Nineteen swimming enthusiasts from Wuhan in Central China's Hubei province, including four men and 15 women, on Thursday started their expedition -- flying to the Arctic to take a swim in the Arctic Ocean.

According to news portal cjn.cn, the 19 professionals, aged 55 on average, are members of the Hanyang Swimming Association. By the time it was founded in 2016, members of the organization had agreed on a plan to travel across the seven continents and four oceans in the world.

Now they've made trips to six continents and have swum in the Pacific and Indian Oceans. In October 2017, eight members traveled on a research icebreaker converted into a cruise ship, starting from Ushuaia, the southernmost city of the world, toward the Antarctic.

"It's a pity that we didn't have a chance to swim in the Antarctic," said Shi Zhengxiang, who led the expedition. "The extreme weather and the threat of attacks from seals and whales made it impossible for a swim."

"This time, we talked to our guide in advance to let us take a swim," Shi said, before the group departed for the Arctic.

According to Shi, the expeditions organized by the swim association are semiguided tours allowing the explorers to make their own routes. The members of the association can register voluntarily and a video-formed disclaimer is needed for every applicant before starting a trip. The disclaimer usually includes a health claim. Professional outfits are also equipped to the swimmers, to help them confront the freezing cold.