Severinsen has a degree in biology and 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. From 1993 – 2003 he played underwater rugby and was a member of the Danish national team.
During university studies in Barcelona, Spain in 1998 – 1999, he played underwater hockey on the Spanish national team.
A fascination with long breath holds underwater drew him to the world of free diving