Traditionally, the “wall” is explained by glycogen depletion, muscle fatigue or dehydration.
But these causes don't tell the whole story.
According to Véronique Billat, our Central Nervous System Acts like a Invisible Governor.
It constantly monitors physiological stress signals, and when danger approaches, it Slow Down the Effort To protect the body.

Ce “Brain Slowdown” Occurs in the form of:

• Feelings of Heaviness or Incoordination
• sudden drop in concentration,
• Want to slow down for no apparent reason.

In other words: the brain talks to you, but you don't always listen to it.

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In his work, Billat and his team use EEG (electroencephalograms), coupled with physiological measurements (VO₂, heart rate, lactate...) and with models ofArtificial intelligence.
Their aim: to detect Early Brain Signals Which Announces the Drop in Performance Before It Even Occurs.

What We Discover is that The Brain Sometimes Reacts Several Minutes Before the Body.
Before the drop in speed, before the cardiac drift, before the wall.

Tomorrow, we could imagine a smartwatch that warns you:

“Your brain is starting to kick in, slow down now to save your finish.”

Sci-fi? Maybe not for long.

Even without AI or electrodes, you can start right now to Run More Mindfully.
Here are three mental signals that deserve your attention:

1. You're dropping out mentally.
   You stop thinking about your stride, you “float” in your effort.
   ➜ It's often an early sign of cognitive fatigue.
2. Your gesture becomes less fluid.
   The arms clench, the stride disunited.
   ➜ The brain is already trying to protect the body.
3. Your self-talk is changing.
   You go from “I Manage” to “I Can't Take It Anymore.”
   ➜ The wall is starting to be built.

👉 In these moments, Slow Down Slightly, take A Few Deep Breaths, and Readjust Your Attention On your movement.
You will often see that the body comes back on its own.

The data on your watch is precious: it objectifies your effort.
But They Don't Say Anything About Your Internal State.
To run “With your brain”, it's not denying technology, it's Use it without obeying it blindly.

Try it on your next long ride:

• Alternate 10 minutes of “internal” listening (without looking at your watch),
• Then 10 “piloted” minutes (following your target pace).
• Then compare the sensations: often, your body naturally adjusts its rhythm more fluidly.

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Current research explores the convergence between Neuroscience and performance.
Tomorrow's runners could benefit from devices that can predict the wall before it occurs.
But until then, the most powerful tool is still free: Your conscience.

Take the time to listen to your mind.
He is your best coach, your best barometer, and sometimes, your best safety brake.

• The brain detects fatigue before the legs.
• The “wall” often starts in the head before it appears on the watch.
• Train Your Mental Listening Improves effort management and longevity while running.
• Running smartly is learning to Listen without panicking.

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• Véronique Billat, Before the Wall: Listen to Your Brain, Not Your Watch!
• Billat, V. (INSERM/CNRS), work on the “central governor” and the regulation of effort.

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