The first thing that comes to mind when the inhaled air-components are mentioned is Oxygen. In fact it is equally important to sustain the right concentration of carbon dioxide for the healthy cells. In a healthy small air sacs inside the lungs there are around 6.5% of carbon dioxide compare to 0.03% in the air we breathe.
Overbreathing is seriously affecting that level of necessary carbon dioxide in the lungs. (This also known as hyperventilation.) The common myth is that the deeper one breathes, the more oxygen one can get into the body-cells. The contrary is the truth. If the carbon dioxide is not at the normal level of apr. 6.5 % in the air sacks and falls below this level through over-breathing, then the oxygen is not entering with the high enough concentration into the blood and to make things even worse, the oxygen carried by the haemoglobin molecules (which are part of the red cells of the blood) will be more trapped as the lowered level of carbon-dioxide strengthen the bond between haemoglobin molecules and oxygen, thus lowering the oxygenation of the tissues. (this is the Verigo - Bohr effect) The tissues of the body then become starved of oxygen (known as Hypoxia).
Oxygen starvation negatively effects all the cells, tissues and vital organs. The asthmatic person experiences a shortness of breath sensation that creates an even further over-breathing stimulation which further deepens the breath. Tissues starved of oxygen then become irritable and the smooth muscle found around bronchi and bronchioles react by going into spasm (an asthma attack). Also decreased carbon dioxide causes increased production of histamine - a potent bronchoconstrictor and also causes underlying inflammation.
Overbreathing upsets the normal acid/alkaline (pH) balance of the blood and as a result the body becomes far more alkaline than normal. This is known as respiratory alkalosis. To correct this the body produces lactic acid to try to balance the pH of the blood and correct the alkalosis. This disturbs the body's metabolism, resulting increased allergies, susceptibility to viruses, tiredness and of course asthma. If breathing is not corrected back to shallow breathing then hypertension could occur that can lead to further deteriation of asthma, sclerosis (hardening) of blood vessels and lungs, myocardial infarction (heart attack) and strokes. These are the body's very defence mechanism against the excessive loss of carbon dioxide.
In a terrible Catch of 22 situation, when suffering an asthma attack, asthmatics try to overbreathe even more in panic, that further increases the alkalosis leading to a worsening in the severity of asthma. The only solution to stop this cycle is to educate the over-breathers so that they can breathe in a shallower way - as the purpose of the Buteyko method, so the body-functions can return to normality over time.
