The Science of Suffering (Part 1)

You’re in control. Your rhythm is steady, your breath smooth, each movement efficient. For a fleeting moment, everything feels effortless – like you’ve found that rare flow where effort and ease exist in perfect balance. But then, without warning, it changes.

At first, it’s barely noticeable. A slight tightness in your legs. A shift in your breathing. A creeping heaviness in your arms. Nothing alarming – just the natural toll of exertion. You tell yourself it’s normal, something to be expected. But discomfort is patient. It doesn’t attack; it builds. Subtle sensations turn into undeniable strain. The effort no longer feels controlled; it begins to take control of you.

Soon, your mind joins the battle. “This is too fast.” “You can’t sustain this.” “You’re going to burn out.” The discomfort, once distant, now roars through your body. Every part of you craves relief, an escape from the rising tide that threatens to pull you under. But this isn’t pain – not the sharp, injury-warning kind. It’s something different, something deeper. An overwhelming too much. Too hard. Too far. This is the hill of discomfort. A relentless incline that grows steeper, more unstable, heavier with every step. You are entering a place where your limits are no longer theoretical but real, pressing against you, daring you to keep going.

And yet, it’s not your muscles that falter first. It’s your mind. Your brain, wired for survival, senses the mounting struggle and projects it forward, warning you that if it feels hard now, it will feel impossible soon. It urges caution, choosing safety over uncertainty, reining you in before your body has truly reached its edge.

Here’s the truth: every effort that lasts beyond 30 seconds is a choice. A decision to stop or continue. And this – this moment where discomfort demands an answer – is where the real race begins. The best athletes don’t run from discomfort; they engage with it. Not through sheer force, but through coping skills. Because beyond that discomfort, past the mental resistance, lies something few ever reach: a place where you discover what you’re truly capable of.

For decades, endurance performance was viewed through a purely biological lens. Scientists believed that the body – heart, lungs, muscles – operated within hard physical limits, like a machine bound by its mechanical constraints. According to this model, an athlete could only go as far as their physiological capacity allowed, with exhaustion occurring the moment they reached that absolute threshold. The brain? It was nothing more than a passive observer, watching as the body inevitably ran out of steam.

But over the last 20 years, this perspective has been turned upside down. A newer, more complete understanding of endurance – called the psychobiological model – has revealed that exhaustion isn’t dictated solely by the body. Instead, it’s the result of a negotiation between mind and muscle, a decision made in the brain. According to this model, athletes don’t quit because they physically can’t continue, but because they reach the maximum level of discomfort they are willing or able to tolerate.

Hard physical limits do exist, of course – but here’s the catch: no athlete ever actually reaches them. There is always something left in the tank. How do we know this? Scientists have tested it. In controlled experiments, subjects are pushed to exhaustion through exercise. When they finally reach their supposed limit, their muscles are artificially stimulated with electrical impulses. And every time, without fail, the muscles continue to contract. The body is still capable of performing – it just needs the right signal.

This tells us something profound: your muscles still have energy, your physiological system is still receptive, your nerves can still transmit impulses. The only thing that has actually stopped you is your brain, deciding that the effort is too much to endure. The artificial electric signals in these studies prove that the physical engine is still running. Now, replace those external signals with the ones your brain could be sending, if only it believed you could keep going.

The true limit isn’t in your legs or your lungs – it’s in your central nervous system. And that changes everything

Discomfort feels like an undeniable force – a wall rising in front of you, demanding that you slow down or stop. In the heat of a race, it seems like an absolute truth, a direct reflection of your body’s physical state. But what if that sensation wasn’t as real as it seems?

Scientists now describe discomfort as an illusionary symptom – not because it isn’t felt, but because it’s not a direct indicator of your body’s true limits. Instead, it’s a safety mechanism, your brain’s way of urging caution before you reach actual physiological failure. This system is essential for survival, but it can also hold you back when misunderstood.

To navigate discomfort more effectively, it helps to see it for what it really is: an emotion. Like fear or anxiety, discomfort is a constructed experience – your brain’s interpretation of bodily signals, past experiences, and future expectations. And just with like other emotions, you can work with it.

Discomfort is a subjective perception of effort – the conscious awareness of how much mental and physical energy it takes to sustain an activity. Studies show that this perception, rather than any objective measure like heart rate or muscle fatigue, is the best predictor of when an athlete will hit their so-called limit. In other words, what you experience as discomfort is your brain constantly weighing the effort required against its expectations of what you can handle.

And here’s what makes discomfort especially tricky: your brain doesn’t just react to right now. It’s constantly evaluating both the past and the future. The moment discomfort sets in, your brain is running a complex equation – considering how much effort you’ve already expended, estimating how much more will be required, and deciding whether the cost seems sustainable. If the answer is no, it intensifies the sensation, as if to say, “This shouldn’t feel good right now.”

But here’s the key: discomfort is not a hard stop. It’s a question. A signal. Your brain is asking, “Are you sure you want to keep going?” The athletes who push through the highest levels of discomfort aren’t necessarily stronger in a physical sense – they’re better at managing their mental responses. They’ve learned to interpret discomfort not as a barrier, but as part of the process.

And once you understand this, discomfort loses its power. Because the moment you recognize it as an illusion, you realize: you don’t have to listen.

In the heat of a race, endurance athletes experience an overwhelming force – an all-encompassing resistance to movement. It’s not localized, yet it feels like it’s everywhere. It’s not just physical, but deeply mental. When asked to describe this sensation, athletes often call it fatigue, sometimes pain, or simply struggle to name it at all. And that’s not surprising.

Discomfort, fatigue, and pain share common neurophysiological pathways, creating significant overlap in how they are perceived. This blending of signals makes it difficult to distinguish between them, especially under extreme effort. But while they may feel similar, understanding their differences is crucial for managing them effectively.

The first step is to ask yourself: Will this feeling disappear once I cross the finish line? If the answer is yes, it’s likely discomfort rather than pain or fatigue.

Pain is typically sharp and localized, a signal of potential injury. Fatigue is a depletion of resources, a gradual slowing down. Discomfort, however, is different – it’s a subjective perception of effort, a warning from your brain that the current intensity is hard to sustain. Unlike true fatigue, which lingers even after stopping, discomfort fades the moment the effort ceases. That’s why, at the finish line, despite your body still being physiologically drained, you immediately feel better – the struggle has simply been turned off.

If you want to isolate the feeling of pure discomfort without accumulated fatigue, try sprinting up a steep hill at max effort. The resistance you feel immediately – that intense internal pushback before your muscles even have time to fatigue – is what high perceived effort feels like on its own.

But here’s the challenge: when discomfort reaches extreme levels, everyone wants to quit. Even the toughest athletes are flooded with thoughts of stopping. This is not a sign of weakness – it’s your brain doing what it was designed to do: regulate effort and prevent perceived risk. The key difference between those who push through and those who give in isn’t physical strength – it’s how they interpret these signals. Because in the end, discomfort is not a command to stop. It’s simply a question: Are you sure you want to keep going?