Breathing does not only take in air — a rhythm that continues even while you sleep
The short answer
Can breathing affect the body beyond taking in oxygen? It creates a pressure rhythm through the trunk and helps venous return, but breathing alone cannot explain several symptoms; sudden breathlessness or chest pain needs assessment first.
Contents
We breathe about twenty thousand times a day.
When I ask why we breathe, most people answer this way: "To take in oxygen." That is right. But what breathing does does not end there.
What a single breath does inside the trunk
The diaphragm is the muscular sheet that divides the chest from the abdomen. Breathe in, and it descends.
When it does, the pressure above it, inside the chest, falls; the pressure below it, inside the abdomen, rises. A single breath creates a rise and fall of pressure through the whole trunk.
Plenty of other things make pressure in the body. There is posture and gravity, there is movement, there is the beating of the heart and the churn of the gut. Measured per event, breathing does not even come out ahead. There are measurements showing that one large shoulder movement puts more pressure on the abdomen than a quiet breath does.
What sets breathing apart is not force but the fact that it does not stop. Movement is occasional, digestion happens when you eat, and posture holds a mostly constant direction. Breathing carries its rhythm on through the moment you fall asleep. Twenty thousand times a day.
The rhythm that helps blood return
The heart pushes blood out powerfully. But the blood coming back is a different matter.
Several forces combine to bring the blood in the veins back to the heart. The pressure left in the vessels pushes it along, the leg muscles squeeze it with every step you take, and breathing is laid on top of that. When you inhale and the pressure inside the chest drops, venous blood is drawn a little more readily toward the heart.
This is called the respiratory pump. It does not mean breathing is the lead actor. It means it is one force among several — one that stays on all day without a break.
The brain has a flow too
This part is interesting lately.
The brain and spinal cord are bathed in cerebrospinal fluid. This fluid does not sit still and pool; it flows — and that its flow moves along with breathing has been confirmed in people. It is a study that watched forty-five people with real-time MRI.
What is interesting is the design of it. The study compared people who had long practiced a traditional Korean breathing discipline against people who had not, and what lined up well with cerebrospinal fluid flow was the length of the inhale and the distance the diaphragm descended.
Whether that flow also washes waste out of the brain is still mostly animal data. What has been confirmed in people is that the flow rides on breathing. That is as far as what we know now goes.
Not a switch that turns the autonomic nervous system on
Breathe in and out, and the heart rate speeds and slows fractionally. The phenomenon has been known for a long time, and that breathing slowly and deeply raises vagal activity at the heart has also been confirmed in people.
Even so, breathing is not a switch that turns the autonomic nervous system on and off. A considerable share of vagal tone is generated independently of breathing. Breathing is not the place where the autonomic nervous system is decided; it is closer to one of the few handles we can consciously reach. I find that more useful, not less.
When someone comes in about a shoulder, I feel the abdomen
When shallow breathing — only the chest heaving — goes on for a long time, the rhythm I have been describing thins out by that much. The neck and the shoulders work along with it. People often say "the neck and shoulders stand in for the diaphragm," but more precisely, they do not stand in — they are used more. Muscles like the scalenes are already working when you breathe comfortably, and as breathing gets harder the sternocleidomastoid is recruited too.
I look at it the other way as well. If the abdomen is taut or the region around it has stiffened, the room for the diaphragm to drop narrows. Then the body uses the neck and shoulders more. You do breathe, but the trunk's rhythm thins.
So I feel the abdomen of someone who came in for shoulder pain, and the region around the diaphragm of someone who came in unable to sleep. People are puzzled at first. That is a natural reaction. (When your breath feels short but the tests are normal)
There is no basis for asserting that swelling, headache, insomnia, and bloating all come together out of shallow breathing alone. Each can arise for different reasons. What I do see is that among people carrying several symptoms for a long time, breathing is often shallow, and looking at breathing alongside can help. That is what I hold from clinical practice, not an established fact.
What Korean medicine has long said
Korean medicine has long said that qi rises and falls. Surging upward makes illness; descending brings ease.
I do not read this only as metaphor.
| The old language | How I read it |
|---|---|
| Qi rises and falls | The rhythm of pressure breathing lays on the trunk |
| Qi surges upward | The rhythm stays high and does not carry downward |
| The breath is shallow and short | The diaphragm descends less, narrowing the rhythm's range |
What the ancients read by laying their hands on the abdomen and chest is having names attached to it now.
Of course I do not explain the body by breathing alone. The body's conditions are set by chemistry, metabolism, and immunity standing side by side. Breathing is a rhythm laid across those axes all day long, and that is why I look at it often. (What herbal medicine does)
If breathlessness comes from the heart or lungs themselves, or if breath suddenly shortens or chest pain comes with it, that is a different matter. You should be examined first.
It repeats twenty thousand times a day. It does not win by force — it accumulates by count.
If you have been carrying several symptoms for a long time, one of them may touch this rhythm.
References
- The negative pressure created on inhalation increases venous return and cardiac output — Respiratory Care, 2011
- Real-time MRI showing that breathing drives cerebrospinal fluid flow in humans — Nature Communications, 2025
- Slow, deep breathing raises vagal activity at the heart — Scientific Reports, 2021
Written by Dr. Heo Ji-young (PhD in Korean Medicine Pathology, Kyung Hee University · former Research Professor of Herbology, Kyung Hee University)
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