"But in temperatures like this, you don’t die of the cold. You drown. Within the first five seconds your body goes into shock..."

"... it’s very difficult to breathe. The only thing I can do is count every stroke, 'One. Two. Breathe. Three. Four. Breathe.' It doesn’t get any better after that. As the cold envelops you, it gnaws at your muscles and they start seizing up. Stretching one arm in front of the other gets harder and harder because you’re shivering – everything feels strained. I’m only wearing Speedos, goggles and a cap; I don’t grease my body for insulation like long-distance sea swimmers usually do, because if a seal or a killer whale goes for me, my team could struggle to drag me to safety.... As I reached the last 150 metres of the swim, I went past a group of elephant seals basking on the shore. Six times the size of a polar bear, they’re slow on land but in the water they’re as slick as they are powerful...."

I'm reading "What it feels like to swim in sub-zero waters/Plunging into the ocean near Antarctica, Lewis Pugh was determined to push the limits of human endurance." It's in The Economist, so "sub-zero" is sub-zero centigrade. It was -3˚C, so only 26.6° Fahrenheit. He goes one "kilometre," and that's 0.6 of a mile. I think it would be easy to run 0.6 of a mile in a bathing suit when it's 26.6°, so it's that mysterious difference between air and water... that and the seals six times the size of a polar bear. But they were sunbathing, not swimming alongside.



That difference between air and water is, of course, huge. Here's the article "What is cold water?" and says water feels "quite cold" to most people when it's 70°. And "cold shock" — where you lose control of your breathing — reaches its "maximum intensity" between 60-50F (15-10C). But you can get past the cold shock. That's what you need to remember if you ever find yourself in that position. The Icelandic fisherman Gudlaugur Fridthorsson swam 6 hours in 41-43F (5-6C) water until he got to shore after a shipwreck that killed the 4 others on the boat. His advantage was obesity.