Lewis Gordon Pugh takes a bracing dip that would kill most of us within a few minutes (Image: Terge Eggum)

PERCHED on the edge of an Antarctic ice sheet, Lewis Gordon Pugh surveys the waves. At 0 °C, water does not get much colder than the sea beneath him. Undeterred, Pugh unzips his jacket, strips down to his swimming trunks and dives in.

Most of us would start to hyperventilate uncontrollably if we dived into such cold water. Pugh doesn’t even gasp in pain but instead starts swimming. In December 2005, when Pugh took this plunge (pictured above), he went on to swim a kilometre in just over 18 minutes. Many ordinary people would drown after just a few minutes in such cold water. Pugh, however, not only survived but went on to make several more long-distance swims in extremely cold water (see graph). So what makes him able to keep swimming in such extreme cold?

A study of Pugh published last month has confirmed that his response to cold water is anything but normal. Remarkably, though, while Pugh may have some innate advantages, it seems his near-superhuman ability is largely down to training – so perhaps it could be something we are all able to learn.

High metabolism

Pugh is far from the first to swim in icy water. There is a long tradition in Russia, China and many northern European countries of carving holes in frozen lakes, rivers or sea ice and diving in, often as part of a cultural or religious ritual. These are normally just quick dips, though: rarely do they involve distance swimming. Japanese and …