To fully understand how to influence hormonal secretions and activities we must first understand the big picture and know the natural cycles that dictate our body’s priorities between thrive or survive.
I can and will explain this in more depth but it is important to get the basic concept to understand and appreciate the intricacies of the individual triggers and hormones. Then we can learn how to use these hormones to maximise health and performance.
The HPA (Hypothalamic Pituitary Adrenal) Axis mediates our survival response.
The Hypothalamus in our brain collects data from our body to inform of potential stressors. The definition of a stressor is “anything that makes a change in our body”. So basically changes to our external and internal environment can instantly trigger a stress response. Our body can’t afford to wait and see if something is life threatening before it reacts, therefore it will trigger a stress response, proactively, just in case. The immune system, inflammatory chemicals, emotional stress, fear, pain, temperature extremes, toxicity, training hard, caffeine etc will all activate the Hypothalamus to initiate a survival response.
The hypothalamus sends a message to the pituitary gland in the form of a chemical called CRF (cortitropin releasing factor) aka CRH (corticotropin releasing hormone) to say stress! The pituitary gland panics and forgets all about the chemicals needed for other metabolic processes and activities, such as the gonads (The HPG axis) and the thyroid gland (the HPT axis) for now and pumps resources toward survival.
The pituitary gland pumps out ACTH to stimulate the adrenal cortex to release the hormone cortisol.
Cortisol has a number of jobs to do to aid in short term and long term survival:
The secreted cortisol gets back to the hypothalamus and pituitary gland in your brain and activates negative feedback receptors to switch off our HPA axis stress response and everything goes back to normal. Cortisol is released to protect us from our own defence mechanisms. Too easy.
You are right that sounds too easy. Life isn’t fair. If it isn’t one stress factor it’s another. We have bills to pay, our jobs to do, everyone else’s jobs to do, everyone else’s jobs to check, our job hasn’t got done, we got bills to pay and then the phone rings. Oh yeah, that’s right; I have bad allergies and a funny gut, and I am bloody sore from training legs 2 days ago.
Basically if cortisol is going back to your brain saying, “Chill I got it covered”, but other stress triggers are coming in, and therefore our brain has to over-ride the cortisol and activate a further more intense stress response. The negative feedback receptors in the brain can desensitize to cortisol and ignore the negative feedback request but the rest of the body is still affected by the cortisol and there is more coming.
Chronic exposure to cortisol is a sign that you are not safe. So don’t relax. Blocked serotonin activity means you will be feeling like if you aren’t punching and running you should at least be hiding, so insomnia and anxiety is common with elevated cortisol. In case of injury and immobilization or hiding cortisol preserves fat and fluid around internal organs and the elevated blood pressure, and fluid retention can start causing problems in the cardiovascular system. The immune system gets constant exposure and is supressed allowing for infection and infestation. Muscles and bone are catabolized to fuel the stress response.
So in the real world we all suffer through various versions and stages of adrenal maladaptation depending on our individual circumstances and types of stress.