The Nose Knows

human nose

Follow your gut instinct. It’s a common phrase. It means your body is telling you are on track or off it. Follow your nose is another common phrase. It has a similar meaning, but from a different perspective, using a different sense. The gut uses your intuition; the nose uses your sense of smell. Like a hound dog on the trail of a villain – the nose knows air that’s good for you and air that’s not.

Now think about what would happen if you were to lose your nose and all of its functions?

You’d have no sense of smell or taste for that matter. And, in fact, you would die an early death from a life of disease.

That’s a dramatic statement I know – but it’s true.

According to famed rhinologist, Dr. Maurice Cottle, the nose has over 30 functions. These functions are related to the sense of smell and also to your health, as related to your breath. It is the breath I have studied most and this aspect of the nose I am most fascinated with at the minute. So what does it do exactly and why is it so important to us?

1. The Nose is a Filter

The average person breathes 20,000 – 30,000 litres of air per day.

But have you ever thought about the quality of the air you breathe?

In 1882, George Catlin remarked that breathing through your mouth is akin to scooping up a glass of dirty pond water and drinking it to hydrate yourself!

Breathing through your nose, on the other hand, is the natural way to filter and clean the air, like drinking water from a fresh mountain stream.

In our modern era, air pollution has reached epidemic proportions, far worse than our water quality. Take Tokyo for example, air pollution in Tokyo has reached such chronic levels that people wear dust masks when out in the streets to filter the fumes and poisons in the air. But have they thought about our natural air filter – the nose?

In London too air pollution is terrible. A friend of mine uses an app called ‘Plume’ with his clients. It measures the air quality in London street-by-street and he re-routes his clients commute to work based on air quality.

Poor air quality isn’t just confined to these major cities either although it is far worse in cities than it is in the country. But think about your life for a moment and where you live. Specifically think about the air pollutants near you….

Are there car fumes?

Do planes fly overhead?

Do people smoke around you?

Do you wear perfumes, deodorants or smellies?

Do you live near a city?

And the list goes on and on.


Now don’t get me wrong. I’m not asking you to go out to the wilderness and live the life of a hermit in a ‘toxin free’ environment. All I’m saying is that you should use your natural filter to optimize your health.

So, let’s play a game of did you ever. It’s simple and it encourages you to think about your environment and your body’s reaction to it…

Did you ever…

… get on an aeroplane and within minutes of the door closing your nose starts to run?

…get off the aeroplane in a new country and your nose dries up?

Or did you ever…

…take a car ride into the country and within one breath you noticed how fresh the air is?

Did you ever…

 …Walk into a room that hasn’t been lived in for years and start sneezing for your life due to the dust.

… get a fit of sneezing when the first cut of the grass comes in spring.

In all of these instances your nose is immediately noticing the change of air quality. It has hair to keep dust and large particles out of your body. It adjusts it’s functions to keep air in or let more air out depending on the scenario and the nose secretes mucus to trap foreign invading particles that don’t belong in your body.

Your nose is a filter. It knows good quality air and poor quality air.

And like that hound dog, it can be trained to be more sensitive to air quality to keep you healthy.

The best way to train your nose is to use it.

Breathe through your nose day and night. Train with nose breathing only and within one month you will become super sensitive to smells – both good and bad – in your environment.

2. The Nose is a Humidifier

I remember living in -40 degree temperatures in Toronto a few years back. When the weather is that cold, the air is sharp like a knife and dry as a desert. The air is fresh but it becomes almost impossible to catch your breath. No matter how big you breathe it feels like you can’t get enough air into your body. This feeling of breathlessness is exacerbated much more when we mouth breathe.  The reason for this feeling is that your nose prepares your body to accept the air you inhale.

city snow

The nose warms and humidifies the air. Much like you would pre-heat an oven to cook the Christmas turkey you also need to pre-humidify the air before your body can use it efficiently.

When you initially step into the cold, your nose will run, and that’s ok. It’s supposed to do that. You’ve just dramatically changed your environment by 10 degrees or more. It takes a little time to adapt but that doesn’t mean you should stop using it.

Use a tissue. Gently blow your nose and continue to nose breathe. If necessary, perform a set or two of Buteyko Steps and this will boost your nose’ adaptation to the cold.

3. The Nose does the same as the Breathing Mask

breathing maskNose breathing is definitely more difficult to perform than mouth breathing.

By it’s very structure it is a smaller hole (or vent) than the mouth and so you can intake less air in.

It sounds counter – intuitive to breathe through the nose so, right? Afterall, if you need air you should use the bigger vent. But this isn’t exactly how your body works. The air resistance provided by the nose is important to get oxygen into your cells and as we will see in a moment, you don’t need as much air as you think you do.

You’re right when you think nose breathing is harder to perform (at least when you begin). When compared to mouth breathing, the nose provides 50% more resistance to air but transports 20% more oxygen to the cells. How is that you may think?

Imagine filling a balloon with air. You have two options:

The first option is to open the neck of the balloon. Even if we widen the opening, do you think more air would just flow inside?

Not much, right. Now if we attach a pump to the widened opening, would we get much air into the balloon?

We would get a fair amount in alright but it would take time and concentration to fill the balloon completely.

Whereas, if we kept the opening in the balloon small. Attached the pump to the balloon. Then the balloon would fill much more quickly.

The same is true for your lungs. When you nose breathe you use a far smaller vent BUT it actually activates the diaphragm (breathing muscle or pump in this analogy) far better than using the mouth.

The second interesting aspect to nose breathing is this: When you’re at rest, your body only breathes through one nostril!

That’s a smaller vent again, but it’s true.

Try this little exercise to show you how true it is. Lie down on your side for 2 minutes and notice what happens the nose as you lay there.

After two minutes, switch sides. Lie on the other side. Give it two minutes and feel what happens the nose.

Did you notice it?

Did you find that your body only breathes through one nostril and that nostril changes when your body position changes – cool, isn’t it?!

This has big implications for thinking about the amount of air we need to breathe in any given minute.

When we consider that asthmatics, diabetics, people with depression and cardiovascular disease all inhale between 13- 17 liters of air per minute.

And yet our body only needs 4-6liters of air per minute.

When we think about the amount we need to breathe vs the amount we are breathing, it makes complete sense to nose breathe.

The only catch is if you have been mouth breathing for a long time, it will be difficult to nose breathe at the start.

Generally, I have found it takes about 1 month of focused practice to adapt to nose breathing. But once you feel the benefits, you’ll be grateful for the work you did to get you there.

Also, here is where the Breathe: 1st Principles Program will help you speed up the process of switching.

4. The Nose traps CO2


As we’ve spoke about in previous blog posts, a certain level of carbon dioxide retained in the body is critical for optimal health performance. The nose plays a vitally important role in managing CO2 levels.

venous fly trap

Too much carbon dioxide in the system and the blood acidifies. Acidic bloods leads to the immediate breakdown of cell function and many systems in the body. In exercise it is linked to a low aerobic threshold, a decrease in performance in all sports and longer recovery period.

Too little carbon dioxide has a similar result on your body but with different mechanisms. Chronically low CO2 (we’re talking long term here) in your body resets the brain to a low CO2 threshold.

 Having a chronically low CO2 threshold does four things to the body:

  1. It gives you the false feeling of needing to breathe in more air and exhale more air (this is a vicious cycle which takes time to reverse).
  2. It upsets the electrolyte balance in the brain cells which may lead to anxiety, panic, and an inability to focus.
  3. It exerts pressure on the kidneys to buffer the blood with bicarbonate in order to balance the blood. The increase workload on the kidneys and the low sensitivity to CO2 leads to a host of diseases linked to hyperventilation and anxiety. These affect all systems of the body. A low CO2 threshold will also decrease performance in sport – people need more time to warm up; performance is affected by the second wind phenomena and endurance is decreased.
  4. It encourages you to mouth breathe. Mouth breathing sets-off a chain of events in the tissues of the body resulting in a retracted diaphragm, forward head posture and rounded shoulders, mis-shapen jaw formation, a ‘bad back’, recurring hamstring injuries etc.

Regulating CO2 is a very important job for the body so.

This is where it comes back to the nose. Nose breathing naturally regulates the flow of carbon dioxide out of the body to meet the body’s needs. Should you need to mouth breathe when performing in sports, know that you are running on empty fumes and about to burn out.

If you have been mouth breathing for a time, know that a return to nose breathing takes time (minimum one month in my experience) but that you will gain huge benefits from breathing naturally, through your nose. These include:

  • Increased endurance and stamina.
  • Calmer mind.
  • Better regulator of energy.
  • Faster recovery periods.
  • Less colds, flu’s and diseases.
  • Decreased risk of injury.
  • Less pain.
  • Better posture.

5. The Nose is a Blood Vessel Dilator

We know that poor breathing habits are associated with heart disease but did we know that good breathing habits can help to reverse heart disease?

Nose breathing has a role to play in opening up the blood vessels by secreting nitric oxide from the paranasal cavities. Now, we could do a whole blog post on nitric oxide (and we probably will at some point) but know this about it for now:

  1.  Nose breathing generates high levels of nitric oxide vs mouth breathing which generates medium levels of the gas.
  2. When you hum through your nose, it generates 15 times more nitric oxide than normal.
  3. Nitric oxide is an anti-bacterial agent, known to eliminate salmonella and other bacteria affecting the respiratory system.
  4. The wonder-drug, Viagra, helps impotent men become erect by increase blood flow to the penis. The mechanism of action for Viagra is based on nitric oxide!

So there you have it. Nitric oxide is awesome – great for heart health, sex life and respiratory health.

When you nose breathe you generate lots of nitric oxide, dilate blood vessels and airways and help the flow of fluids around the body.

Nose breathing as you have seen is awesome for so many other things.


The big 5 benefits we covered in this blog post are:

  1.  Breathing from your mouth is akin to drinking dirty pond water. Your nose is your natural filter.
  2. Your nose will warm and moisten the air as needed by your body.
  3. It’s harder to breathe through your nose but it’s worth it for better oxygen and a stronger diaphragm.
  4. Your nose helps control the pH balance of your blood, keeping you healthy for life.
  5. Your nose is a vaso-dilator – like a natural Viagra!


Caitlin, G., (1882) Shut Your Mouth and Save Your Life – Primary Source Edition. Trubner & Co, London.

Chaitow, L., Bradley, D. & Gilbert, C., (2014) Recognizing and Treating Breathing Disorders. A Multidisciplinary Approach. 2nd Ed. Elsevier

Lundberg, J., (2008). Nitric Oxide and The Paranasal Sinuses. The Anatomical Record. 291: 1479 – 1484

McArdle, W.D., Katch, F.I., & Katch, V.L., (2015) Exercise Physiology. Nutrition, Energy, and Human Performance. 8th Ed. Wolters Kluwer

Severinsen, S., (2018) Nitrogen Oxide – a Pleasant Poison

Timmons, B. H. & Ley, R., (1994) Behavioral & Psychological Approaches to Breathing Disorders. Plenum Press

Leo Daniel Ryan

For 10 years I have dedicated my professional life to coaching clients and personal trainers to achieve their goals. I have worked at the highest levels of industry in both Ireland and Canada.