The Ultimate Guide to Breathing

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😮‍💨 Why learn to breathe properly?

Most people don’t realise just how important breathing is to our quality of life.

Correct breathing can enhance our health, mood, learning, and overall mental / physical performance in life. s

👍 Why do we breathe?

We breathe in order to 1) bring oxygen into our body and 2) remove waste from our body (in particular, carbon dioxide).

So, when we breathe in air we are largely doing this to bring oxygen into the body.

Our cells need the oxygen to generate the energy needed to perform their basic functions, such as moving, dividing, making and breaking down molecules, and communicating with other cells. In particular, our brain cells require a lot of oxygen as they are the most metabolically active cells in our body.

When we breathe out we’re doing this to offload carbon dioxide.

At school we’re taught that carbon dioxide is bad, but this is a common misconception. The truth is only too much of it is bad. We still need carbon dioxide because it plays a vital role in delivering oxygen to the cells and tissues around our body in an efficient way.

So, how does this work in practice? The respiratory system has two major components:

1 The Mechanical Component of Breathing

We bring air into our body through the nose or mouth, down through a rigid pipe called the larynx, before entering the lungs.

The lungs aren’t just two bags of air. Instead, they contain millions of little sacs (called the alveoli), which increase the surface area of the lungs and allow for more oxygen to pass from the air into our lungs and into our bloodstread. They also allow for more carbon dioxide to pass into the lungs from our bloodstream, before expelling it through our nose or mouth.

To inflate and deflate our lungs we rely on two muscles: the diaphragm and the intercostal muscles.

The diaphragm – this a thin muscle that sits below the lungs and above the liver. When we breathe in, the diaphragm contracts, causing it to move down. This gives the lungs more space to inflate with air.

The intercostal muscles – these are the muscles that are between our ribs. When we breathe in, the intercostal muscles contract too, causing our ribcage to move up and expand a bit. Again, this gives the lungs more space to inflate with air.

Nerves control the diaphragm and intercostal muscles to tell them when to contract when we breathe in. In particular, there’s a specialised nerve called the phrenic nerve that originates from the spinal cord in the neck and travels down through the chest and into the abdomen, where it connects with the diaphragm muscle. It’s this nerve that provides the primary motor control for the diaphragm – so when the brain detects the bbody needs more oxygen, a signal is sent down the phrenic nerve to activate the diaphragm muscle. This causes it to contract, creating a vacuum that pulls air into the lungs. This process is known as inhalation.

2 The Chemical Component of Breathing

The two major chemical components of breathing are oxygen and carbon dioxide, which all the cells and tissues of our body need.

In short, oxygen gives energy to our cells and carbon dioxide helps deliver the oxygen to those cells.

In practice, the way this works is as follows: oxygen enters the alveoli in our lungs, which are surrounded by tiny blood vessels called capillaries. The oxygen is able to move across the walls of the alveoli and into the capillaries through a process known as diffusion. Once in the bloodstream, the oxygen gets bound up by proteins in the blood (particularly haemoglobin), which then delivers the oxygen to the various cells and tissues of the body.

But, oxygen can’t be delivered to the cell without carbon dioxide. Carbon dioxide is what lets us liberate the oxygen from the haemoglobin and deliver it to the tissue. This is why carbon dioxide is so important, because it’s part of the vital chemical exhcnage that gives the oxygen in our blood access to the cells/tissues/organs of our body.

Another reason why carbon dioxide is important is because it’s related to to how acidic (or basic) our body is.

If our carbon dioxide levels go way down, then our blood PH levels go up (making us more alkaline). But, at the same time, too much carbon dioxide can lead to something known as respiratory acidosis, which may be caused by asthma, obesity, or diseases that damage the chest’s nerves and muscles. Symptoms include headache, fatigue, feeling out of breath and chronic conditions leading to mental problems, hypertension and possibly heart failure

😬 Unhealthy Breathing

1 Sleep Apnoea

One context where people tend to breathe poorly is during sleep.

In fact, there’s a large fraction of the population that ‘unbreathes’ when they sleep. They’re not taking deep enough or frequent enough breaths, which is known as sleep apnoea.

The negative effects of sleep apnoea can be severe. Firstly, it results in recurrent episodes of hypoxemia, which is where there’s less oxygen coming into your system than necessary. Obviously, if you’re breathing less you’re going to get less oxygen. Secondly, it can increase the chances of a cardiovascular event, such as a heart attack or stroke, and is often the precursor to other bodily disfunctions (mental, sexual, etc.).

One solution to sleep apnoea is to use a CPAP machine. This gently pumps air into a mask you wear over your mouth or nose while you sleep to help you breathe.

Another solution is to fix the root cause of sleep apnoea, which is the way you breathe. In particular, breathing through your mouth, instead of your nose leads to a significant offset sleep apnoea, snoring, and other sleep related issues.

To encourage nasal breathing you can practice breathing through your nose throughout the day (more on this in a bit) or tape your mouth shut with medical tape prior to sleeping. (Some people get concerned they’ll suffocate, but this won’t happen because you’ll wake up if you body feels like it’s running out of air).

2 Overbreathing

Breathing too frequently also causes problems and influences our brain state.

A paper from the Journal of Physiology published in 1998 by Balestrino and Somjen sum this up nicely:

The brain, by regulating its own breathing, controls its own excitability

In short, when we breathe in a certain way, the neurons of our brain are more likely to get engaged (i.e. excited). Too much breathing, makes those neurons very excited (i.e. very engaged).

You might therefore think that excitability is good, but we actually don’t want our brain to always be excitable. Too much excitability can result in a cascade of abnormal electrical activity in the brain that can cause seizures, migrains, and a sharp increase in anxiety.

Unfortunately, many of us have high levels of excitability in our brain because of overbreathing i.e. hyperventilation at rest

One paper that explored how overbreathing changes the pattern of activity in the brain (‘Effects of Voluntary Hyperventilation on Cortical Sensory Response’) found that when people hyperventilate they expel more carbon dioxide than normal, making them hypocapnic (i.e. low levels of carbon dioxide in the body). The lack of carbon dioxide in the body means the oxygen they bring into their body can’t be liberated from the haemoglobin and, therefore, can’t get to vital organs like the brain.

In fact, it’s been observed that about 30 to 40 percent less oxygen gets to the brain and there’s less bloodflow when we overbreathe.

Plus, when we’re in a hyperexcitable state, there’s an increase in the amount of noise (i.e. random electrical activity in the brain). This can make it more dififcult for sensory input (like sound or touch) to be processed properly, as the noise intereferes with the transmission of signals between neurons.

For example, if a person is trying to focus on a conversation in a noisy environment, an overexcitable brain can make it harder to filter out the background noise and focus on the conversation.

❤️ Healthy Breathing

There are two important aspects of breathing healthily: the frequency and the technique.

If you’re breathing normally you should be inhaling about 6 litres of air per minute. If you’re a relatively shallow breather, that’s about 6-12 breaths per minte. If you breathe more deeply, then it’s about 4-6 breaths per minute.

The correct breathing frequency is quite slow, but anywhere around 10 breaths or fewer is optimal. Unfortunately, most people breathe far too many times per minute (with some people breathing as many as 30 shallow breaths every 60 seconds) leading to the same problems outlined above (in the section on overbreathing).

The correct breathing technique is done nasally, as we’ll explore now.

1 Nasal Breathing vs Mouth Breathing

Whenever possible, we should always be breathing through our nose.

One benefit of breathing through our nose is that the increased resistance of nasal breathing improves oxygenation and filtration. When the flow of air into your lungs is slowed down, there’s more time for air to be filtered, humidified and warmed by the nose, which improves oxygenation of the blood. Plus, the nose acts as a natural filter, trapping bacteria, allergens, and other particles before they enter the lungs. This helps to protect the respiratory system from infection and inflammation.

Another benefit of nasal breathing is that it plays a crucial role in the creation and delivery of nitric oxide in the body. This is important for 1) vasodilation which helps to relax and widen blood vessels, improving blood flow to tissues and organs around the body 2) improved oxygenation by opening up the airways and improving blood flow to the lungs, and 3) immune support due to its anttimicrobial and antiviral properties, helping to protect the body against infections and illnesses.

There have also been some studies that link nasal breathing with improved facial aesthetics, that’s discussed at the end of the article.

Also, note, that it’s very normal to breathe in more through one nostril than the other, and for this to change throughout the day. This is called the nasal cycle. Basically, the right and left nostril alternate to control body temperature, blood pressure and brain chemicals:

When breathing through your right nostril, your pulse, blood pressure, body temperature and cortisol levels increase. Breathing through your left nostril has the opposite effect, and cycling between the two maintains your body’s balance. Breathing through your mouth on the other hand disengages the nasal cycle completely, depriving you of its body-regulating benefits

– Nester

2 Training Healthy Breathing

To test if we’re breathing properly, we can do a carbon dioxide tolerance test. This allows us to measue how well we can control our breathing at both the mechanical and chemical level, outlined above.

Note: the results of this test are not linked to physical fitness. You can be very fit and still demonstrate a low carbon dioxide tolerance.

This is how it works:

  1. Breathe normally for a few minutes, so you’re completely relaxed.
  2. When you’re ready, inhale through your nose as deeply as you can.
  3. Measure how long it takes you to deliberately control the exhale until your lungs are completely empty.

This is how to interpret your results:

  1. If it took you less than 20 seconds to fully exhale, you have a low carbon dioxide tolerance. This gives you a score of 3.
  2. If it took you less 20-45 seconds to fully exhale, you have a moderate carbon dioxide tolerance. This gives you a score of 5.
  3. If it took you over 45 seconds to fully exhale, you have a high carbon dioxide tolerance. This gives you a score of 8-10.

Now you’ve got a score, we use this to train our carbon dioxide tolerance through something known as box breathing.

Box breathing is just a breathing technique where you inhale for a count of X seconds, hold your breath for a count of X seconds, exhale for a count of X seconds, and hold your breath for a count of X seconds. And repeat.

So, whatever score you got in the carbon dioxide tolerance test is how long you’ll inhale, exhale and hold your breath for. E.g. if you have low carbon dioxide tolerance you inhale for 3 seconds, hold your breath for 3 seconds, etc.

By practicing box breathing once or twice a week, we can massively improve the efficiency of our breathing and increase our neuromechanical control of our diaphragm. This has a huge number of positive effects, including improvements in our ability to stay calm, reduce anxiety, improve sleep, and reducing the hyperexcitability of the brain.

💨 Other Breathing Techniques and Benefits

1 Stress Reduction

Proper breathing can also reduce stress.

One recent study (‘Brief Structured Respiration Practices Enhance Mood and Reduce Physiological Arousal’) focused on finding out what the shortest and most effective breathing practice is for reducing their levels of stress throughout the day.

The basic takeaway was twofold:

  1. Deliberate breathwork done for about 5 minutes per day for a month leads to greater reductions in stress than 5 minutes of daily meditation. Now, this isn’t to say meditation isn’t useful, because many studies show it is. But, meditation is far better at increasing focus and memory, rather than reducing stress (although it does benefit this too).
  2. The best breathwork for reducing stress is something known as cyclic sighing. Cyclic sighing is where you take one long inhale of breath and a sharp second inhale to fully inflate the lungs, followed by a long exhale. In fact, just one cyclic sigh at any time of day under any conditions is the fastest physiologically verified way we are aware of to reduce levels of stress and to reintroduce calm.

There may also be ocassions where we want to increase our stress through breathing. For example, learning to maintain a calm state of mind during the heightened stress of rapid breathing helps us to manage stress during all areas of our life. So, we can use breathing as a form of self-induced innoculation.

This is what Wim Hof’s method of cylic hyperventilation is all about.

Cyclic hyperventilation involves taking 30-40 active inhalations and exhalations, followed by holding your breath for 10-15 seconds before exhaling again. You then repeat this process up to three more times.

While this is reported to have a number of health benefits, the important idea here is that it increases the level of adrenaline in your body. This is what makes us feel stressed. So, if we can learn to maintain a sense of calm with the increases levels of adrenaline/stress in our body, we’ll be better adapted to manage stress during other life events that trigger adrenaline too e.g. talking in public, going on a date, etc.

2 Heart Rate Variability

The way we breathe also impacts our heart rate. To be precise, when we inhale our heart rate increases and when we exhale it decreases.

Basically, when we inhale our diaphragm moves down, creating more space in the thoracic cavity, which casuses the heart to temporarily get a bit bigger. As a consequence, there’s a higher volume of blood in the heart, which makes the blood move more slowly. The nervous system detects this decrease in speed and sends a neural signal to the heart to speed up the heart rates. The opposite is true when we breathe out.

So, if you want to quickly reduce your heart rate, you just need to make your exhales longer and/or more vigorous than your inhales.

This natural variation in the heart rate during breathing is called respiratory sinus arrhythmia (RSA), and is a normal physiological response in healthy individuals.

It also forms the basis of most breathing practices too. If a breathing practice is designed to increase the heart rate (like the Wim Hof method) then it will emphasise inhalation. If a breathing practice is designed to decrease the heart rate (like the physiological sigh) then it will emphasise exhalation.

3 Learning

The way you breathe also relates to your ability to learn and remember information.

In a review by Jack Feldman (‘Breathing Rhythm and Pattern and their Influence on Emotion’), there’s a discussion of several studies including one that describes the differences in brain functioning when we inhale and exhale. In particular, our ability to remember and learn stuff is greatly increased when we breathe in.

Another paper (‘Nasal Respiration Entrains Human and Limbic Oscillations and Modulates Cognitive Function’) explored this in more detail and found that the brain ramps up its level of activity and increases the signal over the noise of the brain when we’re breathing in (making it easier to detect sensory input, such as sound and touch). It also found that our reaction time increases, especially when breathing in through the nose.

The takeaway then is that if we want to read or learn something it makes sense to increase the intensity and duration of our inhales compared to our exhales, as this makes our brain better at accessing and retrieving information.

The only caveat to this is that when we’re inhaling we’re worse at generating voluntary movements. That’s why it’s recommended to exhale when doing stuff like lifting weights, swinging a club, or punching as it helps us to generate more force.

4 Facial Aesthetics

Finally, there is some evidence that the way we breathe can impact our facial aesthetics.

In particular, evidence from the book Jaws and other orthotropic practitioners suggest that mouth breathing can lead to a narrow jawline, elongate the jaw, develop a high palate, and crooked teeth. This is because when we breathe through our mouth, we don’t engage the muscles in our face that help develop a more symmetrical and proportionate facial structure.

Switching to nasal breathing, especially as a child, can help to reverse these negative effects.

In addition to nasal breathing, there’s more extensive literature on correct tongue posture, which most academics seem to agree with.

In short, the correct tongue posture for breathing involves keeping the tongue in the roof of the mouth, with the tip of the tongue resting gently against the front teeth and the back of the tongue pressing up against the palate. This helps to create a seal at the back of the mouth, allowing for proper breathing through the nose.