Small doses of exercise can reduce the risk of dementia by up to 40%, study finds

As life expectancy increases across the world, the challenge of keeping the brain sharp has become a central issue in public health. Cognitive decline is the leading threat to independence in old age, and dementia now affects millions of families. While no cure exists, growing evidence suggests there is a powerful, simple, and widely available form of prevention: physical activity.

Research shows that age brings biological changes caused by damage at the molecular and cellular level. These changes reduce organ function and impair brain activity. Age itself is the strongest risk factor for Alzheimer’s disease, the most common form of dementia. But scientists have found that lifestyle choices can speed up or slow down the process. Regular movement, endurance training, and good cardiorespiratory fitness are linked to healthier brain aging.

A review published in The Lancet highlights how exercise protects brain function. The analysis, carried out by scientists at the Norwegian University of Science and Technology (NTNU) and the Queensland Brain Institute in Australia, explains the mechanisms.

Exercise boosts blood flow to the brain, reduces inflammation, and supports neuroplasticity—the brain’s ability to form new connections. It also improves immune function and releases protective molecules into the bloodstream. These processes weaken with age, but activity slows the decline.

“Physical activity appears to be one of the most promising measures we have to prevent cognitive decline and dementia,” said first author Atefe R. Tari from NTNU’s Cardiac Exercise Research Group.

One of the most striking findings is that even small amounts of movement can make a difference. High intensity activity in short bursts has shown benefits for both the body and the brain. “We believe it’s time for health authorities to provide clearer advice on how important exercise is for the brain,” said co-author Ulrik Wisløff. “Our review shows that even small doses of high-intensity activity – equivalent to brisk walking where you can’t sing – can reduce the risk of dementia by up to 40 per cent.”

That message is crucial, since up to 70 percent of adults fail to meet current guidelines of 150 minutes of moderate activity or 75 minutes of vigorous activity per week. Tari stresses that small steps are better than none at all. “A little is better than nothing – and it’s never too late to start,” she said.

The science behind these findings shows why fitness is more than a matter of strong muscles or a healthy heart. Endurance exercise directly influences brain chemistry and structure. Animal and human studies reveal how regular activity reduces the inflammation that fuels neurodegeneration.

Exercise also enhances blood circulation, which supplies oxygen and nutrients to brain cells. It improves immune defense, allowing the body to clear harmful molecules before they damage tissue.

Neuroplasticity is another key factor. The brain constantly rewires itself, creating new pathways and strengthening existing ones. Exercise stimulates this process, supporting memory and learning. Tari explains: “These are mechanisms that play an important role in the development of dementia and cognitive decline.”

Public health leaders have long promoted exercise for heart health, but the evidence for its role in preserving mental sharpness is now too strong to ignore. International research supports this conclusion. Their message is the same: even small amounts of high-intensity activity improve brain health.

NTNU scientists propose that national health recommendations should include microtraining or short high-intensity sessions. Such advice could reach the large portion of the population who find it difficult to set aside long blocks of time for exercise. “Exercise is cheap, accessible and has no side effects,” Tari said. “It should be considered a first-line measure to preserve brain health.”

One encouraging aspect of the research is that benefits appear even when people start later in life. Exercise is not only about prevention in youth—it can provide protection for older adults as well.

Tari emphasizes that beginning at any age helps: “And it is never too late to start.” The take-home message is clear. Regular activity, even in small amounts, protects against the processes that damage the brain with age.

By boosting blood flow, calming inflammation, and strengthening neural connections, exercise gives the brain a better chance to stay healthy for longer.

The researchers also acknowledge the challenges ahead. More long-term studies are needed, especially those that track people over decades with consistent exercise routines. Carefully controlled trials will help refine recommendations and show which types of training are most effective.

But while more detail will come with future science, the main advice is already actionable: move more, even if only for short bursts, and the brain will benefit.

As global life expectancy continues to rise, dementia prevention is becoming an urgent issue. With no cure available, prevention through lifestyle may be the most powerful tool. Physical activity stands out as a low-cost, accessible, and highly effective option.

Note: The article above provided above by The Brighter Side of News.

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