The Bohr Effect in Simple Terms
It is essential for our body to maintain a normal arterial blood pH of between 7.35 and 7.45 and our survival instinct makes sure of this, so how does breathing and carbon dioxide fit into this equation?
CO2 is a major factor in keeping these levels regulated and as it is a weak acid it can combine readily with water to form carbonic acid, breaking down even further into bicarbonates ions if blood acidity is too high, attempting to increase alkalinity. Carbon dioxide is easily maintained or removed by the automatic altering of our breath, so this proves to be a vital way to make sure that our pH levels stay healthy. If levels are unable to be regulated by breathing the kidneys will take over in this process of compensation. Perhaps one of the most well known published explanations of the capabilities’ of carbon dioxide is by the early 20th century Danish scientist Christian Bohr, his discovery is known as ‘The Bohr Effect’.
Based on scientific fact, The Bohr Effect reveals to us that how we may feel when we breathe a certain way, doesn’t correspond with the actual reality of what is happening inside our body. For example, when we breathe deeply and more air than is needed is delivered, our tissues cells actually become starved of oxygen. The same is true when taking in too little air as this creates insufficient oxygen in the bloodstream; again the result is less oxygen in tissues. The Bohr effect is a phenomenon that simply states, “Haemoglobin's oxygen binding affinity is inversely related both to acidity and to the concentration of carbon dioxide”.
Haemoglobin molecules are constantly releasing oxygen therefore they cannot ever be 100% saturated, it is not possible to improve the collection of O2 by Haemoglobin which one might believe they are doing when increasing their breathing volume. One molecule carries a maximum of 4 oxygen molecules , their bond is as tight as can be, only releasing when the conditions are ideal ie: dependent on the production of carbon dioxide.
If during an asthma attack, airways constrict and carbon dioxide levels plummet, Respiratory Alkalosis can occur, haemoglobin becomes viscous and unable to release its oxygen to the tissues, the knock on effect means that now less carbon dioxide is produced. Through this process we can see how easily The Bohr Effect can send one spiralling down and into a vicious cycle of decreasing co2 levels and lack of oxygen release. With particularly severe asthma (Status asthmaticas) there may come a point where the bloodstream cannot gain sufficient oxygen and carbon dioxide cannot get out. The gases literally cannot exchange due to the plugging of mucous and as they are cut off from ventilation sections of the lungs will collapse .
So how can we formulate therapy through understanding these events?
Breathe Well Buteyko training is essentially a non-invasive ventilation treatment for asthma suffers, increasing carbon dioxide levels to normal and reducing the chronic and unconscious over breathing that always precipitates an attack. Many studies have reported that, on average, asthmatics are breathing 2-3 times the volume of air per minute (up to 14 litres) than those without asthma (4-6 litres) and generally through their mouths instead of noses (as well as having a predisposition to the asthma gene). Through awareness of The BOHR Effect we know how critical carbon dioxide is and for many regulatory processes in the body. Using a bronchodilator during an attack is an effective way to quickly open the airways and prevent further CO2 loss though relief may be temporary as medications do wear off and can also unfortunately precipitate further attacks by allowing more over breathing and CO2 loss through newly opened airways.
Yet another disturbing and dangerous cycle.
While Buteyko practitioners do not in any way advise on medication reductions or change, most asthmatics that practice the Buteyko technique find that as their CO2 levels rise and breathing normalises, symptoms tend to disappear on their own, as does the need for any medications.
