CO2, Blood pH and Respiratory Alkalosis: Causes and Effects
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. 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
- 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 respiratory alkalosis. 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.
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. 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.
Hence, arterial CO2, 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
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. KP Buteyko and over 180 of his medical 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. Apart from respiratory alkalosis, there are many other negative effects of overbreathing.
Reference pages: Breathing norms and medical facts:
- Breathing norms: Parameters, graph, and description of the normal breathing pattern
- 6 breathing myths: Myths and superstitions about breathing and body oxygenation (prevalence: over 90%)
- Hyperventilation: Definitions of hyperventilation: their advantages and weak points
- Hyperventilation syndrome: Western scientific evidence about prevalence of chronic hyperventilation in patients with chronic conditions (37 medical studies)
- Normal minute ventilation: Small and slow breathing at rest is enjoyed by healthy subjects (14 studies)
- Hyperventilation prevalence: Present in over 90% of normal people (24 medical studies)
- HV and hypoxia: How and why deep breathing reduces oxygenation of cells and tissues of all vital organs
- Body-oxygen test (CP test) : How to measure your own breathing and body oxygenation (two in one) using a simple DIY test
- Body oxygen in healthy: Results for the body-oxygen test for healthy people (27 medical studies)
- Body oxygen in sick : Results for the body-oxygen test for sick people (14 medical studies)
- Buteyko Table of Health Zones: Clinical description and ranges for breathing zones: from the critically ill (severely sick) up to super healthy people with maximum possible body oxygenation
- Morning hyperventilation: Why people feel worse and critically ill people are most likely to die during early morning hours
References: pages about CO2 effect:
- 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: How alveolar CO2 influences oxygen transport
- Oxygen transport: O2 transport is controlled by vasoconstriction-vasodilation and the Bohr effects, both of which rely on CO2
- Free radical generation: Reactive oxygen species are produced within cells due to anaerobic cell respiration caused by cell hypoxia
- Inflammatory response: Chronic inflammation in fueled by the hypoxia-inducible factor 1, while normal breathing reduces and eliminates inflammation
- Nerve stabilization: People remain calm due to calmative or sedative effects of carbon dioxide in neurons or nerve cells
- Muscle relaxation: Relaxation of muscle cells is normal at high CO2, while hypocapnia causes muscular tension, poor posture and, sometimes, aggression and violence
- Bronchodilation: Dilation of airways (bronchi and bronchioles) is caused by carbon dioxide, and their constriction by hypocapnia (low CO2)
- Blood pH: Regulation of blood pH due to breathing and regulation of other bodily fluids
- CO2: lung damage: Elevated carbon dioxide prevents lung injury and promotes healing of lung tissues
- CO2: Topical carbon dioxide can heal skin and tissues
- Synthesis of glutamine in the brain, CO2 fixation, and other chemical reactions
- Deep breathing myth: Ignorant and naive people promote the idea that deep breathing and breathing more air at rest is beneficial for health
- Breathing control: How is our breathing regulated? Why hypocapnia makes breathing uneven, irregular and erratic.
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