This post originally appeared on my substack that you can view here.

I always believed the cause of my Chronic Fatigue Syndrome symptoms were in my body: infections, viruses, mitochondrial issues etc etc, it was a long list of possible causes that I worked my way through.

When I commenced brain retraining DNRS my coach Tessa asked me, “Do you believe the brain is the cause of your symptoms?” I remember answering, “Well, sort of, maybe SOME things are, but I have chronic Lyme Disease, so most of my symptoms are from chronic infections”.

I had seen recovery stories of people with similar symptoms to me and that had convinced me to give brain retraining a go. I also knew I had a dysregulated nervous system and zero capacity for stress. However, I wasn’t fully convinced that it was the reason behind my severe fatigue and brain fog/ neurological issues.

Understanding mould sensitivities was my AHA moment

I understood the link between the brain and mould sensitivities. The explanation for the need for brain retraining in those cases made total sense to me. But for the symptoms of fatigue and brain fog, I wasn’t sure the brain was the cause.

For example, with mould, previously I believed that Chronic Inflammatory Response Syndrome (CIRS) or severe mould sensitivities were a result of toxic mould exposure, poor genetics and an inability to detoxify. I believed the analogy of the ‘mould bucket’ being full, and that you needed to avoid any mould and do intense detoxification protocols in order to heal and empty the bucket. Brain retraining presented an alternative theory.

Yes, the initial exposure to mould may have been real and significant. But what keeps the symptoms going is the brain’s learned association between mould and danger.

If there’s a lot of emotional stress around the initial reaction, that experience gets imprinted more deeply. The brain creates a strong neural pathway that says “mould = threat.” People with CIRS often experience symptoms before they even realise they’ve been exposed. That’s a conditioned response from the limbic system.

The more fear and avoidance there is, the more the brain reinforces that pathway. It sends symptoms to alert the presence of mould as it believes that is what it needs to do to stay safe. This is how CIRS patients become increasingly sensitive to mould, the fear makes the brain continue to associate it with danger. I believe our bodies are built to detox small amounts of mould. A lot of people with CIRS talk about living in mouldy places earlier in life with no issue. The issue now is the brain’s perception, a cross-wiring has occurred in the brain.

The hunter-gatherer brain helps explain this

It helps to look back at how our brain developed to understand this theory more. On being exposed to a threat our hunter-gatherer ancestor’s brains would imprint that threat into memory, in order to ensure safety in the future. For example, if they came across a snake in the bushes, the brain would memorise this experience. Next time they hear a rustle in the grass their heart rate and nervous system will respond before they consciously register it. This is how the brain evolved for survival.

The problem in modern life arises because our hunter-gatherer brain didn’t have a sophisticated pre-frontal cortex and complex, chronic emotions like we have today. Now, our thoughts and emotions can signal the threat response. This is how the brain becomes cross-wired and sends symptoms for things that aren’t actually dangerous, whether that be mould, food, sounds or even movement and energy output.

It took longer to apply this to fatigue

Now, I had to apply the above logic but to the idea of fatigue. Just like CIRS is a sensitivity to mould, chronic fatigue is a sensitivity to energy expenditure. Unlike mould, fatigue didn’t seem to have an obvious trigger. It felt like something that was just happening to me. So the idea that my brain could be recreating fatigue as a protective response felt a bit abstract at first.

Dissecting my health journey helped me to understand things better. My health issues began with a virus, most likely Epstein-Barr and I was diagnosed with Glandular Fever. At the time, I was supposed to be completing a finance internship which for 22 year old me was the absolute, be all and end all. In my mind, missing or failing at this internship was the ‘end-of-the-world’, when I became sick it was the first time in my life that I experienced true anxiety. In my mind, all the work I had done the four years prior studying at university were all for nothing if this virus didn’t go away and allow me to work (it’s ironic looking back at this now).

On reflection, I can see that my stress, emotions and ruminating wired something in. The virus was real, but the meaning my brain attached to it was layered with fear. Somehow the patterning of fatigue became wired into my brain.

At the time I was a classic, type A, high functioning, achievement-oriented person, this laid the ground work for my nervous system to crash. When you are perfectionist and highly strung, the nervous system has a reduced capacity for stress. Mine was already skating on thin ice before this virus tipped it over the edge.

The virus forced me to stop and made me rest. In that vulnerable, emotional state, my brain made the connection: rest = safe, energy = threat. At this time, rest was essential for healing.

From this I believe my brain learnt: “When I am exhausted, I don’t have to perform, I get to stop. It keeps me safe from crashing harder”. Eventually, my brain made the association that energy production = danger. When I utilised energy it would recreate the same symptoms that had protected me during the virus: fatigue, brain fog, shutdown. My brain was trying to make me feel safe in the only way it knew how, by making me stop.

The virus was real. But the pattern got stuck
This doesn’t mean the virus wasn’t real. It was. But what if the brain never updated the story? What if it kept firing off the same old program, even though the danger had passed? It got stuck in a cross-wire in an attempt to keep me safe. When I then became anxious and fearful I reinforced those brain pathways and it became a self-fulfilling prophecy of severe fatigue.

To me, this is no different from what happens with mould. Instead of reacting to an external substance, the brain becomes hypervigilant to internal cues, like physical effort, emotional intensity or stress. It’s still the same protective loop, just harder to see.

You don’t have to fully believe it to start

Believing in this truly helped me with my recovery. I understand it is difficult at the start of the journey to really sit with and believe in it. So another option could be to wonder, “What if I were able to contemplate this as being true, what would that feel like”. That gentle curiosity is all that you need to start this journey (then eventually your symptoms will start disappearing and you will KNOW it to be true)

For me, I didn’t truly accept this idea until I started to feel the changes physically. I find it difficult to articulate the somatic understanding I have of it now. I hope that in some way this idea makes sense to those in the midst of these symptoms now and can be a light bulb moment on your way to a full recovery.

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