Lovers of ice and snow take challenges

As cold waves continue to strike the country's north, some are finding this as an opportunity to take part in some extreme sports.

In Mudanjiang of Northeast China's Helongjiang Province, some sports fans can't get enough of the ice and snow. They are running, swimming and even scuba-diving, all in freezing cold temperatures.

The temperature is minus 20 degrees Celsius.

And for 55 year-old Chen Kecai, this is just a warm up.

He's worked on this skill for over 20 years. In 2010, Chen broke the Guinness World Record for staying in ice naked for 112 minutes.

"I feel so comfortable! Of course it's cold, but I can persist. At first I couldn't do it, but I did it little by little. Then I got addicted to it. It's like others getting addicted to alcohol and smoking."

Chen says being buried in snow is actually not the toughest...not as tough as winter swimming.

In north China, most winter swimmers return to the bank after swimming for just a few minutes.

But for Chen and his friends, 20 minutes is a piece of cake. And they know the benefits.

"Winter swimming can speed up blood circulation."

This is Jingbo Lake, the largest lake in the world created by volcanic lava.

Its extreme conditions have attracted lovers of extreme sports.

This man is preparing to jump from the 12 meter high frozen waterfall.

He is the only one allowed to take the dive here. It took him a long time to train for this.

Rescue workers say, many others have gotten frostbite from winter swimming.

Doctor of Jingbo Lake Rescue Team, said, "It's minus 20 degrees Celsius now. Usually we don't suggest such activities. If you are trying this sport for the first time, it is very likely there could be an accident."

Professional diver Du Xuewen is testing his equipment.

They are preparing for a scuba-dive under the ice.

He weighs over 100 kilos, and wears special gear. But the cold seems just overwhelming.

"I want to get a true sense of warmth. It's cold, my feet are numb now".

But the cold is not the danger. Du says diving under 70 millimetres of ice, one can encounter undercurrents, low visibility and even fishing nets.

But what is it that keeps them coming back for more?

"At first you feel nervous, then it's thrilling and exciting. It's cold, but it's replaced by amazement. When you flip over under water, and look at the ice above you, it's like you are looking at the sun though a crystal. "

As another strong wind hits Jingbo lake, the temperature has gone down even lower. But for these sports lovers, it's all part of the fun.