30s. However, this decline accelerates to over 20% per decade once individuals reach their 70s. With reduced fitness, there is an increased risk of cardiovascular events such as strokes and heart attacks and mortality from all causes, according to the researchers of the latest study.
The study evaluated 61,214 participants between the ages of 39 and 70 enrolled in the UK Biobank study between 2009 and 2010. The participants did not have dementia and were followed for up to 12 years.
The researchers assessed the cardiorespiratory fitness of participants at the beginning of the study by conducting a 6-minute submaximal exercise test on a stationary bike. While neuropsychological tests were used to evaluate cognitive function, the participant's genetic predisposition for dementia was estimated using the polygenic risk score.
During the follow-up, 553 people were diagnosed with dementia. Based on the cardiorespiratory fitness scores, the participants were divided into three equal-sized groups standardized by age and sex.
The analysis revealed that people with higher fitness scores were 40% less likely to develop dementia than those with lower scores. Also, dementia onset was delayed by nearly 1.5 years for those with high scores.
The researchers noted that in those with a moderate to high genetic risk of dementia, high cardiovascular fitness reduced their risk of developing dementia by 35%.
Since the study is observational, the researchers could not establish a direct cause-and-effect relationship. They noted some limitations, including the potential underestimation of dementia cases, as UK Biobank participants are healthier than the general population. Individuals with certain health conditions were excluded from the exercise test, making the study group healthier which may have impacted the findings.
However, based on the current findings, the researchers suggest that "enhancing CRF could be a strategy for the prevention of dementia, even among people with a high genetic predisposition for Alzheimer's disease."
