Mark Cool

Mystery Symptoms When You’re Fit: 2 Tools to Bring Your Nervous System Back to Baseline

The Fit/Sick Paradox: Two Biological Tools That Reset My Nervous System

On paper, I was the picture of health- 6’1”, 170 lbs, fit and highly active. Between barefoot trail runs, kettlebells, yoga, and calisthenics, I looked and moved much younger than my chronological age.
But beneath the surface, my nervous system was misfiring.


I was running a high-stress real estate investing business, and to burn off that entrepreneurial stress, I was playing two-plus hours of pickleball almost every day. I thought I was managing the pressure, but I was actually pushing my physical vessel far beyond its limits.

I began experiencing random clusters of bizarre physical symptoms: coughing fits, heartburn, acid reflux, tachycardia (rapid heart rate), migraines, dizziness, and extreme fatigue. The severity ranged from minor blips to full-blown episodes that would entirely lay me out.

Naturally, I went to the experts. I saw a cardiologist, a GI doc, an allergist, a psychiatrist, and alternative medicine practitioners. My heart was fine. My GI tract was structurally sound. Aside from a mold allergy, I was medically “healthy.”
I wasn’t broken; my biology was just out of alignment. So, I approached it the way I approach everything: as an interesting puzzle to solve.

Here are the two specific strategies I deployed to quiet the physical alarms, reset my nervous system, and return to my natural baseline of calm and groundedness.


Tool 1: Blood Glucose & The Autonomic Nervous System

When you have an ADD brain and are highly active, you are uniquely susceptible to hypoglycemia (low blood sugar).
What I learned is that a blood sugar crash isn’t just a diet issue—it is a mechanical trigger. When your glucose drops, your Autonomic Nervous System (ANS) instantly perceives a threat and shifts into a “fight-or-flight” state to keep you alive. With ADD it’s worse, because ADD brains don’t “ramp down” as easily as neurotypical ones. [A Ferrari nervous system with bicycle brakes].

Because I was already carrying a baseline of business stress and overexerting myself on the pickleball court, my ANS was hyper-vigilant. Even a minor dip in blood sugar would trigger a massive adrenaline dump, triggering intense nervous system overreactions that forced me to ride them out on the sidelines. One was so extreme that I passed out and crashed my Tesla at 60 mph on the highway.

The Solution: I stopped guessing and started tracking. I wore a Continuous Glucose Monitor (CGM) and kept a meticulous food log.
By mapping exactly how my body responded to different foods and exertion levels, I stabilized my glucose. Once the blood sugar roller coaster stopped, the random adrenaline dumps stopped with it.


Tool 2: The Low-Histamine Reset

The second piece of the puzzle was histamine intolerance.
My body had reached a tipping point where it was reacting to almost everything I ate. My upper GI tract had become hyper-sensitive and inflamed. Eating dry, spicy, or high-histamine foods would trigger intense bouts of coughing. That coughing would then mechanically trigger the tachycardia, dizziness, and migraines.
It was a domino effect of inflammation.

The Solution: I went on a strict, low-histamine diet for four weeks.

This wasn’t a life sentence; it was a hard reset. By emptying my “histamine bucket” and taking an over-the-counter antihistamine (Xyzal) along with the supplement Quercetin, I gave my gut the space it needed to calm down.

It was an absolute game-changer.

Before the histamine diet reset, I had limited myself to a very small scope of foods that seemed to be non-triggering- sweet potatoes, chicken breast, salad, not much else. No nuts, no red meat, no spice- no variety.

After a month of reducing that internal friction, I was able to reintroduce a wide palette of foods—even nightshade vegetables and high-histamine foods—without triggering a single episode.


The Takeaway: Optimizing the Human Machine

Learning how to operate this human machine is endlessly fascinating to me.
These two tools—the CGM and the low-histamine reset—didn’t teach me how to be calm. I already knew how to do that. What they did was remove the biological static so my physical body could realign with my mental baseline.

If you are a high-performer dealing with mystery symptoms while the doctors tell you you’re “fine,” don’t ignore the data. Look at your blood sugar. Look at your gut inflammation. Sometimes, finding your peace is just a matter of pulling the right biological levers.


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