For many swimmers the activity can bring cooling relief in the warmest months. For another breed, cool or cold water is not so much a relief as a challenge.

Xing Yuesheng jumps into the ice-cold waters of South Moat, breaking the calm of Longtan Lake Park in the Xicheng district of Beijing. It is Feb 13, and the swimming fanatic is holding the flag of the 24th Beijing Winter Olympics, intent on making a splash as he expresses his joy that the Games are unfolding successfully.

The first time Xing made a mark on river ice was in Yuyuantan Park in the Haidian district of the capital in January 2009. He was inspired by a classmate who had occasionally gone winter swimming on a whim, and the pair started to take a cold indoor bath every morning. They continue to do so and reckon that in all those years they have never suffered a cold.