The two finalists in Finland's annual World Sauna Championships were rushed to hospital before the competition ended, and the Russian contestant died, organisers say.
The "Russian competitor has died in (the) Sauna World Championships," the head of the competition Ossi Arvela said in a statement.
He added that the Finnish finalist had been taken from the competition location in Heinola, 138km north of Helsinki, further south to a hospital in the larger city of Lahti for treatment on Saturday.
He told AFP the two finalists were Russian Vladimir Ladyzhensky and Timo Kaukonen of Finland.
Kaukonen won last year's championships and Ladyzhensky had also figured among the favourites ahead of Saturday's contest, in which participants were asked to withstand a sweltering 110 degrees Celsius for as long as possible.
The "event was interrupted immediately after the accident. (The) competition organisation grieves these sad events," Arvela said.
Police launched an investigation, he said, insisting that "all the rules were followed" and that all the contestants had undergone medical checks before the competition began.
According to Finnish news agency STT, the contest was cut short after about six minutes, and when the doors were opened, both finalists collapsed.
One witness told the news agency they had both suffered serious burns, but Arvela could not confirm the information.
The world championships in sauna sitting have been held in Heinola since 1999, and this year's event drew 135 contestants from 15 countries.
AFP