Understanding HPA Axis Dysfunction (Hint: It’s Not Adrenal Fatigue)

Understanding HPA Axis Dysfunction Hint It’s Not Adrenal Fatigue

“Adrenal fatigue” is a term that's been popularized by the health and wellness media – hey, even I’ve used it years ago. But I think it's time to set the record straight and really dig into what's going on.

Because the term adrenal fatigue has been used to describe HPA axis dysfunction so often, I don't want to completely discredit it. There are still good resources out there using the incorrect term – and in some cases these aren’t quite hitting the nail on the head. So, I'd like to draw your attention to the fact that it's being used incorrectly.

In addition to adrenal fatigue, adrenal exhaustion is another phrase that's commonly thrown around. Both phrases are used to describe extreme fatigue usually brought on by regular stress and supposed reduced cortisol levels.

It turns out, science doesn't support the process of adrenal fatigue as its most often explained – that stress causes low cortisol, which causes fatigue and other symptoms. Instead, that's a slightly more complicated process worth taking the time to understand. Especially since it seems to affect so many.


What is HPA Axis Dysfunction?

First of all HPA stands for hypothalamic-pituitary-adrenal axis, and includes:

  • Hypothalamus – This is a region of your forebrain that connects the autonomic nervous system and the endocrine system with the pituitary gland. Your hypothalamus is important in maintaining bodily homeostasis – through regulating sleep, emotions, body temperature, hunger, thirst, and more.
  • Pituitary gland – This pea-sized gland is found at the base of the brain. The pituitary gland is considered the master gland because it regulates other endocrine glands.
  • Adrenal glands – Your adrenal glands sit on the top of your kidneys and produce important hormones such as adrenaline and cortisol.

Together these three parts work to regulate your stress response, mood, motivation, metabolism, energy levels, and immune system.

The various parts of the HPA axis work together in an interwoven series of webs. It's much like your endocrine system which is often compared to an orchestra –  everything must work together to stay in tune. When any one point in the HPA axis isn't running smoothly, it can affect the next series of reactions, which can affect the following, and on and on. In the case of HPA axis dysfunction, it's like a domino effect that takes off after the body becomes desensitized to stress hormones.

Another way to think about HPA axis dysregulation is to compare it to insulin resistance, which can eventually results in diabetes. Similarly, when the body continuously produces stress hormones it eventually becomes less sensitive and the system can't rebalance the body and restore homeostasis like it once could.

Let's take a closer look at these hormones to get a better understanding of what I'm talking about.


The 4 HPA Axis Hormones

There are four important hormones when it comes to the hypothalamic-pituitary-adrenal axis:

  • Cortisol – Cortisol is the steroid hormone in the HPA axis that gets most of the attention but it's actually only part of the problem. Cortisol sounds the alarm in times of stress, preparing the body for a physical response. Cortisol can be triggered by external and internal factors, meaning it can be kicked on by a fear-inducing boss as well as an unhealthy diet.
  • Corticotropin-Releasing Hormone (CRH) – Also called corticotropin-releasing factor (CRF). This is the stress hormone released by your hypothalamus that stimulates the pituitary gland causing it to release adrenocorticotropic hormone. This too can be caused by external or internal factors.
  • Adrenocorticotropic Hormone (ACTH) – As mentioned above, this hormone is released by your pituitary gland where it then causes the production of glucocorticoids in the adrenals.
  • Glucocorticoids – Cortisol is a glucocorticoid, but there are others within this family produced by the adrenal glands. Glucocorticoids are steroids, which help regulate immune system response primarily through reducing inflammation.

You probably noticed this has a cascading effect. CRH in the hypothalamus triggers the ACTH in the pituitary gland, which then triggers glucocorticoids in the adrenal gland. And on and on.


When Stress Gets Stuck Switched On

The concept of adrenal fatigue is that cortisol gets stuck switched on, which eventually wears out the adrenals. But the problem with this is that many people who believe they have adrenal fatigue often don't have dysfunctional cortisol levels. Scientific literature backs this up. In fact,  in 2016 there was a systematic review published called, Adrenal Fatigue Does Not Exist, which summed up the loose and often poor description of adrenal fatigue along with proof that cortisol burnout is not in a thing.

However, HPA axis dysfunction, which is an alteration in stress response over time (after exposure to chronic stress) has been verified and associated with numerous diseases. In summary, HPA axis dysfunction it's something we could work to understand a little better but in the meantime the existence of the HPA axis dysfunction suggests that we need to take reducing stress very seriously.

With that in mind, here 7 ways to reduce your stress levels.


5 Ways to Reduce Your Stress Levels

  1. Add meditation to your daily practice – Research shows that even 7 minutes a day can be beneficial.
  2. Take sleep seriously – This isn’t just about getting 7 to 8 hours every night, it's about having good quality sleep as well. Make your bedroom a sleep sanctuary by kicking out family pets, using blackout curtains, eliminating sources of EMF, and of course, make sure you don't have any undiagnosed sleep-disordered breathing conditions.
  3. Exercise, but not too much – In my patients with HPA axis dysfunction, I often see high-achieving people who over exercise. While exercise is great, too much can send stress hormones and inflammatory processes into overdrive.
  4. Stick to a schedule – Your body runs on multiple circadian rhythms and this includes your hormones. When you stick to a schedule, you make it easier for everything to run smoothly.   I am strict about getting to bed by 9:30pm in order to get a full 8 hours of sleep and function optimally.
  5. Work on being present – It's easy to get wrapped up in our thoughts, worries about the future and obsessing over the past can take control. When we imagine stressful situations, we cause biochemical reactions in our bodies and this can turn on our stress response.

If you're wondering whether or not you have HPA axis dysfunction you can take my Quiz: Could you have Adrenal Fatigue? Here you’ll find 15 common symptoms that could indicate you might want to see a doctor who is experienced in this condition.






9 thoughts on “Understanding HPA Axis Dysfunction (Hint: It’s Not Adrenal Fatigue)

  1. Addie says:

    Dr. Carnahan,
    Do you ever precept new graduate NP’s? If not, do you know of any functional practitioner’s that do by chance? Thank you!

  2. Jason says:

    The one thing I will concur with, is that AF is a misleading simplified term, but I will also note that studies are not the be all end all of what reality is by any stretch of the imagination, too many are not worth the paper written on, too many variables, corruption, poorly designed etc etc and on and on, and the “Adrenal fatigue does not exist: a systematic review” study is just another prime example, it almost looks like something from Quackwatch, terrible.

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