MRI, PET reveals how extreme athlete ‘The Iceman’ withstands sub-zero weather
Wayne State University radiologists have unlocked at least part of the puzzle behind extreme athlete Wim “The Iceman” Hof’s uncanny ability to withstand freezing temperatures—and it’s shed light on the degree of control the brain can have over the human body.
Hof, a 59-year-old Dutchman who’s withstood sub-zero temperatures while hiking both Mount Everest and Mount Kilimanjaro in shorts and not much else, attributes his abilities to the “Wim Hof Method,” which involves a series of relaxation and deep breathing exercises.
Hof recently underwent fMRI and PET testing at Wayne State, where researchers hoped imaging could offer insight into how his brain withstands the harsh, prolonged cold.
Over three days, Hof practiced his breathing exercises before donning a whole-body suit infused with temperature-controlled water and laying down in the scanner. His brain response was measured as Otto Musik, PhD, and colleagues exposed him to extremely cold and hot temperatures at five-minute intervals.
“From our previous studies, 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,” Musik, a professor of pediatrics, neurology and radiology, said in a release from Wayne State. “However, we observed more substantial differences in an area called periaqueductal gray matter, located in the upper brainstem.”
That area is linked to the control of sensory pain, Musik said. Somehow, Hof was able to stimulate a bodily response to release opioids and cannabinoids to his brain, creating feelings of well-being and reduced anxiety. The scientists said his skin resistance to the cold could also stem from increased sympathetic innervation and glucose consumption in his intercostal muscle, allowing him to generate heat that circulates through his body.
“The willful 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,” Muzik said.
Fellow professor and investigator Vaibhav Diwadkar, PhD, called the possibilities behind these control mechanisms “too intriguing to ignore,” but Musik was more frank.
“It is not mysterious to imagine that what we practice can change our physiology,” he said. “The goal of our research is to ascertain the mechanisms underlying these changes using objective and scientific analyses, and to evaluate their relevance for medicine.”
The researchers' findings have been published in NeuroImage.
After graduating from Indiana University-Bloomington with a bachelor’s in journalism, Anicka joined TriMed’s Chicago team in 2017 covering cardiology. Close to her heart is long-form journalism, Pilot G-2 pens, dark chocolate and her dog Harper Lee.