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  • Writer's pictureMax

The Science of Breathing

Updated: Nov 18, 2020

Who would have thought that we need to consider breathing, it is something that takes care of itself. When we need oxygen we breath in and out, as we exercise we breath quicker, thereby getting more oxygen in to our bodies allowing us to continue to exercise. What if this was wrong? What if we turn the sentence around and consider that it is not the consumption of oxygen rather the removal of used air.

First consider the mechanics of breathing. Breathing is so natural that we don’t even really think about it, but it is amazing, all a result of air pressure and the difference between our internal pressure and the external pressure. Generally, this takes care of itself.

To breath in, our diaphragm is pulled down and contracts, our external intercostal muscles contract and pull our rib cage up and out. Simultaneously, our internal intercostal muscles relax and allow our ribcage to move up and out. This action increases the size of our thoracic cavity, decreasing the pressure within the lungs. This allows air to move into our lungs, pulled in by the difference in air pressure between the air around us and the internal pressure. As we want to breath deeper, the diaphragm is pulled down further, our intercostal muscles contact further increasing the difference in air pressure.

Breathing out happens in reverse, causing an increase in the air pressure within the thoriac cavity which is higher than the air around us, causing air to leave our lungs.

With me so far? Nothing said will change your understanding of breathing, yet.

Now what causes fatigue?

A number of things, well four to be slightly more precise, cause fatigue;

1. A build up of lactic acid.

2. An increase in muscle carbon dioxide (CO2).

3. Lack of energy sources to resynthesise ATP (Anodose Tri Phosphate).


Breathing helps with the first three;

1. Lactic acid is broken down with oxygen and when enough oxygen is present lactic acid is not produced (aerobic glycolis). And if we exercise below our lactate threshold, lactic acid is not an issue.

2. Oxygen can replace the CO2 within the muscles, provided we have sufficient oxygen available to replenish the muscles store of oxygen.

3. Our aerobic system can provide an almost unlimited supply of oxygen and the ability to resynthesise ATP. Provided we work within our aerobic threshold and have enough of a food supply to support this, we can continue to exercise for a very long period of time.

Now consider numbers two and three. If we can speed up the removal of carbon dioxide we can exercise at a higher intensity for longer.

Does that change how you think about your breathing?

Let’s just change the focus of breathing when we exercise, rather than breathing in and taking in more oxygen, we focus on breathing out. Getting rid of the carbon dioxide to allow our muscles to better absorb the oxygen.

In practice, rather than focusing on the breathing in, remember above, that takes care of itself, focus on forcefully breathing out, breathing out the carbon dioxide that is causing the fatigue within our muscles. There is loads of oxygen in the air (about 21%) and the air we breath out is still (about 17%) oxygen rich.

Now do we think about our breathing differently? Focus on breathing out.


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