Ice swimmers

Just as my "afternoon chill" was coming on, I was inexplicably compelled to seek out the stories and images of people swimming in icy waters. I must have seen a story about Lewis Gordon Pugh and remembered seeing a similar swimmer--Lynne Cox, as it turns out--on Sixty Minutes. Both Lewis and Lynne have swum in frozen Arctic and Antarctic waters wearing only a swimsuit, cap, and goggles. He claims to have spent 18 minutes at the North Pole swimming in colder water than anyone else. She describes the sensation in an interview:

You feel an intense cold. In that first moment, your body is changing in huge ways. You're shunting the blood into the core of the body to protect the heart, lungs and brain. And so you are feeling that shift. Your blood pressure is changing instantly. You're hyperventilating. Your heart is beating very rapidly. You're trying to compensate and trying to create heat by moving your arms really fast. I was really focusing on trying to keep my stroke rate so I could create heat. I also swam with my head up, because you lose up to 80 percent of heat through your head.

After years of study, scientists still can't figure out how they can pull off feats that would kill anyone else. It requires a lot of practice, even if you are up for the annual polar bear plunge...