Nose breathing has gained a lot of popularity recently, and social media is full of influencers and celebrities taping their mouths during workouts and when sleeping. So what is all the hype about?
In this article we are going to build on what you’ve learned in the free quick guide to breathing ebook and the first four supporting articles that expand on each topic in the book. We are now going to look at nose breathing: what it is and how it can benefit you both in your running but also in everyday life.
We’re going to begin by looking at some of the common benefits of nose breathing in general and then you’ll discover why these are important. We’ll also uncover why you may not currently want to nose breath and how to go about changing that. Finally, you’ll learn a nose breathing exercise and protocol that you can begin using right away. So, let’s get started.
Nose Breathing Benefits
Some of the common benefits often cited about nose breathing are:
- Filters the air and helps remove allergens and dust
- Warms the air
- Humidifies the air
- Pressurises the air
All of these sound great, and they are, but there is so much more that isn’t often highlighted unless you begin to dig deeper.
- Helps to induce relaxation: When you breathe through your nose the air is slightly restricted which helps to slow down your rate of breathing and encourages better regulation. This slowing down and breath regulation is what promotes relaxation.
However, due to the restriction of the airflow through your nose, you may find this creates some air hunger – a feeling that you don’t have enough air coming in. This can then cause mild panic and lead you to believe that you simply can’t nose-breathe. This is particularly the case if you often suffer from a blocked nose. But you can relax as we’ll look at ways that you can get over this feeling and start to nose-breathe without the panic. - Improves cognitive function: There is some research that supports improved brain function through improved breathing. Actually, the study looked at people with dysfunctional nasal breathing and measured impaired cognitive function leading to the conclusion that efficient nasal breathing helps overall cognitive health and avoids impaired cognitive function. How you breathe also influences the neuroplasticity and predictive models of your brain, so it makes logical sense to deliberately and positively influence these with efficient breathing rather than to leave it to chance.
- Smell is important to us in mapping out our environment in the same way as vision and hearing are. The more efficient you become as a nose breather, the more improved (in general) your sense of smell becomes. If you remember back to the article where you learned about the predictive brain, you’ll begin to understand why a good sense of smell is important in helping to provide your brain with the most helpful information it can get. There is some research that links nasal breathing to improved visuospatial awareness, particularly in a sports environment. It does this through synchronising electrical activity in the brain on a wavelength that appears to improve your visuospatial awareness.
- Improves the recruitment of your diaphragm which leads to more efficient breathing and is strongly linked to the biochemical aspects of breathing. A strong and well activated diaphragm has also been linked to improved midline stability, something that is very important when you are running.
- Increased oxygen uptake in the blood: Nose breathing is more effective at increasing oxygen uptake than mouth breathing. This is something we’ll look at in a bit more detail later on in this article, but for now it’s helpful to know that arterial pressure of oxygen in people who consistently nose breathe increased by 10% over those that don’t.
- Production of nitric oxide: As you breathe in through your nose, you produce a molecule called nitric oxide which helps to maintain healthy lung function and may protect against certain respiratory diseases. Nitric oxide also helps to open up your airways, maximising the available oxygen for transfer to your blood and working muscles.
- Dilation of blood vessels: Nose breathing helps to open up the blood vessels in your lungs that then improves the amount of oxygen being carried around the body and to your working muscles and other tissues.
- Improved blood distribution in your lungs: The nitric oxide produced when you nose breathe helps to improve how your blood is distributed throughout your lungs which has been shown to improve blood by up to 24%. This is particularly the case with the upper areas of your lungs where gravity may otherwise present a challenge to the gas exchange process. Essentially, nose breathing is helping to improve the diffusion of blood from your lungs across into your blood.
I could continue with many more functions of the nose, but this is enough for us to start looking at a little more detail into some of these things so you can begin reaping the benefits of breathing through your nose in a more consistent manner.
Increased Oxygen
Let’s start with increased oxygen because this can seem a bit at odds with the restricted airflow of nose breathing compared to mouth breathing. However, with the help of a small formula it’s easy to see why nose breathing facilitates more oxygen availability.
When we are exercising hard it’s easier for us to take air in through the mouth because we basically get more air in than we do through the nose. However, if you also speed up the rate of your breathing, you actually end up with less available oxygen. Here’s how it works:
Let’s say you are breathing through your mouth and you are breathing at the typical resting rate of between 12 and 20 breaths per minute. Let’s actually say that you are at the healthier end of this scale and you are breathing at 12 breaths per minute.
The amount of air you take in each breath that is usable is known as the tidal volume (TV), and the total amount of air taken in one minute is called your minute ventilation (MV). The typical minute ventilation is around 6 litres: that is, you take in around 6 litres of air per minute. This is represented in the formula below:
Respiratory Rate * Tidal Volume = Minute Ventilation
RR * TV = MV
12 (breaths per minutes) x TV = 6 litres
So TV must be 500ml of air per in breath:
12 x 500 = 6000ml = 6 litres
But, not all of the air you breathe in a single breath can be used for oxygen transfer. Around 150ml per breath remains in various areas of your throat, trachea, bronchi and bronchioles. This is known as dead space air and it cannot be used for gas exchange. So our tidal volume now becomes:
12 x (500 – 150) = 4200ml = 4.2 litres.
That’s 1.8 litres of air that cannot be used for oxygen exchange in the lungs.
Nose breathing generally encourages a slower breathing rate, typically between 6 and 8 breaths per minute, and at rest we are really aiming for a respiratory rate of 6. However, the amount of air coming into the nose remains the same as the mouth breather in the first example as they weren’t overbreathing, something we’ll look at next. So the total amount of air coming in in one minute is still 6 litres.
The amount of dead space air is the same as before, but our calculation now looks like this:
6 x TV = 6 litres
6 x 1000 = 6000ml = 6 litres
6 x (1000 – 150) = 5100ml = 5.1 litres
So you can clearly see that by slowing down your breath rate to around 6 breaths per minute from 12 breaths per minute, you are gaining an extra 20% of air that can be used for oxygen exchange.
Of course the question is: “if I’m a mouth breather can I slow it down and get the same benefit?”. In theory, yes. In practice though, slowing down your breathing when just breathing through your mouth is hard to achieve on a consistent basis. You also won’t get the other benefits of nose breathing such as filtration and the very important nitric oxide.
So, nose breathing combined with slowing your respiratory rate is the preferred method of increasing oxygen in your blood. Doing exercises to help with the pacing of your breathing, such as those you learned in earlier topics in the guide and articles, will help you maintain good pacing in your breathing as your exercise intensity increases.
Over-breathing
You’ve just learned that slowing down your breathing rate can increase the available oxygen for gas exchange – something that is very important when you are running because you need to maximise the amount of oxygen that gets to your working muscles and other tissues.
So, why can’t you just take bigger breaths through your mouth to achieve the same thing? Well, apart from losing the benefits of nitric oxide you will also be breathing in too much oxygen. Not a bad thing you might think, except that it will displace the carbon dioxide in your blood (hypocapnia) and that certainly is not a good thing if it happens over longer periods (hours or days) – so you don’t want to be relying on large mouth breaths to get the oxygen you need.
To understand the issue of persistent hypocapnia (as opposed to deliberate, short term hyperventilation training for a few minutes at a time), we need to refer back to the previous article on biochemistry that included an explanation of your energy systems. If you remember, the higher the intensity of your running the harder it is for your body to get oxygenated blood to your cells. As a result, carbon dioxide builds up and eventually you will get to a point where the cells don’t work well and you’ll be forced to slow down. In practice, this is like starting your 5k race way too fast, rising quickly from aerobic to lactic and possibly to alactic, only to blow up a few minutes later and then having to settle down into a more sustainable pace in your aerobic or lower threshold zone. During this high intensity phase there is a build up of carbon dioxide, or a hypercapnic situation. This is the opposite of what happens when you over-breath, but being in a high intensity situation can force you to hyperventilate and over-breathe to compensate for the carbon dioxide build up and leave you in a carbon dioxide deficit.
As part of the normal cellular processes, the carbon dioxide that is shuttled from your cells is combined with water in the blood to form carbonic acid. The next reaction is to disassociate into H+ (hydrogen ions) and HCO3 (bicarbonate ions). This creates an alkaline buffer that neutralises changes in your blood’s acidity. When you hyperventilate or even just over-breath through large mouth breaths, you start to remove a lot of carbon dioxide. This leaves an excess of bicarbonate ions and a deficiency of hydrogen ions. At the same time, your breathing volume decreases to help restore your carbon dioxide levels. However, this will only work during short-term hyperventilation bouts as you return to normalised breathing quickly, allowing those carbon dioxide levels to settle. With continued hyperventilation or over-breathing, you end up in a constant state of hypocapnia and this impacts on your blood’s pH levels. As a consequence, your kidneys start to offload the excess bicarbonate ions to try and normalise your blood’s pH, making them work harder to maintain this fine balance.
In addition to your blood pH levels, the low level of carbon dioxide can cause other issues. Carbon dioxide is a strong catalyst for releasing oxygen from your blood into your cells, so by over-breathing you end up doing the opposite of what you may think you are doing. It is also a dilator of smooth muscles, the kind of muscle found in some of your airways. Therefore, over-breathing can actually restrict some of your airways, further reducing the effectiveness of your breathing.
Essentially, over-breathing other than when doing specific hyperventilation training exercises for a specific outcome, is going to reduce the available oxygen and hamper your running.
Carbon Dioxide Tolerance
Sticking with our carbon dioxide theme and becoming even more running specific, I just want to go back to the energy systems and the build up of carbon dioxide as your effort level increases.
You’ll remember that as you transition from your aerobic system being dominant to your lactic system becoming dominant, the level of carbon dioxide in your blood starts to build up because your system cannot pump the blood fast enough back to your lungs for the carbon dioxide to be diffused back to the lungs for exhalation. This is a state known as hypercapnia where there is excessive amounts of carbon dioxide and eventually this will help create an environment where your cells cannot perform well so you are forced to slow down so everything can begin to normalise. This feeling of not getting enough air in is called air hunger and you can actually use this state to improve balance and brain function – but that’s for another article.
The good news is that you can increase your tolerance to this CO2 build up so that you can push on for longer in this transition zone between energy systems. Ultimately, this means your speed endurance improves and therefore your race times. Even if you are not motivated by running faster and instead want better endurance, being able to operate for longer with a higher CO2 level means you are more fatigue resistant as you are overall much more efficient.
And the starting point for increasing your tolerance to higher levels of CO2 is by nose breathing, even at rest. This is because nose breathing naturally restricts the airflow by up to 50% compared to mouth breathing. Right away you are dealing with less oxygen going in and less carbon dioxide going out. This is also why you may find nose breathing, even at rest, challenging at first: you are not used to this build of CO2 and a reduction in O2 so you respond to the CO2 trigger to inhale as your brain perceives holding out as a threat. Remember that your brain is a prediction engine and the predictions it uses are shaped by every moment in your life so far. As soon as you start to train your CO2 tolerance, you are also shaping your predictive models for future reference.
So where do you start with this and how can you progress it?
- Start with nose breathing at rest as often as you can, aiming to make it a permanent change.
- You may find it challenging at times, so take a break but always go back to it and push yourself that little more. Nose breathing will actually help you to open up your airways (remember nitric oxide?) so persisting with it is the key.
- Begin to build in nose breathing when you are walking, which will present more of a challenge as the CO2 will build up quicker and you may experience stronger air hunger. Again, take a break and go back to it. Each time you do this you are letting your brain know that it’s perfectly safe and you positively shape those predictive models.
- When you are ready, try some nose breathing when you are on your easy runs. This may only be for 30 seconds to a minute at a time, but it’s all positive graining and positive reinforcement for your brain to build predictive models from and feel safe.
Nose breathing is such an important part of functional breathing, whether you are running or sitting on your sofa, that ignoring it is like ignoring speed work, strength work and other aspects of your run training.
In the next article I’m going to pull everything together and show you how you can improve your breathing in a step by step framework that also takes into account how you are feeling during some of the more challenging aspects of nose breathing, breath holds and rib cage mobilisation.
