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A Comparison of The Oxygen Advantage
and Wim Hof Techniques

This page was created in response to hundreds of emails that we have received asking the question:

What are the differences between the breathing techniques in The Oxygen Advantage by Patrick McKeown and Wim Hof’s Becoming the Iceman?

Instead of answering each individual email, I would like to direct you to the points below.

I’d like to begin by stating that there are many similarities between the breathing exercises offered by both techniques. Both offer significant benefits in terms of health and improvements to sports performance as outlined below. Wim Hof’s breathing technique instructs to take 30 big breaths through the mouth before holding the breath. In the Simulate Altitude Training exercises from The Oxygen Advantage the objective is to breathe normally, and then hold the breath following an exhalation.

Oxygen Advantage Technique:

  1. Meditation
  2. Functional breathing training
  3. Intermittent hypoxic hypercapnic training

Wim Hof Method:

  1. Meditation
  2. Intermittent hypoxic hypocapnic training
  3. Cold water immersion

The Oxygen Advantage technique generates an intermittent hypoxic hypercapnic response (low oxygen, high carbon dioxide). During breath hold exercises, blood oxygen saturation typically drops to about 85% indicating severe hypoxia, while carbon dioxide will increase from normal of 40mmHg to above 50mmHg.

The Wim Hof method generates an intermittent hypoxic hypocapnic response (low oxygen, low carbon dioxide). By the third cycle of hyperventilation followed by breath holding, blood oxygen saturation can drop to as low as 45%, while carbon dioxide can reduce from normal of 40mmHg to 13mmHg. (Syncope hypoxia can occur when SaO2 drops below 60%).

The breath hold exercises in both techniques disturb homeostasis and are a stressor to the body, causing it to make adaptations including possible improved immune functioning. Over the years, breath hold exercises have proven to be very effective for respiratory conditions including asthma. Koxs paper on Wim Hof method states: ‘This study could have important implications for the treatment of a variety of conditions associated with excessive or persistent inflammation, especially autoimmune diseases’.

Below we examine the many positive effects of breath holding following an exhalation. We also examine the physiology of hyperventilation and breath holding from a sports performance perspective.

Exploring the Physiology:

Wim Hof explains that taking deep big breaths prior to the breath hold  “fully charges the body by getting rid of carbon dioxide, allowing more oxygen into the body to roam freely and fill up every cell, and increase pH levels”.

In order to shed some light on this explanation, it is important to examine breathing physiology:

Oxygen uptake in the blood and delivery to the cells

Oxygen is carried two ways in the blood:

  1. 98% of O2 is carried by proteins inside the red blood cells called haemoglobin (Hb).
  2. 2% of O2 is carried dissolved directly in the blood.

Since arterial blood is already almost fully saturated with oxygen (between 95 percent and 99 percent) during normal, healthy breathing, “big” breathing as in the case of 30 large breaths through the mouth, will bring more oxygen into the lungs and increase the partial pressure of O2 in the blood but does not increase oxygen saturation of the blood.

In summary, breathing hard

  • Increases the partial pressure of O2 in the blood.
  • Increases the amount of O2 dissolved in the blood (2% of oxygen is carried dissolved in the blood).
  • Does not increase saturation of blood with oxygen (98% of O2 carried by Hb).
  • Lowers carbon dioxide in the blood. This results in an increase to blood pH (respiratory alkalosis) which in turn increases the affinity of Hb for O2. In other words, the bond between the blood and o2 gets stronger with less o2 being delivered to the tissues. Another factor, is that the loss of carbon dioxide causes blood vessels to constrict resulting in reduced blood flow throughout the body.

Therefore, the question to ask is what effect does breathing hard have on oxygen delivery to tissues and organs including the heart and brain? Overall, does it increase or decrease it?

But what is oxygen saturation exactly, and how does it relate to properly oxygenating our muscles?

Oxygen saturation (SaO2) is the percentage of oxygen-carrying red blood cells (hemoglobin molecules) containing oxygen within the blood. During periods of rest the standard breathing volume for a healthy person is between four and six liters of air per minute, which results in almost complete oxygen saturation of 95 to 99 percent. Because oxygen is continually diffusing from the blood into the cells, 100 percent saturation is not always feasible. An oxygen saturation of 100 percent would suggest that the bond between red blood cells and oxygen molecules is too strong, reducing the blood cells’ ability to deliver oxygen to muscles, organs, and tissues. We need the blood to release oxygen, not hold onto it, and as we shall see later the gas responsible for the release of oxygen from the red blood cells is carbon dioxide. The human body actually carries a surplus of oxygen in the blood – 75 percent is exhaled during rest and as much as 25 percent is exhaled during physical exercise. Increasing oxygen saturation to 100 percent has no added benefits.

Carbon Dioxide: Not Just Waste Gas

For normal, healthy functioning, the body requires a certain amount of both oxygen and carbon dioxide. It is widely recognised that oxygen is a gas essential to life, but many people are surprised to hear that carbon dioxide is not just a waste gas. In terms of breathing, the two work hand in hand.

Taking 30 big breaths in and out through the mouth will lower the concentration of carbon dioxide in the lungs and blood. Carbon dioxide performs a number of vital functions in the human body, including:

  • Offloading of oxygen from the blood to be used by the cells
  • The dilation of the smooth muscle in the walls of the airways and blood vessels
  • The regulation of blood pH

Offloading of oxygen from the blood to be used by the cells

When we take a breath of fresh air into our lungs, oxygen passes from the lungs to the blood where it is picked up and carried through the blood vessels by a molecule called haemoglobin. This oxygen-rich blood is then pumped by the heart throughout the body so that oxygen can be offloaded to cells for conversion to energy. In order to release oxygen from the blood, however, haemoglobin requires a catalyst, which involves the presence of carbon dioxide (CO2).

Physical exercise is a perfect example of these conditions: when we move our muscles, the body requires more oxygen to give us energy and perform at a higher intensity. During exercise, body temperature increases and cells produce carbon dioxide, allowing extra oxygen to be released by the blood to the muscles and organs. John West, author of Respiratory Physiology, tells us that “an exercising muscle is hot and generates carbon dioxide, and it benefits from increased unloading of O2 [oxygen] from its capillaries.” The better we can fuel our muscles with oxygen during activity, the longer and harder they can work.

The concentration of carbon dioxide in the blood is determined by our breathing. The habit of breathing in excess of bodily requirements causes too much carbon dioxide to be exhaled from the lungs, which in turn causes a reduction of the concentration of CO2 in the blood and cells. When carbon dioxide levels are less than adequate, the transfer of oxygen from blood to muscles and organs is limited, leading to poor body oxygenation.

This necessary presence of carbon dioxide was discovered in 1904 by the physiologist and Nobel laureate Christian Bohr, who recognised that CO2 affects the release of oxygen from the blood to tissues and organs. According to the Bohr Effect, when there is an increased pressure of carbon dioxide in the blood, pH drops and oxygen is released more readily. Conversely, when carbon dioxide levels are low, haemoglobin molecules are less able to release oxygen from the blood. The way we breathe determines the amount of carbon dioxide present in our blood, and therefore how well our bodies are oxygenated.

In light of the Bohr Effect, taking 30 large breaths in through the mouth will lower the concentration of carbon dioxide in the blood, thereby limiting the release of oxygen from the blood to the cells.

The dilation of the smooth muscle in the walls of blood vessels

Breathing too much can also cause reduced blood flow to tissues and organs including the heart and brain. For the vast majority of people, 30 big breaths is enough to reduce blood circulation throughout the body, including the brain, which can cause a feeling of dizziness and light-headedness. This will be experienced by many people who hyperventilate prior to breath hold techniques.In general, blood flow to the brain reduces proportionately to each reduction in carbon dioxide. 1 A study by Dr. Daniel M. Gibbs, which was published in the American Journal of Psychiatry to assess arterial constriction induced by excessive breathing, found that the diameter of blood vessels reduced in some individuals by as much as 50 percent.2 Based on the formula [pi] r squared, which measures the area of a circle, blood flow decreases by a factor of four. This shows you how radically overbreathing can affect your blood flow.

The Regulation of Blood pH

In addition to determining how much oxygen is released into your tissues and cells, carbon dioxide also plays a central role in regulating the pH of the bloodstream: how acidic or alkaline your blood is. Normal pH in the blood is 7.365, and this level must remain within a tightly defined range or the body is forced to compensate. Maintaining normal blood pH is vital to our survival. If pH is too acidic and drops below 6.8, or too alkaline and rises above 7.8, the result can be fatal.3 This is because pH levels directly affect the ability of our internal organs and metabolism to function.

Scientific evidence clearly shows that carbon dioxide is an essential element not just in regulating our breathing, optimizing blood flow, releasing oxygen to the muscles, but also maintaining correct pH levels. In short, our body’s relationship with carbon dioxide determines how healthy we can be, affecting nearly every aspect of how our body functions. Better breathing allows carbon dioxide to ensure that all the interlocking parts of our system work together in harmony, allowing us to achieve our maximum potential in sporting performance, endurance, and strength.

Why does Breath Hold Time Improve Following 30 Large Breaths?

In his interview with Joe Rogan, Wim Hof explains that after 30 big breaths: “at a certain point you are so fully charged, pH go to a very high level, you are able to stay without air in the lungs for minutes. You will hold your breathing for much longer than normal because we changed your body chemistry. Carbon dioxide went out, O2 went up, filled up all the cells and the pH levels go up”.

Breath-hold time will increase if you take 30 big breaths immediately prior to breath holding, This is primarily due to a reduction in the concentration of carbon dioxide. The primary stimulus to breathe is not driven by oxygen, but by carbon dioxide. The body breathes to get rid of excess carbon dioxide. At the same time, it is important that the body holds onto a sufficient level of carbon dioxide for normal functioning. By taking 30 big breaths, carbon dioxide reduces in the lungs and blood. By depleting carbon dioxide (the ‘alarm’ to breathe), one is able to hold the breath for longer periods of time until carbon dioxide levels rise again to cause the sensation to resume breathing. For this reason, never perform hyperventilation prior to entering water. With the alarm to breathe depleted, one does not feel the need to breathe. This can result in oxygen levels dropping too low to cause underwater blackout and drowning.

Negative Effects of Mouth Breathing

Dr. Maurice Cottle, who founded the American Rhinologic Society in 1954, stated that the nose performs at least thirty functions, all of which are important supplements to the roles played by the lungs, heart, and other organs.4 In summary, breathing through the nose improves arterial oxygen uptake and delivery, improves ventilation perfusion (gas exchange in the lungs) and acts as a defence against airway constriction including exercise induced asthma.

Mouth breathing, on the other hand, is considered an abnormal and inefficient way to breathe and may induce functional, postural and biomechanical imbalances – all of which can be detrimental to our health and sports performance.5

One of the main drawbacks to breathing through the mouth is that it causes more movement of the upper chest and less movement of the diaphragm.6 The benefits of breathing using the diaphragm are numerous and include activation of the body’s relaxation response along with a more efficient transfer of oxygen from the lungs to the blood (ventilation/perfusion).7

In addition, diaphragmatic breathing helps to prevent the build-up of free radicals in the body. Free radicals are molecules created by the metabolism during the breakdown of oxygen. A certain amount of free radicals is normal, but an overabundance is not ideal as they attack other cells and damage tissues. In one study, researchers found that athletes who performed one hour relaxing and performing diaphragmatic breathing experienced reduced heart rate, increased insulin, reduced glycaemia, higher antioxidant levels and reduced free radical production.8 As well as promoting relaxed breathing, diaphragmatic breathing may also facilitate a lower level of oxidative stress which the researchers concluded could protect athletes from long-term adverse effects of free radicals

reduced free radical production.8 As well as promoting relaxed breathing, diaphragmatic breathing may also facilitate a lower level of oxidative stress which the researchers concluded could protect athletes from long-term adverse effects of free radicals.

Learn the Oxygen Advantage Program online


1. Magarian GJ, Middaugh DA, Linz DH. Hyperventilation syndrome: a diagnosis begging for recognition. West J Med.1983 ;(May; 138(5)):733–736

2. Gibbs, D. M. (1992). Hyperventilation-induced cerebral ischemia in panic disorder and effects of nimodipine. American Journal of Psychiatry, 149, 1589–1591.

3. Casiday Rachel, Frey Regina. Blood, Sweat, and Buffers: pH Regulation During Exercise Acid-Base Equilibria Experiment. (accessed 20th August 2012).

4. Timmons B.H., Ley R. Behavioral and Psychological Approaches to Breathing Disorders. 1st ed. . Springer; 1994

5. Trevisan ME,Boufleur J,Soares JC, Haygert CJ, Ries LG, Corrêa EC. Diaphragmatic amplitude and accessory inspiratory muscleactivity in nasal and mouth breathing adults: a cross-sectional study. Journal of electromyography and kinesiology 2015 Jun;25(3):463-8.

6. Trevisan ME,Boufleur J,Soares JC, Haygert CJ, Ries LG, Corrêa EC. Diaphragmatic amplitude and accessory inspiratory muscleactivity in nasal and mouth breathing adults: a cross-sectional study. Journal of electromyography and kinesiology 2015 Jun;25(3):463-8.

7. Sánchez Crespo A, Hallberg J, O. Lundberg J, Lindahl S, Jacobsson H, Weitzberg E, Nyrén S. Nasal nitric oxide and regulation of human pulmonary blood flow in the upright position. J Appl Physiol 108: 181–188, 2010.

8. Martarelli D,Cocchioni M,Scuri S, Pompei P. Diaphragmatic breathing reduces exercise-induced oxidative stress. Evid Based Complement Alternat Med. 2011:932430.