Four tiny organs produce hormones that regulate everything from our blood pressure and libido to our metabolism and stress response. That's an enormous job!
These organs are…
The hypothalamus, pituitary gland, and adrenal glands.
As with every other part of the body, the adrenal glands do not operate independently. Rather, they are part of a complex system called the hypothalamic-pituitary-adrenal loop (a.k.a. HPA axis). The central nervous system and endocrine system connect via this HPA axis, working together to regulate stress response and hormone balance.
H = Hypothalamus
This almond-sized gland is the link between the endocrine and nervous systems. It sends messages from the brain to the pituitary gland and adrenals. By maintaining body temperature, energy levels, and circadian rhythm, the hypothalamus essentially maintains the body's homeostasis (source).
It is responsible for the production of hormones like:
- Gonadotropin-releasing hormone — ensures normal function of testes and ovaries
- Oxytocin — involved in orgasm, the ability to trust, body temperature, sleep cycles, and the release of breast milk
- Thyrotropin-releasing hormone — triggers the release of thyroid stimulating hormone (TSH), which stimulates release of thyroid hormones, which regulate metabolism, energy, and growth and development
- Corticotropin-releasing hormone (CRH) — stimulates the release of adrenocorticotropic hormone (ACTH), which stimulates release of adrenal hormones, which regulate stress response
P = Pituitary Gland
The pituitary gland — a pea-sized organ — sits at the base of the brain, not surprisingly, near the hypothalamus. It is often called the “master gland” because its hormones control the thyroid, adrenals, ovaries, and testes.
It produces hormones like:
- Growth hormone — essential in early years for healthy body composition and growth in children. In adults, it aids healthy bone and muscle mass and affects fat distribution.
- Adrenocorticotropic hormone (ACTH) — stimulates the adrenal glands to produce hormones
- Thyroid-stimulating hormone (TSH) — stimulates the thyroid gland to produce hormones
- Prolactin — stimulates breast milk production
A = Adrenal Glands
These walnut-sized glands, sitting atop each kidney, control the “fight or flight” response and other chemical reactions throughout the body. Each gland is made up of two parts: the adrenal cortex and the adrenal medulla.
The adrenal cortex, the outer part of the gland, produces hormones like:
- Hydrocortisone, a.k.a. cortisol — is often called the stress hormone because it helps our bodies respond to stress (our “fight or flight” response). Additionally, cortisol helps regulate metabolism, controls the sleep/wake cycle, and suppresses inflammation.
- Corticosterone — works with hydrocortisone to regulate immune response and suppress inflammatory reactions.
- Aldosterone — regulates blood pressure by maintaining the balance of salt and water in our blood.
- DHEA and other sex hormones — in men, are converted into testosterone by the testes. In women, the adrenals are the primary source of these androgens, so their role is very significant.
The inner part of the adrenal glands, the adrenal medulla, produces “non-essential” hormones. That is, you don't need these hormones to survive, but they are still very important. Among other things, these hormones are neurotransmitters, and they prepare the body to respond quickly in moments of danger or trauma. These hormones are:
- Adrenaline, a.k.a. epinephrine — helps regulate the body's “fight or flight” response (how the body responds to stress).
- Noradrenaline, a.k.a. norepinephrine — works with adrenaline during the stress response. It also causes vasoconstriction which results in raised blood pressure.
How The HPA Axis Works
Here is how the HPA axis works… The most important thing to understand is that “adrenal fatigue” involves more than just the adrenal glands. 🙂
- Stressor is present (whether bear or bill collector).
- The hypothalamus secretes CRH (corticotropin-releasing hormone) which tells the pituitary gland to produce ACTH (adrenocorticotropic hormone).
- ACTH prompts the adrenals to make cortisol, adrenaline, and noradrenaline.
- Cortisol raises blood glucose and slows digestion, while adrenaline and noradrenaline increase the heart rate and blood pressure. These actions prepare the body to fight or flee the stressor.
- This cycle continues until your body has enough hormones to deal with the stressor.
- Once cortisol levels begin to decrease, the stress response stops, the body calms down, and hormone levels to return to normal.
These interactions continue until your hormones reach the levels that your body needs, and then a series of chemical reactions begins to switch them off. For example, the cortisol released by the adrenals actually inhibits the hypothalamus and pituitary (so they stop sending signals to produce more cortisol!). This is just one of the automatic switches that we call negative feedback loops, and these loops are one reason why the HPA axis is so extraordinary. (Source.)
So, what happens when there's an interruption of this flow?
Adrenal Fatigue Or HPA Axis Dysfunction?
The term Adrenal Fatigue was first coined back in the 1990s by Dr James Wilson. But it’s not really a very descriptive name for a syndrome like this. You might hear doctors taking about HPA Axis Dysregulation, or HPA-D, which is often used now. They mean the same thing.
The adrenal glands don’t really get ‘tired’ in the way that you might expect. What happens is that, after a period of chronic stress, your body starts to run out of the hormone precursor material that it uses to make certain hormones. As this continues, it becomes more and more difficult for your body to produce the required levels of stress hormones, sex hormones, and other hormones and neurotransmitters. That’s when the ‘fatigue’ starts to kick in, and that’s when you need to offer your body some extra support. (Source.)
Notice the words “chronic stress”? Anything that causes prolonged stress, and subsequently, the prolonged need for and release of stress hormones from the HPA axis, can and does cause adrenal fatigue. However, HPA axis dysfunction, which is the same thing as adrenal fatigue, is the better term. After all, stress affects not only the adrenal glands, but the entire loop.
Furthermore, single, stressful events can and do cause trauma, too. This trauma can put the body in chronic stress mode and cause HPA axis dysfunction as well.
When chronic stress occurs in an individual, the HPA axis continues to release hormones on an accelerated basis. But after time, the overproduction of these hormones leaves the glands of the HPA axis desensitized and they stop recognizing signals to stop producing hormones. The negative feedback loop is no longer functioning as it should and HPA axis dysfunction becomes the norm.
The idea of adrenal fatigue has become popular in natural and alternative health world in recent years. But while many alternative practitioners are focusing on the adrenal glands being fatigued as a result of chronic stress, that is only one part of the equation. It is actually the dysfunction of the entire HPA axis that is creating the symptoms, not simply a dysfunction in the adrenal glands alone. It is the dysfunction of the feedback loop of the HPA axis that ultimately creates the symptoms that people now associate with adrenal fatigue. (Source.)
Symptoms Of HPA Axis Dysfunction
This chronic stress and constant stress hormone production wears on the body. Over time, it can cause a myriad of symptoms, such as…
- weight gain, especially in the mid-section
- brain fog
- thyroid dysfunction
- depression and/or anxiety
- hypoglycemia and other blood sugar problems
- all-day fatigue, particularly in the morning and mid-afternoon
- cravings for salt or salty foods
- depressed immune system/recurrent illnesses or infections
- dizziness when standing (orthostatic hypotension)
- blood pressure issues
- rise in allergies — food, chemical, or environmental
- low libido
- poor muscle tone or loss of muscle mass
- dry skin
- slow wound healing
- inability to concentrate and focus
- memory problems — can't remember why you walked into a room or where your car keys are
- cold hands and feet
Are you familiar with the symptoms of adrenal fatigue? These sound pretty similar, don't they?
“I Feel Awful. Does It Really Matter What It's Called?”
Maybe you have many or most of the symptoms on the above list. Furthermore, maybe you've done your research and have concluded that you actually do have adrenal fatigue.
Yet now I'm telling you it's not adrenal fatigue. Instead, it's HPA axis dysfunction.
You don't really care what it's called; you just want to feel better!
In this case, terms matter. Here's why…
First, let's say you visit your run-of-the-mill, allopathic physician. You describe most of the symptoms above, and ask him about adrenal fatigue. He may look at you funny. You see, the medical community does not recognize the term “adrenal fatigue” as an actual thing. Even many natural-minded physicians don't recognize it.
The adrenal fatigue concept is not supported by peer-reviewed, scientific evidence, nor does it align with our current understanding of HPA axis physiology. If you search for “adrenal fatigue” in PubMed, you’ll find only 12 results … In contrast, if you search for “hypothalamic pituitary adrenal axis” in PubMed, you’ll see more than 19,000 search results, featuring studies linking changes in the HPA axis to everything from Alzheimer’s to obesity. (Source.)
Quite honestly, you may not find an allopathic doctor who recognizes HPA axis dysfunction (HPA-D) either. This is why we always advise working with a qualified functional medicine practitioner or naturopath.
Second, although the adrenals produce cortisol, the brain and central nervous system primarily govern its production. While cortisol testing, via spit or urine, may help identify part of the problem, it rarely identifies the full problem.
Free cortisol, measured in the blood or urine, is not representative of total cortisol production, which is often normal or even elevated but doesn't show in tests (source).
Trust How You Feel, Not The Numbers
When it comes to hormones, always trust how you feel… not the numbers. And find a practitioner who will do the same!
Testing specific hormones is useful, but it is rarely the full picture. So often, hormones aren't tested together to give a more complete picture.
For instance, a diurnal salivary test captures free cortisol in the saliva over a 24-hour period. If your numbers are anywhere in the “normal” range, and your doctor trusts numbers more than how you feel, she may say that your anxiety, hypoglycemia, insomnia, weight gain, and allergies aren't HPA axis-related. Worse, she may say that it's all in your head!
However, if your numbers are within the “normal” range, and you have a practitioner who trusts how you feel, she will continue to help you heal and support your HPA axis through diet, supplements, and lifestyle changes.
Finally, HPA axis dysfunction is not an easy thing to heal, but it is possible. Over the coming months, I plan to share more of my own story. I'll also share how you can nourish, support, and heal HPA axis dysfunction using essential oils, food, lifestyle changes, and supplements.
More Adrenal Health Related Articles:
- What Is Rhodiola? (the anti-fatigue, anti-stress adaptogen!)
- Top 5 Essential Oils For Adrenal Support
- 5 Foods That Are Wrecking Your HPA Axis
- 5 Foods That Nourish The HPA Axis
- 5 Reasons to Heal Your Gut
Have you heard of HPA axis dysfunction? Were you calling it adrenal fatigue? Can you share how HPA-D makes you feel? What are you doing to support your body?
We only recommend products and services we wholeheartedly endorse. This post may contain special links through which we earn a small commission if you make a purchase (though your price is the same).