Alongside cold showers and ice baths, a major part of the Wim Hof Method is a breathing technique with the following sequence:

30 deep breaths faster than normal pace (controlled hyperventilation) Holding the breath at neutral lung pressure for as long as you can do so comfortably A short breath hold for about 15 seconds with the lungs full of air

There are many resources online explaining in detail how to perform this – in particular the official Fundamentals course by Wim Hof* [update: use COVID35 for 35% off]. It is also found in yogic teachings, where it is named Rechaka Pranayama.

But what exactly is happening inside the body during a session of Wim Hof Method breathing? What are the real benefits and why? Let’s take a more detailed look at the Biology…

Holding your breath without the Wim Hof Method

If you hold your breath right now you’ll probably feel an urge to breathe after about 30-40 seconds. This is not because you run out of Oxygen but because the Carbon Dioxide (CO2) level in your bloodstream becomes too high.

When your CO2 levels become too high you feel discomfort, and your diaphragm (below your lungs) may start to twitch as a reflex to force you to breathe.

Phase #1: Controlled Hyperventilation

The main purpose of this phase is to reduce the CO2 levels as much as possible while remaining in a relaxed state. For example the following pieces of advice are commonly given:

Take very deep breaths (“fully in”)

Breathe out as relaxed as possible by simply relaxing the lungs (“let it go” / “never force”)

Breathe somewhat more quickly than natural

During normal breathing your blood O2 levels are around 98% (depending on factors including altitude) so contrary to some misunderstandings this doesn’t really increase O2 levels because it can’t go higher than 100% anyway. You do not in fact get “charged with Oxygen”!

Three common sensations that people experience in these situations are tingling and light-headedness. For some individuals in very deep sessions they might also experience muscle cramps such as the thumb and fingers getting tense. Why does this happen?

Tingling: these pins-and-needles feelings are from the nerves randomly firing, ultimately caused by the low CO2 levels in the blood.

these pins-and-needles feelings are from the nerves randomly firing, ultimately caused by the low CO2 levels in the blood. Light-headedness & muscle cramps: usually, hemoglobin collects O2 at the lungs and releases it around the body. However when the CO2 level is low, the O2 attaches too strongly to the hemoglobin (known as the Bohr Effect) and so the O2 isn’t released so much to the cells that require it.

Additionally, the deep diaphragmatic breathing (“starting from the stomach”) stimulates the vagus nerve of the parasympathetic nervous system, which reduces the body’s fight-or-flight response and causes it to relax. This causes some of the benefits and also helps with the retention in the next phase.

Phase #2: Retention at neutral lung pressure

The purpose of this phase is to decrease the blood O2 level from ~100% to a safe but unnaturally low level for a short period of time. The body responds to this short stress in a variety of very positive ways (a valid example of hormesis) – that form the majority of the health benefits of this exercise.

Remember that in general you can hold your breath until your blood CO2 levels rise above a certain threshold? After reducing the CO2 levels in Phase #1, we can hold our breath much longer until the CO2 eventually rises that high – this can be 3-4 minutes for some people.

However your body is using up O2 throughout the retention, so after about 1 minute your blood O2 is lower than it can normally get. When the O2 level drops far enough, it triggers the body into doing a couple of cool things:

After (very approximately) 90 seconds, a significant amount of adrenaline (epinephrine) is produced.

(epinephrine) is produced. The hypoxia-inducible factor 1a gene is expressed, to help the body make adjustments to better thrive in a low-O2 environment.

Phase #3: Recovery breath (short retention on full inhale)

When we finally need to breathe, we take a very deep breath and hold for about 15 seconds. The purpose of this is to quickly reset the body’s O2 levels. As the blood CO2 levels are now at normal or elevated levels, the body will use this O2 efficiently (again, due to the Bohr Effect).

Most practitioners of this breathing technique could hold this retention much longer than 15 seconds, but Wim Hof recommends this length of time for an efficient reset. Too long, and O2 levels will start to drop again.

At the end you should feel a natural “high” feeling mainly from the relaxation and adrenaline 🙂

Health Benefits of Breathing Technique:

Firstly, please know that the Wim Hof Method does not give you control over your immune system with your thoughts. However, the breathing exercise has various effects on the body (including the immune system) that are difficult to achieve with any other natural method.

For the scientific literature about the most famous experiment where Wim Hof taught 18 subjects to resist the E. Coli endotoxin, read here. For information about controlling your autonomous nervous system with your thoughts, Google for the placebo effect – which is real and works.

The real health benefits to this method can be placed into 3 groups according to their cause:

(1) Benefits from stimulating the parasympathetic nervous system during the deep breaths:

Reduced stress during the exercise and for some time afterwards

during the exercise and for some time afterwards Increased heart-rate variability (HRV)

(2) Benefits from the hypoxia (low O2) during the retention:

More red blood cells are produced so the body can transport O2 more efficiently in the future, so you’ll feel like you have more energy

are produced so the body can transport O2 more efficiently in the future, so you’ll feel like you have Athletes benefit from the red blood cells for short endurance sports, such as football and middle-distance foot races – increased VO2 max

sports, such as football and middle-distance foot races – You can acclimatize to high altitudes before arriving because of the additional red blood cells

before arriving because of the additional red blood cells Stem cells are able to move more easily around the body to help with repair and anti-aging [still unconfirmed but has been shown in rats to increase neural cell regeneration in the brain]

are able to move more easily around the body to help with repair and anti-aging [still unconfirmed but has been shown in rats to increase neural cell regeneration in the brain] The body also produces more mitochondria – the part of the cell that produces creates energy – because it is preparing in case it needs to perform anaerobic respiration in the future

– the part of the cell that produces creates energy – because it is preparing in case it needs to perform anaerobic respiration in the future The hypoxia-inducible factor 1a has been shown to help mice readjust their circadian rhythm – so it may help shift workers and people suffering from jet lag

(3) Benefits from the adrenaline release during the retention:

Increased white blood cells – in fact many people who regularly perform this breathing technique report that they almost never get sick

– in fact many people who regularly perform this breathing technique report that they almost never get sick Reduced inflammation – this can help to some extent with many medical issues such as: Crohn’s disease Depression Joint injuries Rheumatoid arthritis

– this can help to some extent with many medical issues such as: Cortisol (the stress hormone) decreases a few hours after the exercise and stays lower all day

Dangers of the Wim Hof Method Breathing

During Phase #2 (the retention) it can occasionally happen that your O2 levels get too low before you feel the urge to breathe caused by the high CO2. When this happens you will lose consciousness briefly, begin to breathe normally and wake up wondering why your retention was longer than usual. This is nothing to worry about (take it easier next time!) but because of this there are some situations where it is dangerous and irresponsible to perform this method:

Swimming: in this case you will drown and die

in this case you will drown and die Driving: in this case you can cause an accident

in this case you can cause an accident In the shower or anywhere standing: in this case you can fall and hurt yourself

The dangers are serious enough that free-divers are banned from using this technique for their dives.

How to Achieve a Longer Retention:

Wim Hof makes it clear that this method is not a competition – it is for the benefits to health. However if your retentions are always under 2 minutes then I would recommend using the following checklist to help extend the time for additional benefits. If your retentions are generally 2+ minutes then it is not important to extend the retentions but you you could increase the hypoxia-related benefits by doing so.

Please also remember – when the body feels discomfort near the end of the retention and the diaphragm is twitching, you should end the retention – never force!

Be more relaxed before starting the breathing exercise – when you are active or stressed your body converts O2 in to CO2 more rapidly: Retentions are shorter when you’ve recently been active Retentions can be shorter when you have recently eaten Make yourself physically comfortable – e.g. lying down rather than sitting Make yourself mentally comfortable – e.g. put your phone on silent, ensure that no-one will disturb you Mentally scan your body during the retention to find tense muscles to relax

before starting the breathing exercise – when you are active or stressed your body converts O2 in to CO2 more rapidly: Breathe more efficiently: Breathe more deeply during the power breaths to expand the surface area of the lungs so you can remove more CO2 per breath Breathe out in a relaxed way (just let the muscles snap back into their relaxed position) so that you aren’t producing too much CO2 during the effort of breathing Breathe out more deeply to expel more CO2 – but always remain very relaxed Experiment by changing the pace of the breathing

Take more than 30 breaths

Continue training – with practice you’ll understand your body better, your body will have more red blood cells to store Oxygen, you’ll be able to relax more, and your body will become more accustomed to high levels of CO2

More Information:

This article was created by Daniel Timms. If you have any questions about the content here, feel free to contact me.

This breathing technique comes from the Wim Hof Method – which also incorporates other breathwork exercises, yogic movement, and cold exposure, designed (to quote Wim himself) to make you “happy, strong and healthy”.

The official 10-week Fundamentals course currently has a discount of 35% off (coupon code COVID35). Claim that discount at checkout: 10-week Fundamentals course*

This article was written in December 2018 to provide information about this breathing technique, to improve knowledge of breathwork and its effects. In April 2020, the nice people at Wim Hof’s company (InnerFire) provided me with affiliate links for this page (marked with an asterisk*) so that when you buy the Fundamentals course via these links, they can thank me with a small commission that helps fund this site. The price you pay is the same – or actually less, if you use the coupon suggested!

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