The Vagus Nerve vs. Adrenal Insufficiency

What happens when adrenal insufficiency symptoms start to look like nervous system dysfunction?

In this episode, Noah and Eloise explore a question many people with adrenal insufficiency eventually ask: Is this my cortisol, my autonomic nervous system, or both?

Using a My Adrenal Life article as the foundation, they break down the difference between the vagus nerve and autonomic nervous system versus the HPA axis and cortisol system.

The vagus nerve is often described online as a “master regulator,” and it does play an important role in digestion, heart rate, and parasympathetic “rest and digest” activity. But it is not a hormone, it does not produce cortisol, and it does not replace adrenal function.

Noah and Eloise explain why adrenal insufficiency can still feel like a nervous system problem. Low cortisol can affect many of the same body functions the autonomic nervous system is constantly trying to stabilize, including:

• heart rate

• blood pressure

• digestion

• temperature regulation

• stress tolerance

That overlap helps explain why people with adrenal insufficiency may experience symptoms that sound like autonomic instability, including dizziness, nausea, palpitations, shakiness, internal “alarm” feelings, and GI upset.

The episode also takes a careful look at blood pressure patterns, because this is where confusion can become dangerous.

Noah and Eloise explain that:

• classic adrenal crisis physiology is usually associated with low blood pressure

• Primary adrenal insufficiency/Addison’s disease often carries more risk of hypotension because aldosterone deficiency can lead to salt loss and volume depletion

• Secondary and tertiary adrenal insufficiency may still cause dizziness, poor vascular tone, and low-pressure symptoms, even when aldosterone is preserved

• recurrent severe hypertension is not the classic adrenal crisis pattern and may point to something beyond adrenal insufficiency

That distinction matters, because treating every “surge” as adrenal can create real safety risks.

The discussion also covers why some people with secondary or tertiary adrenal insufficiency describe adrenaline-like surges that can feel dramatic, even when the overall problem is still limited cortisol support. These episodes may overlap with autonomic symptoms, but they are not always the same thing as a true adrenal crisis.

Noah and Eloise also highlight an important safety issue: steroids are essential for confirmed adrenal insufficiency, but they are not a general treatment for unexplained hypertensive episodes or autonomic storms. They also discuss why thyroid hormone should not be started in uncorrected adrenal insufficiency without proper glucocorticoid coverage.

Most importantly, this episode offers a more grounded framework for understanding symptoms that can feel chaotic and whole-body. The goal is not to dismiss the vagus nerve conversation, but to place it in the right context.

The vagus nerve matters.
The autonomic nervous system matters.
But adrenal insufficiency is still, at its core, a cortisol deficiency disorder.

If you live with adrenal insufficiency and have ever wondered whether your symptoms are hormonal, autonomic, or both, this episode helps untangle that overlap with more clarity and less fear.

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