This chapter introduces our stress response system and how it works in the sprints of life. Under the best of circumstances and when we are in the pink of health, our stress response system functions like a finely conducted orchestra, and we hardly notice what a marvel of orchestration we live by. Herbert Benson’s studies in the 1970’s of the physiology of transcendental meditation paved the way for the Mind Body Institute and others to practice approaches retraining dysregulated stress responses. A discussion of the distinguishing features of our stress response system leads the concept of allostasis or the cumulative burden of stressors across a lifetime—a measure of the wear and tear of life.