Exercise helps prevent Dementia

In this Article (Index)

• Physical Activity vs. Dementia
• What is Dementia?
• How Does Exercise Help Prevent Dementia?

Physical Activity vs. Dementia

Moderate-to-Vigorous Physical Activity at any Dose Reduces All-Cause Dementia Risk

The most recent article will be published in the March 2025 edition of The Journal of Post-Acute and Long-Term Care Medicine (1). This study used the data from 89,667 adults with an average age of 63 from the UK Biobank study, 56% of them were women. 735 subjects developed dementia over a period of 4.4 years. The study investigated the effects of moderate-to-vigorous physical activity (MVPA) in these older adults.

The health outcomes show that "engaging in any additional amount of MVPA reduces dementia risk, with the highest benefit appearing among individuals with no MVPA."

Specific benefits were noted as follows:

• Each additional 30 minutes per week of physical activity lowered the risk of all-cause dementia by 4%.

Time dedicated to MVPA and dementia risk reduction

Compared to no exercise (zero MVPA) per week, the risk reduction for dementia was:

•  0-34.9 minutes: 41%
• 35-69.9 minutes: 60%
• 70-139.9 minutes: 63%
• over 140 minutes: 69%

It confirms the findings of previous studies that found that regular physical activity has a positive effect on the cognitive function of older adults.

Minimal Amount of Exercise Needed to Prevent Dementia

A 2023 study (2) investigated the minimal amount of exercise (MAE) needed to provide cognitive health benefits. The authors defined the MAE as one bout of walking 1,500 to 3,000 steps or 15 to 30 minutes.

They then studied the effects of MAE on the cognitive health of older people with osteoarthritis, and therefore with mobility issues.

The study analyzed data from the History-Based Artificial Intelligence Clinical Dementia Diagnostic System (HAICDDS) project for 242 participants and found that those who engaged in MAE once or twice a week had a 52% risk reduction of suffering from dementia compared to those who did not engage in MAE. Those who did so three or more times a week had an 81% risk reduction.

Evidence suggests that any amount of physical activity can be beneficial. Therefore, encouraging older adults to engage in regular physical activity, even in minimal amounts, can help improve their cognitive health and quality of life. Chung, YH., Wei, CY., Tzeng, RC. et al., (2023) (2)

Resistance Exercise Training against Alzheimer's Disease

A meta-analysis with more than 250,000 participants conducted in 2022 (3) found that "physical activity was significantly associated with a decreased incidence of all-cause dementia and Alzheimer's disease."

Similar to the other studies it found that physical activity (PA) lowered the risk of all-cause dementia by 20%, Alzheimer's disease by 14%, and vascular dementia by 21%.

PA was associated with lower incidence of all-cause dementia and Alzheimer's disease... supporting PA as a modifiable protective lifestyle factor. Iso-Markku P, Kujala UM, Knittle K, et al., (2022) (3)

What is Dementia?

Senile Dementia is a neurodegenerative disorder that causes a decline in cognition that will interfere with the normal independent day-to-day lives of older adults. It is intimately associated with aging.

Dementia leads to a decline in cognitive abilities, provoking a lack of concentration, loss of higher cerebral cortex function, and loss of memory, judgment, abstract thinking, and personality. It also provokes behavior changes.

Rather than a disease, it is a syndrome. It has multiple causes and different diseases combine to cause a patient's dementia syndrome. In the elderly, Alzheimer's disease, multiple infarct dementia (vascular dementia, multi-infarct dementia), and Lewy bodies are the most common, while tumors and trauma to the brain are the leading causes in younger people. (4), (5)

There is no cure for this progressive syndrome, so symptoms worsen and eventually lead to death.

How Does Exercise Help Prevent Dementia?

The exact mechanism by which physical activity helps reduce the risk of dementia is unknown. Some animal studies and trials suggest two different ways through which PA exerts its brain-protective effects.

The first is by improving blood flow and reducing inflammation. Exercise could also clear away harmful proteins from the brain as shown by animal studies where PA reduces the number and volume of beta-amyloid (Aβ) plaques. It also increases the volume of the hippocampus volume. The hippocampus is a part of the brain that is responsible for cognitive functions like learning, short and long-term memory, and visual-spatial memory. So a larger hippocampus enhances those functions.

The second manner is the neuroprotective effects of exercise. PA increases the synthesis of brain-derived neurotrophic factor (BDNF), a protein that helps neurons grow and survive. This improves neuroplasticity. (6)