Researchers have discovered what gives Dutch adventurer Wim Hof, known as “The Iceman,” an unusual resistance to the cold.
Published in the journal NeuroImage, the study provides new information about how Hof’s brain responds during cold exposure and how he is able to stave off hypothermia. The findings could have relevant applications in the management of certain autoimmune and psychiatric disorders.
Hof has demonstrated an uncanny ability to resist prolonged exposure to the cold. He holds several world records, including the record for spending almost two hours in an ice bath. It is recommended that adults avoid doing so for more than ten minutes.
Hof attributes his ability to withstand cold temperatures for long periods of time to a set of techniques he calls the Wim Hof Method, which includes breathing and mediation exercises.
Until now, scientists were perplexed by Hof’s ability and wanted to understand how it was physically possible. As part of a wider study looking into how the human brain responds to temperature changes, a team of researchers from Wayne State University’s School of Medicine in Michigan studied how Hof’s brain responds to full-body cold exposure.
Researchers manipulated cold exposure by changing the temperature of water in a specially designed suit that Hof wore during the experiment. They observed reactions in his brain using functional magnetic resonance imaging (fMRI) and reactions in his body using positron emission tomography (PET).
Compared to the control group, Hof showed increased brain activity in an area of the brain that controls pain.
“We expected The Iceman to show significant brain activations in a region known as the anterior insula, where the brain’s higher thermoregulatory centers are located,” said Dr Otto Muzik, a professor of pediatrics, of neurology and of radiology and co-author of the study. “However, we observed more substantial differences in an area called periaqueductal gray matter, located in the upper brainstem.”
Muzik noted this part of the brain is thought to regulate pain by releasing opioids, which affect responses to stress and pain, and cannabinoids, which lighten mood. Together, the chemicals can create a sense of euphoria similar to that produced by opioid drugs, such as morphine.
Researchers speculated that Hof’s meditation and breathing techniques trigger the release of these chemicals. “This effect has the potential to create a feeling of well-being, mood control and reduced anxiety,” they said in a press release, thereby contributing to Hof’s ability to withstand extremely cold temperatures.
Researchers also found that Hof’s skin temperature was not significantly affected by cold exposure.
“The wilful regulation of skin temperature – and, by implication, core body temperature, even when the body is being stressed with cold – is an unusual occurrence and may explain his resistance to frostbite,” said Muzik.
The authors suggested their study opens up “intriguing possibilities” and that the findings could have relevant applications in the fields of behavioural and physical health.
The Wim Hof Method could help people manage a variety of medical conditions, ranging from immune disorders to psychiatric conditions, such as anxiety and mood disorders, according to Dr Vaibhav Diwadkar, study co-author and professor of psychiatry and behavioural neurosciences at Wayne State University’s School of Medicine.
“We are in the process of implementing interventional studies that will evaluate these questions using behavioural and biological assessments,” said Diwadkar. “These possibilities are too intriguing to ignore.”