accept and embrace that energy. my definition of stress is what happens in your brain and body that helps you rise to the challenge when something you care about the on the line. >> carrie is a psychologist and the angie harrell author of the book. >> everybody's heard of the fight or flight response. it's one way your body responds to stress. you have this whole -- you go in the mode of immediate survival. you can also have a suppress response called the challenge response. that's the type that gives you courage and helps you perform under pressure. it's a healthy stress response. it's good for your cardiovascular system and good for your immune system. you can have what psychologist call a friend response which is