Brisk walking for two hours a week may help boost brainpower in women at risk of dementia, say researchers.
A six-month study in women with early memory problems found aerobic activity increased the size of the hippocampus – an area of the brain involved in learning and memory.
Canadian researchers claim it’s never too late to undertake regular physical activity based on increasing evidence that it promotes brain health.
They investigated the effect of different types of exercise on the size of the hippocampus because it is very sensitive to the effects of ageing and neurological damage.
The trial involved 86 women with mild memory problems, known as mild cognitive impairment – and a common risk factor for dementia.
The women aged between 70 and 80 years, who were living independently at home, were split into three groups.
They were assigned to twice weekly hour long aerobic sessions of brisk walking; or resistance training, such as lunges, squats, and weights; or balance and muscle toning exercises (the control group).
The size of their hippocampus was assessed at the start and the end of the six month trial period, says a report in the British Journal of Sports Medicine (must credit).
Altogether 29 of the women had before and after MRI scans, which showed the hippocampus was significantly bigger in those completing six months of aerobic training compared with balance and muscle toning exercises.
Resistance training made little difference compared with the balance and muscle toning group.
The women’s verbal memory and learning capacity was assessed before and after using a recognised test and there was some evidence it worsened as the hippocampus got bigger.
Study leader Dr Teresa Liu-Ambrose, of the Department of Physical Therapy, University of British Columbia, Vancouver, said the relationship between brain volume and cognitive performance was complex, and needed further research.
But at the very least, aerobic exercise seems to be able to slow the shrinkage of the hippocampus and maintain the volume in a group of women who are at risk of developing dementia, she said.
‘Given the growing evidence that exercise is beneficial for cognitive and brain health, physical activity should be a standard recommendation for all older adults regardless of cognitive status’ she added.
In Britain, around 820,000 people have dementia, with most suffering from Alzheimer’s.
Previous research has found regular exercise can cut the risk of developing dementia, while other studies suggest keeping the brain active by doing crosswords, playing cards and computer works.
Official guidelines in the UK say people should do 150 minutes of moderate, or 75 minutes of vigorous, exercise every week but three out of four Britons fail to achieve this.
Dr Laura Phipps of Alzheimer’s Research UK charity, said ‘There is growing evidence that regular exercise can help keep our brains healthy as we age.
‘This small trial suggests that aerobic exercise such as brisk walking could increase the size of part of the brain involved in learning and memory, but the study did not look at the long-term effects of these changes on a person’s everyday life.
‘The study reports an unexpected decrease in memory performance in those who showed an increase in hippocampus size, suggesting that the relationship between brain size and memory may not be straightforward.
‘While there is no sure-fire way to prevent the onset of dementia, evidence suggests that there are things we can do to look after our brain.
‘This includes eating a healthy balanced diet, taking regular exercise, not smoking, maintaining a healthy weight and keeping blood pressure and cholesterol in check.’