Home » Blog » Breathwork » CO2 Breathing Therapy

CO2 Breathing Therapy

CO2 Breathing Therapy is breathing training for those with chronic or acute dysfunctional breathing aiming to reduce the associated physical, mental and psychological symptoms that accompany it. Due to the pivotal role Carbon Dioxide has in the use of Oxygen, CO2 Breathing Therapy can also improve patients’ metabolic function.


Most people know CO2 as a by-product of metabolism which can be toxic❗️ In reality CO2 has multiple functions in the body. If you want to learn:

• How does CO2 affect the way we breathe?

• Why CO2 is vital for metabolism?

• How to regulate CO2 levels with CO2 Breathing Therapy?

Read on…


Why is Carbon Dioxide important to humans?

Carbon Dioxide (CO2) allows us to regulate blood 🩸 pH, respiratory rate, and delivery of oxygen (O2) to our cells. Most of the CO2 in the body is produced during energy production [1] and in healthy individuals, it is maintained at 40 mmHg in the blood at all times.

If CO2 was non-essential, would our bodies ensure its constant presence in our bloodstream?

Why is CO2 important in metabolism?

Our body’s capacity to produce energy is dependent on oxygen. Our cells are capable of producing much more energy in the presence of oxygen compared to a non-aerobic state [2]. Approximately 90% of the oxygen in our cells is used for energy production [3]. So how can we ensure the delivery of adequate oxygen to our cells?

Oxygen circulates in our body through proteins called hemoglobin. Based on the Bohr effect, discovered in 1904 by Christian Bohr, hemoglobin in the blood requires CO2 in order to release oxygen (ref). Low levels of CO2 in the blood, increase the affinity of oxygen to hemoglobin, preventing it from moving to the cells [4].

Why am I short of breath if my oxygen saturation is good?

When you are out of breath your body has reached its limit of Carbon Dioxide tolerance. The urge to breathe harder (instead of an urge for more Oxygen) is an urge to get rid of Carbon Dioxide. When most people are out of breath, they tend to breathe faster or take bigger breaths. Both of these actions will offer a temporary release of the air-hunger sensation without affecting cellular oxygenation.

Strange as it may sound, the increase of air in the lungs, is not what is required for better oxygenation of our cells. Our body maintains high oxygen saturation.

By using an oximeter we can easily prove that our blood keeps 95-99% of its total oxygen capacity most of the time.

If our blood constantly maintains good levels of oxygen, why do we “run out of breath” at the end of a strenuous workout or when walking quickly upstairs? Because we have reached our tolerance to CO2 not because we are out of O2.

oxygen transport


In order to grasp how erroneous the idea of air hunger equating to lack of oxygen is, think of the following: During an asthma attack patients are advised to breathe through a brown bag. The reason is to re-inhale the CO2 they exhale so they maintain adequate levels of CO2 in their blood and oxygenate this way their cells.


How can I increase my CO2 levels naturally?

CO2 will naturally increase when you hold your breath or breathe less air than normal. While you can temporarily increase your CO2 levels this way, to establish a higher etCO2 level (the amount of CO2 your blood will maintain at a pH of 7.36) permanently, you need CO2 Breathing Therapy.

CO2 Breathing Therapy involves the daily practice of hypercapnic breathing exercises. Exposing the body to higher levels of CO2 will gradually desensitize the chemoreceptors that monitor respiratory rate → make breathing softer → increase levels of etCO2 & tolerance to CO2.

CO2 pH relationship

A simple exercise to start CO2 Breathing Therapy is the following:


How does CO2 Breathing Therapy improve metabolism?

In order to deliver oxygen to our cells efficiently, we need to prolong our urge for the next inhalation. The beneficial metabolic effect of temporary exposure to an elevated CO2 state has been demonstrated in one study, where the application of CO2 to transcutaneous tissue led to the proliferation of mitochondria, similar to the one observed during aerobic exercise (ref).

oxygen transport


Capnometry-Assisted Respiratory Training

Capnometry-Assisted Respiratory Training, or CART, is CO2 Breathing Training using a capnometer. This way the patient can measure exactly his levels of CO2, and has been shown to have beneficial effects in panic attacks (ref).


Take 🏡 message

Breathing affects many functions in your body and to the extent that CO2 regulation is the key determinant of your respiratory rate, it is worth training your CO2 tolerance. To start your training reach out to me via the contact page.



1. Carbon Dioxide (CO2) is a by-product of fat and carbohydrate metabolism (aerobic and anaerobic). It exists in the fresh air at concentrations of 0.036-0.041% (36-41ppm).

atmospheric oxygen and carbon dioxide levels

source: Cummins E et al., 2019

At 1% (10,000 ppm) concentration it can cause sleepiness and between 7 – 10% suffocation. In one study subjects were exposed to air containing 7-14% of CO2 for 10-20 mins. All subjects had a complete recovery of their physiology 10 mins after the end of the experiment (ref).

Carbon Dioxide (CO2), a natural-occurring product of metabolism, should not be confused with Carbon Monoxide (CO), a flammable gas that does not occur naturally in the atmosphere.

2. One molecule of glucose will produce two molecules of Adenosine Triphosphate (ATP – our body’s energy currency) in an anaerobic state, as opposed to thirty-six molecules of ATP in an aerobic state.

3. Bland, J., Costarella, L., Levin, B., Liska, D., Lukaczer, D., Schiltz, B. and Schmidt, M.A., 1999. Clinical nutrition: A functional approach. The Institute for Functional Medicine, Gig Harbor, Wash, USA.

4. That was 33 years before Han Krebs’ discovered the eponymous Krebs cycle.