genetic lottery sucks
There are a number of scenarios in which the body fails to shut off the flow of stress hormones. The most obvious is simply unrelenting stress. If we never get a break, the recovery process never gets started, the amygdala keeps firing, and the production of cortisol spills over healthy levels. Sometimes the fight-or-flight switch gets stuck in the on position. It can be a function of genetics, according to epidemiological surveys: if you put a random group of people in a stressful public speaking situation, those whose parents suffered from hypertension still show elevated levels of cortisol twenty-four hours after the speech.