Stig Åvall Severinsen (born 1973, Aalborg, Denmark) is a four-time World Champion freediver and holder of multiple Guinness World Records and the author of Træk Vejret – mere energi, mindre stress (2009), published in English in 2010 as Breatheology – The Art of Conscious Breathing.
Severinsen is a cand.scient. in biology and has a Ph.D. in medicine. He began experimenting with holding his breath as a child at the bottom of his parents' pool. He started swimming at the age of 6 and was awarded National Champion four years in a row at 9, 10, 11 and 12. In 1993–2003 he played underwater rugby, and was a member of the Danish national team. During university studies in Barcelona, Spain in 1998–99, he played underwater hockey on the Spanish national team. A fascination with long breath holds under water drew him to the world of freediving.
Combining yoga and his knowledge of physiology in freediving, Severinsen became a record holder of four AIDAfreediving world records. He achieved two Guinness World Records in 2010: in March that year he swam 236 feet (72 meters) under ice wearing only swimming trunks and goggles, exceeding Wim Hof's record of March 2000 by 47.6 feet (14.5 meters); and in April, after inhaling pure oxygen, he held his breath for 20 minutes and 10 seconds in a tank full of sharks at the Kattegat Centre in Grenaa. In May 2012 he was awarded the record of "Longest time breath held voluntarily (male)" by Guinness World Records for holding his breath for 22 minutes; this record was achieved in a tank at the London School of Diving with the water cooled to 30 degrees. In April 2013 in Qorlortoq Lake in east Greenland, he set two new world records for "longest swim underwater - breath held": 500 feet (152.4 meters) while wearing a wetsuit and monofin, taking 2 minutes, 11 seconds, and the following day, 250 feet (76.2 meters) wearing only swimming trunks. He announced that these would be his last record attempts and he would now concentrate on teaching.
Severinsen was chosen "The Ultimate Superhuman" on the Discovery Channel programme Superhuman Showdown, and a documentary about him, Stig Severinsen: The Man Who Doesn’t Breathe, was produced for broadcast on Discovery and on Quest in the UK in October 2013.
In Breatheology Severinsen proposes that through working with the breath, a link can be created between body and mind that enables a person to control stress, increase energy, perform better physically and mentally, alleviate pain and improve health.