Living with dementia magazine June 2012

Evidence suggests that exercise reduces the risk of developing dementia, and it could benefit people with dementia. Research Communications Manager Anne Corbett looks at the case for being more active.

What is good for your heart is good for your head' is becoming an increasingly familiar mantra as print and broadcast media devote more words and airtime to the subject of dementia.

Journalists and public alike are eager for progress - new treatments, better diagnosis, and even the promise of prevention. Unfortunately researchers are still years away from preventing dementia. However, there is good evidence that what we do during our lives can affect the chances of us developing the condition.

All stages of life

Of all the ways to reduce the risk of dementia that have been investigated, the best evidence points to taking regular exercise. The research makes a convincing case for us all to be more active, whatever our age and whether or not we have cognitive impairment or dementia. Exercise throughout life can make a difference.

In 2010, Alzheimer's Society and the BBC convened the ThinkSmart panel of experts to review the evidence about risk reduction in dementia. The panel reported that regular exercise in your 40s can reduce your risk of developing the condition by up to 40 per cent (see alzheimers.org.uk/smartthinking).

Since then, a US clinical trial in 2011 found that older adults taking part in an exercise regime showed better memory function. This study was particularly important because the researchers also detected an increase in the size of the hippocampus, the area of the brain responsible for memory.

Incomplete story

Clinical trials have also shown that exercise in people with mild cognitive impairment (MCI) and mild Alzheimer's disease can improve their symptoms. A study in 2004 found that people with MCI or early Alzheimer's disease who only received counselling continued to decline over one year, while the symptoms of those taking part in an activity programme either stayed the same or improved.

Although this illustrates the potential for exercise to make a tangible difference to the chance of developing dementia and how it progresses, the story is by no means complete. Since studies have used exercise programmes with different types and intensities of activity, it is hard to say exactly what sort of exercise is best.

We know that we don't need to be training at elite levels to see a difference - the 2011 study used exercise of moderate intensity - but we also know that doing aerobic exercise is important. A group of participants in the same study who just took part in stretching exercises did not see any improvement.

We are also unclear about why exercise has this effect. Researchers are reasonably certain that it is partly due to the beneficial effect of exercise on our heart and overall health. Exercise is certainly reducing the risk of vascular dementia, which is caused by problems in the blood supply to the brain which are often related to obesity and other signs of an unhealthy lifestyle. However, evidence also points towards other mechanisms that might directly affect the chemistry of the brain and the way it changes as we age.

Making change

It is important to remember that risk reduction is a complex and imperfect art. Many people will know of someone who has lived an exemplary lifestyle, including regular exercise, and yet has not avoided developing dementia, and vice versa.

While exercise cannot guarantee that a particular individual will not develop dementia, it can have a tangible impact when seen from a population perspective. A risk reduction of up to 40 per cent in a large population translates into thousands of people who would otherwise develop the condition.

A key question is how to implement change in a population. So far we don't have an easy answer to this challenge. Even since the link between lung cancer and smoking was unequivocally confirmed it has taken 40 years for rates of smoking to fall substantially. Research is exploring the most effective ways to encourage sustained behaviour change. There is hope that this could be achieved through a combination of new technologies to engage and inform the public, and through commitment from health professionals and policy makers.

Ultimately however, it is up to each of us to digest the evidence and make an informed decision to make our lives more active and to reduce our risk.

For more information about research into the cause, cure, care and prevention of dementia, visit alzheimers.org.uk/research

Our factsheet Exercise and physical activity for people with dementia (529) is available at alzheimers.org.uk/factsheets, or you can request copies by phone on 01628 529240 or email alzheimers@xcalibrefs.co.uk

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