Wim Hof, the Iceman

Wim Hof, the Iceman, is extraordinarily resistant to extreme cold. His Wim Hof Method (WHM) combines breathing exercises, cold exposure, and meditation. Hyperventilation has been shown to reduce the body’s response to inflammation, but Hof’s extravagant claims of health benefits are not supported by scientific evidence.

Wim Hof, also known as “The Iceman”, is a 61-year-old Dutch extreme athlete famous for his ability to withstand extreme cold. He has set several Guinness World Records for swimming under ice, for prolonged full-body contact with ice, and for a barefoot half-marathon on ice and snow.

The Wim Hof Method 

He promotes his Wim Hof Method (WHM) which consists of three pillars: breathing, cold therapy, and commitment (or meditation). The breathing consists of three phases: 30-40 cycles of hyperventilation are followed by breath retention and finally a recovery breath. The cold is applied through cold showers and ice baths. The third pillar trains the brain to improve willpower and self-control; and teaches people to observe their thoughts, emotions and impulses, without identifying or acting on them.

He was featured in Gwyneth Paltrow’s Netflix series Goop Lab, where he taught Goop staff members to tolerate sitting in the snow and plunging into frigid water wearing only skimpy swimsuits. He explained that his breathing method raises the body’s pH levels. Of course it does, because hyperventilation increases the excretion of carbon dioxide; but that’s not a good thing. It produces a temporary state of respiratory alkalosis, an abnormal disruption of acid-base homeostasis. When hyperventilation stops, the acid-base balance quickly returns to normal. If hyperventilation persists, the person will pass out, and the body’s normal compensatory mechanisms will be able to take over and re-establish homeostasis. Wim Hof cautions against using his method when diving or driving, where passing out could be fatal. In fact, there have been several reports of deaths resulting from his methods.

Alleged benefits

He claims a multitude of benefits including increased energy, better sleep, heightened focus and determination, improved sports performance, increased willpower, reduced stress levels, greater cold tolerance, faster recovery, enhanced creativity, and a stronger immune system. He also suggests that his WHM may be useful to treat cancer and many other specific diseases.

Scientific studies

Wim has an identical twin who lives a sedentary lifestyle without exposure to extreme cold. A study comparing their responses to a challenge of cold exposure found no difference in cold-induced thermogenesis, suggesting that habitual exposure to extreme cold was not a factor. However, both twins did have similarly high levels of cold-induced thermogenesis. This was attributed to the brothers’ practice of a g-tummo-like breathing technique, suggesting that the vigorous isometric respiratory muscle contractions caused increased heat production.

G-tummo breathing techniques have long been practiced in Tibet and are reported to enable practitioners to voluntarily raise their body temperatures. A 2013 study found that forceful breathing during g-tummo increases body heat production, but only temporarily; meditation is required to sustain the response.
“The Influence of Concentration/Meditation on Autonomic Nervous System Activity and the Innate Immune Response” was a case study of Wim Hof by a group of researchers in The Netherlands. It was published in Psychosomatic Medicine in 2012. With ice immersion, the cytokine inflammatory response was attenuated; and with intravenous administration of an endotoxin, the cortisol levels were higher than in previously studied individuals. Their conclusion:

The concentration/meditation technique used by this particular individual seems to evoke a controlled stress response. This response is characterized by sympathetic nervous system activation and subsequent catecholamine/cortisol release, which seems to attenuate the innate immune response.

Another case study of Wim Hof, the 2018 report “Brain Over Body” in NeuroImage by Musik et al. used fMRI and PET/CT imaging. They found changes in sympathetic innervation and glucose consumption when he used his Wim Hof Method (WHM). Imaging showed that “the WHM also engages higher-order cortical areas (left anterior and right middle insula) that are uniquely associated with self-reflection, and which facilitate both internal focus and sustained attention in the presence of averse (e.g. cold) external stimuli”. Their conclusion suggested that “the WHM might allow practitioners to develop higher level of control over key components of the autonomous system, with implications for lifestyle interventions that might ameliorate multiple clinical syndromes”.

In another study from The Netherlands, 30 healthy Dutch males were randomized into an intervention group and a control group. The first group was trained in “third eye” meditation, voluntarily exposed themselves to cold in various ways (such as taking cold showers), and were instructed in breathing techniques. Then they were injected with an endotoxin. In the intervention group, epinephrine levels increased, and anti-inflammatory markers increased, while levels of proinflammatory markers and flu-like symptoms decreased. They claimed to have demonstrated that voluntary activation of the sympathetic nervous system suppresses the innate immune response.

An open-label “proof of concept” study of 24 patients with axial spondyloarthritis was published in PlosOne in 2019. Participants were trained by Wim Hof and then exposed to cold. There was a significant decrease in one inflammatory marker (ESR sedimentation rate) but not in others. They concluded that “the add-on training program used in this study can safely be applied in patients with axial spondyloarthritis and potentially modulates inflammatory response”. They acknowledged several limitations of their study and called for further research.

Conclusion: The science is lacking

A Dutch skeptic, Pepijn van Erp, said it best. He reviewed the scientific evidence and wrote an article about ““Wim Hof’s Cold Trickery“. He says science has shown that hyperventilation reduces the body’s inflammatory response; but that isn’t always desirable. And when it is desirable, that doesn’t necessarily mean there are any practical clinical applications. Inflammation is a normal protective response that promotes healing, and it only becomes a problem when an overactive immune response causes autoimmune diseases. He points out that most of Wim Hof’s claims are just speculation and are not supported by any scientific evidence. I agree. His extraordinary resistance to cold is an interesting fact worthy of further investigation, but I don’t think it justifies taking cold showers or hyperventilating.

This article was originally published in the Science-Based Medicine Blog.

Dr. Hall is a contributing editor to both Skeptic magazine and the Skeptical Inquirer. She is a weekly contributor to the Science-Based Medicine Blog and is one of its editors. She has also contributed to Quackwatch and to a number of other respected journals and publications. She is the author of Women Aren’t Supposed to Fly: The Memoirs of a Female Flight Surgeon and co-author of the textbook, Consumer Health: A Guide to Intelligent Decisions.

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