People with mild Alzheimer’s disease who are physically fit have larger brains than those with the disease who infrequently exercise, new research has found.

The study, published in Neurology, examined 121 people aged 60 or over, around half of whom were in the early stages of Alzheimer’s disease.

Subjects with Alzheimer’s disease who were less physically fit had four times more brain shrinkage than those who were fit.

Dr Jeffrey Burns of the University of Kansas School of Medicine said, "People with early Alzheimer’s disease may be able to preserve their brain function for a longer period of time by exercising regularly and potentially reducing the amount of brain volume lost. Evidence shows decreasing brain volume is tied to poorer cognitive performance, so preserving more brain volume may translate into better cognitive performance. This is one of the first studies to explore the relationship between cardiorespiratory fitness and Alzheimer’s disease".

Rebecca Wood, Chief Executive of the Alzheimer’s Research Trust, said, "This study adds to previous research showing that exercise helps reduce the risk of dementia, and slows down its onset. A balanced diet and regular exercise can improve the quality of life of older people with dementia, as well as those who do not have the condition. Much more research, in a variety of fields, is needed if we are to offer hope to the 700,000 people in the who live with Alzheimer’s and other dementias."

In 2005 Swedish researchers found that people who exercise in middle age are less likely to develop dementia later on.