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The Wim Hof Method

Last week I did an Instagram post and blog on cold therapy. After this I had a couple of questions about the Wim Hof Method. I thought I’d boil down some of the key points in a video. I answer:

✨What is the Wim Hof Method of breathing?
✨What are its benefits?
✨What are the dangers of it?

For those of you who prefer reading I’ll pop the transcript, with some extra graphs to help explain things and references at the end – enjoy!


What the Wim Hof method of breathing is

Wim Hof breathing is controlled hyperventilation flowed by a breath hold – also know as intermittent hypoxic hypocarbia.

How to do Wim Hof breathing is whilst sitting or lying down in a safe and comfortable place, take 30-40 quick, deep breaths, inhaling through your nose and exhaling through your mouth. After these 30-40 breaths exhale and hold for as long as you can. Inhale again, as deep as you can, and hold it for 10 seconds. Repeat this sequence, often 3 times.

Carbon dioxide is the primary driver of air hunger, the signal we want to breathe. So by blowing this off before a breath hold, you can hold your breath for longer.

Some of the studies as to its potential benefits

(please go to the end of the transcript for references used for this video and more!)

So there are some health benefits of practicing the Wim Hof method, some more conclusive in the literature than others.  It is likely these are mediated by controlled activation of the sympathetic nervous system – which is activated by the hypoxic element of the Wim Hof method of breathing. A physiological stress after activation of the sympathetic nervous system in this way is thought to release physiological endocannabinoids – think of that feeling after doing a high-intense workout or going for a run.

Immune system modulation:

One study on the Wim Hof method I find particularly interesting used volunteers as participants, not Wim Hof himself. 12 people (so quite a small study) were randomised to be trained in the Wim Hof method of breathing for 10 days and 12 people who were not trained served as controls. After the 10 days both groups were injected with Escherichia coli endotoxin – a component of E.coli – a common bacterial infection. Those who’d had Wim Hof training had fewer symptoms of infection, transient respiratory alkalosis, raised adrenaline levels, increased anti-inflammatory cytokines (like interleukin 10) and lower levels of pro-inflammatory cytokines (like TNF-alpha and interleukin 6 and 8). Authors concluded that the sympathetic nervous system and immune system can be voluntarily influenced by practicing the Wim Hof method. Yet confounder of this study is a potential for the placebo to be a strong influence – the 12 people who weren’t trained had signed up hoping to learn the Wim Hof method and were indeed promised to be taught following the study. This suggests that those who signed up for the trial already believed in the power of the Wim Hof method and thus might effect the results of the study.

How it alters cold tolerance?

It was previously thought that the Wim Hof method of repeated cold exposure helped to activate brown fat and its non-shivering thermogenesis properties (i.e. it can help keep us warm without us shivering) – this has been disproved by studies several years ago – studies looked at MRI and PET scan to look at his anatomy and his brown fat wasn’t utilised more than someone else of his age. He did have, however, more brown fat than usual. Coincidentally Wim has an identical twin brother who doesn’t practice the Wim Hof method. Studying his brother also has high levels of brown fat, actually higher than Wim, so likely Wim is a genetic outlier in this respect and might help is ability to withstand the cold. At present I’m unaware of any research in humans that demonstrates repeated cold exposure generates greater volumes of brown fat – but please let me know if I’m wrong in this regard.

Research on Monks practicing Tummo (the ancient art of breathing that the Wim Hof method is based upon) and Wim Hof demonstrated that breathing in this manner lead to significant heat being generated by the inter-costal muscles, i.e. the physical work of breathing in this way generated heat – which, when blood passes into the chest can be used to heat the blood as an effective way to warm the blood stream – think of going for a run on a cold day!

Hyperventilation, as we discussed before, blows off carbon dioxide which is acidic, this leads to a term called respiratory alkalosis, which means your blood’s pH becomes slightly higher. This might be related to improved cold tolerance as nociceptors, pain receptors on pain detecting nerves, have acid-sensing ion channel 3 – this is a key target for pain-relieving medication research. A rise in pH seen with a reduction in carbon dioxide can deactivate them – rising the pain threshold.

Finally, there is some evidence controlled hyperventilation accelerates altitude acclimatisation via attenuation of the hypoxic ventilatory response – which is how someone responds to altitude and is a good marker of who will get altitude sickness. It’s thought that increasing your respiratory rate through this response can be protective against altitude sickness – if you do this consciously via the Wim Hof Method you can minimise the negative effects of having an inherently poor hypoxic ventilatory response. This is actually how the altitude sickness drug, acetazolamide, works – it generates a mild metabolic acidosis which stimulates our bodies to breathe harder to blow off carbon dioxide to re-balance our pH and as a by-product you get more oxygen. This does not mean I would recommend you use Wim Hof breathing to increase the rate you ascend to altitude, but if someone has altitude sickness or in an emergency situation it could be a useful took up your sleeve.

Why it can be dangerous

Carbon dioxide is vaso- and bronch-dilatory – that means it widens our blood vessels and breathing pipes. Therefore, when we reduce our levels of carbon dioxide these vessels and breathing tubes tighten, leading to reduced blood flow to brain and in turn dizziness and potential black outs. CO2 is acidic, so as you blow it off your blood becomes slightly more alkaline… A term known as respiratory alkalosis (which we touched on above).

Back at the beginning of the 20th century a Danish physiologist called Bohr discovered the oxy-heamoglobin dissociation curve – sounds complicated so I’ll break it down. 4 oxygen molecules bind to haemoglobin which is in red blood cells. This allows oxygen to travel around your body. Oxygen loads on to haemoglobin in the lungs and gets offloaded in the tissues. One of the mechanisms which helps this offloading process is the higher level of carbon dioxide in the tissues. Carbon dioxide makes oxygen bind less strongly to the haemoglobin by slightly changing the shape of haemoglobin and as such it is released into the tissues. The red blood cell then travels back to the lungs with carbon dioxide on board and the process is reversed, offloading carbon dioxide and picking up more oxygen and the process is repeated.

Blowing off carbon dioxide and the resulting respiratory alkalosis (that slight increase in your blog pH) increases the strength of the bond between haemoglobin and oxygen. This means that less oxygen is released to your tissues….

Check out this graph:

oxyHB curve

(source for graph =

So whilst your air hunger is lower, the availability of oxygen to the tissues is also reduced! This combined with vasoconstriction due to the lack of carbon dioxide, oxygen delivery to the brain can be reduced, risking dizziness and/or black outs. 

…. Therefore, please do Wim Hof if in a safe place, sitting down ideally. As Wim Hof advises, not whilst driving! And do not combine Wim Hof breathing with cold water exposure…. Blacking out in water is never a good idea and even worse if there is a layer of ice on top.

Another warning is about cold shock – cold air inhalation can precipitate heart attacks – so please seek medical advice before starting any cold therapy, especially if you have any heart disease or epilepsy. The cold shock response has resulted in the deaths of many who have fallen over-board – it basically paralyses you whilst triggering you to take a sharp inhalation. Some things we can all do is to gradually increase the time of cold exposure and how cold the water is you’re getting into – don’t go from never having a cold-ish shower to jumping into ice water. And always ensure you have someone with you whilst you’re practicing cold emersion.

So what’s the conclusion? 

Some of the likely benefits of Wim Hof Method are – short term improvements in the immune system, improved sleep, mental wellbeing and stress management and cold tolerance – and likely more. Yet Wim Hof breathing is not a panacea, and you can get similar benefits from other breathing and meditation practices.

Some interesting references:

Voluntary activation of the sympathetic nervous system and attenuation of the innate immune response in humans

The role of outcome expectancies for a training program consisting of meditation, breathing exercises, and cold exposure on the response to endotoxin administration: a proof-of-principle study Frequent Extreme Cold Exposure and Brown Fat and Cold-Induced Thermogenesis: A Study in a Monozygotic Twin

The role of outcome expectancies for a training program consisting of meditation, breathing exercises, and cold exposure on the response to endotoxin administration:a proof-of-principle study

Neurocognitive and Somatic Components of Temperature Increases during g-Tummo Meditation: Legend and Reality

Kirsi, A., Virtanen, M. D., Lidel, M. E., Orava, J., Heglind, M., Westergren, R., Niemi, T., Taittonen, M., Laine, J., Savisto, N. J., Enerbäck, S.,& Nuutila, P. (2009). Functional brown adipose tissue in healthy adults. The New England Journal of Medicine, 360, 1518-1525 Controlled Hyperventilation After Training May Accelerate Altitude Acclimatization [Letter]

The Influence of Concentration/Meditation on Autonomic Nervous System Activity and the Innate Immune Response: A Case Study

“Brain over body”–A study on the willful regulation of autonomic function during cold exposure 

Emma x


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