Physical exercise may reduce the risk of dementia and slow the development of the illness even after a patient has been diagnosed with the ailment.

A study by Mayo Clinic in the US suggests that any exercise that increases the heart rate - especially aerobic activities - helps preserve cognitive abilities and have called it "not to be overlooked" as part of any treatment plans for dementia.

The Mayo team of researches - which included Eric Ahlskog and Yonas Geda - looked at data from one year of aerobic exercise undertaken in large randomised controlled trials (RCT).

The older population taking part in regular exercise was associated with significantly larger hippocampal volumes (a part of the brain) and better spatial memory.

For more details on the study, click here for www.mayoclinicproceedings.com.