Nestor wrote a personal experience into the world of breathing which is a common style done by journalists within realms of science. Other examples would be Born to Run and Natural Born Heroes by Christopher McDougal and The Omnivore’s Dilemma and How to Change Your Mind by Michael Pollan. This style is a tremendous reminder that writing is most certainly a skill. The level of skill is evident when describing complex subjects like carbon dioxide’s relationship with oxygen in the body. It is hard to make something complex – simple; it is even harder to make it memorable.
The point of reading anything is to retain the information. What a first-hand experience does is give a point of view that is personal. This makes the concepts more memorable because it becomes a story. Stories are just more memorable. Along the way you get exposed to the characters that play roles as experts. Their point of view gives a storyline that makes a very advanced subject matter relatable and a result understandable. You are getting a first hand account of someone that is learning a subject.
Through evolution we have changed the structure of airways which has decreased our capacity to take in air efficiently. By increasing the function of inhalation through the nasal passages to leverage the relationship between carbon dioxide and oxygen.
Nestor
The first major concept was through evolutionary responses agriculture and cooking of foods allowed for the intake of more energy dense foods. This created two responses – one being greater energy density of foods which led to higher levels of cognitive function and the other a more narrowed facial structure. The increased cognitive function that led to the development of speech and language. This was followed with a more mobile tongue and smaller lips to make different sounds associated with language. It also lowered the larynx making homo-sapiens the only species that are capable of choking on food. What this did was take a wide and short facial structure and make it a narrow and long facial structure. This lowered the space for air to come in leading to other downstream changes to physiology.
This opening was an absolute savage description of evolution’s impact on the anatomy of the nose and mouth. It set the stage beautifully for how the impact of a more narrow face leads to a smaller airway. From there, the strategy becomes about how a narrowed airway can get more air in. One strategy could be mouth breathing which actually compounds the issue of making the palate softer due to the lesser pressure. A softer palate further the impact on a narrowed airway by having a V shaped arch of the mouth. Nasal breath leads to higher pressures causing a hardening of the tissues of the back of the mouth increasing the airway’s size.
Where the story goes from here is predominantly about carbon dioxide (CO2). The most memorable line from the entire book was “people with larger lungs will live longer.” Where CO2 comes in is people overly breathe, never really hitting full lung capacity. Most people only use 10% of their diaphragms potential in turn increasing stress on the cardiovascular system. This leads to an increased breath rate to meet the demand eventually leading to overly oxygenation of the body. This is where CO2 comes into play.
Personally, I kinda got lost here. I have to admit there is an element of too much exposure to cardiovascular and respiratory function in a performance perspective, which is where I think most of my struggle came from. For the most part, I look at CO2 as a byproduct of exercise intensity and breathe rate was a natural response to increase levels of oxygen. Where Nestor was trying to make the connection was this was with altered breathing anatomy; we have increased oxygen in normal functioning state, which obviously is problematic. The concept is about restoring balance, by lowering breathe rate, taking deeper breaths, and in turn lowering available oxygen and increasing carbon dioxide.
Shallow breath becomes problematic and leads to increased Sympathetic Nervous System (SNS) Tone. Being in a constant state of Sympathetic dominance leads to problems of health. Overly stressed leads to compromised immune system/metabolism/cognitive function. A really interesting point was that the nerve fibers for the SNS are towards the top of the lung. The Parasympathetic Nervous System (PNS) fibers are located towards the bottom of the lungs. Which means that shallow breathing reinforces SNS dominance. The association between increased breath rate and overly oxygenated and SNS dominance was a huge factor in relation to compromised health. The concept of CO2 being the end result of increasing PNS felt somewhat counter intuitive. He made the point that shallow/high frequency breathing is analogous to hyperventilating and drowning in oxygen.
Personally, I wish there were more on oxygen’s ultimate purpose was its relationship to carbon dioxide. Nestor did an incredible job of describing evolution’s role in anaerobic conversion to aerobic respiration. In my mind, this creates a symbiotic relationship between the two molecules in the body. I struggled with the concept that people should slow their breath work to increase CO2. I would have loved a mention of the relative role of CO2 with exercise. I think I would have either resonated or grasped how CO2 could be of value through an exercise discussion.
I did appreciate the dive into some fringe research on CO2 and health. A wider perspective is good. Myopically focusing on solely increasing the function of breath to increase O2 is obviously not the answer. Having a more robust cardiovascular function by using both CO2 and O2 is what matters. This could be considered having high developed anaerobic (CO2) and aerobic (O2) systems. We need to develop a more robust aerobic system by increasing the need for that. If we are relatively weak in aerobic metabolism, this will increase production of CO2. Balance is about understanding the strength of one system, which can come at the expense of its counterpart.
The book itself is definitely a good read. It’s well written. A great blend of personal and scientific. Most importantly, it challenged my notions on the relationship of CO2. Nestor mentioned that fat was predominantly (85%) released through respiration. I paused while reading that and harkened back to Respiratory Quotient and the relationship between CO2 and O2 and what fuel substrate is primarily used. An immediate flashback of being in Ex Phys class in both undergrad and grad school reigned over me. Recognizing that greater amounts of CO2 mean fat is more readily being used as a fuel substrate. It was so easy to jump to that conclusion that we need to exclusively interval based exercise to burn fat. Till we run into a brick wall of development and how we need to strategize that aerobic pathways will be the foundational piece of any anaerobic outcome we may want.