Chemotherapy. Radiotherapy. Surgery. Drugs. That's probably what you expect to be prescribed when you've got cancer - but what if your doctor was to suggest exercise as well? On this week's Personal Best, Gillian Russell looks at whether prescribing exercise is a realistic step... Angela Roberts talks about her experience of exercising during and after chemotherapy for breast cancer. Dr Anna Campbell from Napier University explains how exercise can benefit a cancer patient, what type of exercise and how often might it be useful ... and how much of an impact it can have on our mental health. Plus is there any evidence it might help to prevent recurrence? Personal Trainer Kristeen Pollock describes how her mum's cancer diagnosis led her to start working with cancer patients. Dr Juliet McGrattan explains why her passion for fitness has led her to quit her job as a GP to concentrate on encouraging others to become more active, believing she can have more of an impact on people's health that way than writing prescriptions for tablets. Chris Thompson from Living Streets, the charity behind National Walking Month, talks about this year's #Try20 Campaign, aimed at getting us all to walk more every day and ideally reach the national guidelines of 150 minutes of exercise per week. Richard Forbes joins the Step It Up Highland walking group to find out how much of an impact regular walking is having on their physical and mental health.