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To comprehend what hypoventilation training is, the following pages propose:

1)  A definition of hypoventilation

2) A short history of hypoventilation training

3) An answer to the most frequently asked questions (FAQ)



1) Hypoventilation, what is it all about?

John West, one of the greatest experts in respiratory physiology defines hypoventilation as a "level of alveolar ventilation that does not allow oxygen (O2) and carbon dioxyde (CO2) concentrations to be maintained at normal values". In short, one does not breathe enough. The amount of air getting to lungs, and precisely to the pulmonary alveoli, is reduced.

Hypoventilation can be caused by many medical problems: usage of drugs like morphine or barbiturates that depress the central drive to the respiratory muscles, damage to the chest wall or paralysis of the respiratory muscles, and high resistance to breathing. Hypoventilation is also seen in some obese patients who have somnolence, polycythemia and excessive appetite.

Aside from medical causes, hypoventilation can also occur when one decides to voluntarily decrease the breathing frequency. This is called voluntary hypoventilation.

Thus, hypoventilation training is a method which consists to train with restricted breathing in order to reduce the amount of air entering the lungs.

In practical terms, hypoventilation has to be applied by performing short and well measured breath holds during exercise.

There are two ways to carry out voluntary hypoventilation: at high pulmonary volume or at low pulmonary volume.

Hypoventilation at high pulmonary volume consists of keeping a maximum amount of air in the lungs during the breath holdings. To do so, it is necessary to hold one's breath just after inhaling (figure A).

Conversely, when performing hypoventilation at low pulmonary volume, the breath holdings have to be carried out with partially empty lungs. To apply this hypoventilation technique, one has to first exhale and then to hold one's breath for a few seconds. This is the "exhale-hold" technique (figure B).




The scientific studies conducted by Paris 13 University have shown that only hypoventilation at low pulmonary volume can provoke both an increase in CO2 concentrations (hypercapninc effect) and a drop in O2 (hypoxic effect) in blood and muscle.

This combined hypoxic and hypercapnic effect is essential for obtaining the physiological adaptations that enable to improve performance.

Hypoventilation at high pulmonary volume, used for several decades by swimmers or runners, provokes only an increase in CO2 concentrations.

When the exhale-hold technique is correctly applied, it is possible to obtain a decrease in blood oxygenation similar to what would occur at altitudes above 2000 m.


blood oxygenation 

Level of blood oxygenation and corresponding altitude at the end of an exercise carried out at sea level with normal breathing (NB) and voluntary hypoventilation at high (VHhigh) and low (VHlow) pulmonary volume


(a short history)




French  English 

The first book dealing with
hypoventilation training


Xavier Woorons Respiratory physiology neurobiology
Scientific study on hypoventilation
training (2014)


Discussion about hypoventilation training


xavier woorons international journal sports medicine
Scientific study on hypoventilation
training (2011)


Xavier Woorons sport et vie 147
Hypoventilation training in swimming


xavier woorons european journal of applied physiology
Scientific study on hypoventilation
training (2010)


Press article on hypoventilation
training (french)


Xavier Woorons Respiratory physiology neurobiology
Scientific study on hypoventilation
training (2008)


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