Drs Chris and Xand Van Tulleken investigate the science of exercise and the dangers of inactivity.

Is modern exercise a wellness cult? Or is it a vital cure for a world that’s struggling with ill health and stuck on the sofa? Most of us might like to get a bit fitter, but how easy is it to actually start exercising and give up sedentary habits? In this series Drs Chris and Xand Van Tulleken examine exercise and how best to do it. How much should we be doing? How does it help our bodies? And how does our surrounding environment stand in the way of us getting fitter? Chris is challenged to examine his scepticism towards exercise. Similarly, Xand is asked to look at his new-found exercise evangelism and see what he is really running from. Recently Xand has discovered the joys of physical activity. He’s running, cycling, heading to the gym and playing ping pong like never before. It’s been a real transformation and a way to keep on top of things after years of unhealthy living. His twin brother Chris, on the other hand, is really feeling the aches and pains of middle age. With a busy job and a young family, he has precious little spare time for exercise. After a very active period in his 20s and 30s, Chris is now embracing his ‘Dad bod’ and sliding into a creaky middle age. Xand wants to help him turn things around. Can he do it?

In Episode 4 - Too Late to Change? - the twins meet up with their younger brother J for a session on an exercise bike. This has been a big part of Xand’s journey back to fitness. Will it inspire Chris to become more active? Chris then meets up with Sir Muir Gray, Director of the Optimal Aging Programme and an advisor to Public Health England. Muir shows Chris just how important exercise is for an ageing society.

Presented by Drs Chris and Xand van Tulleken Producer: Tom Woolfenden Sound Design: Dan King Series Editor: Jo Rowntree A Van Tulleken Brothers and Loftus Media production for BBC Radio 4