The body responds to extreme experiences by secreting stress hormones. These are often blamed for subsequent illness and disease. However, stress hormones are meant to give us the strength and endurance to respond to extraordinary conditions. People who actively do something to deal with a disaster—rescuing loved ones or strangers, transporting people to a hospital, being part of a medical team, pitching tents or cooking meals—utilize their stress hormones for their proper purpose and therefore are at much lower risk of becoming traumatized. (Nonetheless, everyone has his or her breaking point, and even the best-prepared person may become overwhelmed by the magnitude of the challenge.)

Helplessness and immobilization keep people from utilizing their stress hormones to defend themselves. When that happens, their hormones are still being pumped out, but the actions they’re supposed to fuel are thwarted. Eventually, the activation patterns that were meant to promote coping are turned back against the organism and now keep fueling inappropriate fight/flight and freeze responses. In order to return to proper functioning, this persistent emergency response must come to an end.

Bessel van der Kolk, The Body Keeps the Score: Brain, Mind, and Body in the Healing of Trauma