American Swimmer Spends 30 Minutes In Water Cold Enough To Kill

(CBS) Lynne Cox is an American woman who's among the best ocean swimmers of our time. But there's something else about her that you may find hard to believe.

Science doesn't fully understand it, but she survives – she even thrives - in water that is cold enough to kill. It is so remarkable that researchers have been trying to figure out how she does it for 30 years.

As 60 Minutes II first reported last winter, when you combine her unique talents with a stubborn streak, there is only one thing left to do - try to swim a mile in the coldest water on earth.

In a world inhabited by penguins and seals, Cox decided to see whether she could survive swimming to Antarctica. Correspondent Scott Pelley reports.

---

A continent larger than the United States, Antarctica lies frozen across the bottom of the world, hidden under cathedrals of ice in a world inhabited by penguins and seals. It's beautiful but dangerous. And no place on Earth is colder, more than 120 degrees below zero in winter.

Cox, 45, has traveled nearly 8,000 miles to test the limits of her endurance there. Wearing only a swimsuit, cap and goggles, this world champion plans to swim a mile in the kind of cold water that, even after all these years, still takes her breath away. It's a feat that no one on record has ever done and lived to tell the tale.

“It sort of just penetrates though your skin right away,” she tells Pelley about first jumping in, “and you’re immersed in it."

After an initial period of doubt about what she is doing, she says, she takes off like a shot. “I’m trying to get warm. It’s freezing, it’s really cold, you know?”

60 Minutes II met Cox in southern California when she was training near her home. She started swimming in cold water as a child and taught herself to push the pain out of her mind.

“If you focus on the cold, then you’re focusing on something that’s not helping you get to where you need to get,” she says.

At 14, she swam California’s Catalina Channel — 21 miles in 12 hours. At 15, she set the women’s and men’s record in the English Channel. Then in 1987, in the midst of the Cold War, she was first to swim from Alaska to the Soviet Union — a five-mile swim through 40-degree water that warmed the Cold War.

---

The swim also fascinated scientists. Based on all they knew, Cox should be dead after that swim.

Professor Bill Keatinge of the University of London, a pioneer in the study of hypothermia, brought Cox to London for experiments in his lab.

“We were able to confirm that she can maintain stable body temperature with her head out of the water and in water temperatures as low as 44 Fahrenheit,” he said. “We’ve got one other person that we know can do that. He was an Icelander who swam ashore from an overturned boat.”

Anyone else would immediately feel the pain like an electric shock, their muscles would flail and the heartbeat would stop in minutes.

“The whole beating of the heart goes completely adrift,” says Keatinge. “In technical terms, ventricular fibrillation. Then, you’re dead in a matter of minutes.”

Keatinge thinks Cox has somehow trained her body to keep most of her blood at her body’s core and away from the skin where it’s exposed to the cold. The blood stays warmer. But there is something else — call it her natural insulation.

“She’s got an extremely even fat layer going right down the limbs and it’s an ideal setup,” he says.

Cox herself thinks this is the key to her success: “If you look at the marine mammals in Antarctica, the whales, the walruses, the seals all have body fat to stay warm. Their blubber is very dense whereas mine will be more like a cotton sweater. But I’m not going to be in as long as they are.”

To reach Antarctica, Cox and her team of friends, including three doctors, set sail on a tourist boat from Ushuaia, Argentina, the southernmost city in the world. They traveled, through the Drake Passage to the Shetland islands. There she takes a test swim in water that is colder than 40 degrees.

The greatest danger to Cox is when she gets out of the water. Because she is no longer moving swiftly, her temperature plunges and the cold begins to assault her heart. In half an hour, she manages to sit up, but it's a struggle. It was only a practice swim, and she has never been this bad off.

In time, she warms, but she's paid a price. Her feet and hands are numb. It's nerve damage and it could be lasting. Back aboard, she rests as the ship sails south toward the colder Antarctic waters.

Two days later, the water's about as cold as water gets. Skin freezes at about 32-degrees, and this water would kill nearly anyone else in five minutes -but that's the water that Cox will be swimming in.

---

In a sense, everything that Cox has done in 30 years comes down to this. Her goal is one mile - and that will take nearly half an hour.

She begins her swim to Antactica as doctors watch for signs of trouble.

Just minutes after it begins, it seems over. Cox is calling for shore and the water seems much too cold. It's been 11 minutes but it feels like an hour.

Four minutes later, maybe out of sheer hope, Cox badly misjudges how far she has traveled. She asks if she’s done a mile, but she's only gone half that far.

But just when her team is prepared to take her in, she gets something like a second wind, perhaps a second warmth, and tries to go the distance.

She's about 21 minutes into the swim. Penguins are coming down from the glacier down to the beach. It almost looks like a welcoming party.

But she's done it. In all of 25 minutes, she's done it. And she's done better than she hoped. Measured by a navigation satellite she’s covered 1.22 miles.

They get her back in the Zodiac and race to the ship, lying on top of her for warmth. On board, her temperature rises, and so does her sense of triumph.

There's no gold medal for swimming the first Antarctic mile, just the warm satisfaction that your place in the world is unique and that your record is certainly safe.