Most Common Cause of Cerebral Hypoxia (Low Brain Oxygen)

People with hyperventilation

(If you want to read about some pseudo-scientific situations that happens with cerebral hypoxia in citizens of the Moon, find and read Wikipedia articles. Here we focus on real Earth stuff.)

Over 90% people believe that a deep or heavy breathing pattern provides more oxygen for brain cells and vital organs. Moreover, over 90% of modern people "practice" hyperventilation 24/7 (see medical studies below). However, overbreathing reduces oxygenation of the human body and all vital organs causing cerebral hypoxia. There is no a single medical study, or physiologist, or medical doctor who has proven or shown that overbreathing improves cerebral or body oxygen levels or is good for us.

"Therefore, I emphasize the fact or law established long ago: the less the depth of breathing, the more the amount of oxygen delivered to the organism, and vice versa, the deeper the breath, the less oxygen is delivered in the organism." Dr. K. P. Buteyko, "Dr. Buteyko lecture in the Moscow State University on 9 December 1969"

Hyperventilation causes cerebral hypoxia (low brain oxygen) You can test these ideas in practice. If you or somebody else takes a hundred of deep and fast breaths, you can easily faint or pass out due to ... cerebral hypoxia or reduced oxygenation of the brain. Why? This picture shows brain oxygen distribution for normal breathing and after 1 minute of hyperventilation. O2 availability for the brain is reduced by about 40% as a result of 1 minute of overbreathing (hyperventilation).

Not only is oxygenation reduced, but glucose crucial to brain functioning is also significantly reduced due to cerebral vasoconstriction.

Cerebral vasoconstriction is a linear (dose-dependent) effect. Professor Newton from the University of Southern California Medical Center wrote, “cerebral blood flow decreases 2% for every mm Hg decrease in CO2” (Newton E, Hyperventilation Syndrome 2004 June 17, Topic 270, p. 1-7 - www.emedicine.com).

A typical sick person (with 12-18 L/min for minute ventilation rates) has, in average, around 20% less oxygen in the brain in comparison with the norm. Their cell oxygenation will be in between these 2 images.

Not only the brain, but all other vital organs will suffer from less oxygen in conditions of hyperventilation, as we are going to learn in the Section devoted to CO2 effects. Apart from the CO2-induced dilation of blood vessels, there is another powerful CO2 effect that also reduces oxygen delivery to cells: the Bohr effect (or Bohr law) that will be considered later. Hence, when we breathe more than the norm, less O2 is released in tissues by red blood cells.

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?

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