Well, the problem is that, most of the time, we aren’t actually fighting for survival when our cortisol spikes. “Think about the Stone Age man. He sees a grizzly bear pop out and tries to attack him, cortisol is a really helpful response,” says Dr Crown. “I think what people worry about now is the fact that we have recurrent psychological or emotional stresses that are not a threat physically but are perhaps a threat to our psychology, we get a similar cortisol response.”

If, for example, you’re in a job that is hugely demanding on your time, where you lack control and a lack of support, you will have “either very frequent cortisol stress responses, or cortisol that doesn’t ever fully settle back to normal again.”

How does exercise impact cortisol?

For all the talk about exercise being a stress reliever, it’s interesting that when you are exercising your cortisol levels will actually go up. “That’s beneficial because during exercise you need to mobilise some of your glucose to keep your blood pressure up. It’s an appropriate response to the stress on your body and your body will use that cortisol to adapt and make changes from the exercise.”

What is cortisol and how can exercise impact levels of the hormone?