• Courtney Cheah

Introducing: the Diaphragm

The Diaphragm is a big, uniquely-shaped muscle right at the centre of our bodies. Our primary breathing muscle, it has attachments to the ribs, sternum and lumbar vertebrae, as well as a fascial connection to the lungs. Its shape is like that of a dome, which flattens out as we inhale, pushing the ribs and abdomen out and creating a vacuum in the upper chest cavity which pulls air into the lungs. When it relaxes, it rises up into the dome shape again, allowing the lungs to release the air in exhalation.

In addition to breathing, our diaphragm has an important role in core stabilisation. Along with other muscles of the abdomen, pelvic floor and lower back, it provides support for your trunk, which when working well, supports ideal posture and looks after your lower back.

So naturally, if the diaphragm is out of whack in some way (usually it’s weak or ‘under-facilitated’), it can create a knock-on effect for other parts of the body.

For example, if your diaphragm is weak because you tend to breathe shallowly, it may mean that your secondary breathing muscles – such as muscles in your neck and upper chest – become overactive as they try to take up the slack. This can create problems such as chronic neck and shoulder pain and associated headaches.

This is a common issue for shallow breathers (which is probably most of us), and especially for those with respiratory issues such as asthma.

The good news is that strengthening your diaphragm is as easy as breathing. Literally.

Regular diaphragmatic breathing practice (otherwise known as ‘belly breathing’) is a great start for resolving biomechanical issues that result from this muscle being under-facilitated. And the good news doesn’t stop there.

In addition to restoring core stability and looking after your lower back, upper back, shoulders and neck, diaphragmatic breathing offers benefits on a physiological level too.

When we breathe, we bring oxygen into our blood via the alveoli in our lungs, and from there it gets distributed to all our cells. If we are breathing shallowly, our alveoli aren’t able to work efficiently. We may take in enough oxygen to live, but perhaps not at the optimum levels required for great health. Research shows that slowing down your breath and increasing the volume of air taken in (ie taking deep, slow breaths) ‘improves ventilation efficiency via alveolar recruitment and distension’ (Russo, Santarelli & O'Rourke 2017). This means that deep belly breathing helps nourish all the cells of your body, by increasing how much oxygen is carried to them by the blood.

The way we breathe is also intimately connected with our body’s stress response. As discussed in an earlier blog, we have two major branches of our autonomic nervous system, the sympathetic and parasympathetic nervous systems, which are familiarly tagged the ‘fight/flight’ and ‘rest/digest’ modes respectively, according to the roles they play for us.

When we are stressed, part of our fight/flight stress response is to take shorter and shallower breaths, which move the chest rather than the lower ribs and abdomen. If this is the way that we breathe habitually, even when we’re not feeling stressed, our bodies can still get the signal that we’re facing danger, which sets us off into ‘fight/flight’ mode. This creates a cascade of physiological responses, such as blood being directed away from your digestive system into your muscles, so you are ready to fight or flee for your life.

This mode is ideally a short-lived response, designed to get us out of danger; but if our habitual way of breathing communicates to our body that we are in danger constantly, we can remain in some degree of ‘fight/flight’ most of the time. As discussed in my earlier blog, this can lead to chronically tight muscles, jaw issues, grinding teeth, trouble sleeping, headaches and digestive issues.

Fortunately, the best and quickest way to flip the switch and go back into ‘rest/digest’ mode is breath. When we breathe deliberately, deeply and slowly, right down into the belly, we send the signal to the body that we’re safe. The body responds by slowing our heart rate, relaxing our muscles, and bringing blood back into our digestive system. This is why, in the face of overwhelm, wise people everywhere tell themselves (and each other), “Just take three deep breaths.”

I will go a step further and encourage you to make appointments with yourself to breathe diaphragmatically every day. If you automatically think “I’m too busy to do that”, or “When will I find the time?” then this is definitely for you.

All it takes is a couple of minutes to sit and breathe.

If you are a habitually shallow breather – as I believe most of us are – it will take practice to get this muscle to work, just like when you start to use any muscle that isn’t in the habit of being used. You may even feel a little fatigued when you’re beginning; but even if you only breathe deeply for two minutes a day, and shallowly the rest of the day, that’s still two minutes your breath was more efficient than usual. In time, with practice, the deep belly breathing will start to feel more natural; eventually, it may even become your new way of breathing.

You can do your belly breathing anytime, anywhere: at your desk, sitting in traffic, when you’re in bed getting ready to fall asleep, waiting for the kettle to boil, walking the dog – the possibilities are endless.

So Here’s How to Do It:

Place your hand on your belly.

Breathe in slowly through your nose, letting your belly expand and push your hand outward as you do. Hold your breath for a second or two, then slowly breathe out through your mouth, letting your belly deflate completely. Wait a second or two before beginning the next inhale if comfortable to do so.

You can do this with eyes closed if it helps you relax.

You can also count as you inhale and exhale – this helps clear your mind of all other thoughts.

Focus on the sensation of your belly pushing out with the in-breath, and relaxing in again with the out-breath.

Try ten in a row, and work up to twenty.

Aim to practice at least once a day.

As you practice, twenty breaths may not feel like enough; you may like to carry on for several minutes at a time. You may even begin to notice how nourished and refreshed you feel when you breathe this way.

This article is for information purposes only, and is not intended to give personal health advice. For more information see your health care practitioner.


Biel, Andrew R., 2005, Trail Guide to the Body, 3rdEdition, Books of Discovery, Boulder, USA.

Russo, M, Santarelli, D, O’Rourke, D 2017, ‘The physiological effects of slow breathing in the healthy human’, Breathe (Sheff), vol 13, no. 4, pp. 298 – 309.

Weaver, Dr Libby 2016, Accidentally Overweight, Little Green Frog Publishing, Auckland.


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