Overview: Michael Mosley tests how vigorously you really need to exercise to start seeing improvements to your physical and mental health. Alain Gregoire cures his lifelong phobia of heights in just two hours using virtual reality. Zoe Williams investigates whether the ten-minute one-to-one GP appointment could be under threat. Giles Yeo tests whether hot or cold drinks are better to cool you down. And Guddi Singh looks into a mystery illness that is often dismissed as a bout of morning sickness.