Finland’s Arctic circle might not seem like a great place to
run a marathon barefoot and in shorts—unless you’re Wim Hof. Hof, better known
as “The Iceman,” has attained roughly two dozen world records by completing
marvellous feats of physical endurance in conditions that would kill others.
Yet even he was understandably nervous the night before his 26-mile jaunt at -4
degrees Fahrenheit.
“What did I get myself into?” he recalls thinking. But from
the moment his bare toes hit the snow, he began to feel “surprisingly good.”
The 59-old Dutchman has climbed Mount Everest in Nepal and
Mount Kilimanjaro in Tanzania—Africa’s tallest peak—wearing shorts. “I’ve done
about anything I can fantasize about in the cold,” Hof said in an interview. He
holds the Guinness World Record for longest swim under ice, and has also
endured the extremes of dry heat, running a half marathon through the Namib
Desert without drinking any water.
Athletes aren’t the only ones interested in these feats. Now
doctors have put the Iceman’s brain—and body— on ice in an effort to better
understand the mental and physical mechanisms that allow Hof to seemingly defy
the laws of nature. Otto Musik, a pediatrician in Wayne State University’s
School of Medicine and his coauthors recently put Hof into a magnetic resonance
imaging (MRI) machine while exposing him to cold water and analyzed what
happened inside his body.
The results, published recently in a study in the journal
NeuroImage, might at first sound more like mumbo jumbo than fact: Researchers
found that Hof is able to use his mind to artificially induce a stress response
in his body that helps him resist the effects of cold. Musik frames it as a
case of “brain over body,” in which Hof activates an internal painkiller
function by conducting breathing exercises, then exposing himself to a threat
like extreme, sudden cold.
“By accident or by luck he found a hack into the
physiological system,” Musik says. He adds that this “hack” allows Hof to feel
euphoric while in a freezing cold environment that would be unpleasant in
normal circumstances. The researchers tested Hof’s responses alongside around
30 control subjects.
The pediatrician had conducted other research on the way the
human body reacts to extreme temperatures. When he heard about a man who sits
in buckets of ice cubes for hours at a time and walks up the Himalayas like it
was a summer stroll through a wine vineyard, he was intrigued.
Hof attributes his success to what he has dubbed the Wim Hof
Method, a type of conditioning that involves a series of breathing exercises he
says anyone can replicate. Rather than by luck or accident, Hof says he learned
his technique by trial and error while going out into nature: “I had to find
the interconnection of my brain together with my physiology.”
The technique first requires relaxation; Hof says he must
find a comfortable place to lie down like a sofa or bed. Then he begins a
series of deep breathing exercises for several minutes, often prompting a kind
of tingling in parts of his body—a sign of hypocapnia, or low carbon dioxide in
his blood. “That’s what nature meant us to do, breathe deep when we are
stressed,” Hof says.
To a degree, Musik’s research supports Hof’s this
hypothesis. After Hof went through his preparation exercises to induce this effect,
Musik put the Iceman into the MRI machine in a special suit they shot through
with shot cold water and hot water in five minute intervals. Some previous
research has shown that this exercise makes Hof’s blood more alkaline, since it
becomes saturated with oxygen.
Musik found that, when exposed to cold, Hof activates a part
of the brain that releases opioids and cannabinoids into the body. These
components can inhibit the signals responsible for telling your body you are
feeling pain or cold, and trigger the release of dopamine and serotonin. The
result, Musik says, is a kind of euphoric effect on the body that lasts for
several minutes.
“Your brain has the power to modify your pain perception,”
he says, adding that this mechanism is particularly important for human
survival. Pain, and the feeling of cold, are basically your body’s way of
telling you something is wrong. Since humans instinctively look to remove the
source of pain or alleviate any sensation of cold, feeling hurt can help us
survive.
But the pain mechanism isn’t always useful. Musik gives the
hypothetical example of someone spraining their ankle while being chased by a
tiger. Many won’t actually feel the sprain in the thick of the moment since
your brain senses the greater danger presented by the tiger. It makes use of
opioids and cannabinoids to inhibit pain signals to allow you to run away and
save yourself despite the injured foot. “Your ankle is not important in this
context,” Musik says.
Rather than being a study of brain over body, the research
really parallels other work on how mental training of a particular skill can
prompt changes in the brain, says Magda Osman, an associate professor of
experimental psychology at the University of London. One study in 2006 looked
into the brains of London taxi drivers compared to bus drivers. Taxi drivers
had more grey matter in their hippocampus, which is the center of hand-eye
coordination skills, ostensibly due to a higher level of navigational skills.
“When we spend a vast amount of time cultivating our mental
and physical skills, this translates into neurological differences when
compared to those that don’t practice these skills to the same degree,” says
Osman.
Musik’s study offers a twist to this thinking: It shows that
breathing, often thought of as an automatic skill, can be willfully controlled.
Harnessing breathing can result in increased activity in the parts of the brain
that deal with thought and action, Osman says, which over time can lead to
significant physical changes.
Yet stress-induced analgesia, Hof attests, will only last a
few minutes at best. For him to continue his ability to resist the feeling of
cold, Musik believes that his body needs to anticipate the continued effect,
which in turn actually helps his body maintain the state it’s in.
“The placebo effect is real,” he says. “This is actually by
generating in your cortex a certain expectation, and this expectation is
fulfilled.” He adds that the expectation triggers the release of more opioids,
serotonin, and dopamine in a kind of self-fulfilling cycle. In other words, the
longer that people jump into holes in the ice practicing this method, the
easier it could get as they get more confident in their expectations.
There may not be any pressing need for the world’s
population to learn how to run barefoot through the snow, Hof says, but the
technique could have other uses. Some of Hof’s patients claim the method has
helped them reduce eczema symptoms or other autoimmune conditions.
While he isn’t totally clear on the biological processes
that help Hof resist frostbite, Musik does thinks Hof’s method might actually
suppress tissue swelling and other immune reactions. He and his coauthors write
that Hof and his followers’ abilities to take more control of their autonomous
systems might have implications in dealing with clinical syndromes.
However, while Hof’s method may work for short periods in
terms of tricking the mind into ignoring extreme cold, it is less clear how the
technique might help human bodies resist the physical effects that one might
expect from climbing snowy mountains in shorts. (Nor does it explain being able
to survive in the desert without water.)
“You can think whatever you want but your body still freezes
and you are dead,” Musik says.
Muzik O, Reilly KT, Diwadkar VA. "Brain over
body"-A study on the willful regulation of autonomic function during cold exposure.
Neuroimage. 2018 May 15;172:632-641.
Abstract
The defense of body temperature against environmental
thermal challenges is a core objective of homeostatic regulation governed by
the autonomic nervous system. Autonomous mechanisms of thermoregulation are
only weakly affected by top-down modulation, allowing only transient tolerance
for extreme cold. There is however, anecdotal evidence of a unique set of
individuals known for extreme cold tolerance. Here we present a case study of a
57-year old Dutch national, Wim Hof, the so-called "Iceman", with the
ability to withstand frequent prolonged periods of extreme cold exposure based
on the practice of a self-developed technique involving a combination of forced
breathing, cold exposure and meditation (collectively referred to as the Wim
Hof Method, henceforth "WHM"). The relative contributions of the
brain and the periphery that endow the Iceman with these capabilities is
unknown. To investigate this, we conducted multi-modal imaging assessments of
the brain and the periphery using a combination of fMRI and PET/CT imaging.
Thermoregulatory defense was evoked by subjecting the Iceman (and a cohort of
typical controls) to a fMRI paradigm designed to generate periods of mild hypothermia
interspersed by periods of return to basal core body temperature. fMRI was
acquired in two separate sessions: in a typical (passive) state and following
the practice of WHM. In addition, the Iceman also underwent a whole body PET/CT
imaging session using the tracers C11-hydroxyephedrine (HED) and
18F-fluorodeoxyglucose (FDG) during both thermoneutral and prolonged mild cold
conditions. This acquisition allowed us to determine changes in sympathetic
innervation (HED) and glucose consumption (FDG) in muscle and fat tissues in
the absence of the WHM. fMRI analyses indicated that the WHM activates primary
control centers for descending pain/cold stimuli modulation in the
periaqueductal gray (PAG), possibly initiating a stress-induced analgesic
response. In addition, 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. However, the
activation of brown adipose tissue (BAT) was unremarkable. Finally, forceful
respiration results in increased sympathetic innervation and glucose
consumption in intercostal muscle, generating heat that dissipates to lung tissue
and warms circulating blood in the pulmonary capillaries. Our results provide
compelling evidence for the primacy of the brain (CNS) rather than the body
(peripheral mechanisms) in mediating the Iceman's responses to cold exposure.
They also suggest the compelling possibility 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.
