TEDx Talk: Why You Feel Breathless—And What You Can Do About It

Why do most runners stop? It’s rarely their legs—it’s their breath. In this TEDx Talk, Patrick McKeown explains why the sensation of breathlessness, not muscle fatigue, limits endurance and performance. Discover how nasal breathing, CO₂ tolerance, and breath training can transform not just sport, but the way you live.

🎥 Watch the full talk below:

Two Runners, Two Stories

Two runners.
Same road.
Same weather.
Maybe even the same training plan.

But they’re telling us two very different stories.

One is running with her mouth wide open—gasping, struggling and breathing hard.

The other—mouth is closed, calm, breathing is under good control.
Her face is relaxed. She is efficient with her breathing.

“Which runner do you relate to?
And more importantly… which one would you rather be?”

Because these two don’t just look different—
They feel different.

And the thing that separates them…
it is not fitness.
It is not strength.
And it is not willpower.

What separates them… is the sensation of breathlessness.

Because when your breathing feels out of control,
your Rate of Perceived Exertion goes up.

It doesn’t matter what your heart rate says;

if your breath says, “This is hard,”
your brain believes it.

But when your breath is calm, steady and under control
That same work rate feels manageable.
Even enjoyable.

Because it’s not just your legs that set the pace.
It’s your perception of breathlessness that decides:

How fast you go
How far you go
And how long you can keep going

Breathlessness isn’t just in your head.
It’s not imagination.
It’s perception—built on real chemistry and nervous system signals
that whisper… or sometimes scream… throughout your body.

The Drivers of Breathlessness Perception

This is where it gets interesting.

There are six key drivers that shape how breathless you feel—
And this holds true whether you’re an elite athlete or a weekend walker.

Take a look at this chart.

The red bars show the impact of breath training.

The white bars?

That’s the effect of physical training alone.

Let’s walk through each of these:

CO₂ Sensitivity: carbon dioxide is the body’s main driver to breathe. Breath training increases your tolerance dramatically. That red bar shoots up. Physical training barely nudges it.

Ventilatory Pattern: How you breathe—is it shallow and fast, or is it light, slow and deep. It is common for athletes to breathe fast and shallow and this leads to increased breathlessness. Breath training improves breathing patterns. So once again, red takes the lead.

Acid–Base Balance – When you over- breathe during exercise, you blow off too much CO₂. This disrupts your blood’s pH balance, making it too alkaline. And as a result, blood vessels constrict and less oxygen gets delivered to your muscles and to your heart brain.

Breath training helps stabilize this chemistry—so you stay more efficient, more focused, and less breathless.

Oxygen Delivery – This is where physical training shines. It builds a stronger heart, your muscles become more efficient. You build endurance.

This is where the white bar takes the lead.

But breath training plays a role here too—by helping your body use that oxygen more efficiently.

It’s not just about oxygen transport in the blood —it’s about releasing oxygen from the blood to where it’s needed.

Respiratory Muscle Fatigue – Both forms of training help here. But breath training—especially with nose breathing and breath holds during exercise—goes further. It improves function and strengthens the breathing muscles.

And finally, psychological Perception: This is the big one. Breath training teaches you to remain calm in the face of air hunger.

It rewires the brain’s response to rising CO₂.

That red bar? That’s rewiring in action.

So what does this all mean?

Physical training builds the engine—it powers the muscles, strengthens the heart, and drives movement.
But breath training tunes the sensors—
It quiets the internal alarms and gives you control over how effort feels.

Because it’s not just about how much you can do…
but it’s about how your body interprets the effort.

And that leads us to a bigger question—
Why doesn’t being fit always mean breathing better?

The reason that physical exercise doesn’t train your breathing is because most people, when they exercise—even at low to moderate intensity—breathe through an open mouth.
It’s common. It feels natural.
Breathing through the mouth during exercise doesn’t train your breathing system.

There’s simply not enough load on it.

And every athlete knows:
if you want to strengthen something, you need to add load.

Your breathing system responds to three types of load:

A mechanical load—how hard your breathing muscles have to work
A biochemical load—how well your body tolerates rising levels of CO₂
And a perceptual load—that raw, often uncomfortable feeling of air hunger

Mouth breathing bypasses all three.

Because your mouth is a bigger space than your nose, you can breathe more air. This reduces air hunger… but it also keeps your breathing system undertrained.

So if you want to feel less breathless,
you have to train the system that causes breathlessness in the first place.

So yes—exercise helps.
But breathing better? That helps even more.

It’s Not Just the Air You Breathe In…

Oxygen Advantage Breathing for Cycling Animation

The real magic in breathing doesn’t happen on the inhale.
It happens downstream.

It’s not just about getting air into the body—
It’s about what happens after that breath enters.

So the real question is:

How much air actually reach the alveoli—the tiny air sacs in the lungs?
How much oxygen transfers from the lungs into the blood?
And how much oxygen is delivered to your working muscles, your brain, your heart, where it’s needed most?

With breath training, you can influence every stage.

And on that note, breathing less air into the body doesn’t mean less oxygen reaching your muscles.
In fact, more isn’t always better when it comes to breathing.

You can be moving a lot of air—but absorbing less oxygen.
You’re breathing more, but getting less.

So to breathe well, it’s not about breathing big.
It’s about breathing smart.

It’s about breathing in a way that supports your whole system—
from inhale to oxygen delivery, from the lungs to the cells.

And that’s something we can train.

Dysfunctional Breathing

A study published in the Journal of Strength and Conditioning Research screened nearly 2,000 athletes—from a wide range of sports, ages, and experience levels.

And what did they find?

The prevalence of athletes with dysfunctional breathing patterns was 90%.

It wasn’t that these athletes were unfit.
Far from it. Many of these athletes were competitive, well-trained individuals.

But their breathing patterns told a different story.

And what can that lead to?

Disproportionate breathlessness—feeling out of breath even when it doesn’t match the effort
Poor recovery post exercise — with the nervous system in a constant state of stress
And because breathing and movement go hand in hand. If breathing is dysfunctional, movement is dysfunctional and if movement is dysfunctional the athlete is at a greater risk of injury.

BOLT Score – Test Your Breathing

Do you want to know how well you breathe?
There is a simple test called the Body Oxygen Level Test or BOLT.

It gives you feedback of how sensitive your body is to the accumulation of carbon dioxide and your perception of breathlessness.

It’s not perfect. But it can reveal how your body responds to air hunger—
and whether your breathing is working for you, or against you.

Here’s how to measure your BOLT:
take a normal breath in and out through your nose. pinch your nose with your fingers to stop breathing and time it in seconds, how long it takes until you feel the first definite urge to breathe. When you resume breathing, it should be normal.

If you have under 25 seconds? That’s a sign of dysfunctional breathing.
25 seconds or more? That’s a marker of functional breathing.

So how do improve your bolt score?

It starts with improving your everyday breathing pattern.
Breathe in and out through your nose, not just during rest and sleep, but during a good part of your exercise too.
breathe light

Breathe slow

Breathe deep

Otherwise known as LSD

Light means breathing less air. It trains your body to tolerate air hunger and higher carbon dioxide.
Slow breathing helps calm your nervous system, shifting you out of “fight or flight” and into a more balanced, focused state.
Deep means breathing with good recruitment of the diaphragm, and less from the upper chest. This provides core stability, supports the spine, and reduces the risk of injury.

And to spice it up a bit, we add in dynamic breath holds.

These are controlled, intentional breath holds— performed after a normal exhalation, while walking, running or any physical movement.

They stress the system— lowering your oxygen and increasing co2 to cause adaptations beneficial to improve exercise performance.

But maybe even more importantly—
they teach your brain not to fear air hunger.

You get comfortable with discomfort.

And as you move your body, pay attention to your breathing —
feel your breathing, follow your breath and every time your mind wanders – bring your attention back to your breathing.

Exercise should not be just training for the body,
it should also be training for your breathing …
and training for your brain.

Adapting to Nasal Breathing

Now, some people ask – “Is it really possible to exercise with your mouth closed?”

Yes, it is.

But it depends on four key factors:

Your BOLT score. The lower your bolt score, the harder and faster you breathe.
Your nasal airway: having a small nasal airway increases resistance to breathing making it more difficult for air to flow freely to and from the lungs.
Adaptation period: this doesn’t change overnight. It takes a few weeks to adapt to nasal breathing during exercise. You are training your body to do more with less.
General fitness: The better your baseline conditioning, the easier the transition. But even unfit people can make huge gains—just by changing their breath.

This isn’t about forcing your mouth closed.

It’s about building the conditions so you don’t need to open it.

The Period of Adaptation

And yes—there is a period of adaptation.
so Initially, it might feel like a step back.

Your nose is smaller than your mouth resulting in less air getting into the body.

Remember the load that we spoke about early on?

The feeling of air hunger is stronger. you might even slow down a little.
But stick with it for a six to eight weeks.

Because your body adapts.
The feeling of air hunger lowers.
And then the benefits begin to stack:
Your heart rate is less during exercise
Your recovery is faster.
You stay calmer under pressure.
You breathe less—and feel less breathless.

Breathing through your nose helps keep you in the steady state of exercise—what exercise physiologists call Zone 2.

It’s the sweet spot: where you’re slightly breathless but still able to hold a conversation.
This is where endurance is built, fat is burned, and your body learns to use oxygen more efficiently.
Nasal breathing anchors you in that zone.
It helps regulate intensity and builds the foundation of your aerobic base

and it’s not that we’re purists here—
We’re not saying never open your mouth.
There is a time for mouth breathing—
when you’re pushing harder, at higher intensities,
when the demand outpaces what the nose alone can handle.

But here’s the key:
Training your breathing system—especially through the nose at moderate intensities—
builds adaptations that carry over.

So even when you’re breathing through your mouth in a hard effort,
you’re still reaping the benefits:
Better CO₂ tolerance
More efficient oxygen delivery
Stronger respiratory system
Calmer perception of effort

These benefits aren’t just limited to nose breathing during exercise.
They transfer—even when the pace picks up, the mouth opens, and the intensity rises.

That’s the beauty of it.
Train smart in Zone 2, and it pays off in Zone 5.

Breathing isn’t a fad.
It’s not a trend.
It’s fundamental.

So let’s return—one last time—to those two runners.

One with her mouth open, breathing hard and fast for a given intensity and duration of exercise.
The other—mouth closed, breathing light and steady, efficient and in flow.

Which one will you be?

Not just in sport—
But in times of challenge.

In life.

Because the way we breathe shapes the way we live.
And when we master the breath,
We stop chasing the air…
And start working with it.