SCOTT SIMON, HOST:
Humans came from dust, says Ecclesiastes. But Bonnie Tsui reminds us that humankind also once sprang from and still seeks water. "Why We Swim" is her latest book, which takes us from ponds to pools to surfers, racers, and a few who have survived icy currents. Bonnie Tsui, who writes frequently for The New York Times and California Sunday Magazine, joins us from her home in Berkeley, Calif. Thanks so much for being with us.
BONNIE TSUI: Thanks so much for having me, Scott.
SIMON: You begin with an amazing story about a man whose name I will not chance to even try and say. But March 11, 1984, what happened on this planet?
TSUI: Gudlaugur Frithorsson (ph). He is an Icelandic fisherman on his fishing trawler with his crew. It's calm waters. It's cold. It's 41 degrees. And the boat overturns. With 41-degree water, within 20 to 30 minutes, we die from hypothermia. But he did not. Everyone else did, and he ended up swimming six hours. And when he finally got to the hospital, the doctors weren't able to discern his heartbeat or read his temperature on the thermometer. But he didn't show any signs of hypothermia, and he was only a little bit dehydrated.
SIMON: He was a strong swimmer, certainly, but was he also saved by his own biology?
TSUI: He was. I like the story very much because it is this distillation of what makes swimming so special for humans. We have to learn how to swim. We're not born knowing how to do it instinctively, and yet there are sort of traces of that evolutionary past still within us, that - our evolutionary past that came from the sea. And so with Gudlaugur Frithorsson, turns out that his body fat was two to three times normal human thickness and more solid. And so he resembled a marine mammal more than a terrestrial mammal, and that saved him.
SIMON: Yeah. Did you grow up feeling a pull into the sea even if it was only Jones Beach in New York?
TSUI: I did. I mean, my family origin story is that my parents met in a swimming pool in Hong Kong. We grew up a swimming family. And so we grew up at Jones Beach, in the pool, lifeguards, swim team. I just always remember feeling more comfortable and happy in the water, actually, than on land. I mean, there's just a sense of magic that you get from being in the water and buoyancy that you just don't have on land.
SIMON: Yeah. You, in this book, talk to swimmers all over the world. Right nearby you, though, you swim in San Francisco Bay without a wetsuit.
SIMON: And there are people, including, I gather, you, who believe that's actually good for you in all ways.
TSUI: It can be. I mean, I have also talked to scientists and researchers who say, you know, if you have cardiovascular risk, don't go into...
TSUI: ...Sudden shock cold water because it could stop your heart. You know, that aside...
SIMON: Stopping your heart aside, yeah.
TSUI: (Laughter).Stopping your heart aside, there are benefits to cold water immersion. And there's been quite a bit of research in recent years where, you know, your dopamine levels go up and your - over time that your cardiovascular system is strengthened. And, you know, there are people - there are things that we knew from cross cultures around the world that there was a water cure. There was - you know, jumping in cold water was good for you and then jumping into hot water and then jumping into cold water. And so we didn't know why exactly. And the science is kind of starting to catch up.
SIMON: What is this brown fat you talk about in this book?
TSUI: Well, this was really interesting. I did not know about brown fat until I started swimming with Dolphin Club swimmers in San Francisco Bay. And so I went to UCSF to talk to the foremost researchers in brown fat. And it turns out that mammals are born with two kinds of fat. White fat, which we all know about, is the energy stores of our bodies. And brown fat, which actually burns and produces heat energy. We kind of start to lose it as we get older, but there are ways to do what's called the browning of white fat, which is to kind of turn it into energy burning tissue. That fat is called beige fat. And so what kind of encourages the development of beige fat is cold water exposure and exercise, among other things. But those have been proven to be causing this change in our bodies.
SIMON: Wonder if you have any words for people who aren't able to swim these days?
TSUI: You know, the water is a draw for us no matter what. And so even if you can't get in the water, if you can walk near it, can look at it, can see it, can, you know, have some of what Wallace Nichols calls domestic waters in your house and, you know, take a bath, a shower, just look at imagery, watch a surf movie - I mean, those things make a difference for our souls and are the way our bodies and brains work. Like, we respond to those set points in the environment. And even if we can't get in the waters right now, you know, the ocean will be waiting for us. The pools will be waiting for us on the other side of this.
SIMON: Bonnie Tsui. Her book - "Why We Swim." See you in the water.
TSUI: See you, Scott.
(SOUNDBITE OF LUNAR VACATION SONG, "SWIMMING")
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