We use the word breath most often to refer to the air we pull in to and pump out of our lungs (or to the action of doing so) as in “Take a deep breath.” But we also give the same word loftier qualities in phrases such as “the breath of life” and in practices like yoga that emphasize breath awareness as a source of health and peace. Other traditions and languages have similar words for breath in both these ordinary and spiritual senses, such as Latin spiritus, Hebrew ruach, and Chinese qi.
But what about the breathing body itself? Unless we are wheezing or short of breath and a doctor checks us out, we usually take the smooth coordination of our lungs, diaphragm, membranes, blood cells, as unremarkable compared to the loftier significance of breath that we might hear about in yoga class or worship service.
We might refocus our wonderment for a moment. The air is, when you come down to it, just a mix of gasses, but our body’s ingenious respiration of them is something to appreciate.
We breathe in air because, as we know, it contains one gas that we must have: oxygen. Less familiar, though, is the step-down system that has evolved to make the most of the fact that, like all gasses, oxygen spreads out from wherever it is most densely packed to where it is less so. Thanks to the step-down process and our blood stream, we move oxygen from the air outside of us to everywhere it has to go inside us, which is to our several trillion—that’s 000,000,000,000—cells.
Why oxygen? Its electrons are arranged in such a way that it interacts eagerly and often with other elements. It’s a potent extrovert. Our cells may get their nourishment from the food molecules they take in but not unless they also have oxygen handy to break the food molecules down. That would be like our eating dinner without having any stomach acid to digest it. No nourishment. Without oxygen, cells go hungry.
But a little oxygen goes a long way. That helps make the step-down process possible. The numbers surprised me. For starters, only about twenty percent of the air that we breathe is oxygen. The rest is nitrogen and a percent or two of other gasses. And of that oxygen that we do take into our lungs, we actually use only about a quarter of it. The rest goes out again when we exhale.
Once it is in our lungs, oxygen must get across the thin lung membrane to the blood stream that will move it around the body. The oxygen in the lung is much denser than whatever oxygen is left in the blood that is returning from the cells through the veins. So the new oxygen spreads easily across the membrane—stepping down—to the oxygen-depleted blood where it hooks up with empty hemoglobin molecules in the blood cells.
As this convoy of oxygenated blood flows near, say, our fingers, the oxygen detaches from the hemoglobin, steps down across the membrane of the cell itself (because there is less oxygen inside), and goes to work on the food particles.
In the process, extrovert that it is, oxygen combines with the unusable carbon dioxide, crosses the cell membrane back out to some empty passing hemoglobin, gets off at the lungs, and then back out to air. Like taking the empty bus back home at the end of a long day.
I argue for the wonderment of a distribution system that pulls in air-borne oxygen in an endless rhythm and is arranged so that the oxygen disperses itself across strategic membranes and loads itself on to the blood for transport to a million million cells that it will help nourish, after which it returns the way it came in. Our stunning respiration makes oxygen look good—even divine.