Walk your brain younger: As little as one hour of exercise a week ‘could reduce the risk of dementia and improve mental fitness’

By Sam Blanchard Health Reporter For Mailonline

Regular exercise could boost your mental fitness as well as physical, and reduce your risk of developing dementia, scientists say.

A study has found people who do more physical activity – even if it is as light as just walking – slow their brains’ ageing process and are less likely to get dementia.

The findings are good news for people who try to stay fit but aren’t marathon runners or Tour de France hopefuls.

The researchers say all exercise, even if it’s less than the two-and-a-half hours per week recommended by the NHS, could be enough to build up and have benefits. Scientists at Boston University studied data from an ongoing heart health study in the US to delve into the benefits of exercise.

They found every extra hour of physical activity in an average week corresponded to a brain age 1.1 years younger.

So someone doing three hours of exercise each week could, over time, maintain a brain effectively three years younger than the average for their age. ’We have really only just begun to uncover the relationship between physical activity and brain health,’ said researcher Dr Nicole Spartano.

The research showed lower intensity exercise, as long as it was enough to get the heart, lungs and muscles working harder, could be beneficial.

Dr Spartano added: ‘Every additional hour of light intensity physical activity was associated with higher brain volumes, even among individuals not meeting current physical activity guidelines.

‘These data are consistent with the notion that potential benefits of physical activity on brain aging may [build up] at a lower, more achievable level of intensity or volume.’

The team said it was not clear how much exercise could be enough for ‘optimal’ protection against dementia, but recommended people do at least 250 minutes per week.

There are various mechanisms through which exercise can help the brain, including improving blood flow and encouraging better sleep.

Scientific studies have in the past found people who do regular aerobic exercise – that which is focused on cardiovascular fitness such as running, swimming and cycling – have more volume in certain parts of the brain.

The hippocampus, which controls learning and emotions, and the prefontal and medial temporal cortexes, which affect thinking and memory, have been found to be larger in fitter people.

Exercising often also improves people’s sleep and reduces stress, both of which can have positive effects on mental health and thinking power.
The Boston team’s research was published in the journal JAMA Network Open by the American Medical Association.

HOW IS EXERCISE GOOD FOR THE BRAIN?

Many scientific studies encourage people to exercise by touting the benefits it could have on their brains – but what exactly does it do?

In a round-up of recent research, Harvard Health Letter’s executive editor, Heidi Godman, explained it can boost the size of certain parts of the brain, improve sleep and stimulate healthier brain cells.

Research by the University of British Colombia showed people who did regular aerobic exercise – such as running, swimming or cycling – have larger and more active hippocampus regions of the brain, which are associated with learning and emotions.

Other research adds that the prefrontal cortex and medial temporal cortex tend to be larger in people who exercise more often – these regions control thinking and memory.

Exercise can also reduce inflammation (swelling), which can damage cells if sustained, throughout the body, including in the brain.

It can also stimulate the production of growth factors, which are chemicals affecting the health of brain cells and the growth of new blood vessels to provide more oxygen to the organ.

Exercise also helps people to sleep better and have reduced stress and anxiety, all of which have been shown to have positive effects on brain power and mental health.