How do Tibetans avoid altitude sickness?


Announcer: Welcome to Stuff You Should Know from HowStuffWorks.com.

Josh Clark: Hey, and welcome to the podcast. I'm Josh. There's Chuck.

Chuck Bryant: Where?

Josh Clark: Right there.

Chuck Bryant: Oh.

Josh Clark: You.

Chuck Bryant: Okay, yeah.

Josh Clark: How's it going, Chuck?

Chuck Bryant: It's going great.

Josh Clark: Good. I'm glad to hear it. I don't know how many times a year you go to Tibet these days.

Chuck Bryant: I had to cut back to two just because of finances and the economy.

Josh Clark: Jet fuel is very expensive.

Chuck Bryant: Very.

Josh Clark: Do you ever fly first class, business class?

Chuck Bryant: Nothing but.

Josh Clark: Oh wow.

Chuck Bryant: Sometimes I fly in the cockpit.

Josh Clark: That's awesome.

Chuck Bryant: Which is above first class, actually?

Josh Clark: Yeah, definitely. That's like pilot class. Do you know a pilot? Is that how you get in or do you just kind of break in?

Chuck Bryant: No.

Josh Clark: You just show up like hey, how's it going.

Chuck Bryant: Yeah. I'm an amiable guy. They let me in there and then they lock the door, of course, for safety reasons.

Josh Clark: Sure, after you're in.

Chuck Bryant: Yes.

Josh Clark: I can see that. Well, when you've been to Tibet, which as I'm sure you know is the rooftop of the world.

Chuck Bryant: Right.

Josh Clark: Right?

Chuck Bryant: Mm-hmm.

Josh Clark: There's all sorts of villages high up on these mountains. Have you toured any of them?

Chuck Bryant: No, I've never been to Tibet.

Josh Clark: Okay. All that was a lie then?

Chuck Bryant: I thought you meant Tibet, Georgia.

Josh Clark: You fly to Tibet, Georgia?

Chuck Bryant: Yeah.

Josh Clark: That's a short flight.

Chuck Bryant: It is.

Josh Clark: No, no, Chuck. We're talking about Tibet, the much disputed province outside of China.

Chuck Bryant: Right.

Josh Clark: I'm not entirely certain. Is it a part of China yet?

Chuck Bryant: I don't know.

Josh Clark: Is it still?

Chuck Bryant: I actually looked today to see if it was, in fact, a country. And I think, technically, they still have to call it a region or a province.

Josh Clark: I gotcha. I know they have the government in exile.

Chuck Bryant: Right.

Josh Clark: Right by the Dalai Lama, who I actually saw once. Did you know that?

Chuck Bryant: Yeah, I did.

Josh Clark: Okay. So anyway, that's the Tibet we're talking about where the Dali Lama hails from.

Chuck Bryant: Right.

Josh Clark: Okay. Well it turns out that there's villages everywhere. I've never visited either. I've just read about it. There's villages on the tops of these mountains, which is why it's called the rooftop of the world. And these people are living at like 16,000 feet above sea level.

Chuck Bryant: Right.

Josh Clark: Which is really high?

Chuck Bryant: Really high.

Josh Clark: Denver, our mile high city, is like 5,000 feet above sea level.

Chuck Bryant: Right.

Josh Clark: So these people make Denver look like nothing.

Chuck Bryant: Yeah, it's technically the 3.03 mile high country or region.

Josh Clark: Right. That's what it's more commonly called.

Chuck Bryant: Sure.

Josh Clark: So if you go, if you're just a regular sea level dweller, like you or I and we go visit Tibet, especially when we're visiting these highest villages, generally, we would get hypoxia.

Chuck Bryant: Exactly.

Josh Clark: Altitude sickness, which is like nausea, dizziness, vomiting, shortness of breath. You can actually die from it. And so you're sitting there puking your guts out, wishing you were dead. And all these Tibetans are running around happy as clams.

Chuck Bryant: Right, Sherpas are laughing at you.

Josh Clark: Sure, yeah. They're doing somersaults and pointing and laughing, yeah. And so you're wondering what is going on here. Why aren't these people all dropping dead of heart attacks left and right? What's going on? Obviously, what you would think is well; they're used to it, which makes sense, right?

Chuck Bryant: Yeah, that's kind of an easy way to explain it.

Josh Clark: It is. It is. But when you think about it, they shouldn't be used to it. Humans shouldn't be used to hypoxia. So have you heard about how Tibetans avoid altitude sickness?

Chuck Bryant: I have, Josh. I read your awesome article. And it actually was really interesting, I thought.

Josh Clark: Oh yeah, I did too, actually. It was one of those assignments where I was thinking this is going to suck, but it turned out really well. And that actually has been my experience the more I thought the article was going to suck, the better it turned out.

Chuck Bryant: Yeah, I've had that same experience, actually.

Josh Clark: Yeah, it's kind of cool. So Chuck, a little background on hypoxia, right!

Chuck Bryant: Right.

Josh Clark: All it is is a lack of oxygen in the blood.

Chuck Bryant: Right.

Josh Clark: And of course, we need oxygen to carry out all sorts of vital processes like staying alive and metabolization and all that.

Chuck Bryant: Sure.

Josh Clark: So these people have been trying to figure out how the Tibetans aren't hypoxic, okay.

Chuck Bryant: Yeah, I know what's coming.

Josh Clark: They actually are hypoxic.

Chuck Bryant: I know. I was kind of amazed by that.

Josh Clark: It is. It's a little amazing. These people are running around. They're hypoxic, but they're not displaying any symptoms. So this, of course, raises a little bit of curiosity among researchers. If Tibetans are hypoxic, how are they not showing symptoms?

Chuck Bryant: Right. Why aren't they just vomiting, nonstop, 24/7?

Josh Clark: What a bad country that would be if that were -

Chuck Bryant: I don't think people would want to go to Tibet if that's the case.

Josh Clark: The national flag is some guy just vomiting.

Chuck Bryant: Hurling.

Josh Clark: Projectile vomiting. So these researchers, I think they were from - I can't remember where they were from, maybe Emory or something.

Chuck Bryant: Case Western.

Josh Clark: Case Western, same thing.

Chuck Bryant: Close, in Ohio.

Josh Clark: Yeah, so these guys from Case Western go and they actually they did this really hands on investigation. They used instruments that can sense different types of particles in air.

Chuck Bryant: Right.

Josh Clark: And they asked Tibetans to breathe into this.

Chuck Bryant: To mouth breathe, which I know is one of your favorite subjects, mouth breathers.

Josh Clark: Well yeah. If they're being asked to mouth breathe, as long as it's not like your default setting.

Chuck Bryant: Right.

Josh Clark: I don't have a problem with it.

Chuck Bryant: So they weren't like your arch enemy, Kiefer Sutherland, famous mouth breather.

Josh Clark: Yeah. So okay, they were mouth breathing, agreed. But they were mouth breathing with Case Western instruments in front of them.

Chuck Bryant: Sure.

Josh Clark: And this is what the people found. This mystery has been solved. And it's pretty interesting stuff. When we exhale, we exhale carbon dioxide. That's like the big star of our exhalation. That's what everybody knows about. We also exhale this stuff called nitric oxide.

Chuck Bryant: Right.

Josh Clark: Which our body gets rid of as a waste product, right?

Chuck Bryant: Right.

Josh Clark: Through respiration. The thing is nitric oxide actually helps dilate blood vessels, okay. So the Tibetans have actually - their bodies have acclimated to hypoxia by keeping more of their nitric oxide in the body.

Chuck Bryant: Right.

Josh Clark: So their blood vessels are dilated more all the time, which means their heart has to work less.

Chuck Bryant: Right, it makes it easier to deliver the oxygen throughout the body.

Josh Clark: Mm-hmm.

Chuck Bryant: It's pretty cool.

Josh Clark: It is very cool. So now we have a perfect example of evolution in isolation.

Chuck Bryant: Yeah.

Josh Clark: Some humans have gone up to where humans aren't supposed to be and have adapted. They're not the only group that's done that. There's some other groups, right?

Chuck Bryant: Indeed.

Josh Clark: So my hypothesis would be that these other groups would display the same phenotype, the same trait.

Chuck Bryant: Right, you would think anyone living at a high altitude anywhere in the world because we evolved, more or less at sea level. Is that correct?

Josh Clark: Yeah, and we're sea level species and we're subtropical species.

Chuck Bryant: Right.

Josh Clark: That's where we're supposed to be.

Chuck Bryant: We're beachcombers, essentially.

Josh Clark: Pretty much, yeah. But of course, we've got our Nordic friends up north and we have our friends down in Chile and these people in Tibet. Humans live where we're not supposed to live. And the Tibetans show that we can adapt.

Chuck Bryant: Exactly.

Josh Clark: But wouldn't you think that we would all adapt the same way, given the similar situations?

Chuck Bryant: I would think so, but we found out, or you found out through your research that's not the case.

Josh Clark: Yes, and actually this has been known for a while. The Tibetan Case Western study was, I think, within the last decade.

Chuck Bryant: Yeah, 2005.

Josh Clark: There's this Frenchman, named Francois Vio, I believe. And in 1890, he visited the Andes. This is another high altitude mountain dwelling people, Machu Picchu, way up on the hill.

Chuck Bryant: Exactly, South America.

Josh Clark: Right. So he goes down there because he had the same question a century or so ago. He wanted to know how these people were living at high altitudes when they should be suffering from hypoxia. Do you know what he found out?

Chuck Bryant: I do.

Josh Clark: And was it that they keep more nitric oxide?

Chuck Bryant: No. Actually, he theorized and was correct that they had more red blood cells, a higher red blood cell count and that's important because red blood cells contain hemoglobin, which is sort of like the FedEx man of your body. Hemoglobin delivers oxygen.

Josh Clark: Right. So their bodies produce more red blood cells.

Chuck Bryant: More red blood cells.

Josh Clark: So it can, I guess every part per million of blood can hold more oxygen than yours or mine.

Chuck Bryant: Right.

Josh Clark: Okay. So we've got two high altitude dwelling groups of people that have evolved in isolation, but have evolved or have adapted differently.

Chuck Bryant: Yeah.

Josh Clark: That's pretty interesting.

Chuck Bryant: Yes. And there's a third.

Josh Clark: There is a third.

Chuck Bryant: Yes.

Josh Clark: You want to tell them about them?

Chuck Bryant: Yeah, the highlands of Ethiopia, which I didn't realize Ethiopia had highlands. I don't know much about that place.

Josh Clark: I didn't either, actually until this very article.

Chuck Bryant: Which is the great part about our job? We learn things all the time.

Josh Clark: Yeah.

Chuck Bryant: So they don't have either one of these, as you know.

Josh Clark: No, and they're living at high altitude as well. I think the Tibetans live the highest up. But both the Andean Dwellers and the people who live in the Ethiopian highlands, they're living at a high enough altitude that they should be hypoxic, right.

Chuck Bryant: Right.

Josh Clark: And also, with studies of them, they haven't turned up - any of the Ethiopian Highlander, they haven't turned up any kind of adaptation.

Chuck Bryant: Yeah, that's the one that really is strange.

Josh Clark: Right. They don't have any kind of oxygen delivery system like extra red blood cells. They don't maintain their NO levels more than normal people.

Chuck Bryant: Right.

Josh Clark: And it's possible that we just haven't found the phenotype, this adaptation.

Chuck Bryant: True, true.

Josh Clark: We haven't figured it out yet. But for all intents and purposes, these people should be dead, dying or vomiting at the very least all the time.

Chuck Bryant: Right, but they're not.

Josh Clark: No, it's weird. It's weird.

Chuck Bryant: Yeah, and you know, Josh, reading this article, it made me wonder, and there may be studies on this. If people from Tibet and the Ethiopian highlands, if they have trouble when they come down to sea level or below, let's say they went to Amsterdam for the weekend, which half of Holland resides below sea level.

Josh Clark: Like up to 20 feet.

Chuck Bryant: Yeah, I wonder if they have problems breathing or if their body adapts to that quickly or what happens there.

Josh Clark: Or if there would be like a rush of oxygen.

Chuck Bryant: Yeah, exactly.

Josh Clark: Like they get too much of it.

Chuck Bryant: Right, they might feel high all the time or something.

Josh Clark: Which would be kind of cool?

Chuck Bryant: Of course it is Amsterdam.

Josh Clark: Yeah, right, right. I think that they would probably feel high no matter what.

Chuck Bryant: Right.

Josh Clark: Yeah. And hello to our Dutch friends! We love you. All right. So other than the Ethiopian highlanders, the questions have been asked and answered. We know why the Tibetans aren't hypoxic and we also know why the Andean dwellers aren't hypoxic.

Chuck Bryant: Right. Well actually, the Tibetans are hypoxic.

Josh Clark: Yes, how they deal with it, sure.

Chuck Bryant: Sure.

Josh Clark: So I think we'll probably revisit it once we finally figure out what's going on with the Ethiopian highlanders.

Chuck Bryant: I think that's a great idea.

Josh Clark: And find out which article that Chuck and I think you should read in these trying economic times. You'll save your finances.

Chuck Bryant: Right, in these trying economic times, I think one article people should read is, "Top five things that devalue your house."

Josh Clark: By Jessika Toothman.

Chuck Bryant: Jessika Toothman, fellow writer. And now is not the time to devalue your home.

Josh Clark: No.

Chuck Bryant: You want to add value to your home, or at least tow the line and keep it dead even.

Josh Clark: Exactly. And Toothman can tell you some easy steps you can take to keep your house from devaluing, depending on how you read it. If you're looking to devalue your house for some nefarious reason, this could be a how-to guide for that as well.

Chuck Bryant: Sure, like spite.

Josh Clark: Fantastic. Well you can find all this stuff, everything we've talked about at HowStuffWorks.com.Announcer: For more on this and thousands of other topics, visit HowStuffWorks.com. Let us know what you think. Send an e-mail to Podcast@HowStuffWorks.com.