Could Exercising Reduce Your Risk of Alzheimer’s Disease?

Alzheimer’s disease (AD), the most common form of dementia, is a debilitating and life-altering neurodegenerative condition that causes the progressive decline of cognitive and behavioral functions, affecting an estimated 6.9 million people in the US alone. Not only do those directly affected suffer, but AD also significantly impacts the quality of life of the patient’s loved ones due to the challenges of dealing with the physical and emotional difficulties associated with AD care (Shah et al. 2024).

On top of this, the healthcare costs of AD are staggering, estimated at $360 billion in 2024, making it one of society’s costliest conditions.

With all this in mind, it’s no surprise that AD is often considered one of the biggest healthcare challenges of the 21^st century.  

So, gleaning precious insights into how to reduce the risk of this devastating disease, particularly cost-effective interventions, is vital. To this end, a recent study investigated whether exercise could be one such preventative factor.

In this blog, we discuss a new study by Wang et al. (2025) that assessed the impact of cardiorespiratory fitness (CRF) on the risk of dementia and AD. 

The Brains of the Operation

First, let’s dive into the study design and methodology.

The researchers utilized a study population derived from the UK Biobank and followed 61,214 participants aged 39–70 for up to 12 years.

To assess CRF, a subset of participants was fitted with an electrocardiographic monitor and asked to complete an exercise test on a stationary bike. Parameters such as heart rate, maximum workload, and maximum oxygen consumption were used to calculate a CRF value based on standard protocols, and this score was classified into low, moderate, and high subsets within sex and age groups.

The cognitive function of the individuals was also evaluated at baseline using tests specifically designed to reflect different cognitive domains that are particularly sensitive to aging and neurodegeneration. The four tests assessed prospective memory, visual memory, verbal/numeric memory, and processing speed. The resulting scores from all four tests were also averaged to produce a global cognitive function score.

Not only was the development of dementia assessed throughout the years, but also the participants’ risk of dementia based on their genetics. A polygenic risk score was generated based on the number and strength of common AD-related alleles present in the genome, and again was classified into low, moderate, or high risk groups.

With the breadth of data available from such a vast cohort of individuals, the researchers were able to carry out robust analyses on the association between CRF and dementia.

Healthy Body, Healthy Mind

Using linear regression models, Wang et al. observed that individuals who had higher CRF were typically also associated with better global cognitive function, and more specifically, higher prospective memory, verbal/numeric memory, and processing speed across different age groups.

Over the following 12 years, 553 of the study participants went on to develop dementia, of whom 223 were diagnosed with AD. Interestingly, those with high CRF had a significantly reduced risk of developing the neurodegenerative disorder, with the total risk of all dementia being reduced by 40%, and the risk of specifically developing AD decreasing by 38% compared to those with low CRF.

Additionally, amongst those who did develop the disease, the onset of all dementia was delayed by 1.48 years in individuals identified with high CRF, as well as a 1.77-year delay in the AD subset, compared to those with low CRF.

But what about individuals who have a higher genetic predisposition for developing dementia? Fortunately, the pattern holds true. Individuals with moderate to high polygenic risk scores who were in the high CRF group had a 35% reduced risk of all dementia compared to those in the low CRF subset.

Overall, the results indicate that high CRF could effectively reduce the risk of dementia, even in those with a high genetic risk.

Food for Thought

While this study demonstrated associations between CRF and dementia, it did not investigate the mechanisms behind this potential protective factor. However, the researchers did propose a few theories.

For example, the risk of dementia has been associated with many aspects that are also related to an individual’s CRF. Poor cardiovascular health, weak lung function, and muscle wasting have all been linked to increased dementia risk. Therefore, interventions that improve these conditions may have beneficial effects on the brain as well (Leszek et al. 2021, Sui et al. 2020, Wang et al. 2022).  

A more direct impact on the brain is that low CRF has been implicated in disrupting cerebral circulation, which may also lead to neurodegeneration and neuroinflammation (Johnson et al. 2016). Further research is necessary to elucidate the precise mechanisms behind the apparent positive effect of CRF on dementia risk.

All in all, the results highlight the benefits of exercise, the main modifiable factor of CRF, for reducing the risk of dementia and AD, even going so far as to alleviate some of the burden of those with a genetic predisposition.  

Current treatments for dementia have primarily focused on managing the symptoms of the disease rather than halting the progression, so finding new, relatively inexpensive ways to prevent the condition, such as exercising and maintaining fitness levels in older adults, is vital.