This document discusses the effects of stress on the body and brain. It describes how stress activates the fight or flight response and increases levels of hormones like adrenaline and cortisol. Prolonged stress can lead to health issues if the body cannot properly adapt. It also discusses how different parts of the brain are involved in stress response, such as the hypothalamus pituitary adrenal axis and reticular activating system. Maintaining good brain and body health through reducing stress, nutrition, sleep, and lifestyle factors can help optimize brain function and resilience.