Epel: We're really adapted to run across the savanna, fleeing from a predator, so you get this huge stress response and then it turns off and no problem, our bodies can do that. The problem is that we deal with these more chronic stressors day-to-day.
Narrator: Chronic stress can be the result of many instances of acute stress or a response to a difficult job, relationship or illness.
Epel: What happens in the brain with chronic stress is our bodies are flooded with more cortisol and the worst part of it is, over time, over years, this high cortisol – this negative feedback loop is all worn out and it doesn't shut off, so that we have more chronically high levels of cortisol.
Narrator: And this can lead to a variety of health problems. For Science Today, I'm Larissa Branin.