Most founders obsess over strategy, capital and talent. Far fewer ask a more basic question: is my brain actually working as well as I think it is?

In Episode 23 of the ReeThink Podcast, I sat down with Dermot Rock – a former soldier, ex‑founder and now creator of Cogn8 – to explore what happens when you treatmetabolism, sleep and movement as the real levers behind executive function, not just “life hygiene”.

Dermot’s story doesn’t start in a lab or a boardroom. It starts with a parachute accident during his army days that left him with facial trauma, a significant brain injury and nearly a decade of seizures, brain fog and concentration problems.

Years later, after building a startup for three years, he watched it hit a regulatory wall and collapse at launch. On paper, regulation is a “basic” founder risk. In his mind, the failure triggered a deeper fear: did my brain miss something obvious?

That question sent him to objective cognitive testing. The results were brutal: by standardised norms, his cognition was “on the floor” – dramatically below where you’d expect for someone operating at his level.

Instead of accepting that as destiny or “IQ”, Dermot turned himself into a long‑term N=1 experiment, using every credible lever he could find to rebuild his cognitive capacity from the physiology up.

Many still think of intelligence as a static number. IQ tests, school labels and early career success all reinforce that idea. Dermot’s experience suggests something different.

He distinguishes between:

• Genetic potential – the raw “hardware” you’re born with.

• Cognitive architecture – how well that hardware is fuelled, maintained and trained.

You might not change your genetic ceiling, but you can meaningfully change how close you get to it, just as a powerlifter can radically increase strength within their genetic range through training, sleep and nutrition.

Using that lens, Dermot systematically rebuilt his cognitive architecture.
He focused on a simple sequence: measure, monitor, manage.

For Dermot – and now for his clients – cognition starts with measurement, not vibes.

1. Measure

   • Comprehensive cognitive testing across 20+ domains (attention, working memory, processing speed, executive function).

   • Detailed blood panels and metabolic markers.

   • Genetic testing where useful.

   • Baseline vitals such as blood pressure and body composition.

2. Monitor

   • Wearables (Apple Watch, Oura, WHOOP) for sleep, HRV and recovery.

   • Continuous glucose monitors (CGM) to track blood sugar stability.

   • Ketone monitoring in some cases.

   • A live dashboard showing how behaviours impact biomarkers in real time.

3. Manage

   • Targeted interventions across metabolism, sleep, exercise, breathing and recovery.

   • Iterative adjustments based on what actually moves cognitive scores, not just what looks good on a habit tracker.

The north‑star metric is always cognitive performance itself: do these changes make you think more clearly, decide more accurately and sustain attention longer?

One of Dermot’s biggest discoveries – and one of the main things he sees in clients – is how much unstable blood sugar quietly wrecks cognition.

A few crucial points:

• The brain is ~2% of body mass but roughly 20% of resting energy demand.

• When energy delivery fluctuates wildly, the prefrontal cortex – the seat of planning, inhibition and long‑term thinking – is often the first to suffer.

• Chronic over‑consumption of refined carbohydrates drives insulin resistance, making it harder for the brain to use glucose efficiently. That shows up as brain fog, poor working memory and shorter time horizons.

In practice, this means that glucose volatility can be as damaging to executive function as sleep loss.

Dermot’s approach is not dogmatic (no fixed “best diet”), but he often uses periods of carbohydrate restriction or tighter timing to restore metabolic flexibility, then layers in nutrient‑dense foods to support brain structure and neurotransmitter production.

Founders increasingly talk about sleep, but often as a self‑care theme, not as a core infrastructure for decision‑making.

Dermot treats sleep as non‑negotiable cognitive infrastructure:

• Around 7 hours of quality sleep appears optimal for adult executive function; chronic undersleep correlates with worse problem‑solving, emotional control and risk evaluation.

• Deep and REM sleep support metabolic housekeeping in the brain: clearance of waste via the glymphatic system, hormonal recalibration and restoration of insulin sensitivity.

• Sleep restriction amplifies amygdala reactivity and weakens prefrontal control, making leaders more reactive and short‑term in their choices.

In other words: you can’t consistently make good calls on chronic six‑hour nights, no matter how disciplined or motivated you are.

Dermot draws a clear line between activity and exercise.

• Activity: walking, general movement, low‑intensity behaviours.

• Exercise: targeted, often uncomfortable sessions designed to move the needle on cardiovascular fitness and strength.

For the brain, Dermot highlights VO₂ max – your maximal oxygen uptake – as a critical but under‑appreciated lever:

• Higher VO₂ max improves oxygen delivery to the brain, supporting processing speed, attention and resilience under stress.

• You don’t necessarily need long sessions; brief, intense bouts (for example, 10–20 minutes) can be enough if done consistently and wisely.

For founders and fund managers, this reframes cardio from “fitness hobby” to cognitive risk management.

The most striking claim Dermot makes is that tiny, momentary dips in clarity can cost millions over a career.

Imagine a high‑stakes operator – a fund manager or founder – going into a key meeting:

• Slightly under‑slept after late‑night prep

• Riding a post‑lunch glucose dip

• Already cognitively taxed from a morning of complex decisions

They may be only 3% off their best in terms of attention, impulse control or working memory. But that 3% could be the difference between:

• Spotting or missing a critical risk factor

• Holding or losing composure in a negotiation

• Responding thoughtfully or snapping at a board member or key hire

Multiply that across hundreds of decisions per year, and you start to see why Dermot believes physiology can be a multi‑million‑euro variable in high‑consequence careers.

At Olympic level, athletes train four years to shave hundredths of a second from their performance. In contrast, many top operators are still running their brains on poor sleep, volatile blood sugar and minimal exercise.

ermot’s long‑term vision is to define and track a measurable state he calls decision‑making readiness.

Rather than relying on gut feel, he imagines:

• A defined band of biomarkers, sleep data, metabolic metrics and cognitive scores that indicate when a leader’s brain is most likely to perform well.

• Dashboards that give founders and investors feedback on their cognitive runway heading into important days.

• Coaching and interventions that focus first on getting someone into that state consistently before layering on tactics like negotiation frameworks or productivity systems.

In that world, board packs and investor memos would be accompanied by a quiet question:

“Is my brain in a fit state to make this call?”

It sounds extreme now. In a decade, it might look like basic risk management.

For founders and investors, the question is no longer whether brain health affects performance. The question is whether you’re willing to treat your physiology like part of your stack – as real and non‑optional as your cap table or your data pipeline.