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Exercise and brain health

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Moving your body

Physical inactivity is one of the modifiable risk factors named in the World Health Organization's 2026 dementia guidelines, which concluded that up to 45% of dementia risk could be prevented or delayed.

WHO recommends increasing physical activity as part of reducing that risk. It is among the better-supported recommendations on the list, and it is the one most people can begin immediately.

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Worth knowing

An important point to keep in mind.

Population-level risk reduction is not an individual guarantee. That means, exercise is associated with better cognitive outcomes across large groups; it cannot promise any one person will avoid dementia.

The goal is to improve the factors you can influence without being attached to a particular outcome and not judging those with dementia for failing in effort.

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How much exercise and what kind

The general physical activity recommendation is, per week: roughly 150 minutes of moderate activity, or 75 minutes of vigorous activity, plus muscle strengthening on two days.

Moderate activity means you can talk but not sing. A brisk walk counts. So does gardening, cycling or swimming at a steady pace. There is no evidence that a gym membership beats a daily walk and the physical activity you genuinely enjoy doing is always better than one you will quickly abandon.

If you are starting from doing very little physical activity, you may be surprised to know the largest gains in the research are seen at the bottom end. That means, going from nothing to 20 minutes of exercise on most days is a bigger change than up-leveling from 40 to 60 minutes. You can do it.

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What is genuinely uncertain

Three things about the effects of exercise on brain health can get overstated in popular coverage, and it is worth knowing which.

  • Mechanism. Exercise plausibly acts through blood flow, cardiovascular health, sleep and mood. However, claims that it specifically grows a particular brain structure in humans are far less settled than headlines may suggest.
  • Direction. People experiencing early cognitive decline may become less active before they are diagnosed, which means the exercise-to-brain-health relationship may be influenced in both directions.
  • Dose. Research cannot tell us how much exercise will change one person’s individual risk.

What remains clear is that physical activity supports your heart, sleep, mood and independence. It may also support cognitive health. That is a strong enough case without overstating what the research can tell us.

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Are my new habits working?

This is the question risk-reduction advice rarely answers.

If you change your habits, how will you know whether your cognition is staying steady? The only way to know is to establish a baseline and measure again over time. A baseline you can repeat turns a hope into something measurable and real.

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