DAVID POGUE: John Castellani is a scientist at the Army’s Doriot test chamber.

Wow.

JOHN CASTELLANI: Yeah, so this is our environmental chamber: 60 feet long...

DAVID POGUE: This gigantic room is designed to re-create every conceivable environment that a soldier might face, from the frigid mountains of Afghanistan, to the 120-degree deserts of Iraq.

JOHN CASTELLANI: …with the wind, and the humidity control.

DAVID POGUE: In order for this place to work, there’s one more thing they need: volunteers.

Will we be seeing one of these poor victims.

JOHN CASTELLANI: The only victim that we’re going to see in here today is yourself.

DAVID POGUE: Castellani “enlisted” me to help test ways of keeping soldiers cool in the heat. To do this, they’ll need to track my vital signs.

MARISSA SPITZ: For core temperature, you’ll be using this rectal probe.

DAVID POGUE: Rectal probe?.

MARISSA SPITZ: It may feel a bit uncomfortable, but.

DAVID POGUE: No kidding.

MARISSA SPITZ: …all the way past, to make sure it doesn’t fall out.

DAVID POGUE: How about I just go in there and tell you how I am? Pretty hot.

MARISSA SPITZ: This is mostly for your safety.

DAVID POGUE: Oh, thanks for thinking of me.

Next, they outfit me in 40 pounds of body armor. And then, it’s into the chamber.

JOHN CASTELLANI: It’s a hundred and four degrees in here.

DAVID POGUE: A hundred and four.

JOHN CASTELLANI: Yes.

DAVID POGUE: Can I get a little lemon.

Within minutes, my temperature is going up.

What is that? An hour.

WOMAN: Actually, it’s been about four minutes.

JOHN CASTELLANI: Their heart rates will start to rise, their core temperatures start to rise.

Your core temperature is around 101.5 degrees Fahrenheit.

Eventually, what will happen is they’ll become a heat exhaustion casualty.

DAVID POGUE: After two hours, I called it quits.

Please tell me there was some valid scientific purpose for that.

JOHN CASTELLANI: There is. I mean, really, what we’re trying to understand is—when we develop this kind of gear—is can we develop it in such a way that we can allow the body to be able to be able to get rid of the heat?

DAVID POGUE: Oh, man.

And why did I get so hot? Because of some basic laws of physics, which I seem to have missed in my high school science class. For example: What is heat? What is temperature? And what is cold.

EDWARD YARMAK, JR. (Arctic Foundations, Inc.): What did they teach you.

WOMAN: Heat is energy.

ERIC CORNELL: Disorganized energy.

BRIAN WOWK (21st Century Medicine): The vibrations of molecules.

ERIC CORNELL: The motion of atoms.

DAVID POGUE: The faster they move around, the more energy they have. That’s heat. Temperature is a measure of how much heat energy they have.

ERIC CORNELL: Temperature is measuring the motion of atoms.

DAVID POGUE: Okay, so heat really is something. It’s energy, motion, and you can measure how much of it you have.

ERIC CORNELL: More and more heat, your temperature goes up.

DAVID POGUE: But cold is another story.

ED YARMAK: Because there’s no cold flow, there’s heat flow.

DAVID POGUE: Really.

ERIC CORNELL: If you take heat out, your temperature goes down.

DAVID POGUE: You mean, you don’t put cold in? No.

ED YARMAK: No. No. There’s really no such thing as “cold.”

DAVID POGUE: So cold is just the absence of heat? So things don’t ever really get colder.

ED YARMAK: No, they just get less hotter.

DAVID POGUE: Yeah, that has a great ring to it. “Making Stuff: Less Hotter.” That just seems backwards.

JOHN CASTELLANI: So, I have a spoon here for you.

DAVID POGUE: But Castellani showed me that how we think “cold” works.

Cold is just rushing right into my flesh.

…can really be the opposite of what’s happening.

JOHN CASTELLANI: Actually the heat from your hand is moving into the spoon, not the other way around. Heat moves from areas of hotter temperatures, or high energy, to areas of lower temperature, or low energy.

DAVID POGUE: You can see it through the eyes of this thermal camera, where warm things, like my hand, show up as light orange, and colder things like the spoon are dark.

And sure enough.

JOHN CASTELLANI: If you put the spoon up against your hand, we can see, heat’s going from your hand into the spoon.

DAVID POGUE: That’s crazy.

The reason I was getting so hot on my forced march was the air was hotter, at a higher energy state, than my skin. So, instead of the heat from my core flowing out to the room, the heat from the room flowed into my core.

The army has a cool solution.

JOHN CASTELLANI: So, David, this is how we’re going to cool you off. So what this is is a cooling garment. It’s essentially going to circulate water through here. We’re going to hook this up to a small refrigerator.

DAVID POGUE: Ooh! I just got chills.

JOHN CASTELLANI: …and keep it at about a nice, cool 70 degrees.

DAVID POGUE: I don’t know, but I’ve been told.

SOLDIERS: I don’t know, but I’ve been told.

DAVID POGUE: …hundred and four degrees gets old.

SOLDIERS: …hundred and four degrees gets old.

DAVID POGUE: Just like last time, my core temperature rises in the 104-degree environment. But this time, the heat’s got somewhere to go: into the vest, and out through the refrigeration unit.

JOHN CASTELLANI: A significant difference: 82 degrees Fahrenheit, compared to last time, when it was up around 95 or 96 degrees.

DAVID POGUE: A vest is best if it is cold.

SOLDIERS: A vest is best if it is cold.

JOHN CASTELLANI: He is feeling better. He seems in better spirits, and those are all the benefits that we see with this particular technology.

DAVID POGUE: An hour and a half later, as they remove my Kevlar vest, that dark blue area, that’s my chest: 78 degrees. Cool, baby.