01/12/2025
Cognitive performance isn’t just about the brain.
It’s about the body the brain is sitting in.
If you look at people in mentally demanding jobs — founders, analysts, clinicians, traders, executives — the pattern is becoming impossible to ignore:
They’re not underperforming because they lack skill.
They’re underperforming because their physiology is saturated.
And the research backs this brutally clearly.
A large multicentre study on >9,000 adults showed that when chronic stress builds up, two things rise together:
• Extracellular water (ECW) — a marker of inflammatory fluid shift
• Drops in HRV — SDNN and RMSSD plummet as autonomic resilience collapses
This isn’t “just stress.”
It’s measurable degradation of the neuro-endocrine-metabolic axis — the same axis that governs focus, decision-making, emotional regulation, and executive function.
Another study demonstrated that increased ECW is not a benign finding. Inflammation and stress shift water from inside the cell to the extracellular space, impairing cellular efficiency and slowing tissue recovery.
And that matters for cognition.
When intracellular water drops, the nervous system becomes electrically rigid. HRV falls. The matrix becomes congested. Mental clarity narrows. Reaction time slows. Fatigue sharpens.
This isn’t psychology — it’s physics.
Even in children and young adults, the same pattern is visible:
• Higher inflammation → higher fat mass
• Higher cortisol → altered HRV
• Both combined → measurable behavioural and cognitive differences
So what does this mean for high-pressure professionals?
Most “cognitive problems” aren’t brain problems.
They’re system problems:
– Under-recovery
– Chronic sympathetic drive
– Flattened HPA axis
– Matrix congestion
– Loss of cellular hydration
– Subclinical inflammation
When these drift, you can have the sharpest mind in the world — but it’s running on a degraded operating system.
For years, only elite performers — F1, MotoGP, Olympic staff — had access to systems that actually measured and corrected these patterns.
That’s changing.
I’ve been working on something that makes these physiological blind spots visible and correctable — in minutes, not months.
I’ll share more soon.
For now:
If you rely on your mind to make high-stakes decisions, start thinking beyond sleep apps and supplements.
Your cognitive output is only as good as the physiological system generating it.
The data is clear.
Most people aren’t “burnt out.”
They’re overloaded — and no one has ever measured it properly.
Something new is coming that will.
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Chrousos G.P. et al. (2022). PPG-HRV & ECW in chronic stress and inflammation. Hormones.
Straub R.H. et al. (2016). Extracellular water & volume overload in RA. Clinical Rheumatology.
Christaki E.V. et al. (2022). Stress, inflammation & body composition in youth. Children.
Stefanaki C. et al. (2016). Early osteosarcopenic features in young adults. Eur. Clin. Invest.