CO2, Blood pH and Respiratory Alkalosis: Causes and Effects

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- Updated on September 10, 2020

CO2, Blood pH and Respiratory Alkalosis: Causes and Effects 1By Dr. Artour Rakhimov, Alternative Health Educator and Author

- Medically Reviewed by Naziliya Rakhimova, MD

CO2, Blood pH and Respiratory Alkalosis: Causes and Effects

Proofread by Thijs Oosting Proofreader on Aug 30, 2019


Old man sleeps in hospitalBlood pH Respiratory Alkalosis is tightly regulated by a system of buffers that continuously maintain a normal range of PH 7.35 to 7.45 (slightly alkaline). When blood becomes more acid (Acidosis), it causes depression of the central nervous system.

When blood pH drops below 7 (severe Acidosis), it can lead to a coma and even death. High blood pH (above 7.45) is called alkalosis. Severe alkalosis (when blood pH is more than 8) can also lead to death. This is often the case during the last days or hours of life in people who are chronically and terminally ill.

Hyperventilation is the most common cause of respiratory alkalosis. Note that overbreathing is exceptionally common in people with chronic diseases (for clinical studies, see the Homepage of this site).

The main mechanisms for blood pH maintenance and control

Red blood cells – Carbonic Acid-Bicarbonate Buffer System
– Protein Buffer System
– Phosphate Buffer System
– Elimination of Hydrogen Ions via Kidneys

Carbon dioxide plays a central role in respiratory alkalosis. Note, however, that tissue hypoxia due to critically-low carbon dioxide levels in the alveoli is usually the main life-threatening factor for the severely sick. As we discussed before, CO2 is crucial for vasodilation and the Bohr effect.

Respiratory alkalosis caused by low CO2 in the arterial blood

This YouTube video clip “Hypocapnia, Respiratory Alkalosis: Key Causes of Deaths In the Most Sick” summarizes numerous epidemiological studies related to ineffective breathing in the severely sick and critically ill people. While oxygenation of cells is even more critical to those that are sick, their breath is undoubtedly fast and deep. 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 certain types of food can cause blood to become more alkaline or acidic. Even so, medical research studies have clearly shown that breathing, blood carbon dioxide, and bicarbonate ions levels have a more significant effect on blood-pH than food. Alveolar hyperventilation, a condition that is common in the sick, reduces cell oxygenation, increases resting blood lactate levels and intensify the production of free radicals due to tissue hypoxia (cells are deprived of oxygen). Moreover, hyperventilation causes diabetic ketoacidosis in genetically predisposed patients and suppresses the immune system and main blood-pH buffer systems of the human organism.

Carbon dioxide modelChanges in carbon dioxide and breathing cause immediate and long-term changes in blood pH. 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 the blood, is the second-largest group of negative ions of blood plasma. Hence, breathing has an immediate effect on blood pH. In order to have healthy body biochemistry, blood pH is tightly monitored within a very narrow range (from about 7.3 to 7.5) by a group of nerve cells located in the medulla oblongata. The same nerve cells control breathing through several independent mechanisms, including peripheral and central CO2 and O2 chemoreceptors.
Hence, arterial CO2 and carbon dioxide, through several independent biochemical mechanisms, can influence blood pH and cause respiratory alkalosis in patients with chronic diseases.

CO2, hypocapnia, and viscosity of blood

Respiratory AlkalosisCO2 also influences the viscosity of blood. Acute hyperventilation and arterial hypocapnia make blood more viscous. This effect is part of the fight-and-flight response (an immediate reaction to stress). While this is useful in the short run to prevent loss of blood (due to bleeding), increased blood viscosity produces a large strain on the heart and can cause other negative effects such as thrombosis (formation of blood clots).

The pH of urine and saliva are mainly controlled by breathing

Dr. KP Buteyko and over 180 of his medical colleagues also found out that CO2 controls and regulates the composition and properties of all other bodily fluids. This includes secretions of the stomach, composition, and properties of saliva, mucus, and pH of the urine. It is observed that for most people with hyperventilation issues, stomach and urinary pH is too low (too acidic), promoting the development of gastritis, ulcers and/or urinary stones. The pH of saliva can also be out of norms for people with low body oxygen levels, especially those with less than 20 seconds for the body oxygen test.
Millions of people try to improve their urinary or salivary pH using foods and supplements, usually without much success. But the answer is literally under your nose. You can find out how the results of the CP test in seconds relate to pH normalization in urine and saliva below in your bonus content.

As people increase their oxygen levels above 20+ s for the morning CP, it is common to see a noticeable improvement in pH numbers. They usually get twice as close to the norm. From 30+ s morning CP and a sensible diet, most people have a normal pH of saliva and urine.