Lungs Oxygen Extraction Rate: Healthy vs. Sick
How efficient are our lungs in oxygen extraction?
What is the
percentage of oxygen that is extracted from the outer air? The lungs oxygen absorption 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 remains in the lungs or 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 air per min that remains in the human body.
Normal lungs oxygen extraction rate (in %)
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), or about
27%. Hence, people with normal breathing parameters retain about
a quarter of the oxygen, the remaining three quarters are
exhaled back.
Lungs oxygen extraction rate in most modern people
As we previously learned, normal
subjects or ordinary modern people breathe about 12 L/min at rest: see Hyperventilation:
Over 90% Prevalence in Normal Subjects (24 medical publications). Since the oxygen demands of modern people at rest are about the same as
for people with normal breathing, modern people have reduced coefficient of
extraction of oxygen from air. In average, it is about 13-15%.
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 only 10% of oxygen, 90% of oxygen in exhaled back. In the severely sick it can be only 5% or less.
Oxygen extraction rate in very healthy people
Those very healthy people, who breathe very little (down to about 1.5-2 L/min or only 3-4 breathe per min), can extract over 50% or more of the oxygen they inhale. The maximum value of the lungs oxygen extraction coefficient (or ideal oxygen extraction rate in humans) is probably close to 70%.
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For more details about respiratory parameters and various health zones, visit the web page with the Buteyko Table of Health Zones. Breathing less also means much fewer toxic fumes, dust particles, pollens, and other dangerous substances from air. This is another reason to learn how to breathe less. |
Check your rate of lungs oxygen extraction using the body oxygen test done after usual exhalation. The normal CP test result is 40 s, which corresponds to 27% for oxygen absorption in the body. The formula is simple: divide your CP in seconds by 40 seconds and multiply by 27%. |
Summary for efficiency of extraction of lungs oxygen
| Health state of people | Oxygen extraction in the lungs |
| People with chronic diseases | Less than 10% |
| Most modern people | About 10-20% |
| People with normal breathing | 27% |
| Very healthy people | Over 50% |
These ideas
about oxygen extraction efficiency in the lung help us to understand why it
is much easier to exercise when we get higher CP. With higher CPs, we start to
extract more oxygen at rest. During exercise, changes in the CO2 level in the
arterial blood are relatively small and, therefore, if we breathe lighter just
before the exercise, we continue to have lighter breathing during exercise as
well (even with unhealthy mouth breathing).
Vice versa, sick people breathe heavier before exercise in the state of rest. Hence, their arterial blood CO2 remains low during exercise too due to heavy panting. Moreover, due to cellular hypoxia and anaerobic energy production mechanism in mitochondria, they generate too much lactic acid during intensive exercise causing severe respiratory distress due to unproportionally heavy breathing.
Reference Web Pages: Breathing norms, Medical Graphs and Tables about Breathing Rates (Minute Ventilation) and
Body Oxygen in Healthy, Normal and Sick People
Breathing
norms Parameters, graph, and description of the normal
breathing pattern
6 breathing myths 6
myths about breathing and body oxygenation (prevalence: over 90%)
Hyperventilation Definitions of
hyperventilation: their advantages and weak points
Hyperventilation Syndrome in the
Sick. Table
1. Western scientific evidence about prevalence of CHV
(chronic hyperventilation) in patients with various chronic conditions
(34 medical studies)
Normal Minute Ventilation in
Healthy Subjects: Easy and Light Breathing (14 Studies)
Hyperventilation Prevalence Present in Over 90% of
Normal People (24 medical publications)
HV and hypoxia
How and why deep breathing reduces oxygenation of cells and tissues of
all vital organs
Body oxygen test
How to measure your own breathing and body oxygenation (a simple DIY test)
Body oxygen in healthy
Table 4. CP (body oxygen level) in healthy people (27 medical
studies)
Body oxygen in sick Table 5.
CP (body oxygen level) in sick people (14 medical studies)
Buteyko
Table of Health Zones with clinical description of most common zones
Morning HV Morning
hyperventilation effect or how and why critically ill people are most
likely to die during early morning hours
References: CO2 Effects Web Pages
Vasodilation: CO2 expands arteries and arterioles facilitating perfusion
(or blood
supply) to all vital organs
The Bohr effect
How and why oxygen is released by red blood cells in tissues
Cell Oxygen Levels and oxygen transport are controlled by
alveolar CO2 and breathing
Oxygen Transport depends on
breathing and these two effects (Vasoconstriction-Vasodilation and the Bohr
effect) are parts of two diagrams that summarize influences of hypocapnia (low CO2
content in the blood and cells) on circulation and O2 delivery
Free Radical Generation takes
place due to anaerobic cell respiration caused by cell hypoxia. Hence,
antioxidant defenses of the human body are also regulated by CO2 and breathing
Inflammatory Response is controlled by
breathing since hypoxia leads to or intensifies chronic inflammation through over-expression
of the hypoxia-inducible factor 1, while normal
breathing reduces these processes
Nerve stabilization takes place due to calmative or
sedative effects of carbon dioxide in neurons or nerve cells
Muscle relaxation or relaxation of muscle cells
is normal at high CO2, while hypocapnia causes muscular tension, poor posture
and, sometimes, aggression and violence
Brochodilation - dilation of
airways (bronchi and bronchioles) by carbon dioxide, and their constriction due
to hypocapnia
CO2: Best Natural Cough Suppressant
and "home remedy" since it calms urge-to-cough nerve receptors located in the
tracheobronchial tree and larynx
Blood
pH regulation and regulation of other bodily fluids
CO2: Lung Damage Healer: Elevated carbon
dioxide prevents injury and promotes healing of lung tissues
CO2: Skin and Tissue Healer
Synthesis of Glutamine
in the Brain, CO2 fixation, and other chemical reactions
CO2 myth
"CO2 is a toxic waste gas" myth
Breathing control
How is our breathing regulated? Why hypocapnia makes breathing uneven and erratic?
Go back to Types of Breathing Patterns and Body Oxygenation
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