Chapter 2: What is Rebreathing?
Everyone, no matter what their age or health, practices some measure of healthy rebreathing at all times. We have done this from the time we were born and will continue until the day we die. It is a simple fact that not all of the air we breathe out, actually gets out. Some air only makes it as far as the throat or mouth cavity, and then is redrawn back into our lungs along with the new fresh air. Some air actually makes it to the outside of our mouth or nose, but then is immediately redrawn (before it has time to mix with the outside air). Therefore when we breathe in, some of the air is new fresh air, while some is redrawn partially spent air (lower in oxygen and higher in carbon dioxide). The act of inhaling again that air which had just been in our lungs, throat and mouth is considered as rebreathing. While we all practice rebreathing, the term “rebreathing” can at some times refer to healthy rebreathing which we all do, while at other times it can be considered depleted and insufficient. For the purposes of this writing I will be using the term “depleted rebreathing” as it reflects upon that situation whereby, through the process of breathing, insufficient new fresh air is being inhaled into the lungs. As a consequence, with each new breath, oxygen is being depleted in the lungs, while carbon dioxide is accumulating, resulting in potential harm to a child or individual. Where I am referring to rebreathing that occurs normally and is of no risk or damage to a person, I will refer to that as normal or healthy rebreathing.
Fortunately, when enough new fresh air is drawn in and mixed with the air that has been redrawn (perhaps a 90 to 10 ratio of new air to redrawn air), there is sufficient oxygen in the lungs to supply the blood with oxygen. The lungs are always a place where oxygen and carbon dioxide coexist. What is significantly important is the proportion or ratio of oxygen to carbon dioxide as there are a range of ratios that are safe, healthy and comforting, while likewise there is a range that is discomforting, deficient and harmful. Let me repeat this. There is oxygen and carbon dioxide in the atmosphere all around us, and there is oxygen and carbon dioxide in our lungs as well. What is important is that there is a proper and sufficient mix of these two in our lungs at all times. How fast we breathe, and/or how deeply we breathe, regulates this mixture.
When the carbon dioxide level gets too high in our lungs, we normally experience a level of discomfort which causes us to breathe quicker, or deeper, or to take an occasional deep cleansing breath, eventually resulting in a reduction of that discomfort. The arcuate nucleus has been speculated as being that part of the brain that may control breathing through our level of discomfort. By holding your breath or breathing excessively, you will experience that discomfort which will persuade you to adjust your breathing to achieve a proper balance between oxygen and carbon dioxide in the lungs. Still little is known about this process, but it is considered that sensors within the lungs signal to the arcuate nucleus, which in turn will cause us to experience the discomfort, which causes us to change our breathing patterns until we regain comfort.
If an insufficient volume of fresh air is drawn in (as is considered for those events where a newborn’s breathing is partially blocked because they are sleeping on their tummy with their mouth and nose forced into the bedding) resulting in perhaps a deficient 10 to 90 ratio of new air to redrawn air, the oxygen content in the lungs can become increasingly depleted and the carbon dioxide content can become excessive. This reduction in oxygen and increase in carbon dioxide may occur with each successive breath to the point that it is no longer healthy for the child, and from some point onward the child is suffering harm. This unfortunate situation can continue if the child does not adjust to the situation, perhaps because they are unaware of the situation due to a malfunctioning (premature) system that doesn’t signal an adjustment for a proper air mix in the lungs, or because the child is physically unable to take deeper breaths or unable to move to improve their situation. It is my contention, and I believe that of many others, that if this continues for a period of time, the result will be death; and that this death is considered as a SIDS death.
To repeat, depleted rebreathing is simply the event where insufficient new air is being drawn into the lungs of a newborn to the point that it is harming the child. I wish to add here that depleted rebreathing can occur to older children and adults who sleep with their heads underneath their bedding. This is what I will argue is a significant cause of Alzheimer's disease.
You may ask why depleted rebreathing in infants younger than one year occurs resulting in harm to the child, while older infants may not experience depleted rebreathing? What is happening within this pre one year old age group (it can happen for some who are slightly older than one year, as well)? Shortly we will look at those conditions that could enable this to occur. However, first I would like to explain why I consider depleted rebreathing to be the cause of SIDS.