The reason why stress affects us so much is that our body really hasn’t changed much in 60,000 years. Cortisol is a stress hormone produced in the adrenal glands (little glands that sit on top of the kidneys) which are hard wired to the body’s ‘fight or flight’ survival response. 60,000 years ago this would’ve been essential to either fight or run away from a wild animal.
It’s an ancient survival mechanism that was designed to deal with short spikes of stress, not the constant bouts we now experience due to our ever-increasing life load. Our bodies are still wired like this but they can’t tell the difference between real danger and emotional stress. They can’t work out if you’re running away from a wild animal or sitting at our desk with a coffee getting stressed over spreadsheets! The fight or flight response is the same: it re-directs resources to the lungs, heart, brain, eyes and away from what it deems unnecessary like the digestive system or the reproductive system.
Chronic stress down regulates our digestive system and with it our guts - hence the link with stress and IBS. The gut is home to two thirds of the immune system – it’s the biggest natural barrier to the outside world aside from the skin so if this isn’t functioning well, the barrier to the inside, our blood stream, won’t be up to the task. We see this in research where high levels of cortisol reduces secretory IgA, an immunoglobulin housed in our gut mucosal membrane essential to our gut’s immune integrity.
Cortisol is our body’s natural anti-inflammatory which increases during stress events in case we get injured (60,000 years ago that would’ve been quite useful, not so much now!). There is no differentiation - up regulation of the immune system occurs during each stress event regardless of a physical wound or emotional stress. In short spurts, cortisol helps to boost our immune system by limiting inflammation but longer bouts of stress can actually raise cortisol further and cells start to become resistant to its effects, similar to how we can become insulin resistant when levels of insulin are too high. The immune system starts to become dysregulated and inflammation increases.
So what can we do about it? I always say I can’t do anything about my client’s stress levels sadly but I can help you become more resilient to your everyday stress load: