Review highlights the value of exercise for the prevention of dementia and brain ageing

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I’ve written before that my experience is that individuals believe their physical health and wellbeing is generally much more controllable than their mental function. Many believe, for example, that lifestyle modification can keep, say, heart disease or type 2 diabetes at bay, but that their risk of dementia is essentially in the lap of the gods.

While the brain is perhaps a special organ, it’s an organ nonetheless. It is therefore susceptible to a range of factors that can affect it’s functioning, including in later life. One factor that has received considerable attention here in recent years is exercise. This week saw the publication of a review study in the Mayo Clinic Proceedings which summarises the state of the evidence here so far [1].

The review highlights the evidence which links exercise in midlife with a reduce risk of dementia and ‘mild cognitive impairment’. These studies are interesting, but actually don’t tell us that exercise is beneficial for brain function – only that these two things are associated.

The review also, though, looks at trials where individuals have been put on an exercise regime and the effect of this monitored. The evidence shows that exercise does indeed have the capacity to improve ‘cognitive scores’ (brain function).

Some of these studies have shown structural changes in the brain as a result of exercise, including enlargement of the hippocampus (a part of the brain concerned with memory) and a reduction in the loss of grey matter.

The mechanisms behind how exercise helps to preserve or even improve brain function are complex. One potential mechanism concerns the stimulation of what are known as ‘brain derived neurotropic factors’ which, among other things, facilitate brain cell communication. Exercise is also known to stimulate blood supply to the brain.

Exercise also likely has the capacity to reduce the risk of ‘cerebrovascular disease’. Caused by narrowing in the vessels supplying blood to the brain, this can lead to small (often symptomless) ‘infarcts’ (death of brain) tissue, and eventually lead to what is sometimes termed ‘multi-infarct dementia’.

My belief is that walking represents possibly the best form of ‘aerobic’ exercise for older individuals, for a variety of reasons, some of which I share here. Nothing more strenuous and difficult than walking has been associated with improved brain function in later life (see here), and has even been shown to improve the structure and function of the brain (see here).


1. Ahlskog JE, et al. Physical exercise as a preventive or disease-modifying treatment of dementia and brain aging. Mayo Clinic Proceedings 2011;86(9):876-884

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Walking versus running

I recently read an interesting editorial in the Journal of American College of Cardiology about the relative benefits of walking and running [1]. The editorial

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