Deep Breathing Dangers and Benefits
Deep breaths and changes in brain/body oxygen
Most people believe in benefits of deep breathing. They say, "Do any deep breathing since it is good for you". These people also assume that breathing more air and automatic (unconscious) deep breathing provides us with more oxygen, while CO2 is toxic. Even modern yoga books say that CO2 is a waste gas.
The image on the left shows effects of 1 minute of deep and fast breathing (more air is delivered to the lungs) on brain-oxygen level.
Normal breathing, as medical textbooks claim, provides the arterial blood with nearly ideal or maximum possible oxygenation: about 98-99%.
How to get deep breathing benefits
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, such breathing means breathing less air (!) in comparison with the previous breathing pattern. This is a healthy "deep breathing" exercise, although it is wrong to call it "deep breathing". If you breathe less and accumulate CO2, the correct name is "reduced breathing". By the way, classic yoga Sanskrit texts do not have any references about deep breathing. This Yoga 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, indeed, in order to be effective, should be done as slowly as possible. (See Yoga web pages for details of traditional hatha yoga teaching and quotes from ancient Sanskrit manuscripts. The link to Yoga web pages is in the top menu.) Therefore, if we consider biochemical changes in compositions of main gases in the lungs and blood (carbon dioxide and oxygen), Pranayama or slow breathing exercises are examples of shallow or reduced breathing (breathing less air than before the practice). As a result, it is silly to call Pranayama a "deep breathing" exercise.
Therefore, in the remaining part of this article, deep breathing will mean breathing more air with reduction in alveolar CO2 levels? In medicine, it is called hyperventilation.
Scientific evidence about 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 proved the same fact: more breathing means less oxygen in body cells.
Many of these studies can be found on CO2-Vasodilation web page (see links below) that provides 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 cause symptoms
However, there is one real advantage of deep breathing. It is called 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 effects of hypoxia and hypocapnia.
Deep breathing causes breathing difficulties and more coughing
Those people who have some 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 less oxygen gets 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 search for deep breathing exercises for heart failure patients. Others are looking for deep breathing to fight fatigue. Some medical doctors, nurses, and physiotherapists demonstrate deep breathing or lumbar deep breathing to their patients. These medical professionals encourage coughing and deep breathing postoperatively or deep breathing for patients with pneumonia fantasizing 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 exact parameters of breathing for ideal health. Very few of them can answer a simple but important health question: "Which unconscious breathing pattern provides us with maximum body oxygenation?"
Medical research studies and physiological science could not find any deep breathing benefits or advantages. There is not a single study that have 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 level drops to a quarter or fifth of the physiological norm.
Deep breathing during correctly done Pranayama only looks deep for naive people. In fact, the goal of Pranayama is to accumulate more CO2 due to reduced minute ventilation. Hatha yoga masters should have only 1 breath per minute pr 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 importance of normal carbon dioxide concentrations for various organs and systems in the human body. This website has hundreds of research papers that have proven 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.
Belief in the usefulness and benefits of deep breathing (or hyperventilation) is one of the greatest superstitions that exists among the general population in the West. Deep breathing myth is also common among modern yoga teachers and can be found on their websites, articles and books.
Therefore, it is suggested that patients with asthma, bronchitis, pneumonia, COPD, cystic fibrosis, and other respiratory problems must not practice coughing out their mucus and deep breathing postoperatively. If they breathe less, their bodies will produce less mucus and cilia will work better to remove any existing mucus (since cilia also require more oxygen and blood supply for better work). Any deep abdominal breaths should be done as slowly as possible, only as an exercise, with the purpose to increase CO2 in the body and breathe slower and less later. Patients with pneumonia should follow the same rules, if they want to improve their health. Deep breaths can fight fatigue and heart failure only if these patients accumulate more CO2 during exercise and breathe less afterwards or, even better, 24/7.
Historical roots of the deep breathing myth and CO2 myth
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. In his classical experiments, mice died in a closed glass jar in an atmosphere containing large quantities of carbon dioxide and almost no oxygen. A candle also quickly expired in this air.
That was probably the time when a superficial understanding of respiration produced the idea that carbon dioxide was “toxic, waste, and poisonous” gas while oxygen brought life and vigor. “Take 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, the author of the first physiological textbooks gave the following explanation of this ignorance,
“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 in 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 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 analyzes deep breathing, breathing patterns, and corresponding oxygenation of tissues and explains that deep unconscious breathing reduces brain O2 content.
Reference pages: Breathing norms and the DIY body oxygen test:
- Breathing norms: Parameters, graph, and description of the normal breathing pattern
- Body-oxygen test (CP test) : How to measure your own breathing and body oxygenation (two in one) using a simple DIY test
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 body tissues
- Nerve stabilization: Carbon dioxide has powerful calmative and sedative effects on brain neurons and nerve cells
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