Prof Peter Elwood on exercise link to avoiding dementia
10 December 2013 Last updated at 11:36 GMT
A long-term health study of men living in the Caerphilly area has found exercise can play a significant role in reducing the risk of developing dementia in later life.
The Cardiff University study, which began with 2,235 men in 1979, found factors including diet and not smoking had an impact on preventing illnesses developing in older age.
However exercise had the single biggest influence on dementia levels.
Professor Peter Elwood, who led the study, said it had clearly shown a real association between lifestyle and the risk of developing a range of illness including dementia, heart disease, diabetes and stroke.
But he was keen to stress that an overall healthy lifestyle was key, and not just singling out one aspect such as exercise.
He said: "Prevention is your responsibility and my responsibility. How I live will determine the kind of ageing pattern I will have, the kind of disease I will have."