The Powerful Benefits of Increased CO2 Tolerance in your Body


The mitochondrion is the energy centre of cells, where most cellular oxidation takes place, and most ATP (adenosine triphosphate) is produced.

As the site of the major cellular respiration processes of the citric acid cycle and oxidative phosphorylation, the mitochondrial matrix is not only the destination of O2, but also the site of CO2 production.  O2 and CO2 have to be transported across the cell membrane, the inner and outer mitochondrial membrane, either to reach the destination, in the case of O2, or to be released outside the cell (CO2).

As an article on mentions, "Carbon dioxide tolerance is the body's ability to handle a temporary imbalance of CO2 and oxygen. The higher your tolerance, the longer you can hold your breath. Like breathing work, training to increase CO2 tolerance has gained popularity for its ability to improve physical and mental health."

Oxygen is vital for energy metabolism. For oxygen to reach the cells, the presence of CO2 is imperative.  This is because the supply of O2 requires an exchange of gases (CO2 and O2) at the cellular level. Haemoglobin, a protein in our blood responsible for transporting CO2 and oxygen, releases the oxygen bound to it in the presence of higher CO2 concentrations. And it releases CO2 in the presence of higher concentrations of O2.

The relationship between O2 and CO2 in the body is explained by the Bohr and Haldane effect:

Bohr - A high concentration of CO2 in the cells causes a low pH, i.e. an acidic environment, which causes haemoglobin to discharge more O2 into the cells and absorb CO2 and is known as the Bohr effect.

On the other hand, a high O2 concentration in the lungs causes haemoglobin to release CO2 and absorb oxygen. This is known in chemistry as the Haldane effect.

The higher the concentration of CO2 in your mitochondrial matrix, the more efficiently your body can use oxygen and thus produce more energy.

Apart from better oxygen management, why would you want to have higher CO2 concentrations in your body? Let's see.


Effects of Balanced CO2 Levels in the Body

- Higher CO2 concentrations in the body can produce more energy through proper mitochondrial oxidation or phosphorylation, i.e. conversion into Adenosine Triphosphate which is the source of our energy to perform all the activities we set out to do.


- The presence of sufficient CO2 in the body allows vitamin K to perform its function better, especially the reactions that depend on vitamin K2.  If you remember, we take vitamin D3 with K2 to make calcium bind to the right places in our body, i.e. in bones and teeth, while preventing calcification of soft tissues.  In addition, vitamin K2 promotes hormonal health.


- The presence of CO2 is crucial for the health of your gut.  A balanced gut flora has a diversity of good bacteria, known as obligate organisms; and a limited number of "bad" bacteria or facultative organisms (which refers to bacteria that can survive in an oxygen-rich environment).  When there is a proliferation of bad bacteria your gut becomes vulnerable to a host of ailments from predisposition to frequent flus to dysbiosis, candidiasis, irritable bowel disease and much more.

For this reason, your colon should be a low-oxygen environment with plenty of CO2 as this ensures the proliferation of good bacteria capable of breaking down complex carbohydrates and providing short-chain fatty acids to our cells.

- One of the most attractive features of CO2 in the body is that when it is eliminated, it can help remove excess calcium and sodium from the body. 

This results in the elimination of what is known as free water or fluid retention, and this is because CO2, when combined with water, is transformed into carbonic acid.  Carbonic acid is hydrophilic, so it quickly leaves the cell, taking with it some of the oppositely charged ions, such as calcium and sodium. 

Moreover, as CO2 has a similar function to methylene blue in terms of its anti-inflammatory properties and modulation of calcium in the body, it has been considered as a treatment for bunions, among others, as this condition is the consequence of calcium accumulated in the wrong place.

- Lack of O2 in the tissues means higher CO2 levels which leads to increased blood flow, production of more O2, reduced inflammation and angiogenesis (formation of blood vessels).

A review by the International Journal of Molecular Sciences compiles the studies that support these observed benefits of administering therapeutic CO2 and is very interesting.

"Sustained tissue hypoxia or lack of O2 in tissues is associated with many pathophysiological conditions, such as chronic inflammation, chronic wounds, slow-healing fractures, microvascular complications of diabetes and metastatic spread of tumours. This prolonged oxygen (O2) deficiency in tissue assemblies creates a microenvironment that favours inflammation and initiates cell survival paradigms.  Elevated tissue carbon dioxide (CO2) levels push the tissue environment into 'thrive mode', leading to increased blood flow, increased O2, reduced inflammation and enhanced angiogenesis."

The conclusions of this review were that

CO2 activates angiogenesis (creation of new capillary vessels) not mediated by hypoxia-inducible factor 1a;

CO2 is strongly anti-inflammatory,

CO2 inhibits tumour growth and metastasis, and

CO2 can stimulate the same pathways as exercise and therefore acts as a critical mediator in the biological response of skeletal muscle to tissue hypoxia.

- CO2 prevents the accumulation of lactic acid in the cell.  Lactic acid is a by-product of inefficient carbohydrate metabolism that suppresses efficient glucose oxidation and overloads the liver's energy supply.

Higher CO2 concentrations improve oxidation and thus prevent lactic acid accumulation because full oxidative phosphorylation, i.e. proper carbohydrate metabolism, can occur.

- CO2 production is a practical way to manage symptoms of depression.  Research conducted by the HHP Foundation found that people with a higher CO2 tolerance had less anxiety at the critical moment. This suggests that increasing your CO2 tolerance for anxiety can help you maintain a sense of calm not only during everyday life, but also at times when you have to deal with difficult situations.

- Increased CO2 tolerance can help improve athletic performance.  The more CO2 you can tolerate, the slower your heart rate will be. Running with a low tolerance causes your heart to beat fast, which will cause you to feel out of breath and fatigue sooner. Being able to tolerate more carbon dioxide (CO2) means that your heart continues to beat slowly, allowing you to increase your running pace over a longer period.


How can you Increase your CO2 Levels or Tolerance?

It is true that having a large amount of CO2 in the body is harmful. However, when you do breath retention exercises where you start to accumulate a small amount of CO2, it will notify your brain of the need to breathe. Therefore, when you increase your tolerance to CO2, you can temporarily hold your breath by gradually increasing the retention time, such as by practising techniques where you do several rounds of inhalation and exhalation followed by a retention period. Also, maintaining slow, deep breathing during periods of high stress; and finally, avoiding hyperventilation.

There are several methods to increase CO2 tolerance, here I explain some of them, and maybe one of them will catch your attention and motivate you to practice it. Among them, box breathing or 4-4-4-4; numbered breaths; the Buteyko method; or my favourite: the Wim Hof method. 


Box Breathing

This technique involves inhaling for a count of 1 to 4, pausing for a count of 1 to 4, then exhaling for a count of 1 to 4 and pausing again for a count of 1 to 4. This breathing exercise is one of the easiest to perform and perhaps the main benefit is immediate stress relief. People looking to improve their CO2 tolerance will benefit from this exercise as it incorporates air retention.

Other benefits:

Helps control hyperventilation

Relieves anxiety

Reduces blood pressure

Promotes calmness and relaxation



Sit or lie down in a comfortable position.

Inhale through your nose for a count of 4.

Hold your breath for a count of 4.

Exhale through your mouth for a count of 4.

Hold your breath for a count of 4.

Repeat this cycle as many times as you wish.

People who can benefit from this technique: Anyone, including athletes to people with very stressful jobs.


Numbered Breathing

This is a breathing exercise that is performed by increasing the duration of exhalations, holds and inhalations by one count with each repetition. This technique can help calm the mind, reduce stress and promote relaxation as it requires your attention to keep track of your inhale, hold and exhale periods by de-emphasising what is troubling you or weighing you down. It is also considered another relatively easy exercise that exercises the lungs.

Main benefits:

Slows breathing rate

Promotes relaxation

Reduces and stabilises heart rate

Reduces blood pressure


Get into a comfortable position with your eyes closed.

Breathe out through your mouth until you feel your lungs empty.

Inhale thinking of the number 1.

Hold your breath for a count of 2 and then exhale for a count of 2.

exhale for a count of 2.

Then inhale again, but now thinking of the number 2.

Hold your breath for a count of 3 and then exhale for a count of 3.

 exhale for a count of 3.

Continue this exercise up to the number 8.

Suitable for: Anyone who needs to correct their breathing.


Buteyko Method

This is a breathing technique consisting of various breath-holding exercises. Buteyko Breathing is often performed to improve lung function or to treat general health problems.  Emphasis is placed on the ability to hold the breath which, in turn, also builds CO2 tolerance.

Main benefits:

Improves lung function.

Preserves stem cell health

Increases resistance to bacterial infections

Promotes relaxation

Helps regenerate new brain tissue



Sit upright in a chair or on the floor.

Try to relax your breathing muscles.

Spend a few minutes breathing normally.

Follow the exercise steps Control Pause or Maximum Pause.


Control Pause

After the last normal exhalation, hold your breath.

Pinch your nose with your thumb and forefinger.

Continue to hold your breath until you feel the need to breathe, then exhale through your nose.

Spend 10 seconds or more breathing normally.

Repeat as many times as you feel necessary.


Maximum Pause

After the last normal exhalation, hold your breath.

Pinch your nose with your thumb and forefinger.

Continue to hold your breath until you begin to feel moderate discomfort, then exhale through your nose.

Spend 10 seconds or more breathing normally.

Repeat as many times as necessary.

These are examples of exercises that are suitable for beginners. However, the Buteyko Method is a breathing technique consisting of a variety of exercises that can be learned through workshops and training.

Method that is suitable for: Swimmers and freedivers, or for people who have breathing difficulties.


Wim Hof Method

This technique is part of a method that includes three pillars: breath-holding, exposure to cold and a commitment to be consistent. As for the breathing technique, this method has several types, depending on the objective. To increase CO2 tolerance, here I focus on the most common technique which is a mixture of abdominal and diaphragmatic breathing favouring expansion of the abdomen and rib cage during inhalation and contraction during exhalation, carrying a calm but focused rhythm.


Improved lung capacity

Reduction of stress and anxiety

Decrease in heart rate and blood pressure

Increased respiratory muscle strength

Improved digestion

Hormone function (in my case as anecdotal experience)


Sit or lie down in a comfortable position.

Inhale deeply through the nose, concentrating on the abdomen, trunk expanding outwards as you inhale and feeling the air you inhale reaching the neck and larynx.

Exhale the air (not all of it) slowly and evenly through the nose or mouth.

Continue with this rhythm of deep breathing, focusing on filling all the cavities from the abdomen to the head with each inhalation.

After about 30 breaths, exhale and hold your breath until you feel the need to breathe again. As you calmly allow CO2 to accumulate in your body, what Hof describes as the seer emerges. Psychonauts and people who work with ancestral medicines understand what I mean: the conscious perception of timelessness and the network that connects your body and mind.

Inhale and hold that air for at least 15 seconds. This allows you to balance yourself while prolonging the insights gained during the holding time.

Then gently exhale.

You can repeat the exercise for several rounds, and you will find that in each round you can last much longer holding the air, i.e. accumulating CO2 and consequently becoming more tolerant to it.

The bonus with the Wim Hof method is that the cold exposure aspect, in this case it can be showers or ice water baths, also requires a kind of slow breathing where you inhale through your nose and can exhale calmly either through your nose or your mouth.  By maintaining this breathing rhythm, you find your calm and manage to hold the cold water for several minutes, the important thing is to seek and maintain calm and concentration.  Here, of course, you also train and increase your CO2 tolerance.

The third pillar of this method refers to the commitment of perseverance that is required to get to know and experience what your body is capable of.

The invaluable advantage of Wim Hof's method, or at least on my part, is that I have embraced it as a meditative discipline.  I think it is an ideal form of meditation for us Westerners who have difficulty in focusing our attention and finding calmness in dealing with complex situations.   It is by awakening our capacity for concentration and determination that we discover the superhumans that we are.

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