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By Dr. Artour Rakhimov, Buteyko breathing teacher and educator

Breathing education
Part 9. Evolution of air on Earth and its impact on our breathing?

Click on the picture (on the right side) to watch the video clip "Evolution" (it will open in a new window).

How is it possible that a human being, one of the smartest species on Earth, can kill itself, and over 90% people die this way, by over-breathing? Is it nature so silly to create this way? In order to answer these questions we need to consider changes in air composition on Earth.

When there were no life on Earth, air has no oxygen (since oxygen is a very reactive substance), while CO2 was a part of the volcanic gases that formed air during those times. Geological studies suggest that CO2 concentration was up to 10-12% or even more. Thus, when the first organic substances and life forms appeared on Earth (from about 5 billion to 1 billion years ago), our atmosphere did not have any measurable amounts of O2, according to Professor Maina (Maina, 1998), who wrote the book The gas exchangers: structure, function, and evolution of the respiratory processes about development of respiration and breathing in various creatures living on Earth in the past and now. He is one of the leading modern authorities on respiration of different life forms.
Appearance of the first vertebrates (about 550 millions years ago) and the development of prototypes of human lungs took place when air was made up of only about 1% O2, while having much higher percentage of CO2 (Maina, 1998), likely over 7%. Normal air today has many times more O2 (about 20%) and only a fraction of the CO2 (0.03%). However, our cells now still live in the air that existed hundred millions years ago: “But the cells of animals and humans need about 7 % CO2 and only 2% O2 in the surrounding environment. This is the way how our cells live: cells of the heart, brain, and kidneys” (Buteyko, 1977).
Hence, most of the time our lungs were developing and evolving in conditions when the CO2 content was high (up to 7-12% during the first stages of development), with gradual decline, and low O2 values (about 1% or less during the first stages). During these stages the process of control of breathing by the nervous system was also developed. Since this primitive air had very little O2, our evolutionary predecessors could get more oxygen in tissues by breathing more. Since any stressful situation, digestion, search for food, mating, playing, and any other activity required more oxygen, hyperventilation became the fundamental reflex or instinct. Only totally peaceful stress-free rest had low metabolic rate where heavy breathing would not give any advantage for survival.
On the other hand, however heavy was breathing of these primitive creatures in the past, they would still get the main nutrient, CO2, from air. The CO2 content in tissues had to be even higher than in air and these creatures would never develop spasms of coronary vessels, bronchi, other smooth muscles, or abnormal excitability of the nerve cells, or muscular tension or any other above-mentioned negative effects. Hence, nature did provided primitive creatures with ability to function without all above-discussed physiological flaws.
However, the main parameter of our environment, our air, had dramatic change during later stages of our evolution due to advance of green life that transforms CO2 into O2 during photosynthesis. These events could be reflected on the following picture.

Fig 1.1 CO2 and O2 values in air during early stages of development of our lungs, in our cells now and in modern air.

We can see that air had dramatic change during evolution. It now has too much oxygen and almost no CO2. Hence, the chief parameter of our environment (we can survive for days or weeks with no water or food, but only for minutes with no air) became abnormal in its composition. It is only existence of our lungs that protected us from extinction. Nature could not anticipate this cardinal change in air, but it did provide us with the means for survival.

For the list of the quoted references click here

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