HPA-D vs Adrenal Fatigue

You’ve likely heard of adrenal fatigue, and if you’ve heard of HPA-D you’re keeping up with the Joneses. 

What you probably don’t know, however, is that adrenal fatigue is not really a thing anymore, and many people think HPA-D is the new name for adrenal fatigue, but that’s incorrect, too. Let’s get a few terms straighten out.

Adrenal Fatigue: a catchall term blaming the reason for just about any symptom you can think of on the adrenals under-producing the stress hormone called cortisol.

HPA (hypothalamic-pituitary-adrenal axis): a body system circulating messages from the hypothalamic part of the brain to the pituitary gland in the brain to the adrenal glands on top of the kidneys. The HPA axis is responsible for regulating many body processes including the immune system, digestion, energy, mood and emotions, and sexuality.

HPA-D (hypothalamic-pituitary-adrenal axis dysregulation): the chronic activation of the body’s stress-response system due to pain/hidden inflammation, dietary stress or emotional stress. If the HPA axis is constantly in overdrive, the body’s cells, tissues and organ systems become resilient to changes in physiological needs (stress) and the metabolic reserve is depleted.

HPA-D is often confused with adrenal fatigue, but they are not the same. The term adrenal fatigue seems more tangible and it’s easier for our brains to process, but HPA-D is a lot more involved than just the adrenals being overworked. In truth, if you call it “adrenal fatigue” you’re incorrectly placing all the blame on one small part of the system instead of the whole. HPA-D correctly accuses the brain for not doing its part in regulating body processes. 

Chris Kresser, a leader in functional medicine, provides some helpful facts to clear up the confusion between adrenal fatigue and HPA-D [1]:

Many (if not most) people with so-called “adrenal fatigue” don’t have low cortisol levels. Their free cortisol, when measured in saliva, may be low, but their total cortisol production (including cortisol breakdown products measured in urine) is often normal or even high.
Even when cortisol is low, it is rarely because the adrenals are “fatigued” and unable to produce it. Cortisol production is governed primarily by the brain, central nervous system, and tissue-specific regulatory mechanisms, not the adrenal glands themselves. The vast majority of people with low cortisol have normally functioning adrenal glands; the problem is further “upstream,” in the brain and CNS.
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—and one of them is a systematic review published in 2016 called “Adrenal Fatigue Does Not Exist”! 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.

As mentioned above, prolonged activation of the HPA axis can cause resilience to changes in the body’s physiological needs (stress), and the metabolic reserve will become drained. To unpack these concepts: if we are under a lot of stress, resilience can drop, BUT, if you have a good metabolic reserve, you can manage occasional bouts of stress and recover fairly well. However, if you are constantly battling stress (due to pain/hidden inflammation, dietary stress or emotional stress), that metabolic reserve is going to drain quickly until it’s gone. That’s when the body is thrown into dysregulation.

I like Chris Kresser's banking analogy to explain this [2]: 

If you have a good balance between making withdrawals and making deposits and you’ve got a lot of deposits in a big bank account, you can withstand a period where you’re making more withdrawals because you’ve got that reserve there to back you up. But if you’re constantly making withdrawals over a long period of time and you’re not replenishing with deposits, then over time that account is going to be overdrawn.

HPA-D has been linked with many diseases including, but not limited to, the following [2]:

  • depression
  • obsessive–compulsive disorder
  • alcoholism
  • diabetes
  • obesity
  • PTSD
  • hyperthyroidism
  • hypothyroidism
  • chronic fatigue syndrome
  • fibromyalgia
  • premenstrual tension syndrome
  • rheumatoid arthritis
  • asthma
  • eczema

That’s a pretty big deal.

The key to controlling the HPA axis is diet, exercise and lifestyle habits. If you are experiencing any of the issues above, PLEASE reach out to me. Sign up for a 20-minute Health Discovery Session for $49 and we’ll get you started on a path toward better health today 

Want to read a real live person who struggled with HPA-D and overcame it? Check out Jenny’s story

https://kresserinstitute.com/adrenal-fatigue-hpa-axis-dysregulation/
https://chriskresser.com/myth-of-adrenal-fatigue/




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Heidi Toy FNTP

I help people all over the world heal by identifying and treating the root cause of their body imbalances. Through diet and nutrition, I guide them towards wholeness and balanced lives.

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