Updated: Mar 14
Take a deep breath. Notice what did that feel like? Take one more and notice where you felt your breath most prominent. Did your chest move? Did your belly move? What about your side ribs and back ribs? Did you breathe through your mouth, nostrils, or both? Did you take a big sigh? How big was your breath? These are important questions to ask about deep breathing. Deep breathing is important, especially when shallow chest breathing seems to be the norm. Does deep breathing mean breathing in more air? Do we actually need to take bigger breaths?
Before going any further it is important to understand how breathing works. Breath mechanics are fairly straight forward. On the inhalation, the diaphragm (a dome-shaped muscle that divides the thoracic and abdominal cavity) contracts as it pulls down toward the abdomen and widens into the lower ribs. As the diaphragm contracts, the ribcages expands, and the pressure within the thoracic cavity lowers. The pressure change acts as a vacuum and draws air down into the lungs. On the exhale the diaphragm relaxes, the ribcage goes back to its resting shape, which creates a high-pressure change in the lungs and slowly pushes air out of the body.
Air naturally gravitates toward areas of low-pressure, so when the ribcage increases in size the pressure drops inside the lungs and air flows in. The opposite happens on the exhale, the ribcage decreases in size, raising the pressure within the thoracic cavity, and air leaves the body. The exhale happens passively. We don't need to contract to squeeze the air out (although we certainly can). The effort happens on the inhale as the diaphragm contracts and flattens down into the abdominal cavity. There is a pretensioned elastic quality to breathing that keeps the act of breathing efficient and effortless as possible. If we needed to squeeze out every exhale with a muscular contraction we would burn out pretty fast. To get a feel for the elasticity of breathing take an inhale in through your nostrils, down into the widening of your lower ribs, and expansion of your belly. Now relax everything. Notice how the air of your breath effortlessly leaves your body. Our breath has a rebound, similar to when we stretch a rubber band, the effort is on the stretch. When we let go the elastic returns back to its original shape. It is important to note and emphasize here that the diaphragm moves down on the inhale and up during the exhale. That might seem a bit counterintuitive because it might not immediately feel that way, and possibly feels quite the opposite. To feel for this movement, place your hand on your upper abdomen and take a breath through in your nostrils and notice if you can detect the downward movement of the diaphragm, it will show up as your lower ribs widening and the belly expanding outward. Notice the upward and narrowing sensation of the exhale.
The diaphragm is the main muscle we use to breathe, but it is not our only breathing muscle. An analogy that helps is to think of the diaphragm as the engine of a car. We need more than just an engine to drive a car, such as a transmission, gas, brake, gas pedal and so on. So, for the most part, all the muscles that surround and wrap around our thorax and abdomen are in some way used to assist the breath whether that is shifting gears, steering, acceleration or de-acceleration. We have another diaphragm in our pelvis, the pelvic floor which is shaped like a bowl. Ideally, with good breathing habits, both diaphragms move down on the inhale and up on the exhale.
A common misconception is that we can breathe air into our belly or even our hips (perhaps you have heard that once or twice in a yoga class) but in reality, air can only enter our lungs and doesn't actually fill the belly, rather the movement of our diaphragm pushes into the abdomen and that creates a shape change. Go back in time a bit and imagine that you are sitting on a water bed, if someone were to sit next to you, your side of the bed would bulge upwards as that person sunk down. It is a displacement of the contents of the water bed that cause it to change shape. Same thing happens when we breathe, sort of, we aren't really water beds. You can create movement in you hips and belly but that is not not from air flowing in.
If air is not entering the hips or belly where is it actually going? When we inhale air begins its journey into the body by first traveling down the trachea, from there it hits the crossroads of our bronchi which divides air into the right and left lung. From there it journeys into smaller branches that sprout off of the bronchi called bronchioles. Ideally air travels all the way down the bronchioles and enters tiny air-filled sacs called alveoli. There are around 300 million alveoli in the lungs. Capillaries which are super small blood vessels surround the alveoli, the relationship between alveoli and capillaries is how oxygen gets into the blood. Hemoglobin is a protein in red blood cells that holds onto and carries oxygen through our bloodstream.
The lower lungs are wider than the upper lungs and that shape promotes greater blood flow in the lower lungs, that is why it is important to breathe deep into the lungs. If you imagine how a tree grows from the trunk up to the leaves and then flip that upside down the image is very similar to the trachea, bronchi, bronchioles, and alveoli. The trachea is the trunk, the bronchi and bronchioles are the big and little branches, and the alveoli are the leaves. It is quite a stunning connection to make, considering that we call trees the lungs of the earth. During photosynthesis trees take in carbon dioxide and release oxygen. We do the inverse. We breathe in oxygen and exhale carbon dioxide.
What is happening on a chemical level when we breath is equally important to understand. The biochemistry of breathing is more complex than the mechanics and in a lot of ways is counterintuitive to what we think we know about breathing. Taking in a bigger breath, or more air doesn't necessarily mean that we are getting more oxygen into the body. This is where it gets a little confusing and to make it a little less confusing it helps to understand the role of carbon dioxide in our body. Carbon dioxide is essentially a by-product of our metabolism. It is created in our tissue cells when we break down fats and carbohydrates and convert them to energy. Carbon dioxide leaves the tissues and travels through the blood to the lungs and is eventually exhaled out.
Carbon dioxide is a waste gas so it makes sense to get rid of it all right? Not quite, carbon dioxide also serves another purpose that is crucial to releasing the oxygen from our blood into our tissues. The Bohr Effect better explains this and is the chemical observation that there needs to be a certain amount of carbon dioxide present in the blood for the hemoglobin in our red blood cells to let go of oxygen. Once hemoglobin releases the oxygen, the oxygen can then oxygenate our tissues (muscles, heart, brain and so on). A simple and incredibly basic example of this is it's like buying something. In this example, carbon dioxide is the currency used by the tissue cells to "buy" oxygen from the hemoglobin. If there is not enough carbon dioxide, red blood cells won't "sell" the oxygen, instead they will keep it until the tissues come up with enough carbon dioxide. Also important to note, levels of carbon dioxide in the body have a direct effect on the regulation of blood pH and this is important because pH levels must be just right for our metabolism to work and for our internal organs to function. Breathing affects the pH levels in our blood. When the blood is too alkaline the body slows down the breath so carbon dioxide levels can rise, and when the blood is too acidic the body breathes more to get rid of the carbon dioxide as acid. Simply put, we need carbon dioxide in the body, not too little and not too much.
Yes, we do need to get rid of excess carbon dioxide and when oxygen enters the lungs on the inhale, carbon dioxide leaves on the exhale. When we take in more oxygen or a bigger breath, we exhale more carbon dioxide. There are receptors in our brain that keep track of carbon dioxide levels, blood ph, and oxygen levels. When carbon dioxide levels get too high for these receptors they tell the body to take a breath, so levels can regulate again.
When we are more active, our metabolism ramps up and begins to produce more carbon dioxide. That is why we breathe heavier when we are working hard, the body is bringing oxygen in and getting rid of excess carbon dioxide. When we do less we don't need to breathe as much because the body is not producing carbon dioxide in large amounts. Overbreathing happens when we start breathing in more air than we need. If we tend to breathe heavy and big when we are at rest, the body in a sense gets confused and we lose breath efficiency. If we breathe too much when we aren't moving than we most likely are breathing way too much when we are active, hence the feeling of being winded or needed to catch your breath when climbing up a few flights of stairs, or running. A calm, quiet and slow rhythm to the breath is appropriate when we are resting so that our oxygen and carbon dioxide levels are regulated. When we get into aerobic activity we take those regulated levels with us and are better able to breathe easily without feeling out of breath.
Breathing is like eating, the body needs it to survive, but too much, or too little, can become a problem. When we breathe too much, the receptors in the brain that monitor carbon dioxide levels end up becoming sensitive to carbon dioxide will prompt the act of breathing even more, which in return lowers the carbon dioxide levels in the body. In other words, the body loses its tolerance to healthy carbon dioxide levels, and with that lessened tolerance, we lose the ability to efficiently get oxygen into our tissues. Overbreathing is a harmful ongoing cycle where our body is tricked into thinking that more air means more oxygen. When we feel short of breath because our tissues aren't getting enough oxygen, we breathe in more oxygen, and in return exhale out the carbon dioxide our body needs to properly receive oxygen, so we begin the next big breath in and the same thing happens all over again. Overbreathing can bring on feelings of anxiety and tension by keeping us locked in our sympathetic nervous system (fight or flight) and can also show symptoms of fatigue, brain fog, and chronic muscle stiffness. One of the easiest ways to overbreathe is to breathe through the mouth. A good place to start creating better breathing habits is to breathe through the nostrils. Keep in mind that if you habitually breathe through your mouth whether you are resting or active, nostril breathing can feel really awkward and funky at first, that will soon pass as you begin to create new neural pathways in the brain and open up the nasal cavity.
To sum it up, Patrick Mckeown In his book The Oxygen Advantage states:
"The crucial point to remember is that hemoglobin releases oxygen when in the presence of carbon dioxide. When we overbreathe, too much carbon dioxide is washed from the lungs, blood, tissues, and cells...causing the hemoglobin to hold on to oxygen, resulting in reduced oxygen release and therefore reduced oxygen delivery to the tissues and organs. With less oxygen delivered to the muscles, they cannot work as effectively as we might like them to. As counterintuitive as it may seem, the urge to take bigger, deeper breathes when we hit a wall during exercise does not provide the muscles with more oxygen but effectively reduces the oxygenation even further. In contrast, when breathing volume remains nearer to the correct levels, the pressure of carbon dioxide in the blood is higher, loosening the bond between hemoglobin and oxygen and facilitating the delivery of oxygen to the muscles and organs."
So what does all of this have to do with taking a deep breath? Technically deep breathing is great but deep breathing doesn't necessarily mean big heavy breathing. The problem is that our culture often confuses a deep breath for a bigger breath. We can breathe a relatively small amount of air into our lungs and as long as it travels down into the tiny air-sacs, the alveoli, it is a deep breath. Oftentimes I see a "deep breath" look like a hyper exaggeration of breathing which manifests as a big inhale into the upper chest which causes the ribcage to lift forward and up. This is followed by a deep sigh on the exhale (often through the mouth) as the shoulders collapse forward and the ribs sink back down. In this case, there is not too much diaphragmatic movement happening, most of the work is happening in the shoulders and upper chest which bypasses the natural and effortless breath mechanics inherent in the diaphragm.
Try taking a deep breath by first closing your mouth so you are breathing through your nostrils, and slowly draw air down into your low lungs, expanding into the lateral (side to side) movement of your low ribs, notice the expansion spiraling around your rib cage to your spine, all the way through your intercostals (muscles in-between ribs). Allow your abdomen to swell. On the exhale find a slow calm release of air through the nostrils, without sighing, pushing or squeezing. Follow the exhale to its completion and pause for a moment at the bottom of your exhale before you begin your next inhale. With this kind of deep breath, you might notice that the inhale can be felt as expansive, and has a sensation of descending into the belly rather than puffing up and stiffening through the upper chest and throat. You might notice that the exhale actually feels like your chest is slowly floating upwards rather than dropping and collapsing. When we deep breathe in this way we are not necessarily bringing in more air. Our bodies intrinsically and naturally have an ability to breathe deeply, but to tap into that we need to first shed some bad habits and misconceptions, so the body can naturally do what it does.
Deep breathing can be very relaxing to the body and can stimulate the parasympathetic nervous system (the part of our wiring that tells us to chill, aka rest and digest). Deep breathing also can take the diaphragm through a range of motion that moves the viscera on a three-dimensional level. That movement is crucial to optimal function in the gut and the pelvic floor. We have probably all felt at least one point in our life what it feels like to be stagnate in the gut, it feels horrible. Imagine a stagnate pool of water and what collects in it over time compared to flowing spring. Movement is necessary for the health and oxygenation of water just as much as it is for our tissues such as our cells and organs. It is important to move with our breath. When the diaphragm moves well, it has all sorts of benefits in the body. It promotes the flow of lymph, and massages the vagus nerve (which essentially chills us out).
One of the most common cues I hear with deep breathing is to take a really big breath in and sigh out a big exhale. We can probably all agree that a heavy sigh feels really good, especially if we hold a lot of tension in the shoulders, neck, and jaw. A heavy sigh is also symbolic of letting go and getting rid of what is useless, or harmful. On that level a heavy sigh makes sense, but unfortunately, like with everything else, we can overdo it. One of the symptoms of disordered breathing is involuntarily sighing or yawning multiple times throughout the day. Frequent sighing can be compensation for bad breathing habits such as shallow chest breathing, or overbreathing. In this post I don't mean to imply that all other forms of deep breathing are bad and this is the right way. Sometimes variety is key, but it is important not to get stuck in ideas of breathing that could potentially be harmful. Sometimes with breathing it is important to consider that less is more, and bigger is not always better.
So deep breathing does not need to be big breathing to bring oxygen into the brain, heart, and other tissues. The occasional heavy sigh or big breath is not a problem but if sighing becomes habitual to calming down or finding presence it might be doing more harm than good. The same goes for heavy loud "deep breathing". Bringing attention to the breath is one of the easiest ways to quiet to the mind. Breathing slowly and deeply can be enough to mellow out a busy, anxious, distracted or frustrated mind, and in this case, breathing more air is not necessary. It is important to understand what is happening when we breathe not just on a mechanical level but also on a chemical level. With more knowledge and understanding about breathing, we can develop more efficient habits. With better-regulated breathing, the mind can also regulate and find a sense of peace.
Mckeowen, Patrick."The Oxygen Paradox" The Oxygen Advantage. New York, NY, HarperCollins, 2015.
Farhi, Donna. "Catching Your Breath" The Breathing Book. Canada: Fitzhenry & Whiteside Ltd, 1996.
Kaminoff, Leslie and Amy Matthews. "Dynamics of Breathing". Yoga Anatomy. 2nd Edition. United States, Human Kinetics, 2012.