2012-10-23 04:28:53
By Michelle Roberts Health editor, BBC News online
Exercising in your 70s may stop your brain from shrinking and showing the signs
of ageing linked to dementia, say experts from Edinburgh University.
Brain scans of 638 people past the age of retirement showed those who were most
physically active had less brain shrinkage over a three-year period.
Exercise did not have to be strenuous - going for a walk several times a week
sufficed, the journal Neurology says.
But giving the mind a workout by doing a tricky crossword had little impact.
The study found no real brain-size benefit from mentally challenging
activities, such as reading a book, or other pastimes such as socialising with
friends and family.
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More research is also needed to tease out how physical activity might be having
a beneficial effect
Dr Simon Ridley Alzheimer's Research UK
When the researchers examined the brain's white matter - the wiring that
transmits messages round the brain - they found that the people over the age of
70 who were more physically active had fewer damaged areas than those who did
little exercise.
And they had more grey matter - the parts of the brain where the messages
originate.
Experts already know that our brains tend to shrink as we age and that this
shrinkage is linked to poorer memory and thinking.
And previous studies have shown that exercise helps reduce the risk of dementia
and can slow down its onset.
But scientists are still baffled about why this is.
'Never too late'
Exercise increases blood flow to the brain, delivering oxygen and nutrients to
brain cells, which may be important.
Or it may be that as people's brains shrink, they become less inclined to
exercise.
Regardless of why, experts say the findings are good news because exercise is
an easy thing to do to boost health.
Dr Simon Ridley, head of research at Alzheimer's Research UK, said: "This study
links physical exercise to fewer signs of ageing in the brain, suggesting that
it may be a way of protecting our cognitive health.
"While we can't say that exercise is the causal factor in this study, we do
know that exercise in middle age can lower the risk of dementia later in life.
"It will be important to follow these volunteers to see whether these
structural features are associated with greater cognitive decline over the
coming years. More research is also needed to tease out how physical activity
might be having a beneficial effect."
Prof James Goodwin, head of research at Age UK, the charity that provided the
funding for the research, said: "This research re-emphasises that it really is
never too late to benefit from exercise, so whether it's a brisk walk to the
shops, gardening or competing in a fun run it is crucial that, those of us who
can, get active as we grow older."