Wim Hof

Hof appears in the music video for "My Last Breath" by James Newman, the United Kingdom entry for the Eurovision Song Contest 2020.

People have died while attempting the Wim Hof Method. Four practitioners of the WHM drowned in 2015 and 2016, and relatives suspected the breathing exercises were to blame.

When exposed to cold, the human body can increase heat production by shivering, or non-shivering process known as thermogenesis in which 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, as practiced in the Wim Hof Method, would have comparable effects. The Hof brothers are identical twins, but unlike Wim, Andre has a 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 concluded that, "No significant differences were found between the two subjects, indicating that a lifestyle with frequent exposures to extreme cold does not seem to affect BAT activity and CIT." 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 researchers cautions that the "results must be interpreted with caution given the low subject number and the fact that both participants practised the g-Tummo like breathing technique."

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 23 January 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; and surpassed in 2019 by Josef Köberl of Austria, with a time of 2 hours, 8 minutes and 47 seconds.

On 26 January 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.

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 and shoes. In 2016 he reached Gilmans point on Kilimanjaro with journalist Scott Carney in 28 hours, an event later documented in the book What Doesn't Kill Us. In September, he ran a full marathon in the Namib Desert without water, under the supervision of Dr. Thijs Eijsvogels.

On 16 March 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 corneas 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.

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. Hof has been the subject of several medical assessments and a book by investigative journalist Scott Carney.

Hof was born in Sittard, Limburg, Netherlands as one of nine children, (in order of birth; Rob [1954], John [1955], Marianne [1957], Wim and Andre [1959-identical twins], Ruud [1961], Ed [1962], Marcel [1964], Jacqueline [1967]) Hof has six children, four of them with his first wife Marivelle-Maria (Also called "Olaya"), who died by suicide in 1995, a son, born in 2003 to his girlfriend, and a son born in 2017 to his last girlfriend. When he was 17 he felt a sudden urge to jump into the freezing cold water of the Beatrixpark canal. Hof has said that his sadness over the loss of his first wife was formative in leading him to develop techniques to face low temperature environments.