The Most Important Part of Your Brain You’ve Never Heard About

And Why It Decides Whether You Have Energy or Don’t

Dr. Justin Dearing  |  The Dearing Clinic

Key Points

• Your brain has a control center for energy — and most doctors never test it. The insula, a deep region of the cortex, reads your body's internal signals and determines whether your autonomic nervous system runs in repair mode or survival mode — directly controlling how much oxygen, nutrients, and stimulation your cells actually receive.
• Chronic fatigue and brain fog are often a delivery problem, not a production problem. Mitochondria aren't broken in most patients — they're starving. When the autonomic nervous system is locked in sympathetic dominance, the "pipes" that deliver oxygen, fuel, and stimulation to neurons are effectively closed.
• The gut-brain connection isn't a wellness trend — it's a clinical mechanism. Leaky gut, microbiome dysbiosis, and chronic gut pathogens send continuous "threat" signals to the insula via cytokines and vagal pathways, keeping the nervous system locked in defense mode 24/7.
• Autonomic dysregulation rarely looks like anxiety — it looks like you. Waking at 3am, taking days to recover from normal activity, brain fog under cognitive load, and sensitivity to light and noise are all classic signs of a dysregulated autonomic nervous system that standard labs will completely miss.
• Mitochondrial supplements won't work if your autonomic system is still closed. Cold plunges, red light therapy, IV nutrients — the science is real, but the results won't hold in a body stuck in sympathetic overdrive. Sequence determines whether these therapies produce lasting change or just a temporary flicker.
• Testing is the turning point. HRV, qEEG, PNOĒ metabolic testing, microbiome analysis, and blood-brain barrier markers reveal what's actually driving the pattern — making it measurable, and therefore correctable.
• Restoring the autonomic "operating system" must come before recharging mitochondrial production.Addressing gut integrity, immune burden, and nervous system regulation first is what allows oxygen therapies, photobiomodulation, ozone, and nutrient IVs to actually land and hold.
• This is why you've plateaued. If you've tried every protocol and the results don't last, it's almost never the wrong therapy — it's the wrong order. The work was real. The sequence wasn't.

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Every neuron in your body needs three things to survive and function. Oxygen. Nutrients. Stimulation. That’s it. Strip everything else away, and those three inputs determine whether your brain works or doesn’t. Whether your mitochondria produce or conserve. Whether you feel like yourself or like a slower, foggier version of who you used to be.

Almost no one in the chronic fatigue and brain fog conversation talks about what delivers those three things. They talk about the cells. They talk about the supplements. They talk about the protocols. But they skip the system that decides whether any of it ever reaches the cells that need it.

That delivery system is your autonomic nervous system. And the part of your brain that controls it is the most important piece of neuroanatomy most patients have never heard of.

Meet the Insula

The insula is a section of cortex tucked deep inside the brain, folded between the temporal lobe and the rest of the cortex. It sits so deep it doesn’t show up in casual brain anatomy diagrams. It’s been studied for decades in neuroscience, and in the last fifteen years its role has become clearer than ever.

The insula is the brain’s interoceptive center. It reads the internal condition of your body, integrates the signals, and sets the autonomic tone based on what it finds. It is the part of your brain that decides whether your body is in survival mode or repair mode at any given moment.

It does this by listening to three streams of input.

• ‍The immune system — through cytokines and inflammatory markers circulating through the body and signaling into the brain.‍
• The blood-brain barrier — whether it’s intact and selectively filtering, or compromised and letting peripheral inflammation reach brain tissue that should be protected.‍
• The gut — through GALT (the gut-associated lymphoid tissue, which holds about seventy percent of your immune system), through microbiome metabolites, and through vagal afferent signals carried up from the enteric nervous system into the brainstem and the insula directly.

When those signals say the body is safe, the insula lets the autonomic nervous system shift toward parasympathetic regulation. Delivery opens. Neurons get oxygen, nutrients, stimulation. Mitochondria produce.

When those signals say the body is under threat, the insula keeps the autonomic system locked in sympathetic defense. Delivery closes. Neurons run on less of everything. Mitochondria conserve. The patient feels exhausted, foggy, reactive. The labs come back normal because nothing is catastrophically broken — it’s all just running on conservation mode.

What the Autonomic System Actually Delivers

Your autonomic nervous system runs in the background, every second of every day, deciding what state your physiology is in. It also controls the delivery of all three things your neurons need.

• ‍Oxygen — through your breathing pattern, your heart rate, your vascular tone, the circulation that carries oxygen out to your peripheral tissues and deep into your brain.‍
• Nutrients — through your digestion, your absorption, your blood flow to the tissues that need fuel, the mobilization of glucose and fats from storage.‍
• Stimulation — through sensory gating, attentional networks, your brain’s ability to receive and integrate input rather than defending against it.

In balance, all three reach the cells that need them. Mitochondria produce. Neurons fire cleanly. The body operates from a place of capacity.

Stuck in sympathetic dominance, all three get restricted at the same time. Breathing goes shallow. Peripheral circulation closes. Digestion slows. Sensory input gets filtered through threat detection rather than integration. The cells that need oxygen, nutrients, and stimulation get less of all of it.

This is also why so much of the biohacking conversation about mitochondria misses the mark. Cold plunges, red light panels, mitochondrial supplements — there’s real science behind a lot of it. But a single session in a body locked in sympathetic dominance produces a flicker that doesn’t hold. The therapy is fine. The delivery system is closed.

Your Mitochondria Are Not the Problem

Most patients arrive at my clinic having been told they have “mitochondrial dysfunction.” They assume their cells are broken. The cells are usually fine. They’re starving.

Mitochondria can’t produce ATP without oxygen, fuel, and the right signaling environment. When the autonomic nervous system restricts all three, the mitochondria do exactly what they’re supposed to do — they downshift into conservation. They protect themselves. They wait for conditions to change.

This is why a patient can take every mitochondrial supplement on the market and feel almost nothing. The cells aren’t refusing the inputs. They can’t access them. The pipes are closed.

Why the Gut-Brain Axis Is Real — Really Real

This is where the gut-brain conversation stops being trendy and gets clinical.

If your gut is leaky, your microbiome is dysbiotic, or you’re harboring chronic pathogens, the immune signaling reaching the insula never says safe. It says threat. Constantly. Every minute of every day.

• ‍Leaky gut allows bacterial fragments — lipopolysaccharide, or LPS — to cross from the intestine into systemic circulation. The immune system reads this as infection. Cytokine signaling to the brain rises. The insula reads threat. Autonomic tone locks into defense.‍
• Chronic gut pathogens — small intestinal bacterial overgrowth, parasites, candida overgrowth, persistent viral reservoirs — produce constant low-grade immune activation. Same signal to the insula. Same autonomic outcome.‍
• Microbiome dysbiosis disrupts the production of short-chain fatty acids and neurotransmitter precursors. Vagal afferent signaling into the brainstem and insula changes. The brain receives different input than it would from a healthy gut, and it responds by shifting autonomic state accordingly.‍
• A compromised blood-brain barrier lets peripheral inflammatory signals reach brain tissue directly. The insula gets bombarded with threat input that should never have crossed into the brain in the first place.

This is the snowball that defines most chronic cases. Gut compromise drives chronic immune signaling. The insula reads threat. The autonomic nervous system locks in defense. Delivery to neurons closes. The brain — running on conservation — can’t regulate the gut, the immune system, or the blood-brain barrier the way it should. All three get worse. The signaling intensifies. The autonomic system locks in deeper.

Patients have been in this loop for years before they walk into my clinic. They’ve tried gut protocols. They’ve tried adrenal support. They’ve tried meditation and breathwork and supplements aimed at calming the nervous system. Each piece works partially, because each piece is real. But the loop keeps spinning because no one has addressed the layers in the right sequence.

Why Patients Don’t Know They Have Autonomic Dysregulation

Autonomic dysregulation is invisible on standard labs. There is no blood marker that flags it. The conventional medical system isn’t built to measure it, and most functional medicine providers don’t either — they run hormone panels, food sensitivity panels, and gut tests, and none of those catch what the autonomic system is doing.

It also doesn’t always feel like what people expect. Autonomic dysregulation isn’t necessarily panic attacks or obvious anxiety. More often it looks like:

Wired but tired. Waking at three in the morning with a racing heart. Recovery from exercise or stress that takes days when it used to take hours. Reactivity to stimuli — light, noise, decisions, conversations — that didn’t used to bother you. Brain fog that gets worse under cognitive load. Digestion that fluctuates with stress. The inability to downshift even when nothing is wrong.

Most of my patients have been living with some version of this for years. They’ve adapted to it. They don’t know what it would feel like to have a regulated nervous system because they don’t remember.

We measure it. HRV testing reads autonomic regulation in real time. qEEG shows the deeper network patterns driving that regulation. PNOĒ shows what the autonomic state is doing to oxygen utilization at the cellular level. Microbiome and immune testing reveal what’s driving the threat signal upstream. Once a patient sees their own data, the entire frame shifts. That’s what’s been wrong.

Why We Work the Autonomic Layer First

Most clinics — including most functional medicine clinics — work the production side first. Mitochondrial supplements. IV nutrients. Hormone optimization. Sometimes red light, sometimes peptides. They get short-term wins. The wins don’t hold because the insula is still reading threat and the autonomic system is still closing delivery.

We invert that.

We address the upstream layers first. Calm the immune signaling. Restore gut integrity. Support the blood-brain barrier. Retrain the autonomic networks at the brain level. The insula starts receiving different input. It stops reading threat. The autonomic nervous system begins shifting toward regulation. Delivery opens.

Then everything we layer in afterward — oxygen therapies, mitochondrial activation, nutrient repletion, hormonal support — actually lands. The same therapy that produced a brief flicker in a closed system produces durable change in an open one.

This is why our work holds when other providers’ doesn’t. We’re not running better protocols. We’re running them in the right order.

How We Restore the Operating System

Measurement first. Always.

qEEG and HRV show how the autonomic networks are regulating. GI mapping and microbiome testing show what’s driving the threat signal from below. Neural Zoomer and barrier markers show whether peripheral inflammation is breaching into the brain. PNOĒ shows what all of it is doing to oxygen utilization at the cellular level.

Then we work the layers.

Gut and Immune Restoration

Clearing chronic pathogens. Restoring microbiome diversity. Healing intestinal permeability. Reducing systemic inflammation through targeted nutrients, herbs, and lifestyle work. The insula stops getting threat signal from below.

Functional Neurology

Targeted sensory and motor inputs — visual, vestibular, proprioceptive — driving plasticity in the specific networks the qEEG flags. This includes direct work on the insula and the broader interoceptive networks that read body state.

Neurofeedback: Three Different Approaches

• ‍Standard neurofeedback trains the faster brain frequencies — alpha, beta, theta, SMR. These produce real results for attention, focus, and many clinical presentations. The limitation is that they work at the cortical layer, the outer brain activity that sits on top of the deeper regulatory systems. For patients whose primary problem is autonomic dysregulation, the cortex calms during the session and drifts back afterward because the deeper systems haven’t changed.‍
• LENS neurofeedback delivers a passive electromagnetic signal back to the brain based on the brain’s own EEG output. For trauma-related dysregulation and certain stuck patterns, LENS can produce shifts other approaches struggle to reach. I use it in specific cases.‍
• ISF neurofeedback — Infra-Slow Fluctuation neurofeedback — works at the slowest frequencies the brain produces, below 0.1 hertz. These are the frequencies that govern autonomic balance, large-scale network coordination, and the baseline state your nervous system rests in. They are the frequencies the insula and brainstem actually operate on. For chronic autonomic dysregulation, ISF reaches what the other approaches don’t. The shifts tend to be slower to appear but more durable once they take hold, because we’re working at the level the rest of the nervous system organizes around.

For most of the chronic, complex cases that define this clinic’s work, ISF is what changes the picture.

When the upstream layers shift, the autonomic nervous system shifts with them. Delivery opens. The body that has been running on conservation mode finally has the conditions to do something different.

Then We Recharge Production

Now the mitochondrial work lands differently. The same therapies that produce a flicker in a closed system produce durable change in an open one.

Oxygen — HBOT and EWOT

PNOĒ measures both oxygen delivery and utilization. Medical-grade hyperbaric oxygen therapy means a hard-shell chamber pressurized to 1.5 to 3.0 atmospheres with 100 percent oxygen — distinct from the soft-sided home chambers running at 1.3 ATA with ambient air, which are a different therapy entirely. The pressure forces oxygen into solution in the blood plasma, reaching tissues that have been quietly under-perfused for years, including areas of the brain that need it most.

EWOT works through a different mechanism — high-concentration oxygen breathed during graded exercise, driving oxygen deep into tissue via increased cardiac output and capillary recruitment. Most patients benefit from both.

Photobiomodulation

Specific wavelengths of red and near-infrared light, delivered at high enough intensity, drive cytochrome c oxidase activation — the final enzyme in the mitochondrial electron transport chain. The Avant LZ30 laser we use delivers roughly two hundred times the joule output of older systems, reaching the photon density threshold needed to activate mitochondria in deep tissue.

Ozone Therapy

Major autohemotherapy with UV blood irradiation creates a controlled oxidative challenge that upregulates the body’s own antioxidant and mitochondrial defenses. It also continues to clear chronic immune burden as it reaches deeper tissues with restored circulation. For chronic infection, autoimmune patterns, and post-viral cases, ozone changes the immune story in a way nothing else does.

Nutrient IVs

Once the system is coming back online, raw materials land differently. High-dose IV vitamin C — sodium ascorbate, not ascorbic acid — supports immune function, collagen synthesis, and oxidative balance. B vitamins, magnesium, glutathione, amino acids. The cells can finally absorb and use them.

Why Sequence Matters

Order is determined by measurement. Severe gut and immune burden tells us to lead with the upstream work. Severe autonomic dysregulation with cleaner gut findings tells us to lead with neurology and ISF. Severe oxygen utilization compromise on the PNOĒ tells us to bring oxygen earlier in the sequence.

What stays constant across every patient: we never work the production side as if the operating system doesn’t exist. And we never work the operating system without addressing what’s driving its state from below.

The Body Comes Back Online

Three things every neuron needs. One system that controls whether they get them. And underneath that system, a chain of upstream layers — gut, immune, blood-brain barrier — all feeding the insula, all setting autonomic tone, all determining whether your mitochondria produce or conserve.

When the chain restores, patients describe something specific. Energy doesn’t just rise — it stabilizes. Cognition doesn’t just clear — it stays clear. Sleep deepens. Recovery shortens. Reactivity quiets. The body that has been running on backup power for years finally has the full system back.

Not because we treated every symptom. Because we restored the layer every symptom was downstream from.

If you’ve done the work and hit the plateau, this is almost always why. The work was real. The order was wrong. And it’s measurable. Which means it’s correctable.

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Frequently Asked Questions (FAQs)

1. What is the insula and why does it matter for chronic fatigue?

The insula is a deep region of the brain that acts as the body's internal monitoring system. It reads immune signals, gut health, and inflammation levels, then sets your autonomic nervous system to either repair mode or survival mode. When it reads "threat," energy and cognition suffer — regardless of what supplements or therapies you're taking.

2. Why do my labs come back normal if I feel this bad?

Autonomic dysregulation doesn't show up on standard bloodwork. Most patients look completely normal on conventional panels while their nervous system is actively restricting oxygen, nutrient delivery, and cellular function. Specialized testing like HRV, qEEG, and PNOĒ metabolic analysis is required to see what's actually happening.

3. What is the connection between leaky gut and brain fog?

When the intestinal lining is compromised, bacterial fragments enter the bloodstream and trigger an immune response that reaches the brain's insula — keeping the autonomic nervous system in defense mode and restricting blood flow, oxygen delivery, and cognitive function. Healing the gut is often the first step toward clearing brain fog.

4. Why aren't my mitochondrial supplements working?

Mitochondria require oxygen, fuel, and proper signaling to produce energy. If your autonomic nervous system is locked in sympathetic dominance, all three are being restricted at the cellular level. The supplements aren't failing — they simply can't reach the cells effectively until autonomic regulation is restored first.

5. What does autonomic dysregulation actually feel like day to day?

Most people don't recognize it because it doesn't feel like a panic attack. It feels like being wired but tired, waking at 3am with a racing heart, needing days to recover from normal activity, sensitivity to light and noise, and brain fog that worsens under mental load — even when nothing is acutely wrong.

6. Can chronic gut issues really cause neurological symptoms like fatigue and cognitive decline?

Yes — through several overlapping mechanisms. Gut pathogens, dysbiosis, and intestinal permeability create ongoing immune activation that continuously signals threat to the brain. A compromised blood-brain barrier allows peripheral inflammation to reach brain tissue directly, while disrupted microbiome function alters the vagal nerve signaling the brain uses to set autonomic tone.

7. Why do treatments like hyperbaric oxygen, red light therapy, and ozone work for some people but not others?

The difference is almost always sequence. These are legitimate, evidence-supported therapies — but in a body where the autonomic nervous system is still locked in defense mode, their effects are short-lived. When autonomic regulation is restored first, the same therapies produce durable, compounding results instead of a temporary flicker.

8. What is the correct order of treatment for chronic fatigue and brain fog?

Sequence matters more than most patients realize. The most effective approach starts by addressing gut integrity, chronic pathogens, and immune burden — changing what the brain's insula receives. Autonomic retraining follows. Only once the operating system is stabilizing do oxygen therapies, photobiomodulation, ozone, and mitochondrial support produce lasting results.

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