Get to Know Your HPA Axis

Posted by Anna-Marija Helt PhD on 4th Jun 2019

Your HPA Axis: Why it’s so important to your daily vitality.

The HPA axis has been getting quite a bit of attention lately. Given the relentless stress that a lot of us feel, our stress-response mechanisms get a heck of a workout. Whether it’s your job, the media, traffic, family responsibilities or money, you may want to know more about what your HPA axis is doing to cope with all this.

Your primary bodily systems that copes with stress are the HPA axis (Hypothalamus, Pituitary, and Adrenals), and the Sympathetic Nervous System which are intertwined. a bidirectional pathway that senses a threat and then mediates the response.

Your brain senses a threat and starts to respond to it even before the HPA axis is fully activated. Ever been startled and gotten goosebumps before you realized what happened? That’s the sympathetic nervous system in action. 

What happens is that another part of your brain, the amygdala reads input from your eyes and ears to sense danger, and then tells your hypothalamus that there’s a threat. Right away, your hypothalamus creates a “fight-flight- or-freeze” response via the sympathetic nervous system which talks directly with the adrenal glands. 

Your adrenals sit on top of your kidneys and, in response to a stressor, tell your heart and lungs to work harder, increase the blood supply to your skeletal muscles so you can run or fight. Your adrenals also activate your Central Nervous System (CNS) to increase vigilance, and draw energy away from functions not relevant for facing the immediate threat: digestion and reproduction, for example. There are receptors throughout your body for adrenalin and noradrenalin called “adrenergic receptors”.

Shortly after the fight-flight-or-freeze response, the HPA axis kicks in and triggers your adrenals to respond by producing cortisol, which like adrenalin or noradrenalin, has receptors all over your body. Cortisol is often referred to as the “stress hormone”. This second, slightly slower part of the stress response keeps your sympathetic nervous system turned on until the perceived threat is gone. At this point, cortisol drops and your parasympathetic nervous system kicks in to chill you out. This branch of your nervous system is responsible for the “rest-digest-and-reproduce” mode that you, ideally, spend a good amount of time in.

So, what happens when you’re frequently stressed out?

Back in the day, the danger sensed may have been a bear, or a raid by the group that lives over the mountain. In many places, the stressor may be the threat of (or actual) violence, perpetuated by individuals, groups of various ilk or by governments. For others, the stressor may be an obnoxious boss or an upstairs neighbor. Doesn’t matter... your amygdala doesn’t distinguish amongst these various stressors and the resulting physiology is the same.

While our stress response has kept us going as a species, we get into trouble when the amygdala continuously thinks we’re under siege. So if you have an aggressive boss or you’re constantly running behind in an overly-scheduled day, the long term result is vigilance from chronic Central Nervous System activation leading to insomnia and fatigue, along with cardiovascular disease, weight gain from increased appetite and calorie storage, weakened immunity, reproductive issues...the list goes on, but you get the point.

It's not really "Adrenal Fatigue." It's HPA Axis Dysfunction.

Rather than “Adrenal Fatigue” which many of you have heard of, the term “HPA axis dysfunction” more accurately reflects what happens in response to chronic stress. The idea of adrenal fatigue has been around for a while. It’s the concept that the adrenals get worn out after long term stress and become unable to continue producing adequate levels of the various hormones that they make, such as cortisol. And, there are rodent studies showing structural changes in the adrenals after prolonged stress.

In reality, though, many folks are fatigued from stress because of several things happening in the larger HPA pathway. The HPA pathway partially shuts down (relatively speaking), which may be a deliberate decision by the body to reduce the damage from chronic high cortisol exposure. And that's why it got mis-labeled Adrenal Fatigue.

It’s more complicated than the idea of Adrenal Fatigue. Here is a great summary article with more details. And here's a well-researched scholarly book if you want to dive really deep into this topic. 

Fantastic ways to keep your HPA axis healthy and happy:

We can steer ourselves away from an over-active stress response and HPA axis dysfunction in a variety of ways.

1) Breath work - Taking deep “belly breaths” can be helpful. Belly breaths can stimulate your relaxation response. You can also take large chest breaths. Expanding the chest while breathing triggers parasympathetic receptors in the chest wall and is, thus, calming. Breath work with visualization is also helpful. I once had a colleague who was highly stressed out at work when her research project was not going as hoped and she would take several minutes to sit at her desk and breathe while visualizing a flower slowly opening and closing.

2) Meditative Movement - Yoga, Tai chi, Qi gong, and similar mindful movements which combine breath with moving, are all highly beneficial for bringing your parasympathetic nervous system back into dominance.

3) All Movement - Walking, jogging, swimming or other physical activities, especially when stress is more acute, can help burn off the nervous tension and loosen up the body. Sweating is incredibly beneficial.

4) Connect - It can be easy to isolate yourself when chronically stressed, but don’t. Go to dinner with friends or family. Smile at people you encounter at the store (it’ll make you both feel better). Talk to your partner if you have one. Play with the dog. Sit with your houseplants or in your garden.

5) Eat - Healthy fats and protein along with lots of veggies at each meal. This helps stabilize blood sugar levels. Large blood sugar swings contribute to HPA axis dysfunction.

6) Avoid inflammatory foods such as sugar, alcohol, refined flour, and fried foods. Chronic inflammation also contributes to HPA axis maladaptation.

7) Night Time - Make sure your surroundings are dark when you’re going to bed. No bright lights, bright screens, etc., as you move through your evening. These things disrupt our circadian rhythm...our normal response to the cycle of light and dark which, in turn, disrupts proper HPA axis function.

8) Botanicals -  Consider supportive herbs for reducing tension and supporting healthy HPA and nervous system function. Many of the best herbs for adrenals are known as Adaptogens. These are defined as biological response modifiers of botanical origin. Even a single dose of such plants may help the body function better in the face of an acute stressor. But longer term use of Adaptogens as a tonic can be even more helpful.*

Caveat: Be careful that you don’t get into the habit of using adaptogens as a crutch to go even harder in life...that will simply precipitate a crash. If you’re getting buzzed from an adaptogen, either you’re taking too much or it may not be “your herb”.

Six Supportive herbs for your well-being:

  • Milky Oat Tops (Avena sativa or Avena fatua) - Though not generally considered an adaptogen, Milky Oats have been used traditionally as a nourishing tonic for the adrenal glands, the thyroid (more on that in my next article) and the nervous system. They’re great for folks who are experiencing burnout and that annoying tired-wired feeling that prevents good sleep. Many herbs are drying, while Milky Oats are more of a Yin tonic, moistening the body. *
  • Ashwagandha (Withania somnifera) - This is a highly valued herb in the Ayurvedic system of health and has become hugely popular in the West. Its effects extend to the HPA, HPT (T for thyroid) and HPG (G for gonad) systems, as well as the nervous system. Ashwagandha is helpful for bolstering energy while also being calming (unless overdosing, then it’s overly stimulating). If using it tinctured, which has a more stimulating energy, take it during the day. If using at night, use the powder warmed in some milk, ghee, coconut milk or other fat. Ashwagandha should be used sparingly with thyroid over-function. It’s a warming herb, so if you notice that you tend to run hot, this may not be your herb.*
  • Eleuthero (Eleutherococcus senticosus) - The late, great herbalist Michael Moore used eleuthero to attenuate the response of the limbic system to stress. He used it specifically to “cool” the hypothalamus. Eleuthero is a good one for those who go go go. Not to keep them going, but as part of a bigger plan to tone it down to the HPA axis with a bit of herbal help. It also has less potential to be stimulating than Asian Ginseng. In a study of work stress among sailors, Eleuthero had effects on the adrenal cortex, the Sympathoadrenal System (SAS) and the Peripheral Nervous System (PNS).*
  • Schisandra (Schisandra chinensis) - Considered to be another solid adrenal tonic, but also has effects in the pituitary gland and hypothalamus. In sailors who worked a night shift, Schisandra, like Eleuthero, had multiple effects on the adrenal cortex and Sympathetic Nervous System.*
  • Rhodiola (Rhodiola rosea) - This is a fantastic herb and was one of the original herbs considered an adaptogen. Rhodiola may response of the hypothalamus to stress. Studies show a variety of effects on noradrenalin and other neurotransmitters (dopamine, serotonin) in the brain. This is a drying herb, so you may want to use it only a few days per week if you have a very dry constitution (eg. very dry skin; dry mucous membranes; and hard, dry stools.*
  • Hemp-derived Cannabinoids (Cannabis sativa) - CBD is included in the range of Cannabinoids available in a full spectrum formula. Considered an adaptogen, CBD fits perfectly into your body's Endocannabinoid System's receptors. Your Endocannabinoid System directly communicates with your Central Nervous System, so when CBD and other Cannabinoids are introduced, they are helpful for informing your body that you can relax. Cannabinoids have been shown to calm anxiety, lessen stress-induced depression, improve sleep, and reduce inflammation.*

  • Conclusion. The health and well-being of your HPA Axis is absolutely critical to so many aspects of your body. And therefore the better you cooperate with your HPA, the better you'll sleep, the more energy and stamina you'll have, and the better your mood and patience will be. 

    Stay tuned. The next article in this series tackles the hypothalamus-pituitary-thyroid axis! 

    Love Your Body!   Love Everybody!

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