Exercise is good for you in all kinds of ways, there is no medicine like it to prevent a whole range of illnesses. But for some endurance athletes, exercise also comes with increased risk of a heart condition called atrial fibrillation.We look for the right way to think about the risks around exercise. Reporter: Paul Connolly
Series Producer: Tom Colls
Sound Engineer: Graham Puddifoot
Editor: Richard Vadon(Picture: A cyclist training in the mountains
Credit: anton5146/Getty Creative)