The Peter/Paul Principle
Running takes a toll on the body. But to whom does that toll get paid?
When we run, we engage a massive amount of skeletal muscle, provoke enormous hormonal action, and light up our entire neurological network. When we are running, throughout our body there is a never-ending stream of trade-offs happening between energy stamina versus fatigue resistance, muscular power versus endurance strength, and core-system regulatory function homeostasis versus survival instincts, all developed across the millennia by the evolutionary process. But as we have previously noted, the body is biased towards doing the least amount of work possible for the most result. Accordingly, distinct controls over, and adaptations to, endurance and strength-based activities have evolved in humans. We’re not going to go over the entire litany of physiological actions in running here. We’re going to focus on our respiratory muscles, and the critical role they play in our running performance. Or, more precisely, the role they play in our inability to have the running performance we desire.
Quick recap on the aerobic process in running. We take a breath. Air filters down into the alveoli, the microscopic balloons in our lungs where the exchange of oxygen (O2)and waste gases, primarily carbon dioxide (CO2), occurs. The oxygen molecules travel via red blood cells (RBCs) through the bloodstream down to the muscle fibers, where they are absorbed into the cell’s mitochondria, the powerhouse of the muscle fiber. The mitochondria uses O2 and glucose, the most basic form of sugar, to power the reactions which cause the muscle fibers to move. This chemical reaction creates waste products, mainly CO2 and water (H2O). These waste gases are dispersed back into the bloodstream to be expelled by the body via the lungs.
Two things to note in the preceding paragraph: One, how the process of aerobic respiration starts. We take a breath. Two, the location of the muscle fibers to which the O2 molecules travel is not disclosed. Are these fibers we’re talking about in the leg muscles? The chest? The heart? The answer is, of course: All Of The Above. Every single muscle fiber in our body, from our head to our toes, goes through this same exact process (also note we’re sticking to the aerobic process only - things get complex as we move into the anaerobic realm). So it’s these two primary functions — the act of breathing and how it powers aerobic muscular respiration while running — where we’ll be focusing our discussion.
So to begin, let’s take a look at the physiology of our respiratory system. There’s two channels by which air enters our lungs: our nose and our mouth. Both channels empty into the trachea, which then branches out throughout the lungs into ever smaller and smaller channels, until the air that is pulled in reaches the alveoli. What is interesting is this evolutionary dual-channel design; we can choose which route we wish to have the air enter and exit. We can even choose both paths simultaneously.
It is known that for daily living, the most beneficial way to breathe is by inhaling through the nose. This has a number of important benefits for our health, such as filtering the air before it gets down to the lung tissue, warming and humidifying the air so that it matches the ambient conditions within the lungs, and nasal breathing generates nitric oxide (NO2), also known as Laughing Gas at the dentist office. Nitric oxide relaxes and expands the blood vessels, allowing the heart to pump more oxygen-carrying blood cells throughout the lung tissues. It has also been shown that by breathing through the nose, we increase the lung’s capacity to absorb oxygen due to the added pressure resistance.
All good things come to an end eventually, and it’s no different with nasal breathing. When running, at a certain point, our metabolic demands overwhelm the ability of nasal breathing to take in enough oxygen to meet demand. This is the point when mouth breathing becomes dominant. Again, it must be stressed that at this point, which for most occurs at or slightly above the first ventilatory threshold (VT1), while there is a slight increase in demand for oxygen by the muscles, it is actually the need to get rid of carbon dioxide and other waste gases that is driving the demand for faster and/or deeper respiration. While there are some individuals who have adapted to and are comfortable in breathing exclusively through their nose, even at maximal effort, these individuals are the exception to the rule. We at Breath Runner encourage as much nose breathing as practical, but do not want anyone to artificially limit their performance on the basis of some influencer’s recommendation, no matter how well-intentioned. Keep in mind, that if nose breathing was the End-All Be-All Greatest Way to Breathe Ever For All Things, we would have evolved with completely separate respiratory and digestive tracts, like dolphins and whales did. But we didn’t, and need to respect the fundamental realities of our body’s needs when we’re pushing the limits.
That being said, it’s equally important to understand that that “running out of oxygen” feeling when we’re pushing ourselves to our limits is NOT actually a lack of oxygen! It’s a overwhelming build-up of carbon dioxide in our bloodstream, and it is our tolerance to that, as well as the accompanying acidification, which ultimately determines both our ability to nose breathe as long as possible, as well as the amount of time we will be able to spend at our upper limit. It is in THESE dimensions of aerobic performance — our CO2 tolerance, and our lung capacity — where we feel the Breath Runner Method excels. Let’s dig in to see how.
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