Kilometer 35: Where My Real Race Begins
There is a moment in every marathon—and in every Ironman—when the race stops being physical and becomes psychological.
For me, that moment consistently arrives around kilometer 35.
Up to that point, preparation carries me. My pacing strategy works. My fueling plan is structured. My breathing is controlled. I am executing a system I built over months of disciplined training.
But then something shifts.
My legs feel heavier. My stride loses elasticity. The rhythm that once felt automatic now requires intention. My glycogen stores are nearly depleted. Neuromuscular fatigue accumulates. Every step sends a slightly louder signal to my brain: Slow down. Protect yourself. End this.
This is where instinct enters the conversation.
And instinct is not interested in performance.
It is interested in survival.
When My Brain Tries to Protect Me
The concept often described as the “Central Governor” suggests that the brain regulates effort to prevent catastrophic damage. Whether understood as a literal neurological control system or as a broader regulatory framework, the lived experience is clear:
My perception of effort rises sharply before my body has truly reached its limit.
Research associated with the National Institutes of Health reinforces what endurance athletes repeatedly experience. Perceived exertion often accelerates faster than measurable physiological decline.
In practical terms, that means I am often stronger than I feel at kilometer 35.
But perception does not present itself as a theory.
It presents itself as urgency.
It whispers:
“This is unsustainable.”
“You miscalculated.”
“You cannot maintain this pace.”
If I am not mentally prepared, I start making subtle but decisive mistakes.
I delay taking carbohydrates.
I shorten my stride inefficiently.
I look at competitors instead of my cadence.
I emotionally downgrade my goal.
None of these decisions feel dramatic in isolation.
But together, they shift the trajectory of the race.
That is why I do not rely on motivation. I rely on structure.
The Decision Zone: Perception vs. Capacity
If I were to visualize the final 10 kilometers of a marathon, I would draw two curves.
The first curve represents my actual physiological capacity. It declines gradually, reflecting substrate depletion and muscular fatigue.
The second curve represents my perceived exertion. This one rises sharply after kilometer 30.
The space between these curves is the decision zone.
At kilometer 35, my perceived effort may feel close to maximum, while my measurable capacity still allows structured performance.
The “Wall” is not simply a metabolic event.
It is a perceptual amplification.
My task is not to eliminate fatigue. That would be unrealistic.
My task is to prevent perception from dictating premature decisions.
And that is where mental models become decisive.
Mental Model One: How I Use Chunking to Regain Control
Seven point two kilometers remain at kilometer 35.
If I allow my mind to process that number in its entirety, the distance feels overwhelming. My brain begins to simulate prolonged suffering. The horizon stretches. Fatigue multiplies.
Instead, I deliberately reduce the problem.
Psychological principles discussed by the British Psychological Society emphasize that breaking complex challenges into smaller units lowers cognitive load and restores a sense of control.
So I narrow my focus intentionally.
I run to the next aid station.
I maintain cadence for the next 500 meters.
I count fifty calm, controlled breaths.
I do not think about the finish line.
I think about the next step.
Chunking works because magnitude overwhelms me more than effort itself. When I shrink the magnitude, I stabilize my thinking.
Each small target completed reinforces agency.
Momentum returns—not because I feel strong, but because I feel structured.
Mental Model Two: Inversion – Clarifying Action Through Failure
When fatigue intensifies, asking myself, “How do I achieve my goal?” feels abstract and cognitively heavy. My brain is not operating at full executive capacity.
So I ask a simpler question.
“What would guarantee that I fail right now?”
The answers are immediate and concrete.
If I stop drinking, I will cramp.
If I skip carbohydrates, I will fade rapidly.
If I surge emotionally, I will collapse later.
If I allow negative internal dialogue to dominate, I will disengage.
Inversion simplifies complexity.
By identifying the behaviors that ensure breakdown, I illuminate the behaviors that ensure continuation.
Under stress, my brain is highly sensitive to threat. Instead of fighting that bias, I use it as a compass.
Failure defines the boundaries.
Inside those boundaries, execution becomes clear.
Mental Model Three: What I Can Still Control
At kilometer 35, I cannot control everything.
I cannot fully control my finishing time anymore.
I cannot control other athletes.
I cannot control the weather.
And I certainly cannot eliminate discomfort.
What I can control are execution variables.
Frameworks such as the “4 C’s,” often referenced in performance education platforms like Strength and Conditioning Education, resonate strongly with my racing experience:
Confidence.
Control.
Commitment.
Challenge.
Confidence reminds me that I prepared for this moment deliberately.
Control narrows my attention to breathing, posture, and cadence.
Commitment keeps me engaged with the process instead of negotiating with pain.
Challenge reframes discomfort as proof that I am operating at the edge of growth.
When I shift my focus to what remains controllable, emotional noise decreases.
Clarity returns.
A Race That Reshaped My Thinking
In one Ironman race, after a demanding bike leg under rising temperatures, I began the marathon cautiously but ambitiously. My fueling was precise. My pacing calculated.
By kilometer 32, fatigue accumulated faster than expected.
By kilometer 35, walking seemed reasonable.
The internal narrative shifted quickly.
“You misjudged the heat.”
“This pace is unrealistic.”
“Protect what you have left.”
Instead of reacting, I paused internally and applied inversion.
“What would make this a disastrous finish?”
The answer was obvious.
Stop fueling.
Let cadence decay.
Focus on competitors passing me.
Mentally disengage.
So I selected one variable: cadence.
For the next ten minutes, nothing else mattered.
Not speed.
Not placement.
Not the clock.
Only rhythm.
Aid station to aid station.
Step by step.
My physiology did not dramatically change. But my perception recalibrated. Structure replaced panic.
I finished that race not because I felt powerful, but because I maintained cognitive discipline.
That experience fundamentally changed how I understand endurance.
Fitness determines potential.
Clarity determines realization.
Why This Matters Beyond Sport
The mechanisms I experience at kilometer 35 are not limited to racing.
In business and leadership, extreme pressure produces similar distortions.
Perception narrows.
Time horizons shrink.
Emotional impulses intensify.
Without structure, decisions become reactive.
Chunking becomes strategic segmentation of complex projects.
Inversion becomes structured risk management.
Focus on controllables becomes operational excellence.
Resilience is not about suppressing emotion.
It is about preserving clarity when perception becomes unreliable.
How I Train for Kilometer 35
I do not hope to think clearly under pressure. I train for it.
During long sessions, I deliberately rehearse the final phase. I simulate decision fatigue. I practice narrowing focus when energy is low.
I script my internal dialogue in advance.
“Cadence and posture.”
“Fuel now.”
“Calm is fast.”
I automate my nutrition strategy to remove emotional negotiation.
Organizations such as AOK emphasize preventive strategies in health. I see mental resilience the same way. It must be developed before crisis appears.
You do not rise to ambition when under stress.
You fall to the level of your preparation.
The Real Race Always Comes Late
Anyone can execute when fresh.
Anyone can follow a plan when energy is high.
But performance is revealed when fatigue distorts perception and quitting feels rational.
Kilometer 35 is my proving ground.
It is where instinct and intention collide.
And every time, the outcome depends on whether I default to emotion—or execute a system.
Work With Me
If you are preparing for a marathon, an Ironman, or a high-stakes professional challenge, I invite you to go beyond physical preparation.
In my Performance Coaching, I combine:
• Individualized endurance programming
• Structured mental model training
• Race simulation under fatigue
• Decision-making frameworks for extreme pressure
Together, we build more than fitness.
We build cognitive stability when it matters most.
Kilometer 35 will come for you.
In racing.
In business.
In life.
The question is not whether fatigue will appear.
The question is whether you will meet it with instinct—or with structure.
If you are ready to develop clarity under pressure and execute at your true capacity when others begin to fade, reach out to me.
Let us design your system deliberately.