What it feels like to swim in sub-zero waters

All I had to do was swim a single kilometre. It’s just that humans aren’t designed for immersion in -3˚C water. I was going to be the first person to swim in South Georgia (a remote island in the south Atlantic, east of South America and north of Antarctica), starting at the British scientific station and ending near the grave of Sir Ernest Shackleton, the polar explorer who led four expeditions to this part of the world, only to die of a heart attack during his last one.

If an untrained person were to dive into freezing water, death would come quickly. Even after all my preparation, as I braced myself for the plunge I knew my body would be fighting with all its might to stay alive.