Physical activity may benefit older women at risk for dementia, according to a recent study HealthDay reported.

British researchers found that exercising at least twice a week seem to boost the size of the hippocampus, the area of the brain involved in verbal memory and learning, among women whose intellectual capacity has been affected by age, HealthDay reported.

The hippocampus is very sensitive to the effects of aging and neurological damage.

For the study, researchers tested the impact of different types of exercise on 86 women, aged 70 to 80, who had mild memory problems, also known as "mild cognitive impairment," which researchers say is a common risk factor for dementia.

For six months, study participants were assigned to either twice weekly hour long sessions of aerobic training (brisk walking); resistance training such as weights and squats, or balance and muscle toning exercises, HealthDay reported.

The size of the hippocampus was assessed at the start and the end of the six month period with an MRI scan, and their verbal memory and learning capacity was assessed before and afterward using a validated test.

Researchers found that the total volume of the hippocampus in the group who had completed six months of aerobic training was significantly larger than that of those who had lasted the course doing the balance and muscle toning exercises. No such difference was seen in the other groups.

However, despite an earlier finding in the same sample of women that aerobic exercise improved verbal memory, there was some evidence to suggest that an increase in hippocampal volume was associated with poorer verbal memory.

This evidence suggests that the relationship between brain volume and cognitive performance is complex, and requires further research.

However, researchers said the findings do indicate that aerobic exercise does slow the shrinkage of the hippocampus in women who are at risk for developing dementia.

The findings from this study were recently published online in the British Journal of Sports Medicine.