Hof immersed in an ice bath, 2007
|Born||20 April 1959|
Sittard, Limburg, Netherlands
|Other names||The Iceman|
Wim Hof (born 20 April 1959), also known as The Iceman, is a Dutch extreme athlete noted for his ability to withstand freezing temperatures. He has set Guinness world records for swimming under ice and prolonged full-body contact with ice, and still holds the record for a barefoot half-marathon on ice and snow. He attributes these feats to his Wim Hof Method (WHM), a combination of frequent cold exposure, breathing techniques and meditation. But skeptics question whether or not his identical twin brother's similar brown fat composition shows that Wim's tolerance of cold is mostly a result of his genetics.
Preliminary and proof-of-principle studies of Hof's method, as well as similar breathing practices, have shown that hyperventilating can temporarily suppress the innate immune response as well as temporarily increase heart rate and adrenaline levels. Exposure to even mild cold temperatures has been previously shown to increase "brown fat" which is associated with better blood glucose regulation. Hof is the subject of The New York Times bestselling book What Doesn't Kill Us, which tells the story of how the investigative journalist Scott Carney took an assignment supposedly to debunk the WHM but ended up learning Hof's techniques. He is also the subject of the Vice documentary Iceman in which journalist Matt Shea learned the WHM.
Hof was born in Sittard, Limburg, Netherlands as one of nine children, one of whom (Andre) is an identical twin brother. When he was 17 he felt a sudden urge to jump into the freezing cold water of the Beatrixpark canal.
On March 16, 2000, Hof set the Guinness World Record for farthest swim under ice, with a distance of 57.5 metres (188.6 ft). The swim at a lake near Pello, Finland was filmed for a Dutch television program, and a test run the previous day almost ended in disaster when his cornea started to freeze and he was swimming blind. A diver rescued him as he was starting to lose consciousness. A new record of 76.2 metres (250 ft) was set by Stig Severinsen in 2013.
On January 26, 2007, Hof set a world record for fastest half marathon barefoot on ice and snow, with a time of 2 hours, 16 minutes and 34 seconds.
Hof has set the world record for longest time in direct, full-body contact with ice a total of 16 times, including 1 hour, 42 minutes and 22 seconds on January 23, 2009; 1 hour, 44 minutes in January 2010; and 1 hour 53 minutes and 2 seconds in 2013. This was surpassed in 2014 by Songhao Jin of China, with a time of 1 hour, 53 minutes and 10 seconds.
In 2007 Hof climbed to an altitude of 7,200 metres (23,600 ft) on Mount Everest wearing nothing but shorts and shoes, but failed to reach the summit due to a recurring foot injury. In February 2009, Hof reached the top of Mount Kilimanjaro within two days wearing only shorts. In September, he ran a full marathon in the Namib Desert without water, under the supervision of Dr. Thijs Eijsvogels.
Wim Hof Method
Wim Hof markets a regimen, the Wim Hof Method (WHM) that he claims will help with, among other things, sleep, willpower, sports performance, stress, creativity and immune system. Testimonials on his website claim to have improved illnesses such as rheumatoid arthritis and multiple sclerosis. The method involves three "pillars": cold therapy, breathing and meditation. It has similarities to Tibetan Tummo meditation and pranayama, both of which employ breathing techniques.
There are many variations of the breathing method. The basic version consists of three phases as follows:
- Controlled hyperventilation: The first phase involves 30 cycles of breathing. Each cycle goes as follows: take a powerful breath in, fully filling the lungs. Breathe out by passively releasing the breath, but not actively exhaling. Repeat this cycle at a steady pace thirty times. Hof says that this form of hyperventilation may lead to tingling sensations or light-headedness.
- Exhalation: After completion of the 30 cycles of controlled hyperventilation, take another deep breath in, and let it out completely. Hold the breath for as long as possible.
- Breath retention: When strong urges to breathe occur, take a full deep breath in. Hold the breath for around 15 - 20 seconds and let it go. The body may experience a normal head-rush sensation.
These three phases may be repeated for three consecutive rounds.
Resistance to cold
When exposed to cold, the human body can increase heat production by shivering, or non-shivering thermogenesis in which brown adipose tissue (BAT), also known as brown fat, converts chemical energy to heat. Mild cold exposure is known to increase BAT activity. A group of scientists in the Netherlands wondered whether frequent exposure to extreme cold would have comparable effects. The Hof brothers are identical twins, but unlike Wim, Andre has a normal sedentary lifestyle without exposure to extreme cold. The scientists had them practice Wim's breathing exercises and then exposed them to the lowest temperature that would not induce shivering. They found no significant difference in the response. Both had rises of 40% of their metabolic rates over the resting rate, compared to a maximum of 30% observed in young adults. However, their brown fat percentage – while high for their age – was not enough to account for all of the increase. The rest was due to their vigorous breathing, which increased the metabolic activity in their respiratory muscles.
The related g-Tummo practice is called "psychic heat" practice because it is accompanied by intense sensations of heat in the spine. It involves special breathing accompanied by meditation involving mental images of flames at certain locations in the body. There are two types of breathing, "forceful" and "gentle". A scientific study found that only the forceful type results in an increase in body temperature, and that meditation was required to sustain the temperature increase. 
Health benefits of cold exposure
Several studies have shown that exposure to cold increases brown fat and the capacity for non-shivering thermogenesis. It also reduces white adipose tissue, the form of fat related to obesity. There is some evidence that brown adipose tissue may reduce the risk of diabetes through uptake of glucose and lipids. Practices such as cold bathing have been common at least as far back as Roman times, and numerous health benefits have been claimed, but long-term benefits are not yet supported by randomized controlled trials.
Immune system suppression
Hearing that some researchers at the Radboud University Medical Center in the Netherlands had a way of measuring the immune response in humans, Hof visited them and stated that he could modulate his immune system. Although he thought it unlikely, Peter Pikkers was impressed by Hof's feats involving cold resistance, so he and his PhD student Matthis Kox decided to test the claim. They took blood samples before and after a regimen of breathing, meditation and an 80-minute full-body ice bath, and found that afterwards there were greatly reduced levels of proteins associated with the immune response.
The test that Pikkers and Kox had devised was for the innate immune system, a rapid immune response that distinguishes invaders from the body's own cells and eliminates them. They injected an endotoxin that stimulated the response. Most subjects respond with flu-like symptoms (fever, headaches and shivering), and affected cells release signalling proteins called cytokines. Hof had no flu-like symptoms and half as many cytokines as control subjects. Moreover, after he had trained some volunteers for a week, they too had reduced symptoms.
Pikkers and Kox attributed the effect on the immune system to a stress-like response. In the hypothalamus, stress messages from the brain trigger a release of adrenaline, which increases the pumping of blood and releases glucose, both of which can help the body deal with an emergency. It also suppresses the immune system. In Hof and the trained subjects, the adrenaline release was higher than it would be after a person's first bungee jump. It is not yet known which part of the training (cold exposure, breathing or meditation) is primarily responsible for the effect, or whether there are long-term training effects.
Wim Hof has been accused of overstating the benefits of his method, giving false hope to people suffering from serious diseases, and some of his claims have been uncritically reported by the media. On his website he says that it has reduced symptoms of several diseases including rheumatoid arthritis, multiple sclerosis, and Parkinson's disease; He has also said it might cure some forms of cancer. Wouter van Marken Lichtenbelt, one of the scientists who studied Hof, stated that "[Hof's] scientific vocabulary is galimatias. With conviction, he mixes in a non-sensical way scientific terms as irrefutable evidence." However, Van Marken Lichtenbelt goes on to say: "When practicing the Wim Hof Method with a good dose of common sense (for instance, not hyperventilating before submerging in water) and without excessive expectations: it doesn't hurt to try."
Someone who hyperventilates before submerging in water can experience a shallow water blackout, with potentially fatal consequences. Four practitioners of the WHM drowned in 2015 and 2016, and relatives suspected the breathing exercises were to blame. The WHM website advises doing the exercises in a safe manner and location.
Hof has six children, four of them with his first wife, who died by suicide in 1995, and a son, born in 2003 to his second wife. Also a son in 2017. Hof feels that sadness over the loss of his first wife was formative in leading him to develop techniques to face low temperature environments.
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