- Updated on September 10, 2020
By Dr. Artour Rakhimov, Alternative Health Educator and Author
- Medically Reviewed by Dr. David Walker, CPA, Licensed Psychologist
Deep breathing and changes in brain/body oxygen
Most people believe in the benefits of deep breathing. They often say things like, “Take a couple of deep breaths – it will calm you down.” Such people often assume that breathing more air (and automatic, unconscious deep breathing) provides more oxygen to the human body. Most of them also think that CO2 is toxic. Many modern yoga books even state that CO2 is a wasteful gas.
The image on the left shows the effects of 1 minute of deep and fast breathing (more air is delivered to the lungs) on brain-oxygen levels.
Normal breathing, as medical textbooks claim, provides the arterial blood with nearly ideal or maximum possible oxygenation: about 98-99%.
How to get benefits of deep breathing
Some people imply that deep-breathing exercises and techniques should be very slow (as during correctly practiced hatha yoga Pranayama) so that one accumulates more CO2 in the blood. However, this type of breathing results in breathing less air (!) and therefore has completely different effects on body oxygen than the above-mentioned breathing pattern. This kind of breathing exercise is healthy and should not be called “deep breathing.” The correct terminology for breathing less air and accumulating CO2 is “reduced breathing.” The fact that no references to deep breathing can be found in classic yoga Sanskrit texts supports this statement. There is a link to a webpage that provides quotes from most famous ancient yoga texts about breathing. The link is provided right down here as your bonus content.
The following Yoga Benefits page provides the exact quotes.
For results of more than 40 clinical studies that measured breathing parameters in healthy people and people with diseases, see the Homepage of this site.
Pranayama, to be effective, should indeed be done as slowly as possible. (See Yoga web pages for details of traditional hatha yoga teaching and quotes from ancient Sanskrit manuscripts. The links to Yoga web pages can be found in the top menu.) Therefore, if we want positive biochemical changes in compositions of the predominant gases in the lungs and blood (carbon dioxide and oxygen), Pranayama or slow breathing exercises need to be shallow or focus on reduced breathing (after the practice the student should be breathing less air than before). As such, it is silly and above all incorrect to call any type of Pranayama a “deep breathing” exercise.
Therefore, any notion of deep breathing in the remaining part of this article will point to a way of breathing where more air is taken in, and more C02 is lost (reduction in alveolar CO2 levels). In medicine, this is called hyperventilation.
Scientific evidence about the dangers of deep breaths
“Cerebral blood flow decreases 2% for every mm Hg decrease in CO2” Professor E. Newton, Hyperventilation Syndrome, 2004 June 17, Topic 270, p. 1-7 (www.emedicine.com). This fact is based on tens of studies that prove the same fact: breathing more leads to less oxygen in body cells.
Many of these studies can be found on the CO2-Vasodilation web page (see links below) that provide tens of references proving that low arterial CO2 (hypocapnia) reduces blood flow for the brain, heart, kidneys, liver, colon, stomach, and other vital organs.
Deep breaths can be useful to detect symptoms
While deep breathing is damaging for your health, temporary deep breathing still has one useful application. It can be used in situations where certain parameters need to be tested. This kind of testing is called a hyperventilation provocation test or deep breathing test. The benefits of this test are in the immediate reproductions of symptoms of some chronic diseases (heart disease, asthma, panic attacks, epilepsy seizures, and some others). This deep breathing test has been used by hundreds of doctors for decades. It helps to discover the most vulnerable system or organ in people with many chronic conditions. The web page Hyperventilation Provocation Test provides numerous clinical studies and medical quotes.
Deep breathing can cause horrible chest pain
Angina pain is one of the most unpleasant pains. In 1997, the American Journal of Cardiology published results of a study with the title, “Hyperventilation as a specific test for diagnosis of coronary artery spasm” (Nakao et al., 1997). 206 patients with cardiovascular disease were asked to hyperventilate. All of them had angina pain due to coronary artery spasms and tissue hypoxia.
Even people without diagnosed heart disease can experience chest pain due to deep breathing that causes CO2 losses and body hypoxia. Others can experience back pain, spasm in the stomach muscles or other difficulties and problems due to the effects of hypoxia and hypocapnia.
Deep breaths cause breathing difficulties and coughing
People with respiratory conditions (such as severe asthma, bronchitis, emphysema, COPD, and so forth) often experience breathing problems or breathing difficulties since CO2 is a powerful bronchodilator. Therefore, overbreathing immediately causes bronchospasm and can cause less oxygen to get into the arterial blood since some bronchi and bronchioles can collapse completely. This is how they develop and worsen their health problems.
Millions of people are looking for benefits or advantages of deep breathing
Millions of people look for deep breathing exercises to cure their health issues (many among them are patients with heart failure). Others are looking for deep breathing to fight fatigue. Some medical doctors, nurses, and physiotherapists advise deep breathing or deep lumbar breathing to their patients. These medical professionals often encourage coughing, and deep breathing after surgery or deep breathing for patients with pneumonia inclining that deep abdominal breathing improves health. Thousands of ordinary people believe in deep breathing benefits. Most alternative health leaders are in the same state of confusion about the exact parameters of breathing for ideal health. Very few of them can answer a simple but important health question: “What unconscious breathing pattern provides us with maximum body oxygenation?”
Medical research studies and physiological science could not find any deep breathing benefits or advantages of hyperventilation. There is not a single study that has proven or shown that, in ordinary conditions, people need to get rid of as much carbon dioxide as possible or that there are some mysterious benefits of deep breathing. In fact, a human being will die within minutes if carbon dioxide levels drop to a quarter or fifth of the physiological norm.
Deep breathing during correctly performed Pranayama exercises, only looks deep to naive people. However, the goal of Pranayama is to accumulate CO2 by reducing minute ventilation. Hatha yoga masters should only have 1 breath per minute or even less during this yoga practice. See Yoga web pages for more detail.
At the same time, thousands of professional medical and physiological studies and experiments have proven the adverse effects of acute and chronic overbreathing (hyperventilation) and hypocapnia (low CO2 levels) on cells, tissues, organs and systems of the human organism. Many professional publications and available scientific evidence confirm the importance of normal carbon dioxide concentrations for various organs and systems in the human body. This website has hundreds of research papers that prove that carbon dioxide is a regulator of numerous vital processes (see links below). Most of all, low CO2 in the lungs causes low O2 levels in body cells.
The idea that deep breathing (or hyperventilation) is useful and beneficial for the body or mind is one of the greatest superstitions that exists among the general population in the West. This myth is also common among modern yoga teachers and can be found on their websites, articles, and books.
Especially in the medical sector, professionals should advise their patients appropriately. Patients with asthma, bronchitis, pneumonia, COPD, cystic fibrosis, or other respiratory problems, that have recently undergone surgery should be advised not to cough out their mucus or breath deeply. If they breathe less, their bodies will produce less mucus. Reduced breathing will also cause Cilia to work better to remove any existing mucus (since cilia also require more oxygen and blood supply for better work). Any deep abdominal breathing should only be done as an exercise and should be performed as slowly as possible with the purpose of increasing CO2 in the body. After such exercises, the patient should be breathing slower and less. Patients with pneumonia should follow the same rules if they want to improve their health. Deep breaths can only fight fatigue and heart failure if these patients accumulate more CO2 during the exercise and breathe less afterward, or even better, 24/7.
Historical roots of the deep breathing and CO2 myths
In the 1780s, French scientist Antoine-Laurent Lavoisier determined the composition of air. He also discovered the mechanism of gas exchange during respiration. Oxygen is consumed for the production of energy, and carbon dioxide is expelled as an end product. Many mice died in his classical experiments, where he put the animals in closed glass jars exposing them to an atmosphere that contained large quantities of carbon dioxide and almost no oxygen. Candles also quickly expired in such environments.
The superficial understanding of respiration that carbon dioxide is a gas that is “toxic, waste, and poisonous” and that oxygen brings life and vigor, probably started around that time in our history. “Take a deep breath,” “Breathe more air – it is good for your health,” “Breathe deeper, get more air in your lungs, we need oxygen,” etc. became popular phrases. Even now, some scientific publications contain such misleading sentences, as “Respiration is the process of oxygen delivery.”
Yale University Professor Yandell Henderson (1873-1944), the father of cardiorespiratory physiology and the author of the first physiological textbooks, gave the following explanation about this misconception:
“Likeness of Life to Fire. Lavoisier’s supreme contribution to science and particularly to physiology was the demonstration that, in their broad outlines, combustion in a fire and respiratory metabolism in an animal are identical. Both consist of the union of oxygen from the air with carbonaceous material: and both result in the liberation of heat and the production of carbon dioxide…
The human mind is inherently inclined to take a moralistic view of nature. Prior to the modern scientific era, which only goes back a generation or two, if indeed it can be said as yet even to have begun in popular thought, nearly every problem was viewed as an alternative between good and evil, righteousness and sin, God and the Devil. This superstitious slant still distorts the conceptions of health and disease; indeed, it is mainly derived from the experience of physical suffering. Lavoisier contributed unintentionally to this conception when he defined the life-supporting character of oxygen and the suffocating power of carbon dioxide. Accordingly, for more than a century after his death, and even now in the field of respiration and related functions, oxygen typifies the Good and carbon dioxide is still regarded as a spirit of Evil. There could scarcely be a greater misconception of the true biological relations of these gases…
PHYSIOLOGY. **Relations of Carbon Dioxide and Oxygen in the Body.**
Carbon dioxide is, in fact, a more fundamental component of living matter than is oxygen. Life probably existed on earth for millions of years prior to the carboniferous era, in an atmosphere containing a much larger amount of carbon dioxide than at present. There may even have been a time when there was no free oxygen available in the air. Even now, such animals as ascaris will live and be active in an atmosphere of hydrogen and entirely without oxygen”
Henderson Y, Carbon dioxide, in Cyclopedia of Medicine, ed. by HH Young, Philadelphia, FA Davis, 1940.
This YouTube video analyses deep breathing, breathing patterns, and corresponding oxygenation of tissues and explains that deep unconscious breathing reduces brain O2 content.