Why Taking a Deep Breath Can Do Wonders for Your Health

by Sylvie Le , DPT, PYTC April 12, 2021
Why Taking a Deep Breath Can Do Wonders for Your Health

The nervous system is one of the body’s primary communication systems.

When it comes to the breath there is one specific branch of the nervous system that is important to understand: the autonomic nervous system (ANS).

The ANS controls the internal bodily processes and organs that we have no or very little conscious control over, such as heart rate, digestion, temperature, the need to go to the bathroom, and breathing.

The ANS has two key divisions: the sympathetic nervous system (SNS) and the parasympathetic nervous system (PSNS). You might know these already as the fight-or-flight response (SNS) and the rest-and-digest mode (PSNS).

Fight-or-Flight vs Rest-and-Digest

When we are in a stressful situation the SNS kicks in – heart and breath rate increases, we are more alert, and our muscles start to activate, whilst unnecessary energy-consuming bodily functions, such as digestion, are suppressed.

This is helpful for genuinely life-threatening situations, but we are not primed to spend large amounts of time in this heightened state. Many of us operate at a low level of chronic stress a majority of the time, which is detrimental to our physical, emotional and psychological wellbeing.

We should, instead, be spending most of our time in the PSNS, which governs the body in regular states, ensuring good digestive function, quality sleep, and in general greater wellbeing.

So how can we reduce stress, and make sure our PSNS is dominant? I think we all know that telling ourselves to ‘relax’ doesn’t work. We need to find a way to communicate directly with our nervous system, but we can’t just instruct the heart to slow down or our gut to digest properly. But we do have one ANS function we can easily access and influence: the breath.

The Vagus Nerve

Vagus Nerve

What is the Vagus Nerve and Where is it Located?

The vagus nerve is the longest cranial nerve (CN X) in the body. It starts in the head and then meanders down through the chest, innervating the heart and lungs, before heading down into the abdomen and innervating many of the digestive organs. Not only does the vagus nerve connect our head, heart and gut, but it is the main nerve of the parasympathetic nervous system.

Stimulating the Vagus Nerve

Stimulating the vagus nerve is a way to activate the parasympathetic nervous system. We all have our own inbuilt stimulator available to us at all times: the breath!

There has been extensive research on how different contemplative well-being practices, including yoga and tai-chi, that have an emphasis on the breath lead to stimulation of the vagus nerve. Physical benefits range from heart health to decreasing inflammation, mental health benefits, as well as cognitive improvements from attention to creativity.

Diaphragmatic breathing: Stimulate the Vagus Nerve Using the Breath


Diaphragmatic or “belly” breathing is a way we can stimulate the vagus nerve. All breathing is technically diaphragmatic, but what this term refers to is a conscious lengthening, slowing down, and deepening of the breath.

The vagus nerve is stimulated both when the breath rate slows down (i.e. you take fewer breaths per minute), and also on the exhale. This is why you might work with a breathing ratio in a yoga class, perhaps inhaling for a count of four and exhaling for a count of eight.

Although the intention of diaphragmatic breathing is to breathe as deeply as possible, the breath should not be forced. If you modulate the breath in a way that feels uncomfortable or restricted, you are likely to trigger a stress response in the body. Just the act of simply bringing awareness to the breath can modulate it enough to activate the PSNS.

Diaphragmatic Breathing Exercise

Have a go at this simple breathing exercise right now.

  1. Check you are sitting comfortably, shoulders soft and spine long.
  2. If you like, place your hands on the belly.
  3. Become aware of the breath. You can inhale and exhale through the nose, or inhale through the nose and exhale through the mouth. Whichever you prefer.
  4. See if you can get the breath to expand into the belly, without forcing it. If this feels challenging in any way, just focus on finding a tiny bit more space in the torso by using the breath, it doesn’t need to reach the belly.
  5. Perhaps the breath expands into the sides of the body and the lower back too. Maybe you can comfortably fill the belly and keep expanding the breath into the ribcage, all the way up to the collarbones.
  6. Notice the very end of your exhales. Is the exhalation as complete as possible, or are you holding on to some of your inhale? Let your inhales be long and deep, and your exhales be slow and complete.
  7. Take five breaths like this.

I hope this was helpful (and relaxing)! You can also check out our YouTube video to guide you through this powerful breathing exercise!

Although it’s nice to have a designated time and space to really let yourself soften fully into the breath, you can do a version of this literally anywhere! Next time you have road rage, try taking just one big inhale and sighing the exhale out. In an exam or work presentation, just notice how you are breathing and consciously slow it down for a few breaths –– nobody will know what you are doing, but it could help with both calm and clarity.

There are a lot of fancy breathing exercises and ratios you can explore, but when it comes to the breath I have always found that simplicity is key.

Author: Sylvie Le, DPT, PYTC

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