Share on PinterestMaintaining cardiorespiratory fitness could help lower the risk of dementia even in those who have higher genetic risk for it. Image credit: Justin Paget/Getty Images.
- More than 55 million people globally live with dementia.
- Past research shows that certain lifestyle habits, such as being sedentary, can increase a person’s dementia risk.
- Previous studies have shown that exercise could help lower a person’s dementia risk by as much as 20%.
- A new study now suggests that people with high cardiorespiratory fitness may have a lower dementia risk over the long term.
Researchers estimate that more than 55 million people around the world live with dementia — an umbrella term for several brain conditions that negatively impact memory and social skills.
While scientists are still unclear as to what actually causes dementia, past research indicates that certain lifestyle habits — such as smoking, an unhealthy diet leading to obesity, and being sedentary — can increase a person’s risk of developing dementia.
At the same time, previous studies have shown that lifestyle interventions such as regular exercise can potentially help lower a person’s dementia risk by 20%.
Now, a new study recently published in the British Journal of Sports Medicine reports that people with high cardiorespiratory fitness — referring to how well a person’s circulatory and respiratory systems are able to move oxygen to muscles during exercise — may have lower dementia risk over the long term, including those who are genetically predisposed to the condition.
Cardiorespiratory fitness and dementia: What is the link?
For this study, researchers analyzed data from more than 61,000 people in the UK Biobank. All were dementia-free at the time of enrollment into the UK Biobank study, and between the ages of 39 to 70 years.
At enrollment in the UK Biobank study, participants were asked to complete a 6-minute exercise test on a stationary bike to assess their cardiorespiratory fitness.
According to the authors of this study, a person’s cardiorespiratory fitness declines as they age. It declines between 3% and 6% when a person is in their 20s and 30s. This increases to more than a 20% decline per decade when a person is in their 70s or older.
This is not the first study to look for a link between cardiorespiratory fitness and dementia risk. A study published in July 2021 found that cardiorespiratory fitness may be a “modifiable physiological attribute” to help delay the progression of Alzheimer’s disease, the most common form of dementia.
And research published in March 2023 showed that cardiorespiratory fitness was independently associated with a lower risk of Alzheimer’s disease and related dementias.
All participants also underwent neuropsychological testing to determine their cognitive function and were genetically tested for Alzheimer’s disease upon enrollment in the UK Biobank study.
High cardiorespiratory fitness lowers dementia risk, delays onset
During a follow-up period of up to 12 years, almost 10% of study participants developed dementia.
This study’s researchers found that the incidence rate ratio of all dementia for people with high cardiorespiratory fitness was 0.6 and onset of dementia was delayed by 1.48 years, compared to those with low cardiorespiratory fitness.
Additionally, scientists discovered that a high cardiorespiratory fitness reduced all dementia risk by 35% among participants with a genetic predisposition for dementia.
In their study, the researchers state that cardiorespiratory fitness might be used as a predictor of cognitive health, and “enhancing [cardiorespiratory fitness] could be a strategy for the prevention of dementia, even among people with a high genetic predisposition for Alzheimer’s disease.”
Potential noninvasive method for reducing dementia risk
Medical News Today spoke to José Morales, MD, a vascular neurologist and neurointerventional surgeon at Providence Saint John’s Health Center in Santa Monica, CA, about this study who commented it was not surprising that individuals with high cardiovascular fitness have a lower risk of developing dementia.
“The strengths of this study are the longitudinal follow-up of a large cohort, stratification of their dementia risk, and an objective measurement of cardiovascular fitness,” Morales, who was not involved in the research, explained. “Data such as these may help motivate patients/people concerned or at risk for dementia to engage in regular exercise.”
“Almost everyone wants a nonpharmacological method of reducing their individual risks,” he added. “These and related findings can provide people with a sense of agency and self-determination, as well as inform societal efforts to maximize well-being.”
Why exercise is important for brain health
MNT also spoke with Jasdeep S. Hundal, PsyD, ABPP-CN, a board-certified clinical neuropsychologist and director of The Center for Memory & Healthy Aging at Hackensack Meridian Jersey Shore University Medical Center in New Jersey about this research.
“My initial reaction to these kinds of studies is always one of optimism and validation for our approach,” Hundal, who was not involved in this study, said.
He added that:
“The fact that the findings emphasize the critical role of [cardiorespiratory fitness] as a modifiable factor in reducing dementia risk even among individuals with a high genetic predisposition, is very encouraging and reassuring since this is something that we have been counseling in our clinics for years.”
“Dementia remains one of the leading causes of disability and dependency among older adults, with no definitive cure available,” Hundal continued. “While the newer anti-amyloid medications show some promise, they are not curative. So, identifying ways to lower dementia risk is crucial because it empowers individuals to take proactive steps toward prevention.”
He further noted that he and his colleagues often stress that exercise and physical activity are powerful tools for maintaining not just physical health, but also cognitive health over the lifespan, and that it can be neuroprotective for the aging brain.
“Studies like this expand our understanding of modifiable risk factors, such as fitness, which can complement genetic and pharmacological approaches,” Hundal added. “This not only benefits patients but also reduces the societal and economic burden of dementia.”
What should dementia research look at next?
For the next steps in this research, Morales said he would like to see “repeated measures of cardiovascular fitness over a longitudinal study period would be valuable to determine the cumulative effects of [cardiovascular] fitness over a lifetime, as well as determine if certain epochs of aging are particularly affected by this variable.”
Hundal said that future research should focus on intervention trials to establish a causal relationship between increasing cardiorespiratory fitness and reducing dementia risk.
“It would also be valuable to investigate the specific mechanisms by which [cardiorespiratory fitness] impacts brain health, such as its effects on cerebral blood flow, neuroinflammation, and beta-amyloid protein accumulation,” he continued.
“Additionally, studies involving more diverse populations and older adults could help confirm the generalizability of these findings. Exploring practical strategies for implementing fitness programs in clinical and community settings is another crucial step,” concluded Hundal.
