How Does Pranayama Work? The Science of Breath Retention (Kumbhaka)

How Does Pranayama Work? The Science of Breath Retention (Kumbhaka)

In This Article

Breath Retention / Intermittent Hypoxia

Breath retention, called kumbhaka in Ayurveda and yoga, is considered the most important aspect of pranayama or yogic breathing techniques.2 While it’s a practice that takes time to learn, research shows intermittent hypoxia (aka not having enough oxygen for short periods of time) has numerous side benefits, including neuroplasticity, stem cell production, enhanced nitric oxide production, increased EPO, and more.4,7

Surprisingly, brief states of hypoxia actually cause a surge of oxygen from the blood into the tissues. One might think holding your breath would cause progressively less oxygen in the body’s tissues, but it actually supersaturates them!

Breath retention (intermittent hypoxia) is like your very own hyperbaric oxygen chamber, which athletes and medical doctors use to enhance performance, recovery, and neuroplasticity.5-7

Science of Intermittent Hypoxia

Ayurvedic pranayama breathing techniques with breath retention (kumbhaka) elicit a state of brief intermittent hypoxia. During hypoxia, which, by definition, means there is depleted oxygen in the blood, carbon dioxide (CO2) builds up in the tissues, triggering an urge to breathe.

According to the Bohr Effect,4 buildup of CO2 during breath retention (hypoxia) triggers release of oxygen. Oxygen is attached to hemoglobin in the blood, and is then unloaded into the tissues. Hemoglobin is a protein that carries oxygen to the tissues and CO2 as waste back to the heart and lungs for removal.

Most people have a blood oxygen saturation level of 95-98%, which sounds very high. However, this number is only a measure of oxygen in the blood—not the tissues, where oxygen is needed to energize and repair. Once oxygen is unloaded from hemoglobin due to a breath hold, it can be utilized by tissues.4 CO2 is then picked up by hemoglobin, escorted to the lungs, and breathed out.

Build Your CO2 Tolerance

Nose breathing techniques, as I wrote about in my first book, Body Mind, and Sport, along with pranayama with breath retentions, are important to build a higher level of CO2 tolerance. The more CO2 the body is comfortable living with, the greater amount of oxygen is freed to drive energy and repair. Regular practice of nose breathing exercise, nose breathing sleep, and breath retention are key to experiencing benefits of intermittent hypoxia.

It’s important to build CO2 tolerance (ability to tolerate a safe buildup of CO2 without feeling urgency to breathe). Today, because so many of us have become mouth breathers, there is a strong tendency to over-breathe with each breath (some 26,000 times a day). Over-breathing will build oxygen in the blood, which is a good thing, but it will also over-remove CO2. Without a healthy (but safe) buildup of CO2, oxygen will stay attached to hemoglobin and oxygen saturation in the tissues will be compromised.8

Having excess oxygen in the blood, along with over-breathing out CO2, will cause the blood to build up acidity. CO2 tolerance, or a higher concentration of CO2 in the tissues, acts as a natural buffer for the acid, which keeps the body in a healthier, more alkaline state. Over-breathing can build up acidosis and, for example, slow removal of lactate acid from the muscles and compromise energy and performance.4

Buildup of CO2 will cause the body to breathe. If too much CO2 accumulates, we will suffocate. Somewhere before suffocation, during brief intermittent periods of hypoxia (breath holds), an emergency repair message is released, causing a cascade of repair and recovery systems to turn on.

A main driver of this response is a molecule called hypoxia-inducible factor 1 (HIF-1).7 This molecule is responsible for what some call superhuman effects.

Benefits of HIF-1

  • Intermittent hypoxia [HG1] has been found to enhance neuroplasticity, the capacity of neurons and neural networks to change connections and behavior in response to new information, sensory stimulation, development, damage, or dysfunction.1,3

    In other words, our brains are designed to change, adapt, cope, and repair in the face of trauma, stress, a changing environment, and sensory input. Breath retention may therefore be a valuable tool for mental and emotional neurological repair.7

    Note: I refer you to an article I wrote called Cleanse Emotional Trauma with Ayurveda. Here, Ayurveda describes how emotional trauma or hurtful impressions are felt in the heart (sadhaka), carried to the brain via prana vata, and written into fatty myelin sheaths of the brain’s white matter, where they are recorded by tarpaka kapha. Breathing and vibrational techniques like prayer and chanting have been shown to change brainwave patterns and increase neuroplasticity, which may play an important role in changing old emotional patterns of behavior and the future of neuropsychology.
  • Hypoxia has been shown to increase hemoglobin levels through formation of erythropoietin (EPO).2 EPO was made famous when Lance Armstrong was caught doping his blood with EPO and was stripped of his six Tour De France victories. Yes, science suggests intermittent hypoxia from breath retention can boost EPO and enhance athletic performance.7
  • Hypoxia boosts stem cell production. This was discovered when scientists measured stem cells in fetal circulation. The embryo in a mother’s womb breathes in a very low partial pressure of oxygen, about equal to Mount Everest. This hypoxic environment is so important for multiplication and growth of stem cells. After birth, when oxygen levels rise, stem cell production declines and future stem cell production is restricted to a few locations, such as bone marrow. Researchers suggest stem cells from bone marrow migrate to various tissues, and such migration may be facilitated by even a few minutes of hypoxia every day. 7
  • Hypoxia supports formation of growth factors, such as vascular endothelial growth factor (VEGF), which leads to formation of new blood vessels (angiogenesis). With heart patients, this can lead to formation of coronary collateral circulation.7
  • Hypoxia induces the enzyme nitric oxide synthase (NOS), whose role is to produce the 1998 Noble Prize-winning panacea molecule nitric oxide.3 Nitric oxide (produced during nose breathing but not mouth breathing) is perhaps the body’s most potent defense against damage of oxidative stress (free radicals).7 Nitric oxide contributes to dilatation of coronary arteries when needed and is involved in the quick vasodilatation required for erection of the penis. Intermittent hypoxia can be an effective treatment for erectile dysfunction.7
  • Hypoxia has been shown to increase resistance of tissues to various insults and injuries, including radiation and aging.7
  • Hypoxia has been shown to protect and repair damaged DNA by inducing production of a transcription factor called p53, aka Guardian of the Genome.7

I hope this has convinced you to try some pranayama with breath holds. Want to learn how? Learn some Ayurveda and breath retention practices here.

NOTE: Before practicing breathing exercises with breath holds, check with your medical doctor to be sure you are a candidate for such a practice.

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Dr. John


  2. Swami Satyananda Saraswati. Asana Pranayama Mudra Bandha. Yoga Publications Trust, Munger, Bihar, India. First printing 1969

9 thoughts on “How Does Pranayama Work? The Science of Breath Retention (Kumbhaka)”

  1. I am curious about the relationship between intermittent hypoxia and one’s constitution and the season. More specifically, will intermittent hypoxia contribute to heat buildup in people with a pitta dosha or in the summer?

  2. Thanks for this article. I’m hoping this kind of breathing will help bring more health to me. I have problems with brain fog with various auto immune dis-eases. I’m anxious to learn it and get started! I’m doing heart-brain coherence meditation and am seeing some improvement with that. [it is causing detox symptoms, sometimes within minutes.]

  3. This article has been very insightful for me – hypoxia manifests first for a brief period though. Thereafter, Bohre’s effect comes into effect when the urge to breathe becomes dominant and breath then unfolds spontaneously.
    Dr. U. P. Singh

  4. Hello,
    Would intermittent hypoxia support the heal from cancer ? when i mean support i do not mean that it would heal the cancer i mean a parallel way to boost the immune system
    I am very curious about it !
    would be great to get answer on this
    thank you very much in advance

  5. Can anyone clarify, it was explained to me under the ice mans routine of breathing to Hyperventilate until your limits, then take a deep breath and hold to your limit. ?
    Is this the same thing as above?

    • Hi Fabio,

      No, the emphasis in Ice Mans breathing is higher oxygen and what I am teaching is how to build CO2 tolerance comfortably and how to activate the diaphragm which is weak with most.

      Both are good but subtle differences.

      Be Well,
      Dr. John


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