Walking 'boosts memory power'

Walking about 40 minutes a few times a week is enough to preserve memory and keep ageing brains on top form, research shows. Moderate exercise increased the size of the hippocampus, an area of the brain that makes memories, in 120 volunteers.

The year-long trial, published in Proceedings of the National Academy of Sciences, showed performance on memory tests also improved.

Exercise may buffer against dementia as well as age-related memory loss. The latest work looked at healthy people in their 60s rather than people with Alzheimer's or other forms of dementia.

But the findings have important implications for ageing societies faced with a dementia time bomb. In the UK, 820,000 people have dementia, and this figure is set to double by 2030.