The Bohr Effect

“Over the oxygen supply of the body carbon dioxide spreads its protecting wings”

The Bohr effect is named after the Danish physiologist Christian Bohr, who in 1904 discovered the relationship between carbon dioxide and the uptake of oxygen into the cells, tissue, and organs of the body. Understanding the Bohr Effect requires that we suspend our common understanding of breathing and oxygenation, as this is absolutely crucial for gaining a theoretical grasp of the Buteyko Method. Normally we think of breathing as the inhalation of oxygen (the good stuff), and the exhalation of carbon dioxide (the bad stuff), but this is an oversimplified description of the breathing process and does not take into account the real purpose of breathing, nor does it address how oxygen actually gets from the blood to where it is needed, ie the kidneys, liver, brain, etc.

To understand the Bohr Effect we must first understand what it is that we are breathing and what it is that our bodies require. The air we breathe is a mixture of nitrogen (78%), oxygen (21%), and traces of water vapor, carbon dioxide, argon, and various other components. The 21% oxygen that we breath provides us with more than enough of our actual need. However, what is unknown to most people is that the air we are breathing contains 200 times less carbon dioxide than what we need. The human organism requires approximately 6.5% carbon dioxide in the lungs and yet the air we breathe is only .034%. We are carbon dioxide rich relative to our environment. It therefore follows that if we over breathe or hyperventilate we will not gain any more oxygen than we already have because the air already has more than enough oxygen to meet our needs, but we will lose carbon dioxide. This would not be a problem if what most of what we were taught about carbon dioxide was true, that it is just a waste gas. However, this is where the popular understanding must be discarded and the true role of carbon dioxide needs to be comprehended.

Far from a waste gas, it is carbon dioxide that is responsible for the separation of oxygen from the hemoglobin in the blood so that it can be absorbed by the cells and tissues of the body. The hemoglobin in our blood is 98% saturated with oxygen, but without the proper level of carbon dioxide this oxygen remains bound to the red blood cells. So paradoxically, the more we over breathe, the more carbon dioxide we lose and therefore the less oxygen is actually absorbed into the body. Simply put, hyperventilation results in oxygen deficiency. The proper role of the respiratory system is not to simply pump air in and out of the lungs but rather to maintain the proper ratio of oxygen to carbon dioxide. When this ratio is disturbed, a whole range of illnesses and defense mechanisms that are usually confused for illnesses are the result.

In addition to the oxygenation of cells and tissues of the body, carbon dioxide also has several other important functions in the human organism. First, carbon dioxide in the form of carbonic acid is the central factor in the regulation of the body’s ph. If the carbon dioxide level is too low this will result in a shift of the ph toward alkalinity, which will weaken the immune system and make us much more vulnerable to allergies and viruses.

Carbon dioxide is also a smooth muscle dilator and is responsible for the aperture of all blood vessels, bronchi and bronchioles. High levels of carbon dioxide leads to the dilation of blood vessels and hence increased blood flow to the brain and the body’s organs. Likewise, the drop in carbon dioxide leads to constriction of blood vessels and a decrease in blood flow to the brain and organs, and places a strain on the heart as it faces more resistance in the pumping of blood. The spasming of blood vessels can result in a range of symptoms from migraine headaches to angina and even heart attacks and strokes. Low levels of carbon dioxide have a similar effect on bronchi, leading to constriction and spasming of the airways which results in the wheezing, breathlessnesses, and tight chest that is commonly experienced by asthmatics and those suffering from COPD.

Another important role of carbon dioxide is that of regulator and stabilizer of the nervous system. Carbon Dioxide is a natural tranquilizer of the nervous system. The effect of chronic hyperventilation and subsequent lose of carbon dioxide is a heightened excitability of the nervous system, which can lead to problems with anxiety, irritability, insomnia, and even paranoia and other mental and emotional disorders which greatly effect the quality of our lives and relationships.

These are just a few of the important functions of carbon dioxide in the human organism. Because of the relatively low amount of carbon dioxide in our environment, we have evolved lungs whose purpose is not to simply act to pump air in and out of the body, but rather to maintain the correct ratio of carbon dioxide and oxygen in the body, which in turn acts to regulate many important functions. The purpose of the Buteyko method is to correct dysfunctional breathing so as to bring this ratio into balance. With this understanding, we no longer see oxygen as “good” and carbon dioxide as “bad” or simply a waste gas. With an understanding of the Bohr Effect, we know that not only do we need carbon dioxide for many of the body’s functions, but that the very uptake of oxygen depends on the proper level of carbon dioxide. With this in mind we can accurately say that the optimal level of carbon dioxide equals the optimal uptake of oxygen.