Understanding the biological process of respiration

There are two forms of breathing that you’ve likely heard about, diaphragmatic breathing and intercostal breathing. One is exactly as it sounds, breathing via the diaphragm. Intercostal breathing, means breathing via your intercostal muscles, which are located in the rib cage region (thoracic cavity).

Let’s try an interactive respiration exercise together. I want you to close your eyes and take in a long deep breath through your nose. From there, hold that breath in for as long as it feels natural (do not force yourself to hold your breath). Now, exhale the breath via your mouth. Did you feel your stomach expand? If so, that’s what we would consider diaphragmatic respiration

The calming effects of breathing are fascinating but not the only interesting aspect of respiration. Did you know, you just switched your breathing from an involuntary process to a voluntary process. This is one of the only systems in the body that allows you to take control on demand or slip back into the involuntary process. There are two systems that control respiration, the pre-Bötzinger complex and parafacial nucleus. The pre-Bötzinger complex is in charge of rhythmic breathing (rhythmogenesis), an example could be your typical inhale, exhale breathing patterns. The parafacial nucleus controls the voluntary process of respiration, for example if you consciously take two inhales. Our bodies are incredible, and typically both pathways are working in parallel to ensure continuous breathing with minimal disruption.

Now that we’ve discussed the mechanical aspect of respiration, we can discuss why breathing is a vital component for optimal health and how most of us breath very ineffectively.

We often hear about the negative effects that carbon dioxide has on our body and environment, but we rarely hear how its essential to effective oxygen absorption and brain function. Meaning, our bodies actually require carbon dioxide in order for us to absorb oxygen. When the carbon dioxide and oxygen ratio’s are imbalanced, two things can occur; There is not enough carbon dioxide present to liberate the oxygen from the hemoglobin in the blood, and thus you will have a reduction in oxygen to the brain. Additionally, it can cause restrictions in vasodilation, causing less blood flow to the brain. Both reduction in blood flow and oxygen to the brain can cause your brain to become hyper-excitable (meaning, that the neuron’s threshold for how active they can be, has been exceeded). Once the brain becomes hyper-excitable, consequences such as anxiety, difficulty learning and your ability to perceive threats in the environment is delayed.

So how do we avoid a hyper-excitable brain state? Breath less.

On average, you need approximately 6 litres/per minute of oxygen (which has been calculated to be about 12-13 shallow breaths). Most adults exceed 6 litres of oxygen per minute due to excessive shallow breaths (15-30 shallow BPM). This state is similar to hyperventilation, which in turn causes you to offload too much carbon dioxide and thus leads to the hyper-excitable brain state. Essentially, breathing less is the key. If we focused on deeper, longer inhales through the nasal pathway, and longer exhales; we could meet our target of 6 litres of oxygen per minute. The reason I noted to use your nasal pathway (which is diaphragmatic respiration) is because it creates greater air pressure in the lungs due to the resistance of air flow. This allows for you to bring in a higher volume of oxygen to the lungs.  Try it out, take a breath through your nose and then exhale. Now try taking a breath through your mouth. Which pathway brought in more oxygen?

So, the next time you are in a situation that brings you anxiety, stress or fear. Remember, breath..slowly.

Resources:

Effects of voluntary hyperventilation on cortical sensory responses Electroencephalographic and magnetoencephalographic studies (https://link.springer.com/article/10.1007/s002210050680)

Breathing Rhythm and Pattern and Their Influence on Emotion (https://www.annualreviews.org/doi/10.1146/annurev-neuro-090121-014424?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub++0pubmed)

Nasal Respiration Entrains Human Limbic Oscillations and Modulates Cognitive Function (https://www.jneurosci.org/content/36/49/12448)