Your body releases cortisol in response to stress, which prepares you to fight or flee. This is a useful response in our early years when the stressors were things trying to hurt, kill, or eat you.

But modern day stressors are different — deadlines, colleagues, managers. We aren’t running or fighting these stressors, so the cortisol stays in our body keeping us in a constant state of alert. That heightened state is a big strain on the body.

Running burns off cortisol the way the body naturally intended.

Transcript
Corporate America and desk jobs are slowly poisoning your body. And the antidote to that is running. What happens is when you are stressed from deadlines, working relationships, whatever it is, your body respond to that stress by releasing cortisol. And that's a good thing because cortisol gets your body ready to fight, or to run away. Back in the day, that was helpful because the dangers you dealt with war people trying to kill you or to eat you, and cortisol, get your body ready to run and get away. But those aren't the stressor we're dealing with now. And so when you get stressed and the cortisol builds up in your body, you're in this constant state of fight or flight and that slowly is just overworking everything in your body. doing physical activity like running or any exercise burns off that cortisol the way your body naturally intended to, to help make sure that you're ready to respond to the stress in a healthy way.