Exercise in later life: How it can make a difference
7 May 2014 Last updated at 07:55 BST
Exercise can feel much harder the older we get. But why does this happen and can we do anything to keep fighting fit?
Bruce Paton, a physiotherapist at the Institute of Sport, Exercise and Health, explains how the heart and muscles change with age as a 30 and 70-year-old volunteers battle it out on the treadmill.
Pictures courtesy of the Science Photo Library