We all know what we eat and how we live our lives has an impact on the way we look and feel. Tonight, the pair will be travelling the world to find out the best ways for keeping us fit and strong into old age. They'll explore what sort of exercise is best – dance or conventional gym – and visit a community in Los Angeles with one of the highest life expectancies in the US to find out what they're doing right.
Chris also undertakes a social experiment with a little help from Hollywood make-up to discover how the public treats the elderly, while both undergo tests to learn how well they are truly ageing.
How To Stay Young, BBC One, 9pm
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