What is the HPA axis and why you should care

What is the HPA axis and why you should care

The hypothalamic-pituitary-adrenal (HPA) axis is a feedback system connecting your brain to your adrenal glands – the latter of which produce adrenaline, noradrenaline and the stress hormone cortisol in response to how you are experiencing your world. But what does that mean exactly?

Stress physiology 101 

Put simply, if you perceive a threat in your environment then chemical messages are first sent from the hypothalamus (this is the area of your brain involved with memory so the perceived ‘threat’ is based upon some previously remembered experience - whether that’s consciously or unconsciously). These signals are picked up by the pituitary gland (also located in your brain), which responds by sending its own set of chemical messages to your adrenal glands located above your kidneys. The adrenals then release the ‘alarm messengers’ adrenaline and noradrenaline - making your heart speed up, your breathing rate increase, and blood race to fuel your muscles. All this so you can physically either ‘fight or take flight’ from whatever the threat is. Your adrenals also secrete the stress hormone cortisol for several hours following a stressor, and it’s the presence of this latter hormone at sufficient blood concentrations that your hypothalamus then picks up on and knows when to moderate it’s signal to switch the ‘alarm’ off again. Hence the HPA axis is a feedback loop.

Introducing the modern-day tiger

So you see, this is an essential system that helps keep you safe and able to run away when you encounter a tiger, for example. But it’s a system that also responds in a similar way if you feel you will get into trouble for running late to work or a meeting, or you have an assignment due tomorrow you haven’t completed, your boss is a bully and you dread encountering him or her, you see your credit card bill and it’s higher than you can afford to repay easily, you have an argument with someone, you feel vulnerable in some way, you feel your work lacks purpose, or any and all of the modern day stressors unique to your situation you are encountering – they are simply the new ‘threats’ and unfortunately your brain doesn’t know these are not life threatening (unlike the tiger); it signals the alarm each time anyway.

Now that’s all very interesting you may be thinking – but what do I do with that information? Well, knowing this happens physiologically it may make more sense why talk of ‘stress busters’, becoming more mindful, the increased interest in yoga, or the myriad of advertisements for ‘relaxing breaks’ have become more and more mainstream in the past 5 to 10 years. They were always there, but the global wellness industry has grown and ‘how to relieve stress’ articles are more common now because the impact of stress is now acknowledged as a real issue affecting all people in the modern world.

…and how this relates to you

Maybe you are thinking ‘but I don’t feel stressed’, and you could of course be correct, but you see the effects of stress are insidious and don’t have to reveal themselves as feelings of overwhelm, anxiety, or ‘I cannot cope’ (though they might). Instead the impact of these chemical messages on your body over time reveal themselves as fatigue, unrestorative sleep, a mind that never seems to stop racing; perhaps it’s simply a feeling of ‘not being quite right’ - as though you get through the day but don’t exactly have the energy levels you’d love to enjoy.

If this is you, or someone you know, then it’s wise to take heed as this ongoing pressure on your body, though subtle, over time can raise blood pressure, which affects your heart and eventually your kidneys; stress can also lead to less than ideal eating and exercising patterns, is associated with increased weight, mood changes, menstrual irregularities, poor digestion… the list goes on.

Reframing the word ‘stress’

As I mentioned in my previous post, stress is not a dirty word – it’s simply the name given to your natural physiological response to a perceived threat – but the threats have changed over more recent decades. The effects of these new stressors are something we all need to own and respond to in new ways, as our busy lives are unlikely to change anytime soon. This may mean changing your schedule to help prioritise more sleep, or regular exercise; refusing to be a slave to food marketing and pollute your body any longer with refined, processed convenience foods and invest in more natural wholefoods that support positive mood and health. You may also need some applied nutrition and/or herbal supplementation tailored to your needs and situation if correcting these foundations of health have helped but not completely resolved the sleep/energy/digestive/mood or other imbalance you may be experiencing to your satisfaction.

Wellbeing in progress

This is not just talk as I practice many of these things myself, even when it’s not easy. I know I’m busy and under pressure frequently, so I choose to offset this reality with spending each day balancing life’s expectations of me with choices that help build resilience. I have a daily yoga and/or meditation practice though it takes time and schedule juggling. I choose the foods I eat carefully (not perfectly 100% of the time, but at least mindfully). I also hike regularly, prioritise 7-8 hours sleep every day, am slowly building a social network here in Hong Kong, and use a personalised herbal tonic along with a few nutrients that optimise my energy production. It works for me most of the time, but wellbeing is a work in progress so everyday I choose to reflect on how I’m feeling and make even better choices sometimes to not only feel well, but also stay well.

What you can do for yourself

If there are areas you feel could be improved with regards to wellness and building resilience against everyday stressors, then start with the basics such as daily (or at least every other day) exercise outside, swapping refined, processed energy-draining foods for more nourishing wholefoods, and/or speak to your herbalist or naturopath about what tonic formula is indicated for your situation to give you that additional boost or support. Remember, it’s your life and I suspect you want to live well and with vitality, so be mindful of how you perceive your world and take steps to manage the physical impact of any stressors you face.


By Jo Herbert-Doyle, Naturopath

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