In the previous section we began to look at how when we are functioning optimally our breathing will naturally adapt perfectly to the demands placed upon us. In particular we looked at how the location of the expansion caused by our breathing changes depending on the amount of load or level of activity of the body. There are actually four ways in which our breathing will change to adapt to the demands placed upon us.
- Location of expansion
As has already been mentioned, when the body is at rest, the expansion will be lower down in the body in the abdomen, when the body is active or has high levels of demand on it the expansion will be higher up in the ribcage and shoulders. This is primarily for structural reasons. When the body can allow itself to be relaxed and loose, the flexible abdomen is able to expand and contract more which is the easiest way for us to breathe. As the body needs to become stiffer to brace for load, the abdomen has to contract harder to support the spine and the expansion needs to move upwards into the stiffer ribs and shoulders.
- Speed of breathing
The lower our activity level, the less our need for oxygen, so in general the slower we will breathe. The higher our activity level, the greater our need for oxygen to fuel our activity and in general the faster we will breathe.
In order for us to inhale, our postural muscles need to relax and lengthen in order to accommodate the expansion caused by breathing. To exhale our postural muscles contract to reduce the space in the body and empty the lungs. We have already looked at this in terms of the TVA muscle with abdominal breathing, and the same is true of the other postural muscles. So for structural reasons, in general when we are more relaxed, our inhalations will be longer as our body can afford to let the postural muscles lengthen and relax for longer periods of time without risk of harm, and when we are more active our exhalations will be longer as our body needs the postural muscles contracting more of the time to help support motion and protect the body.
You can think of it a bit like eating habits. When you’re on holiday you likely spend more time eating, because you don’t have as many other demands on your time as usual and eating requires you to relax and take time out from other things. This is like inhaling. When you are working really hard and are really busy, it is likely that you only take quick meals as this is all the time you can spare before getting back into the other things you need to do.
- Mouth or Nose
In really simple terms, our nose is a smaller hole than our mouth, so when our activity levels are lower and we don’t need as much oxygen we will tend to breathe through our nose, and when our activity level is greater and we need more oxygen we will tend to breathe through our mouth.
There are a couple of other good reasons why we tend to breathe through our noses more when relaxed and through our mouths more when we have high activity levels.
Behind the nose there is a cavity with several turbinates in it. These structures cause turbulence in the air as it passes by them causing any impurities to come into contact with the mucus membranes lining this cavity, allowing them to be filtered out. These tissues have a spongy type of structure which can easily fill with large amounts of blood. The high level of blood flow in this area helps to warm and humidify the air to the right level before it continues down to the lungs.
This filtering and humidifying of the air makes it easier for the lungs to process making it the preferable way to breathe whenever possible, but it also slows the flow of air down significantly. So when the body’s requirement for quantity outstrips its need for quality, it will switch over to mouth breathing, allowing it to pass much more air in and out of the lungs quickly.
There is also another benefit to breathing through the mouth when the body has high levels of physical demand put on it. The filtering mechanisms in the cavity behind the nose create back pressure to the flow of air out of the lungs. This back pressure and slower flow of air means that when breathing through the nose there is a very low risk of the lungs emptying too quickly and collapsing. On the other hand, the free flow of air when breathing through the mouth creates very little back pressure. This means that sudden loads or impacts on the body could more easily cause a rapid emptying of the lungs and possibly collapse. To prevent this from happening, the body naturally activates the postural muscles more when breathing through the mouth so that they are ready to brace and protect the lungs from sudden emptying. This greater muscle activation leads to greater strength which is useful if this is required to meet the demands being placed on the body.
All of these changes tend to occur grouped together. So when we’re most relaxed, we will breathe through our noses, this will tend to cause expansion mostly in our lower abdomen, it will be slow and the inhalations will be quite long. When we’re most active, we will tend to breathe through our mouth, the expansion will be more in our ribcage or shoulders, our breathing will be fast and the exhalations will be quite long. There are also many possible combinations of these factors that can occur on the continuum of activity levels between very relaxed and very active depending on the specific demands placed on the body.
Understanding these relationships can help us to use our breathing to support our desired physical and psychological state. By consciously choosing how we breathe we lead our body and mind towards our desired state in a particular situation.