Welcome to the second episode of the six-part series Professor Sir Muir Gray, talking about how we can help people live longer, better.

In this episode we talk about how we lose fitness as we get older and how we often wrongly blame natural ageing for this process. We then go on to cover the four aspects of physical fitness - strength, stamina, suppleness & skill.

Sir Gray was knighted in 2005 for his contributions to the health service, developing Britain's breast, cervical, maternal and child screening programmes, creating the national library for health, Cochrane collaboration and he is currently the director of the optimal ageing programme.