If an epidemic is defined as a disease that affects whole populations without having a medical cure, then the epidemic of modern life is stress. Itself not a disease, stress instead leads to a breakdown in the body's internal balance, or homeostasis, and from that point onward, if the stress isn't relieved, damage occurs from within. Ironically, most modern people in a developed country do not experience acute stress, the kind that triggers a full-blown fight-or-flight response. There is no battlefront, civil war, rampant violent crime, or struggle over food and water to contend with.

Our epidemic is silent and hidden, in the form of low-level chronic stress. The natural purpose of the body's stress response is to trigger heightened alertness and energy for a short period, a matter of minutes or at most an hour, when fighting or fleeing is a matter of survival. When stress becomes chronic, a "normal" way of life that people believe they have adapted to, stress hormones become a drip-drip in the background of the physiology, and over time, three stages of damage begin to appear: