CO2, Blood pH and Respiratory Alkalosis
Blood pH is tightly regulated by a system of buffers that
continuously maintain it in a normal range of 7.35 to 7.45 (slightly
alkaline). Blood pH drop below 7 can lead to a coma and even death due
to severe acidosis. This causes depression of the central nervous
system. High blood pH (above 7.45) is called alkalosis. Severe
alkalosis (when blood pH is more than 8) can also lead to death, as it
often happens during last days or hours of life in most people who are chronically and
terminally ill.
Hyperventilation is the most common cause of respiratory alkalosis.
The main mechanisms for blood pH
maintenance and control are:
- Carbonic Acid-Bicarbonate Buffer System
- Protein Buffer System
- Phosphate Buffer System
- Elimination of Hydrogen Ions via Kidneys
Carbon dioxide plays one of the central roles in this blood pH abnormality. Note, however, that tissue hypoxia due to critically low carbon dioxide level in the alveoli is usually the main life-threatening factor in the severely sick. As we discussed before, CO2 is crucial for vasodilation and the Bohr effect.
The main conclusion that relates to breathing in the severely sick is that their breathing is very fast and deep, while oxygenation of cells is critical. This is the reason why regardless of the health condition critically ill patients are often provided with pure oxygen. You can read all these medical abstracts on the web page How do we breathe when we die?
Many people believe that if you eat certain foods, it can cause your blood to become more alkaline or acidic. Medical research studies have clearly shown that breathing and blood carbon dioxide and bicarbonate ions levels are more significant factors in blood pH control. Alveolar hyperventilation that is common in the sick reduces cell oxygenation, increases resting blood lactate levels, intensifies production of free radicals due to tissue hypoxia (cells are deprived of oxygen), causes diabetic ketoacidosis in the genetically predisposed patients, and suppresses the immune system and main blood pH buffer systems of the human organism.
Changes in carbon dioxide and breathing cause immediate and long-term
effects of blood pH. They are not necessary the same. The immediate
effects are simple: higher CO2 content causes blood acidification and
pH decrease, while reduced carbon dioxide levels increase blood pH often causing
death in the critically ill (see a review of medical studies below).
Long term effects depend on the direction of change (moving closer to
normal breathing or not), genetic factors, existing pathologies, diet,
physical exercise, thermoregulation, and many other parameters.
CO2 gas, when dissolved in blood, is the second largest group of negative ions of blood plasma. Hence, breathing directly affects blood pH. In its turn, blood pH is tightly monitored within a very narrow range (from about 7.3 to 7.5) by the group of nerve cells located in the medulla oblongata in order to have normal body biochemistry. The same nerve cells control breathing by through several independent mechanisms, including peripheral and central CO2 and O2 chemoreceptors.
It is not a surprise that even mildly sick patients suffer from blood pH abnormalities due to breathing since they breathe about 2-3 times more than the medical norm. For review of 34 medical studies click here (the Table with minute ventilation data).
Hence, arterial CO2, carbon dioxide, through several independent biochemical mechanisms can influence blood pH and causes respiratory alkalosis in patients with chronic diseases.
CO2, hypocapnia and viscosity of blood
CO2 also influences viscosity of blood. Acute hyperventilation and
arterial hypocapnia makes blood more viscous. This effect is a part of the
fight-and-flight response (an immediate reaction to stress). While useful in
a short run to prevent blood losses due to bleeding, increased blood
viscosity produces a large strain on the heart muscle and causes other
negative effects leading to, for example, thrombosis (formation
of a blood clot).
Dr. K. P. Buteyko and his colleagues also found that CO2 controls and regulates composition and properties of many all other bodily fluids, including secretions of the stomach, composition and properties of saliva and mucus, pH of the urine. For example, for most people, in conditions of hyperventilation, stomach and urinary pH become too low (too acidic) promoting development of gastritis and ulcers, or urinary stones.
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?
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
Back to Effects of carbon dioxide on human health
| Disclaimer | Copyright © 2011 Artour Rakhimov | About Artour | Contributions | Contact details | Promote this site |