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Optimal Breathing



Our breath is the one thing we have with us for the whole of our lives! It is a beautiful constant and without it we die. When a baby is born everyone waits for them to take a breath…and then let it out with a cry! When we die, it is with a final long exhalation. Our breath is a great gift and with every breath we have the chance to be thankful for the precious gift of life. However, many of us suffer from some fundamental breathing problems which exacerbate (or cause) many health problems and put our bodies under a lot of stress. This blog is about optimal breathing and how to recover the breathing patterns that lower stress and activate the parasympathetic system.


Nasal Breathing

The most important thing is to make sure you are breathing correctly, and all research shows that this means through the nose not the mouth. Nasal Breathing has many, many physiological benefits compared to mouth breathing. First of all, the nose is a much better filter than the mouth and 75% of all particles (that includes viruses) do not make it past the mucous membranes and cilia of our nose. Since the air around us is full of bacteria, viruses and chemicals, the nose if a fabulous first line of defence!

Secondly, nitric oxide is an important chemical that is only produced in large quanitieis in the nasal sinuses. As a vasodilator, it helps widen the bronchial tubes and it also has antimicrobial properties which also kills viruses and bacteria. A research study from 2005 showed that nitric oxide inhibits the replication of the SARS virus (and interesting CV19 also belongs to the same virus lineage as SARS). It is safe to say nitric oxide is broadly antifungal, antiviral and antibacterial and therefore highly important.

Thirdly, nasal breathing slows down our respiration rate by increasing the amount of carbon dioxide in our bodies. Research shows that CO2 is needed in order for our blood cells to release oxygen (this is known as the Bohr effect).[1] If we are continually inhaling large gulps of air the body has less CO2 and therefore, ironically, oxygen is trapped in the bloodstream rather than released into the body. Your brain, heart, muscles and eyes all consume lots of oxygen, but they won’t be getting it.

It is also interesting to note that CO2 has antibacterial properties that inhibits disease-causing bacteria. CO2 has been used in food packaging since the 1930’s to keep food fresh and in 2005 a research groups from Sweden published papers showing how 100% CO2 reduced the risk of infection in open surgical wounds.[2]


Diaphragmatic Breathing

Ideally, we all should be breathing through our nose with our lower belly (diaphragm) moving in and out rather than our chest. Many of us unfortunately breath with quick shallow breaths and large chest movements and often with our mouths open. This leads to less nitric oxide and an imbalance of CO2 in our bodies, which creates stress and activates the sympathetic system (fight or flight system).

Diaphragmatic breathing is essential in order to get oxygen down to the lower lungs and to activate the parasympathetic system (rest and digest system). You should be aiming to breath slowly and calmly through the nose – six breaths per minute has been shown to reduce hypercapnia and hypoxia.[3] Slow, relaxed breathing with your diaphragm fully activated is also vital for the lymphatic system which, because it has no pump, depends on the diaphragm to move lymphatic fluid around the body. As you know, our lymphatic system is an important part of our immune system and removes waste from all the organs in our abdomen.

How do I know if my breathing is not right?

Lots of sighing or yawning: These are indications of low CO2 tolerance levels and a red flag warning of ineffective or shallow breathing.

Asthma or blocked nose: Mouth breathing has been shown to cause airways to shrink and this leads to asthma and blocked noses.

Illnesses and infections: Poor or ineffectual breathing leads to poor air circulation and lower pressure in the nose and sinuses, thus creating an environment beneficial for bacterial growth and inflammation.

What shall I do?

Develop awareness of your breathing patterns

A simple experiment taken from The Oxygen Advantage will give you a good example of oxygen levels in your body and also your CO2 tolerance level. You can take the BOLT test here and also read more about how to reduce breathlessness and improve oxygen delivery for better sleep and improved core strength. HeartMath is another excellent way to do this. It uses self-regulating techniques and technology to help build resilience and strengthen our ability to prepare for stress and our capacity to recover from it. It is a great way to manage energy and it is one of the tools I use to balance emotions, calm an overactive mind and replenish energy levels  You can find out more about it here or in your consultations.

New breathing habits

You want to aim for slow, low and small breathing so that your diaphragm moves and not your chest. This is deep breathing rather than shallow chest-breathing. CO2 levels determine our breathing cycle so it is important to increase your CO2 tolerance level. Think about taking little breaths and prolonging your exhalation while still breathing slow, calm breaths through the nose. Many of my clients have found this Functional Medicine breathing sheet useful for breathing techniques to sooth the soul.

Sleep tape

Many people have trained themselves away from mouth breathing so that they reap all the health benefits of nasal breathing. Sleep tape is a good way of ensuring your mouth stays closed through the night so you are forming good habits as you sleep. Often people find that they have slept really well, without waking up numerous times as well!

Hum your favourite song!

Research at the Karolinska Institute in Sweden shows that ‘the oscillating airflow generated during humming produces a dramatic increase in sinus ventilation’. In human studies in vivo and in a sinus/nasal model, this meant a dramatic increase of the airflow in the sinuses (up to 15 or 20 time more).[4] You might like to try this exercise from Anders Olsson based on this research if you have a stuffy nose or chronic sinusitis.

If you are interested in reading further, these books are an excellent way to find out more about optimal breathing:

  • Breath by James Nestor
  • The Oxygen Advantage by Patrick McKeown
  • The Wedge by Scott Carney
  • Conscious Breathing: Discover the Power of Your Breath by Anders Olsson


With every blessing,



Emma Maitland-Carew – Registered Nutritional Therapist

Dip.ION, mBANT, CHNC Registered Practitioner,

Metabolic Balance® Coach, HeartMath Coach.



[1] Riggs AF. (1988) ‘The Bohr effect’, Annual Review of Physiology 50: 181–204.

[2] Persson, M., Svenarud, P. Flock, J. et al.(2005) ‘Carbon dioxide inhibits the growth rate of Staphylococcus aureus at body temperature’. Surgical Endoscopy And Other Interventional Techniques 19, 91–94.

[3] Bernardi, L., Gabutti, A., Porta, C., & Spicuzza, L. (2001). ‘Slow breathing reduces chemoreflex response to hypoxia and hypercapnia and increases baroreflex sensitivity’. Journal of Hypertension, 19(12), 2221-2229.

[4] Mauro Maniscalco, M. Humming, nictric oxide and paranasal sinus ventilation (Karolinska University Press, 2006).

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