Shortness of Breath Causes: Chest Breathing, Low Body O2

What Causes Shortness of Breath?

Shortness of breath causes related to those factors of mechanics of breathing that relate to ineffective breathing patterns. Ineffective breathing reduce oxygen delivery to body tissues. Among the common breathing abnormalities are mouth breathing (e.g., on exertion or during sleep) and thoracic (of chest) breathing. Both causes of shortness of breath drastically reduce oxygen transport to cells. Chest breathing does not provide oxygen for lower parts of the lungs that get about 6-7 times more blood than the top portions of the lungs due to gravity.

Brain oxygen levels for normal breathing and after hyperventilation However, the main cellular cause of shortness of breath is due to the predominant hypoxic drive (oxygen drive) caused by tissue hypoxia (low oxygen levels in cells). Breathing of healthy people is mainly controlled by CO2 levels in the blood and brain. Oxygen drive is about 50-100 times weaker. For example, if the surrounding air composition changes to 100% O2, the person would not notice that. However, in CO2 levels in air is increased just by 1%, there is an immediate increase in minute ventilation that is noticeable for the person and surrounding people.

In sick people, the situation is different. Due to low levels of oxygen in the brain (see the image on the left), oxygen drive becomes the main factor that controls breathing. Why do sick people have low brain oxygenation? This table explains why the main causes of shortness of breath relate to tissue hypoxia.

Minute ventilation rates (chronic diseases)

Condition	Minute ventilation	Number of people	All references or click below for abstracts
Normal breathing	6 L/min	-	Medical textbooks
Healthy Subjects	6-7 L/min	>400	Results of 14 studies
Heart disease	15 (±4) L/min	22	Dimopoulou et al, 2001
Heart disease	16 (±2) L/min	11	Johnson et al, 2000
Heart disease	12 (±3) L/min	132	Fanfulla et al, 1998
Heart disease	15 (±4) L/min	55	Clark et al, 1997
Heart disease	13 (±4) L/min	15	Banning et al, 1995
Heart disease	15 (±4) L/min	88	Clark et al, 1995
Heart disease	14 (±2) L/min	30	Buller et al, 1990
Heart disease	16 (±6) L/min	20	Elborn et al, 1990
Pulm hypertension	12 (±2) L/min	11	D'Alonzo et al, 1987
Cancer	12 (±2) L/min	40	Travers et al, 2008
Diabetes	12-17 L/min	26	Bottini et al, 2003
Diabetes	15 (±2) L/min	45	Tantucci et al, 2001
Diabetes	12 (±2) L/min	8	Mancini et al, 1999
Diabetes	10-20 L/min	28	Tantucci et al, 1997
Diabetes	13 (±2) L/min	20	Tantucci et al, 1996
Asthma	13 (±2) L/min	16	Chalupa et al, 2004
Asthma	15 L/min	8	Johnson et al, 1995
Asthma	14 (±6) L/min	39	Bowler et al, 1998
Asthma	13 (±4) L/min	17	Kassabian et al, 1982
Asthma	12 L/min	101	McFadden & Lyons, 1968
COPD	14 (±2) L/min	12	Palange et al, 2001
COPD	12 (±2) L/min	10	Sinderby et al, 2001
COPD	14 L/min	3	Stulbarg et al, 2001
Sleep apnea	15 (±3) L/min	20	Radwan et al, 2001
Liver cirrhosis	11-18 L/min	24	Epstein et al, 1998
Hyperthyroidism	15 (±1) L/min	42	Kahaly, 1998
Cystic fibrosis	15 L/min	15	Fauroux et al, 2006
Cystic fibrosis	10 L/min	11	Browning et al, 1990
Cystic fibrosis*	10 L/min	10	Ward et al, 1999
CF and diabetes*	10 L/min	7	Ward et al, 1999
Cystic fibrosis	16 L/min	7	Dodd et al, 2006
Cystic fibrosis	18 L/min	9	McKone et al, 2005
Cystic fibrosis*	13 (±2) L/min	10	Bell et al, 1996
Cystic fibrosis	11-14 L/min	6	Tepper et al, 1983
Epilepsy	13 L/min	12	Esquivel et al, 1991
CHV	13 (±2) L/min	134	Han et al, 1997
Panic disorder	12 (±5) L/min	12	Pain et al, 1991
Bipolar disorder	11 (±2) L/min	16	MacKinnon et al, 2007
Dystrophia myotonica	16 (±4) L/min	12	Clague et al, 1994

We see that all these groups of patients suffer from chronic hyperventilation or alveolar hypocapnia (CO2 deficiency) in the lungs. Normal breathing in healthy people is imperceptible: it is small and light (500 ml for tidal volume and 6 L/min for minute ventilation at rest for a 70-kg person). Hyperventilation leads to tissue hypoxia (or low cell oxygen levels) regardless of arterial CO2 changes and the presence of the ventilation-perfusion mismatch.

The main causes of shortness of breath: hyperventilation and chest breathing

Secondary causes of shortness of breath

Overheating, meals (or overeating), anxiety, and exertion all lead to hyperventilation (and alveolar hypocapnia). Therefore, these are other lifestyle-related shortness of breath causes. The factors that increase the work of breathing are constriction of airways due to alveolar hypocapnia, chest breathing (due to spasmodic Group of medical people diaphragm), obstruction of airways due to mucus and inflammation and increased blood viscosity. Mouth breathing worsens breathlessness due to reduction in NO (nitric oxide) absorption and reduced alveolar CO2.

Numerous medical studies have found that exertion (or physical exercise), stress, anxiety, meals (or eating), overheating, attempts to breathe deeply, deep breathing exercises, night sleep, poor posture, pregnancy and many other factors causes shortness of breath. All these factors also intensify breathing and reduce alveolar CO2 levels through overbreathing. Therefore, it is logical that these factors cause shortness of breath.

People with shortness of breath generally have less than 10-14 seconds for the body oxygen test. These are very poor results since the normal result is about 40 seconds. The main symptoms of shortness of breath disappear, when they get about 20-25 seconds for the body oxygen test. This is based on experience of thousands of people, as well as results of the published Ukrainian clinical trial on cancer (see Cancer Section). Hence, both physiological and clinical considerations clearly demonstrate that low cell oxygenation, due to chest breathing, possible mouth breathing and hyperventilation are the causes of shortness of breath.

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

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
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

References (shortness of breath or breathlessness)

Thorax. 2011 Mar;66(3):240-6.
Neural respiratory drive, pulmonary mechanics and breathlessness in patients with cystic fibrosis.
Reilly CC, Ward K, Jolley CJ, Lunt AC, Steier J, Elston C, Polkey MI, Rafferty GF, Moxham J.

Rev Esp Cardiol. 2005 Oct;58(10):1142-4.
[The circulating NTproBNP level, a new biomarker for the diagnosis of heart failure in patients with acute shortness of breath].
[Article in Spanish]

Aust Fam Physician. 2005 Jul;34(7):541-5.
Shortness of breath - is it chronic obstructive pulmonary disease?
McDonald CF.
Institute for Breathing and Sleep, Austin Hospital, Heidelberg, Victoria, Australia.

Int J Cardiol. 2002 Sep;85(1):133-9.
Origin of symptoms in patients with cachexia with special reference to weakness and shortness of breath.
Coats AJ.

Medsurg Nurs. 2000 Aug;9(4):178-82.
Helping patients with COPD manage episodes of acute shortness of breath.
Truesdell S.
Division of Pulmonary and Critical Care Medicine, Henry Ford Hospital, Detroit, MI, USA.
The most disabling and frightening symptom experienced by patients with COPD is dyspnea. Even with the use of bronchodilators, the symptom may not be completely relieved. Patients often develop their own strategies for managing shortness of breath, including the use of a breathing technique called pursed-lip breathing. Although most nurses are familiar with this breathing technique, they often have difficulty assisting patients to use it during acute episodes of shortness of breath. A strategy is described which nurses can use to assist patients in implementing pursed-lip breathing effectively during episodes of acute dyspnea.

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