There is an interesting phenomenon around the word deep when it relates to our breathing – something of a cultural confusion. In general, for some unknown reason, people in our culture have erroneously equated the word deep as it applies to breathing as meaning something along the lines of “full” or “big.” If we look up the word deep in the online Oxford Languages Dictionary, we find that the word deep actually has two different meanings, the first, “extending down from the top or the surface” and the second meaning “very intense or extreme.” It turns out, that when it comes to our breathing, the difference between these two definitions is actually extremely important.
When we consider breathing, the concept of deep relating to depth or distance from the surface is an important one to grasp — as far from the surface of our nose, leads us down to our diaphragm. I often say one of the most interesting things about this fascinating and multi-faceted muscle – which is our primary muscle of respiration – is that few people use it optimally. You would think when it comes to the most important process we can consciously engage with in our body, that we would have some type of relationship with the muscle responsible for this action. For most people, this is simply not the case –and the diaphragm is left functioning at a fraction of its capacity or in a very dysregulated way.
The origins of the word diaphragm come from the root “fence” or “division”, and we have many different “diaphragms” in our body. When it comes to breathing the one that is most important is the thoracic or “respiratory” diaphragm which separates the upper torso containing the heart and lungs from the lower torso containing the abdominal organs. The pelvic diaphragm at the base of the torso and the diaphragm at the shoulders are also important and play a role in our breathing as well.
The thoracic diaphragm is a bit of an engineering marvel and is responsible for more than just our breathing. It is also an important postural muscle (which is why those that have poor breathing habits often experience low back pain), plays a role in assisting the closure of our esophagus at the stomach (which is why those that have poor breathing habits often struggle with acid reflux) and also helps us to “bear down” as we push out number 1 and 2 from our body (which is why those that have poor breathing habits may also suffer from digestive issues like constipation).
When it relates to breathing, the respiratory diaphragm receives a signal from the brain via the phrenic nerve which causes it to contract and push down towards the hips against the abdominal organs. When breathing is optimal, the pelvic floor (pelvic diaphragm) is also involved in that it opens and allows the abdominal contents to nestle down into it. The respiratory diaphragm then continues pressing down against them and this pressure causes the rib cage to open up and out with the help of the intercostal muscles in between the ribs. When the rib cage opens up, this causes air to flow in and fill the lungs. When the diaphragm relaxes back up, the rib cage softens back down and air is pushed back out.
As the respiratory diaphragm is comprised of skeletal muscle like the muscle fibres contained in our bicep, we can actually strengthen this muscle and refine it’s dexterity with practice – just like we can improve the functioning of our arm to throw a ball harder, softer or any other myriad of variations.
This is all great when our respiratory diaphragm is functioning properly. The issues arise when this muscle has gotten lazy, forgotten, frozen or has gone awry – in some cases even reversing its normal function in a process known as “paradoxical breathing.”
When we find ourselves in stressful, or overwhelming situations, one of the first things that happens is our breathing and the functioning of our diaphragm becomes affected. The diaphragm can get tense and frozen as we become fearful and sometimes that tension is not released from the body. The diaphragm can also get lazy from lack of use like any other muscle and becomes stiff and weak. Due to the fact that the diaphragm is the primary muscle of respiration and respiration is likely the most important action we can consciously control in our body – having a well functioning diaphragm is super important!!!
When our diaphragm is not functioning optimally, we tend to recruit other muscles in the chest, neck and shoulders to help us breathe, albeit very shallow focused mostly in the chest. This is ok in the very short term, but when it becomes a habit, these muscles simply aren’t designed to move up and down 20,000 ish times per day. These secondary muscles of respiration then become sore, tight, and exhausted from overuse and our breathing suffers as a result. This can make it very challenging to get a deep breath when we need to and can make exercise very challenging as well when we need to increase our respiratory volume to meet the energetic demands of the body.
In general, we want our breathing to be deep in the sense that it involves the respiratory diaphragm that is far from the surface as opposed to being very intense or extreme, because the respiratory diaphragm is also something of a hub in that central part of our torso. The diaphragm is wired in to the well known vagus nerve which plays a role in many of the functions of our body like heart rate, respiratory rate, digestion, etc. Most of the fibres of the vagus nerve run up from the lower part of the body, relaying information along this super highway from the gut to the brain.
The diaphragm has also been referred to as “seat of contemplation” or “second mind.” This lower mind is sending information up to our thinking mind and when our diaphragm is functioning well, this is all great. When our diaphragm is frozen or lazy from lack of use, it becomes a problem, because that second mind is sending signals to the thinking brain that all is not well downstairs. Likewise when we are breathing very intensely or in an extreme fashion as suggested by our alternate definition for the word deep. This causes our nervous system to become activated and can induce a fight or flight stress response which isn’t generally what most of us want or need more of in our lives. Likewise, when we take a deep breath with the second definition of “intense or extreme” or a big, full breath, we engage that same stress response within the body.
When we take a deep breath with the first definition of engaging the diaphragm which “extends from the surface” in a smooth and controlled way, this sends signals via the vagus nerve to the rest of the body and the thinking brain that “everything is ok.” We can think about the ideal action of our diaphragm looking like that of a jellyfish, moving gracefully up and down in the water. This action may be hard to recruit if we have long lost connection with our seat of contemplation, second mind and primary muscle of respiration. The degree of that movement is related to the energetic demands of the body and big is not always better when it comes to breathing. As I have discussed in some of the other posts, volume is important when it comes to breathing as well.
Nose breathing can help us more easily access the respiratory diaphragm — as can focused deep breathing exercises (consciously, in moderation) to loosen and strengthen the diaphragm. If we simply place our hands on our lower ribs and take a full breath in, we want to feel those lower ribs push out towards the sides. If this is challenging for us, like any other muscle, we want to practice that motion and build the strength and dexterity that will meet the demands of our breathing when we need it the most. Simply bringing more awareness to this area of the body can help us reconnect to this incredibly important and versatile muscle!