Peter Bogelund looks exhausted. He huffs and puffs as his legs struggle to turn the wheels of his exercise bike. Peter is 69 and is obese, the legacy of a life spent drinking, smoking and never doing any exercise. A labourer since leaving school at 14, Peter is now in training for his life. Four weeks ago, he was diagnosed with stage three bowel cancer and will need surgery. But first he must undergo a punishing training schedule to prepare his body for the operation, training four or five