The Science of Breathing Retraining
Breathing retraining defined
The primary goal of breathing retraining is to normalise each aspect of the breathing pattern (rate, rhythm, volume, mechanics and use of the nose), for all situations (awake, asleep, at rest, during eating, speech and exercise). The specific goal of breathing retraining is to achieve physiologically normal breathing.1
The Buteyko Method of breathing retraining
The Buteyko Method of breathing retraining is named after the Russian physician and medical researcher Konstantin Pavlovich Buteyko, 1923–2003.
It is based on his research into the link between breathing dysfunction and a range of breathing-related disorders. Our breathing retraining programmes are based on those developed by KP Buteyko to help alleviate symptoms caused by dysfunctional breathing.
The mechanism by which dysfunctional breathing and over-breathing (hyperventilation) disturb the balance of oxygen and carbon dioxide in airways and blood is described in medical text books and nicely summarised in these two tutorials:
K P Buteyko, 1923–2003
A pattern of over-breathing, where the depth and rate are in excess of metabolic needs of the body at that time.2 During hyperventilation the rate of removal of carbon dioxide from the blood is increased. As the partial pressure of carbon dioxide in the blood decreases, respiratory alkalosis, characterised by decreased acidity or increased alkalinity of the blood, ensues. In turn, alkalosis causes constriction of the small blood vessels that supply the brain.3
The Bohr Effect
At the end of the 19th Century, carbon dioxide was found to influence the bond between oxygen and haemoglobin. If the levels of carbon dioxide in arterial blood are lower than normal, this leads to difficulties in releasing oxygen from haemoglobin. This is known as the Bohr Effect, first described by Christian Bohr in 1904.
The Bohr Effect and the oxy-haemoglobin dissociation curve
The Bohr Effect states that in the presence of carbon dioxide, the oxygen affinity for haemoglobin decreases. In other words, an increase in blood carbon dioxide level and corresponding decrease in blood pH causes haemoglobin to bind to oxygen with less affinity. This effect facilitates oxygen transport as hemoglobin binds to oxygen in the lungs, but then releases it in the tissues, particularly those tissues in most need of oxygen. This is because when a tissue's metabolic rate increases, its carbon dioxide production increases.
In addition to this, loss of carbon dioxide during hyperventilation can trigger smooth muscle to constrict around airways and blood vessels, reducing the availability of oxygen to the brain and body tissues. This can trigger constriction of bronchi and bronchioles, experienced as chest tightness in asthma and contributes to nasal congestion.4, 5
The chemistry of respiration
Breathing disorders such as asthma, sinusitis and hay fever may be considered as a consequence of hyperventilation/over-breathing.4, 5, 6 Over-breathing disturbs the balance of oxygen and carbon dioxide in our lungs and blood vessels.7
To understand the hazards of over-breathing (hyperventilation) it is necessary to cover some basic principles of respiration and the essential role of carbon dioxide.
Respiration serves to deliver oxygen to cell tissues where it is needed and to remove excess carbon dioxide via the lungs. Oxygen is transported within red blood cells in the blood attached to haemoglobin molecules or oxy-haemoglobin. Each haemoglobin blood protein can carry up to four oxygen molecules. Oxygenated blood is circulated with great precision to those parts of the body where it is most required.
By ingenious design, the cells neediest of oxygen are those that produce the most carbon dioxide, carbon dioxide being a by-product of cellular metabolism. Carbon dioxide diffuses across the cell membrane into the blood vessels. The increase in carbon dioxide saturation of the blood acts as a vasodilator (relaxing the smooth muscle in the blood vessels) ensuring the free flow of oxygenated blood to the oxygen-hungry tissues. In addition to this, elevated carbon dioxide levels in the blood facilitate the release of oxygen from haemoglobin; this is known as the Bohr Effect.
The hazards of hyperventilation
Anyone who has experienced dizziness or "seen stars" after a violent fit of coughing, blowing up party balloons or an air mattress will be familiar with the effect that breathing too much air has on reducing oxygen supply to the brain. If breathing large volumes of air is supposed to be beneficial, why does it make us dizzy?
Hyperventilation, or over-breathing, does not add oxygen to arterial blood. This is because under normal physiological states arterial blood is close to saturation with respect to oxygen and is simply not able to absorb more.
Normal oxygen saturation values are 97% to 98% in a healthy individual.
However, over-breathing depletes carbon dioxide in airways and arterial blood producing a condition known as hypocapnia. Hypocapnia reduces oxygen availability to our cells in two ways:
- As blood levels of carbon dioxide drop during hyperventilation, smooth muscle can constrict around blood vessels restricting the flow of oxygenated blood to the tissues.
- Lower levels of carbon dioxide dissolved in the blood shift blood pH towards a state known as respiratory alkalosis and the haemoglobin which transports oxygen in the blood binds more tightly with the oxygen reducing its release to the body tissues.
Over-breathing and cerebral hypoxia
The figure below shows how even a few minutes of over-breathing (hyperventilation) can starve your brain of oxygen. If one minute of hyperventilation can do this, imagine the toxic effect on your body from a lifetime of over-breathing.
Functional MRI scan of a human brain showing oxygen saturation of haemoglobin.
Red and yellow areas correspond to highest oxygen saturation of haemoglobin
The left-hand image shows normal oxygen saturation in a healthy breather's brain. The right-hand image shows oxygen availability in the brain is reduced by 40% as a result of about a minute of over-breathing (hyperventilation). Not only is oxygen availability reduced, but glucose critical to brain functioning is also markedly reduced as a result of cerebral vasoconstriction (from Litchfield 2003).8
In summary: If we breathe within normal parameters, this mechanism works very well to deliver oxygen to brain and body tissues. By contrast, over-breathing (i.e. breathing more than the physiological norm) can upset this delicate balance, thereby reducing oxygen delivery to cells and potentially resulting in a range of possible compensatory mechanisms.
Over-breathing and its effects on health
Over-breathing can trigger asthma attacks, panic attacks, migraines and exacerbate a range of disorders including breathlessness, shortness of breath, asthma, hypertension, heart palpitations, irregular heartbeat, dizziness, spacey feelings, tingling in hands and feet, numbness, light headedness, fatigue, sleep apnoea, cold hands and feet, digestive disorders including gastric reflux, bloating, irritable bowel and stress disorders.
The scientific basis linking dysfunctional breathing to these symptoms and disorders is documented in numerous studies and medical text books and explained in our introductory seminars. Copies of published research and studies are available on request. You will also find many of these in the section for health professionals on this website.
At the Buteyko Breathing Clinic we can help you enjoy restful snore-free sleep, relieve symptoms of asthma and other respiratory disorders, reduce stress and enjoy better health and well-being by helping you change the way you breathe.
Read feedback from Buteyko Breathing Clinics' clients and clinicians »
If I had to limit my advice on healthier living to just one tip, it would be simply to learn how to breathe correctly.
Dr Andrew Weil
I now understand that the stress of daily life promotes deep breathing – a bad habit fortified by the widely prevailing notion that moving a lot of oxygen into our lungs is a good thing.
Professor, King's College London
1 Adapted from: Graham, T. Relief from Snoring and Sleep Apnoea. Penguin Aus., 2012, Chapter 10 - The breathing retraining approach
2 Chaitow L, Bradley D, Gilbert C. Multidisciplinary Approaches to Breathing Pattern Disorders. Harcourt 2002
4 Sterling, GM., Clin Sci, 1968 vol 34
5 van den Elshout, FJJ et al., Thorax, 1991
6 Adelola O.A., Oosthuiven J.C., Fenton J.E. Clin Otolaryngology.2013
7 Laffey JG, Kavanagh MB N Engl J Med, V 347 2002
8 Litchfield P.M. A brief history of the chemistry of respiration and the breathing heart wave. California Biofeedback.Vol 19 No.1 (Spring 2003)