When we breathe in, we take up oxygen and release carbon dioxide from our blood. Our blood is usually already fully saturated with oxygen (about 99% saturation) and breathing deeply does not raise that saturation. Breathing deeply does, however, release a lot of carbon dioxide. This, in turn, lowers the “urge to breathe”.
The brain stem, specifically the pons and medulla oblongata, is sensitive to carbon dioxide. Having too much carbon dioxide in the blood will trigger your brain stem to breathe. By removing carbon dioxide from the blood through deep breathing, this impulse to breathe from the brain stem is lowered.
In short, the lower the level of carbon dioxide, the longer you can hold your breath. The impulse is just not triggered yet.
Furthermore, by systematically and deeply breathing in and out, the pH-value in the blood increases (making the blood more alkaline) whereas the acidity lessens. Normally, on average the pH-value is 7.4. By exerting the breathing techniques, this becomes significantly higher and can even go up to 7.75. As a result, 3 important physiological changes happen:
You can experience lightheadedness, as the arteries and veins to the brain and body close slightly in reaction to the alkalizing blood. You can experience a tingling sensation in the limbs and muscles, due to the lowering of the available calcium ions in the blood. Removing free calcium ions increases muscle excitability.
The red blood cells carrying oxygen have a difficult time releasing their payload of oxygen. Why? Because acidity normally triggers the release. If the blood is too alkaline the oxygen bound to the red blood cell does not release. This makes that the cells and tissues can’t receive oxygen even though blood oxygen saturation is at 100%. The oxygen is simply “stuck” to the red blood cell. This is also known as “Hypoxia”, which is defined as a deficiency in the amount of oxygen reaching the tissues.
This might sound scary, but this mild hypoxic state caused by the controlled deep breathing is soon back to normal again. At the final deep breath, breathing out and holding the breath will allow the blood to re-establish acidity and allow red blood cells to begin releasing their oxygen. Whilst holding the breath, no new oxygen comes back into the blood. As a result, oxygen saturation in the blood lowers and lowers as the body uses it up. Remember, there is also less carbon dioxide which makes the breath holding easier as well!
The body is now experiencing a short-term form of hypoxia, which is a form of stress at the cellular level. Cells are not getting the normal levels of oxygen and their metabolism begins to shift. This stress will signal the body to react and strengthen. The body’s sympathetic responses is activated and the pathways necessary to deliver that oxygen to cells are strengthened. These pathways could include a number of different systems, such as increasing red blood cells, increasing lung capacity, improved circulation and improved metabolic efficiency over the long term.
This short-term period of hypoxia is a positive stressor. It signals the body to react and strengthen and to better deal with stress in the long term. How does this work?
Let’s take a look at Radboud’s endotoxin study (2014) where they measured trained participants performing the breathing technique. Their blood first alkalized through the breathing, and then acidified during the breath hold, releasing the oxygen to the tissue and lowering blood oxygen saturation. The breathing technique was performed for multiple rounds, lowering and lowering blood oxygen saturation at every round!
Another interesting physiological effect of the breathing method is the increased level of adrenaline in the blood. The Radboud study recorded such large amounts of adrenaline in its participants, it is speculated that the breathing method had an influence on the adrenal medulla, located in the adrenal gland. This is one of the most abundant sources of adrenaline in the body and given the elevated levels the study recorded in the participants, it would make sense the breathing method had an influence over this important sympathetic response. An influence we didn\'t think was possible before the Radboud study!
The breath is powerful. Your experience with it can be a very deep one. Bubbling up the unconscious mind, breaking stale patterns and powerfully experiencing one’s vitality. Enjoy its depth.
