Exercising in your 70s 'may stop brain shrinkage'

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.