Stress is a biological process, not simply a feeling, and this book examines how it unfolds inside the body.Stress is a biological process, not simply a feeling, and this book examines how it unfolds inside the body. You will learn how the nervous and endocrine systems respond to perceived threats, how hormones such as cortisol and adrenaline coordinate short-term reactions, and what happens when these systems remain active over long periods. The book explains the physiological basis of adaptation and recovery, including the roles of sleep, inflammation, and the immune system in restoring balance. Drawing on established research in physiology and neuroscience, it offers a clear, factual account rather than general advice. This book was generated by artificial intelligence, and its content has been structured to provide an accessible introduction to the biology behind everyday stress responses.Stress is a biological process, not simply a feeling, and this book examines how it unfolds inside the body. You will learn how the nervous and endocrine systems respond to perceived threats, how hormones such as cortisol and adrenaline coordinate short-term reactions, and what happens when these systems remain active over long periods. The book explains the physiological basis of adaptation and recovery, including the roles of sleep, inflammation, and the immune system in restoring balance. Drawing on established research in physiology and neuroscience, it offers a clear, factual account rather than general advice. This book was generated by artificial intelligence, and its content has been structured to provide an accessible introduction to the biology behind everyday stress responses.