Oxygen Absorption Rate in Lungs | Lung Efficency at Capturing Oxygen
How efficient are our lungs in oxygen extraction?
What is oxygen absorption rate by the body and how efficient are your lungs at capturing oxygen from the air? The lungs oxygen retention rate in sick people and most modern people is much less than normal because they breathe much more than the medical norm (see links with dozens of studies below). Indeed, if they extract about the same total volume of oxygen as healthy people, their rate (percentage or efficiency) of extraction is much less. Let us consider these effects in detail. We can start with the normal values for breathing at rest.
Normal gas exchange parameters
Composition of outer or inhaled air:
Composition of the expired air:
From Summary of values useful in pulmonary physiology: man. Section: Respiration and Circulation, ed. by P.L. Altman & D.S. Dittmer, 1971, Bethesda, Maryland (Federation of American Societies for Experimental Biology).
During normal breathing, oxygen content in the inhaled air is 20.9%, while in the expired air is 15.3% (see above). Hence, 5.6% of air is extracted or captured as oxygen. This oxygen remains in the lungs and is used by the human body. If we multiply this result by 6 L/min (normal minute ventilation), it is equal to 336 ml of oxygen per min that is captured and retained by the human body.
How efficient are our lungs at capturing oxygen from the air?
Oxygen absorption in the body (in %) or the efficiency of extraction of oxygen from air is 5.6% (left in the lungs) divided by 20.9% (total oxygen in outer air). The result is about 27%. Hence, people with normal breathing parameters retain about a quarter of the oxygen, the remaining three quarters are exhaled back.
Why might some people be more efficient at capturing oxygen than others?
Since most people breathe much more than the medical norm, they capture much less of inhaled oxygen. Note that overbreathing also reduces O2 content in body cells and promotes chronic diseases.
Oxygen extraction rate in people with chronic diseases
People with chronic diseases breathe about 12-18 L/min (as we learned from the Minute Ventilation Table for the Sick) or about 2.5 times more than the norm. Since they have about the same metabolic rate or oxygen demands, chronic hyperventilators extract much less oxygen, and most of oxygen being exhaled back. In the severely sick oxygen retention can be only a few percent.
Oxygen capturing rate in very healthy people
Very healthy people breathe very little, down to about 1.5-2 L/min or only 3-4 breaths per min, as during deep menfdulness meditation or reduced breathing exercises popular among devoted Buddhists. The meditators and breathing students can extract close to 50% (or even more) of oxygen they inhale. The maximum value of the lungs oxygen extraction coefficient (or ideal oxygen extraction rate in humans) is probably close to 70%.
Chart: Efficiency of lungs at capturing oxygen from the air
The Chart below provides exact numbers for oxygen extraction rates in percents for different groups of people. It answers the question "Why can some people be more efficient at capturing oxygen in their lungs?". You can find the exact number for different groups of people including people with chronic diseases, most modern people, people with normal breathing, and finally very healthy people, including those who practice Buddhism. This Chart with all numbers is located right below here as your bonus content.
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