How to Breathe Better

I heard about a guy who had written books on two topics. One was about breathing and the other was about freediving. I can honestly say I’ve never been very interested in breathwork and freediving, where you dive deep underwater, holding your breath. I can’t think of anything more terrifying and unappealing. So the fact that I’m excited to interview James Nestor, a journalist who I only know from his books on freediving and breathing should tell you something about how interesting this man is.

NESTOR: I did not set out on this journey to prove or disprove anything. I talked to the freaks, but I also talked to renowned researchers at top institutions. I talked to everybody. They said, “This is so easy. If we know it works, why aren’t people doing it?” So, what I want to do is give people information so that they can choose what road they want to take.

Welcome to People I (Mostly) Admire, with Steve Levitt.

James Nestor’s books have forced me to rethink everything I thought I knew about the human body and its limits. And his work is not just applicable to elite athletes or people trying to dive 300 feet underwater. I’ve changed how I breathe when I sleep at night because of research in his book. Listening to James Nestor, I suspect you also will learn something that’s applicable to your life.

*      *      *

LEVITT: People sometimes say to me, “I love Freakonomics. What other popular economics book would you recommend?” And you know what my answer is? I say, “What you should really read is Deep by James Nestor.” I just absolutely love your book.

NESTOR: Thank you very much. Appreciate that.

LEVITT: So the primary subject you explore in Deep is freediving. Could you define what freediving means?

NESTOR: Freediving is both a sport and an activity. As a sport, it is when you challenge someone else to take a single breath of air and see how deep you can dive without passing out. As an activity it is a form of underwater yoga in which you hold your breath and you use your two lungs as your scuba tanks and you explore the underwater world. And so that latter, activity part of freediving, I’m a big fan of — the competition part, not so much.

LEVITT: Well, let’s start with the competition part because the numbers are so amazing. The deepest unaided free dive is 334 feet. That’s 102 meters. No equipment at all, not even fins. And to appreciate how absurd that is, I want my listeners to start by taking a deep breath. Now hold that breath and imagine that you swim straight down for more than the length of a football field. You’re still holding your breath. And then you’ve got to swim back up the length of a football field. You’ll cover 200 meters. And the Olympic swimmers, I did some calculations, they’re going to breathe 50 to 60 times when they cover 200 meters. It just seems completely impossible.

NESTOR: It seems impossible and I thought it was impossible until I was sent on an assignment to go write about this. And when you see it, especially when you don’t have any background in freediving, which I did not at the time, you see what the human body is capable of doing, and then you start to realize that so many of the limitations that have been put on us are probably misguided.

LEVITT: What makes it even crazier is how the pressure increases the deeper you go. The weight of the water is pressing on you. I think you wrote in your book that at 300 feet, a Coke can is crushed by the pressure. How strong do those forces get?

NESTOR: Every 30 feet, the pressure doubles. So your lung size at the surface is going to be halved by the time you get to 30 feet, and then by the time you get to 60, it will be a third of the size. By the time you get to 90, a quarter of the size, on and on and on. So by the time these people are getting down to 300 feet, their lungs are the size of two clenched up fists, or two oranges. Even when you’re diving at shallow depths, you feel this transformation occur in your body. And so I can’t imagine what it feels like at 300 feet. I will never know. I have done a lot of freediving at shallower depths, but I will never want to dive that deep.

LEVITT: Now, before people actually did these extreme free dives, if you would ask scientists, experts on the human body, whether it was possible for a human to survive this, I suspect they would have said no way, right?

NESTOR: They all said no until around the ’50s and ’60s, when people started betting one another to see how deep they could dive. According to our calculations, 100 feet was the absolute maximum, and by maximum, that was the breaking point. The pressures were so extreme, you know, three times that of the surface, it would crush your organs, it would crush your lungs, it would crush your heart, and you would die. And that understanding had been around for a long time, at least in the Western world. And then people started diving to 100 feet and they started diving to 150 feet and 200 and 300 and more. And we realized that there was something lost in this equation. And it was that we are imbued with something called the mammalian dive reflex, which protects us at extreme depths.

LEVITT: Tell me about that. What is the mammalian dive reflex?

NESTOR: Well, this is the reflex that dolphins have, that seals have, that other marine mammals use to be able to dive down thousands of feet and stay down there for an hour at a time. It’s a series of reflexes that equipped your body to handle the pressure. Your organs will not burst because other fluids are able to become more accessible to them. They become more porous. Your heart rate will slow down. The lowest heart rate ever reported in a conscious, aware human was about seven beats per minute. And that was with a freediver. That is not supposed to be possible. And yet these freedivers keep busting the rules over and over again.

LEVITT: I have to admit, I’m confused. So, you call it a mammalian dive reflex, which suggests that it’s this long-standing evolutionary thing, but if you map back all the way to when we crawled out of the water — 400 million years ago in the transition from water to land, I can’t really see where it’s been very useful for anyone ever since. Have they thought about the evolution of this crazy trait?

NESTOR: It hasn’t been very useful in industrialized societies because we have fishermen and other people to go out and get our food. But if you look at coastal communities throughout thousands and thousands of years — the Greek pearl divers, indigenous communities in Japan that were harvesting seafoods and diving down to 100 feet, 150 feet, and those cultures have been around for thousands of years. If you live in the mountains, it’s not very useful perhaps, but it’s nice to know that we just have this in our DNA somehow that just allows us to be able to access deep water without dying. And I know this stuff seems crazy until you go and splash cool water on your face and you can hear and record your heart rate lowering around 20 percent. That’s part of the mammalian dive reflex.

LEVITT: So just getting your face wet already starts to trigger some of these phenomena.

NESTOR: Yes, and that’s why people do that when they get stressed out.

LEVITT: There are some hints in babies of this dive reflex, though I’ve always been afraid to test it out on my own children. I’ve heard you can just throw newborns into the water and all sorts of good things happen.

NESTOR: Don’t do this at home everybody. But having said that, I’ve seen that happen. I’ve seen infants go into the water and they reflexively open their eyes. They know how to hold their breath and they start breast stroking instinctively. So where does that come from? I don’t know. So many people assumed that we are not meant to be in the water, even though we came from the ocean and our blood contains, you know, such a similar chemical composition as seawater and the amniotic fluid is very similar to that as well. So the ocean is still within us. It’s just so many of us don’t access it, so we’re divorced from it.

LEVITT: Are there any documented cases where somebody just simply doesn’t have these features that most humans seem to have?

NESTOR: I have never met anyone that wasn’t able to feel this within an hour of being in the ocean with some very preliminary freediving training. So I believe all of us have it. But maybe some people have more of a natural inclination towards it. Other people maybe less so, but that doesn’t mean they don’t have it.

LEVITT: Now, a key element to freediving is the ability to hold your breath. And the first time I ever learned about the extremes of holding one’s breath was from a TED Talk by the illusionist David Blaine. It’s probably my all-time favorite TED Talk. And a regular person like me — I think I’m pretty typical in this regard, I can hold my breath for about a minute before it gets extremely uncomfortable. But David Blaine, on the Oprah Winfrey Show, holds his breath for over 17 minutes to set the world record at that time. And I think a lot of people thought it was just fake because he’s a magician, but have you seen that TED talk? And what do you think of it?

NESTOR: I have, yes. He used supplemental oxygen, David Blaine, which is flooding your lungs, your bloodstream, with oxygen and then holding your breath. I think the longest time now is closer to 20 minutes.

LEVITT: 24 minutes and 37 seconds. 

NESTOR: There you go.

LEVITT: I suspect also that physiologists would have said that’s totally impossible.

NESTOR: Yeah, but they say everything is impossible until people — I mean, with holding your breath, I have been told by numerous people that you are going to inflict brain damage after two minutes because that’s the amount of time that oxygen is circling in your bloodstream. If you don’t have that, cells are going to start to die, yada yada. It’s just not correct. I have met freedivers in their 80s in Japan and in France who have been doing this, they claim, every day of their life. And they are perfectly present in every way.

LEVITT: Two of the things that I think make your books so good, in my opinion, are first, how well you describe the science behind the things that you’re studying. And second, that you’re actually crazy enough to go and do all these extreme activities yourself and then write about what it feels like.

NESTOR: So it was actually in 2011 that I was sent by Outside Magazine to Kalamata, Greece to cover the world freediving championship. And that was my first exposure to seeing freedivers do what they do. And then I spent about two-and-a-half years researching and writing Deep. I did not intend to become a freediver at all. But the other freedivers that I was writing about said, “If you’re going to understand this, you have to understand it from the inside.” That doesn’t mean to try to dive down to 300 feet. It just means to begin to understand how your body operates; begin to understand your connection to the ocean; begin to understand the art of breathing. And so I took their invitations and it’s something I still do.

LEVITT: So before you started freediving, you could hold your breath for how long?

NESTOR: About a minute maximum.

LEVITT: Okay. And then you trained. What’s the longest you think you’ve ever held your own breath?

NESTOR: About four minutes, four and a half minutes, which is not very good because if you gave me a half an hour of your time and you were in reasonable health, I would get you holding your breath more than three minutes. I’ve seen this every single time. It does not take a lot of training. It is reminding yourself of your innate abilities. It’s not learning a new skill.

LEVITT: Can you describe what it feels like physiologically as you hold your breath? There’s stages, right, that your body goes through?

NESTOR: The beginning is very pleasant. You feel this slight pressure in your lungs, you calm your mind down, you feel your heart rate lowering, you feel your body calming. So it’s not a physical challenge at the beginning; it’s a mental challenge to see how deeply you can meditate into that moment. That pleasant part starts extending. At the beginning, maybe it only lasts 30, 40 seconds and then the miserable part starts in. And you have to weather that miserable part to get your CO2 threshold up high enough that you can extend that pleasurable part for a little longer. But eventually you can get to the point where about two-and-a-half minutes is pleasant. It just feels like an extremely deep meditation. And then the other minute and a half gets progressively less comfortable.

LEVITT: In the book you write about the spleen?

NESTOR: That’s part of the mammalian dive reflex. So the spleen is filled with this fresh oxygenated blood and it’s there in case of emergencies. But when we are diving, the spleen responds and it depends how good you are of a freediver. Some people it happens very quickly, other people it takes a lot longer. And that spleen releases fresh oxygenated blood. It is such a weird feeling inside of your body to feel this thing you didn’t think existed suddenly turn on and wake up. It’s like a turbo boost and it allows you to stay under the water longer because you have more fuel in the tank.

LEVITT: And when that happens, if you’re underwater, that’s like a timer going off. You’ve got this extra boost, but it’s also telling you you’re on to some other stage, and you’ve got to think about whether you’re in the right depth of water given the stage that you’re at.

NESTOR: That’s right. You have to really listen to your body and the people who get in trouble freediving are the ones who hear these signals and ignore them. When you feel the spleen release, you feel this warmth coming in from the inside of your body. It’s a gentle reminder, “We’re getting at the end of our supply. It might be time to come up to the surface and grab a breath of air.”

LEVITT: Now, something that confused me initially in your book is that free divers who are pushing these extremes in competitions, they go unconscious underwater with a surprising frequency. And then rescue divers will race to save them and drag them to the surface. But it takes a while — I don’t know, a couple of minutes — to get them out of the water. And it seems like they should be dead. Their lungs should be full of seawater. But then when they get to the surface, people yell, “Breathe!” And they miraculously open their eyes and they spring back to life.

NESTOR: Our bodies are a beautiful machine equipped with all these different layers of redundancy to make sure we don’t die under the water. First is feeling uncomfortable. The second thing is that spleen release. And I would say the third or the fourth is when you go unconscious, and your body knows to reflexively close the throat off. Where it gets into really troublesome water, so to speak, is when people then go over the limit at which the body can be continuing to close the throat. And when the lungs fill up with water, then it’s really bad news. But I was just absolutely shocked to see these people unconscious 50 feet underwater, 60 feet underwater, you know, they look like ragdolls, lifeless, come up to the surface, slap their face, “Breathe, breathe,” they take a huge breath of air, and they get out of the way and they’re giggling about it.

LEVITT: So we’ve been focusing on the extremes of freediving, competition, world records, but there’s also this practical and scientific use for the techniques. Could you describe Project CETI?

NESTOR: I named it Project CETI as kind of a riff on the other SETI with an S. This is CETI with a C, as in cetaceans, which are dolphins and whales. While I was researching with these freedivers, they introduced me to different ways of breathing to hold your breath, right? How to really fill up your lungs so you can hold your breath for minutes at a time. They also introduced me to different ways of breathing to heat your body up and to help reduce symptoms of chronic conditions. All the while, they were using freediving to connect more deeply with marine animals. Because when you freedive, you are completely silent. And if you’re hanging out with dolphins or seals or whales, they view you as one of their kin because they watch you go up to the surface to get a breath of air, which is what they do, and then they watch you swim back down in silence. And so in this state of freediving, and not scuba diving, which is very disruptive to everything around, these animals tend to take you into their pods. And I know this sounds like some new-age dream, but it happened to me numerous times, and I can’t wait for it to happen again. But when they take you in, they try to communicate with you. Dolphins do this, and whales do this, by sending out these clicks that you can actually feel in your chest cavity. And these clicks allow them to literally see within your body. This is sonar, right? They are looking with frequencies of sound, into your body. They also use these clicks as a form of communication. So Project CETI was founded around the idea of trying to understand dolphin and whale communication by freediving with them, because only freedivers are allowed this intimate access.  

LEVITT: And then you record the clicks, and as I understand it, the idea is that one would use modern machine learning A.I. technologies to try to translate those clicks into the meanings, to actually use it to come to understand what they’re saying to one another, and potentially to be able to talk with the whales. Is that the ultimate idea of it?

NESTOR: That’s exactly what’s happening right now with two organizations, which are kind of at war with one another, which is great because that makes them even more competitive. So, Project CETI and Earth Species Project, they are both recording whale clicks, and they are processing all of them through machine learning, through large language models, through A.I., to try to crack this code. And I think they’re going to do it. The sad thing is this started off as a project that was focused on creating a deep human connection with these animals in order to learn more about them, which is why free divers came in so handy, because once you have this experience of diving face to face with a 60-foot long whale that could kill you in 30 different ways but instead chooses to welcome you into their pod and communicate with you, you never really are able to see the world in the same way again. So that was the original intention until a bunch of academics got involved and said, “No, that’s an insurance nightmare. We have to go back to using machines and hydrophones,” which is basically where it is now. But I think what they’re truly missing is there’s something special that happens in that connection that you can’t get from being afar. I’m convinced of that. But maybe in a later iteration that will come back.

LEVITT: The research into human echolocation is also mind blowing. Could you talk a little bit about that?

NESTOR: So echolocation is a form of sonar. It’s when you’re using sound to see what’s out in the world, using your ears instead of your eyes. So we’ve known that bats do this in pitch darkness, and we know that dolphins do this and whales do this, but we had never really considered that humans also had this ability. And this is very similar to that mammalian dive reflex. We have the ability to see in the dark with our ears. And I saw a really wonderful demonstration of this with somebody who lost his sight when he was 14-years-old. His name is Brian Bushway. He’s in Los Angeles. And after a few months, he started seeing things around him just by listening very carefully. Then he developed a way of clicking just like dolphins or bats do, this very specific click where he could focus those clicks into areas and see a very detailed view of what was around him so well that he’s able to ride a bike down a city street.

LEVITT: Get out of here! No way.

NESTOR: I watched him do this! He can quote unquote, “see” a tennis ball across a dining table by clicking in this certain way. And after half an hour of training, he put a blindfold over me and had me focus on getting the right frequency of clicking. And it just turns on. I don’t know how else to explain it. Something turns on and allows you to sense things with your ears. And when they took some of these blind echolocators and they put them in an M.R.I., they found that the visual cortex lit up when they were echolocating. So what they were seeing with sound was really no different from what we’re seeing with our eyes.

We’ll be right back with more of my conversation with author James Nestor after this short break.

*      *      *

LEVITT: Let’s turn to your more recent book. It’s called Breath. I have to say that even after loving the book Deep, I was skeptical about Breath. The book that I imagined you had written before I read it was a book that wasn’t very good. But luckily the book that you actually wrote was totally different than the one I expected. Maybe the single biggest argument you make in the book is that breathing through your nose is way better for you than breathing through your mouth. Could you talk about one or two of the most convincing and interesting scientific studies on the topic?

NESTOR: The most interesting part of the nasal breathing, mouth breathing situation is how it affects our sleep. I had never been taught anything about this. I didn’t even know that any science existed in this world. But it turns out, it’s been around for 30, 40 years, and there’s dozens and dozens of studies showing that when we breathe through our mouths, we tend to have much more disrupted sleep. We tend not to have as long of a time in deep sleep. We tend to snore more. We tend to choke on ourselves, something called sleep apnea. Beyond that, when we breathe through our mouths, we are breathing in everything that’s in the air without a filter. That means dust, allergen, mold, whatever’s in your room, you’re just breathing that in, which is quite the opposite of the nose, which is our body’s first line of defense. The one thing I’ve heard more than anything else since this book has come out is people have said, “I’ve trained myself to close my mouth at night, and my snoring’s gone, my sleep apnea is greatly reduced, my sleep scores are through the roof, changed my marriage, it’s changed my life, it’s changed my health.” From such a simple thing we can gain so much.

LEVITT: I am a mouth-breather at night. I have been my entire life. And I’d heard people talking about various ways to fix it. And as I went to sleep, I would be focused on breathing through my nose, and then as I drifted off, I could feel myself going to mouth breathing. So finally, I did one of the things that you mentioned doing in the book, which is I started taping up my mouth. And you talked about using a little piece of tape, but that didn’t really work for me. So I literally just duct tape over my entire mouth. And I thought the first time I did it, “This is crazy. I’m going to last 15 minutes. I’ll feel claustrophobic.” Because I always thought the reason I was breathing through my mouth at night was because I was having trouble getting air through my nose. And the thing was, it didn’t take any adjustment. It was totally natural to me. And so, now, more often than not, I just duct tape myself up before I go to sleep. I’ve never measured any obvious benefits, but it comes without any cost or any pain, so I just do it.

NESTOR: I think if you did choose to measure your sleep, you would find definite improvement. Some people see a transformative improvement from doing this. And you are unlike many people, including myself, where it took me a few weeks to get used to this. I thought it was a terrible idea and the next night I said, “Oh God, I have to do this again. I guess it’s part of research. I gotta figure it out.” And I kept doing it. And now, if I don’t have tape nearby, I’m that guy walking around a city at midnight looking for a Walgreens, trying to find my fix of micropore tape. The duct tape, I do not suggest anyone do. There are many other forms of tape that are meant to be put on skin, and they come right off. But if duct tape’s working for you, I won’t take that away from you.

LEVITT: To many people, it’s intuitive that breathing correctly at night could matter. But the benefits of nose breathing go far beyond. Could you talk about some of the more far-out things? Things that maybe are going to make people say, “No way, that’s not really possible.”

NESTOR: The first thing you have to consider is how nose breathing is different than mouth breathing. So we get about 20 percent more oxygen when we’re breathing through the nose versus equivalent breaths through the mouth.

LEVITT: So out of the same amount of air, we get more oxygen out when it comes through the nose. Why is that?

NESTOR: Because we are breathing more slowly and because there’s more pressure. When we are exhaling through the nose, as opposed to the mouth, that back pressure allows our lungs to absorb more oxygen. When you are breathing through the mouth, you tend to be breathing very shallow. And when you’re breathing too shallow, you have to take so many more breaths to get the same amount of oxygen. That breath is not descending low into the lungs, and it’s the lower areas of the lungs that absorb the most oxygen, so you’re just bringing in breath to exhale it without ever using it. So nose breathing, when you are slowing down your breath, you are also sending your body signals that you are safe and relaxed. Stress can be significantly reduced. Your brain will be able to better function. There have been studies that have shown you can make better decisions, you can regulate your emotions much better, when you are just breathing through the nose. When you are breathing through the mouth, you’re sending those opposite signals. You’re telling your body, “There’s an emergency. You need to ramp yourself up to either fight off this lion or to run away from it.” And I will say beyond sleep, one of the things that really blew me away was that just converting to nasal breathing can significantly reduce the symptoms of asthma, and not many asthmatics are told about this.

LEVITT: It seems kind of like it would be the opposite. Do they understand the physiology of how it benefits asthmatics?

NESTOR: They absolutely do. So the vast majority of asthmatics and people with anxiety — this is why those two different populations, there’s so much cross pollination between them — the vast majority of them have very low CO2 in their exhaled breath. And the reason is because they are constantly over-breathing because they associate holding their breath, that increase of CO2, with having an attack. And so their bodies have responded by breathing like this all day long. It turns out the more you breathe that way, it actually helps to bring on those attacks. So by training these people to breathe through the nose, which forces you to breathe more slowly, more rhythmically, can have a really transformational effect. It’s just very sad that asthmatics are given bronchodilators and steroids and told to go away, instead of giving them some basic breath training.

LEVITT: Could you talk more about carbon dioxide? Because if you had asked me what the role of carbon dioxide was in the human body, I would have said, “Oxygen is the fuel and carbon dioxide is the pollution that’s left over,” just this poison to our body and the only thing we’re trying to do is get rid of it.

NESTOR: I had learned the same thing. I think that’s where it gets confusing for people because we’ve understood that too much CO2 is bad, which is true in the atmosphere. I mean, look what’s happening with climate change. It wasn’t until I was a couple of years into the research in this book where I started to find all this very interesting science from the early 1900s in which they were discovering that it was actually only in the presence of carbon dioxide that oxygen was able to release from red blood cells and get into the hungry cells which use that oxygen to make energy. So if you have a lower amount of carbon dioxide, it’s harder for that oxygen to release. So it’s harder for your body to produce energy. You need a balance of carbon dioxide and oxygen in your body to efficiently produce energy.

LEVITT: What you’re saying is counterintuitive. Because when I think about my very crude, high-school-science model of the body, you breathe in oxygen, and the oxygen is in your bloodstream, and that determines how much oxygen is in the organs. But what you’re saying, I think, is that the more carbon dioxide that you get into your bloodstream, the more oxygen you’re going to get into your organs, which is where you need the oxygen. Did I get that right?

NESTOR: You did, and if you were confused, you’re in the right place. Because I was as confused as anyone, and I had to talk to so many biochemists to get my head around this. This does not mean you should go out and start huffing CO2 right now. That’s a bad idea. What it means is we need a balance of these two things in order for our bodies to operate properly. You can get by having low CO2. Millions of people do this — a lot of asthmatics, a lot of people with anxiety. But just compensating is not the same as being healthy. We need a balance of CO2 and oxygen in the body.

LEVITT: It seems like what you’re saying is that for many or most people, maybe for athletes, for instance, if you could find a way to have a higher level of CO2 it would improve your performance. Have people figured out ways of doing this and has it been successful in increasing their ability either to perform sports or other activities?

NESTOR: Yes. And of the elite trainers I know — I know about a half a dozen of them — this is their very first thing that they do with their athletes that come in. They assess their breathing. They say their breathing is usually a disaster. And they focus on that first and foremost. I want to be clear that it doesn’t mean you have to be nasal breathing through every single stage of every activity you’re doing. If you’re about to dunk on someone in the N.B.A. finals, like who cares how you’re breathing? If you ever watched Michael Jordan, right before he dunks, he takes this huge breath of air. And then he does his thing. But if you look at LeBron now, what is he doing when he’s not out on the floor? He’s sitting in a chair and he’s practicing breathwork. He’s breathing in and out through his nose because it is so much more effective for recovery. So for people in sports performance, breathing is absolutely essential.

LEVITT: So the other day I went hiking — and I knew we’d be talking, so I’ve been thinking a lot about nose breathing. And I made it my goal to only breathe through my nose the whole hike. And things were going great. I was thinking about the 20 percent more oxygen that you were talking about. And then the incline got steep and breathing through my nose, I felt like I was suffocating, like I was going to die. And I started breathing through my mouth, and I immediately felt fine. Was I really not getting enough air, or is that just a trick my body’s playing on me?

NESTOR: Next time you go on a hike, bring a pulse oximeter with you and place it on your finger. And when you feel that suffocating feeling, I want you to look at the pulse oximeter, and there is a very good chance your oxygen hasn’t changed at all. If you are like most people, it would be between 96 and 99 percent. What has changed is your CO2 in your body has gone up. And that is our trigger for breathing. It’s not oxygen. So when CO2 reaches a certain level, it triggers chemoreceptors which tell our brain that we need to start breathing. So what you’re feeling is that accumulation of CO2, and the more that you practice breath work, the easier that process will get because your threshold for CO2 will go up. And that is the key behind athletic performance. And it’s also the key that a lot of people are using to help people with asthma, anxiety, emphysema, other breathing issues to help reduce their symptoms.

LEVITT: So when you say have the CO2 threshold go up, it’s really just the mental. It’s becoming accustomed to that feeling like you’re going to die and realizing you’re not really going to die.

NESTOR: Exactly. And when I was first researching this, I had that same feeling. I said, “This is impossible.” I had a trainer put a pulse oximeter on me and put me on a stationary bike and breathe so slowly, I felt I was dying. And I watched my oxygen stay consistent the entire time. And he said, “Listen, this is all about CO2. Oxygen is easy. That’s the low-hanging fruit. It is all about manipulating your tolerance for CO2.”

LEVITT: Throughout your book you talk about research, but I really get the impression that mainstream Western medical research has devoted shockingly little attention to the topic of breathing. And there’s these occasional renegades who come along and they often produce study results that are extremely impressive. And it seems like if you were a scientist in this field, you’d say, “Wow, that’s the kind of bandwagon I want to get on,” or, “That’s impossible. I’m going to go disprove it.” But that doesn’t really seem to be how science is working in this area. It seems like ignoring these results has been what’s happened. Is that your impression, having researched it a lot?

NESTOR: Sadly, yes. And I don’t know how much more science they need. I don’t know how many more studies to convince them. Half of my extended family are doctors, including pulmonologists. And I had them read different versions of this book. And a few of them said, “About 90 percent of this I’ve never heard of.” And these are people that are pulmonologists — they’re the breathing specialists. When I say, “What is the best way of breathing? You know, is there a certain breath count? How many seconds on the inhale?” They say, “I don’t know. I deal with lung cancer. I deal with car accidents. I don’t have time for this.” And so I think it has less to do with the people and their curiosity and more to do with a system in which people have to be so sick before they’re able to see doctors often. And then those doctors do not have any time to spend with these people and teach them breathing techniques? I mean, are you kidding me? When you’re seeing 15 patients an hour, they say, “Here, this is going to take care of this for now and come back if it gets worse.” And I’m not blaming doctors at all. I just think that it is very clear that we have all the science and all of the techniques to help so many people — not only with respiratory problems, but with weight issues, with depression, with anxiety and more with some very simple lifestyle changes. And I did not set out on this journey to prove or disprove anything. I talked to the freaks, but I also talked to renowned researchers at top institutions. I talked to everybody. They said, “This is so easy. If we know it works, why aren’t people doing it?” So, what I want to do is give people information so that they can choose what road they want to take.

LEVITT: Now the claim is that what you call over breathing, the mouth breathing and the shallow breathing, is a modern phenomenon emerging in the last 300 years. And then you talk in the book about this evidence of how the shape of the human skull has changed dramatically, and is deeply influenced by our environment. Is that right?

NESTOR: Yeah, it is. So what has happened in just the last few centuries is that we’ve completely changed our food supply. We used to eat raw, whole foods that were unprocessed, that required a lot of chewing. And since the industrial revolution, we developed all of these different ways to manufacture foods to strip them of so much of their fiber and so much of their qualities that would require us to chew. So we’ve produced and processed these foods almost pre-chewed in some ways. I mean, think about the food you ate today. I think about the food I ate today. Hardly any chewing at all. And after a single generation, this is what Robert Corruccini found, 50 percent of a population that converts to this soft industrialized diet will have crooked teeth because their mouths have grown so small that they no longer have space to hold all those teeth in place when they’re straight. And by the second generation, it’s about 70 percent of the population. Third generation is about 80, 85 percent. And fourth generation, here we are, look around, about 90 percent of us have crooked teeth. It’s not natural and it’s from industrialized food.

LEVITT: So, you’re saying that because we’re not using our muscles to chew difficult foods, our jaws are shrinking, and that’s leading to crooked teeth. But I think more importantly, from your perspective, it’s interfering with the development of the pathways that allow oxygen into the lungs. Am I getting that right?

NESTOR: That’s exactly what happened. You have crooked teeth, which means your mouth is too small, which means you have a smaller airway, which is why you are going to be much more apt to suffer from breathing difficulties.

LEVITT: And so people know this because if you look at skulls from 500 years ago, they just look different?

NESTOR: Absolutely. Look at ancient skulls. Look at any pre-industrialized society and look at the skulls. I’ve looked at hundreds and hundreds of these. And all of them, it doesn’t matter where you take the skull from, we all had perfectly straight teeth, just like every dolphin has perfectly straight teeth.

LEVITT: So I’m in my 50s. I had the most crooked teeth of any human who has ever lived. I still have the plaster version of what I look like and it was unreal. Would it be sensible for me to think about trying to chew a couple hours a day on something hard? Would that lead to any recovery or is the damage done in my case?

NESTOR: What that would do is it would help to tone your airways. As we get older, our airways tend to get flabby, just like other parts of our body, because they don’t get exercise. So, if you learn how to chew more, and even do some exercises with your tongue, you can help to firm up the airway, which will allow you to breathe better. This is called myofunctional therapy. To answer the first part of the question, can you change your facial shape, your mouth at this stage, with just chewing hard foods? Probably not, because a lot of that foundation is set when you’re younger, which is why it’s so important, from around two to three, up until around 16 to 17, to be having this correct oral posture, because you are setting the stage for how your mouth is going to grow, how your teeth are going to grow, and how you’re going to breathe later on in life.

LEVITT: So with my children, I should be giving them difficult to chew foods? Or I’m not really sure what — but it seems like if this is important, we should be telling parents what to do.

NESTOR: The first thing you should do for your kids is to teach them proper oral posture before you try to change their diets because you know that’s not going to go too well. So proper oral posture is having the tongue on the roof of the mouth. The tip of that tongue should be just behind your front teeth. The lips should be lightly touching, so your mouth is closed, and there should be about two millimeters of space on your back molars. Most importantly, it helps open up your airway. And if you’re young, that pressure of the tongue will help to gently expand that upper palate, especially if you are in the ages from around three to four on up to around seven or eight. That’s the most important time to have this proper oral posture.

LEVITT: Now, we’ve been talking about breathing in a sort of scientific and arm’s length way. But then there are these amazing things. Wim Hof, the Dutch guy, what he’s done comes to mind. Could you talk about his accomplishments and what the broader implications are?

NESTOR: Wim Hof was this sort of vagabond hippie guy who got into all of this yoga and ancient Bon Buddhist breathing practices and got so good at it that he was able to hang out in frozen lakes for many minutes at a time. The better he got at it, the more he wanted to test himself. He spent almost two hours, it was like an hour and 50 minutes, I believe, covered in ice in downtown Manhattan. That’s supposed to kill you — supposed to suffer from frostbite or hypothermia. He got out of the ice bath, had a cup of coffee, went on with his day. Another example, and this is from a great study from around 10 years ago, is he said, “Well, what I’m really doing is bolstering my immune function. This is why people need to breathe this way and expose themselves to cold.” So some researchers said, “Let’s test this.” So they shot him up with the endotoxin of E. coli, which for any normal person would make us severely ill. And he breathed in this way, stimulating his immune system, and he suffered no symptoms. And then they brought in a bunch of random subjects who had never done any breathwork before and after four days all of them that had gone through his program were able to have this ability to bolster their immune function as well. So we know it’s real. It’s been measured. You can turn on your immune system with breathing.

LEVITT: And what kind of breathing does he do?

NESTOR: He’s most famous for this very vigorous technique called Wim Hof method, even though when I was talking to him, he kind of laughed. He’s like, “You know, this is 2,000 years old.” But he has branded it as Wim Hof method and it’s about 30 very deep big breaths, then you take a big inhale, you release about half of that air, and you hold your breath for a couple of minutes, or three minutes, or four minutes. And you do about three to four rounds of this. What’s most interesting to me is you feel great after doing it, but it’s the studies that have been done — mostly case studies with people with severe autoimmune diseases, and how after a few weeks of cold exposure and breathing this way, their C-reactive proteins that were completely off the charts are at a normal level. Now there are probably thousands of people with autoimmune diseases that haven’t been getting any help from anywhere else that have turned to this, and it’s done them a lot of good.

You’re listening to People I (Mostly) Admire with Steve Levitt and his conversation with author James Nestor. After this short break, they’ll return to talk about how James handled his unexpected success.

*      *      *

James Nestor’s publishing success came relatively late in life. I’m curious to hear both how he pulled that off after a decade spent toiling in a cubicle for his day job, and how he’s adjusting to his new status as a guru of sorts.

LEVITT: We’ve been talking about your books, but one thing we haven’t talked about is how unlikely, in many ways, the success of your books has been. You came to book writing somewhat late. Your first career was as a copywriter and you did that for quite a long time before starting to moonlight as a freelance journalist. And I imagine even that transition from copywriter to freelance journalist was really difficult. But then to go from that to best-selling author, all the odds are stacked against you. Why do you think you succeeded where so many others don’t?

NESTOR: I think it’s because writing, for me, has always been an outlet. It’s something that almost felt like cheating because I enjoyed it so much. And so when I had a, quote, “real job,” which I did for years and years — writing copy, managing different writers, very stable job — this is what I would do to feed my soul at nighttime and on weekends. And it wasn’t until several years of freelancing that I decided to cut the cord, that if I wasn’t going to do this now, I was certainly never going to do it. And it was really hard for a few years. And I really, really struggled, but every time I was able to find that time and sit down and to immerse myself into these worlds, I just knew that this is what I wanted to do. I cannot believe that I’m able to do this for a living now. It’s still a complete shock to me and I’m just waiting for the rug to be pulled out from under me any moment.

LEVITT: It almost seems to me like one of your secrets is you just have good taste. You know what’s interesting, and you latch onto things that other people will find interesting. Do you think that’s a fair assessment of why you’ve been so successful?

NESTOR: Well, I think that’s the case with any writer. I mean, how many subjects come across your desk, right? And so editing, I think, is one of the most important parts of writing. The writing, the creative part, I think, is very easy. But it’s the editing out. And I’m lucky enough that the things I was most passionate about, these crazy stories about these crazy people doing crazy things, people were interested in those.

LEVITT: Since your book Breath came out, you’ve become a guru of sorts? I suspect you never imagined you’d find yourself in that position.

NESTOR: If you could see me, I was very much cringing at that moment because I can’t stand when people, especially writers, switch positions and then take on this superiority — this very opinionated way of disseminating information. I think that is antithetical to journalistic ethos and I think that you constantly have to be open to changing your mind, to saying, “I was wrong about that. I’m going to correct myself in the future.” And when you put yourself up on a pedestal to say, “This is what I’ve learned. Come to me, all these disciples, I’m going to teach you the ways.” Then you’re no longer a journalist and you’re no longer able to be objective. I hope to God I’m not in that position now. I first and foremost want to be a reporter. And then what comes after that will just be an extension of me being objective and curious about things.

LEVITT: So when I said, “a guru,” what I mean by that is with your book Breath, you’ve pulled together a set of ideas that a large group of people see as extremely valuable, and they see you as the purveyor of that information. And they come to you seeking knowledge — willing to, you know, pay a lot of money to hear what you have to say. And the power dynamic that emerges I find to be fascinating, and I experience it all the time as a professor with students. But when you run retreats for people who are trying to learn breathing, I suspect the power dynamic is just incredibly extreme.

NESTOR: So those retreats were the only way I felt I was able to deliver this information to the thousands and thousands of people who have been writing me over the last few years, begging for information to help their asthmatic kid, to help their emphysemic grandfather, on and on and on. I mean, I had to hire different people to handle those emails. It was just nonstop. And I’m not a pulmonologist. I’m not a yoga instructor. I’m a reporter. I happen to go out and learn a bunch of what I thought was interesting and valuable information that I put into the book. But they kept coming. And they’re like, “It’d be really great if, you know, I was able to learn this in person.” So my idea was there are so many breathing retreats and yoga retreats, and they only teach one thing. I said, “Huh, what if every single day you expose people to a completely new breathing modality?” So they could try it out and then they could see which one resonated with them the most and then they could take that and leave. So I am not the one teaching the breathing techniques. I stick to my position of presenting and doing slideshows, but I bring some of the best people in the world, real breath instructors, who show up and transform people. There’s no drugs in this thing, there’s no subscriptions, there’s no supplements. This is breathing. And this is something you can take with you the rest of your life. So that is why we ended up doing those. And I do like one or two a year because I just don’t have time for it. And it was a way to reconnect with these people and learn a few new things and be reinspired to talk about this stuff longer.

LEVITT: I had the author John Green on this podcast and he had written a number of successful books and then he wrote The Fault in Our Stars, which was a massive hit, a cultural phenomenon. And he described being totally unprepared for the experience and — I think it’s fair to say — paralyzed by his success. Do you feel some of those same pressures given your own recent successes?

NESTOR: This was all behind the backdrop of Covid. So the book came out like a few weeks after lockdown, and some people thought we had done that on purpose, which I thought was very interesting. This book was printed a year before. I had worked on it for six years. People are like, “How dare you take advantage of this respiratory pandemic.” So it came out and I had nothing else to do. I was in San Francisco, which locked down first and most severely. I was just like doing interviews all day long and responding to everybody until it got to the point where I felt like a fake after a while because I kept regurgitating the same things, but I was not moving my own knowledge base forward and I wasn’t exploring the things that got me extremely excited. So I had to pull back and I’ve pulled back so severely now because, after four years of doing this, without sounding melodramatic, you start to feel damaged. And that’s one of the reasons I’m moving to Portugal, right? I’m going to be in a different time zone to just sort of fall back into that creative space, to immerse myself back into new worlds and learn new things. I don’t want to sound too precious here about all of this. I cannot tell you how appreciative I am to be in this position to do this for my livelihood. At the same time, I am not one of those people who just feeds off of a constant stream of energy and attention. Where I sort of regain my power is when I’m left alone to research and create things, which is what I’m in the process of doing right now.

LEVITT: I’ve been able to find no trace online of what you’re working on. Are you willing to say anything about it or is it completely under wraps for now?

NESTOR: I never talk about it because the moment you start talking about it is the moment it starts changing. And that thing you talked about two months ago is now something completely different. So I am just keeping it very much under wraps, but I cannot tell you what a thrill it’s been to get back on the road and start to explore things that are not supposed to be possible, and yet there they are right in front of your face happening every day. So I’m absolutely thrilled about it, and I hope by next year I’ll have it all wrapped up.

James Nestor’s strategy of saying nothing about his next project is working on me — my interest just gets greater and greater. As if it wasn’t obvious from our conversation, I highly recommend James Nestor’s books. One is called Deep, the other Breath. He does a wonderful job of bringing together both great storytelling and making complicated science understandable.

LEVEY: Hi, listeners. Morgan here. I’m the show’s producer. This is the part of the show when we normally take a listener question, but today Steve has a favor to ask of you, listeners. Hi, Steve.

LEVITT: Thanks, Morgan. Today I am usurping agenda power because, as you know, Morgan, a few years back I helped launch an organization called Data Science 4 Everyone. It’s a consortium that is working with an enormous number of partners to try to get more data analysis, data awareness, data exposure to kids in K through 12 education.

LEVEY: Who does this organization work with?

LEVITT: Well, we work with all sorts of people, but the movers and shakers in this area are what are called state math leads. These are the people designated in a particular state who are in charge of the math curriculum, and they are powerful people who are able to influence what happens on the ground. But we also work with governors and with Congress and with teachers — basically we work with anyone who will work with us to try to change math curriculum.

LEVEY: As you’ve talked about many times on this show, changing curriculum in this country is not an easy task. So how’s that going so far?

LEVITT: You’re right, it is really hard, and I would say that it’s going way better than I expected. So it all started many years ago when I was guest host on a Freakonomics Radio episode that was criticizing the existing math curriculum.

LEVEY: That episode is called “America’s Math Curriculum Doesn’t Add Up.” It’s episode 391, and it’s from 2019.

LEVITT: 2019, yeah, so it has been five years now. And the reaction to that episode was overwhelming. I was shocked how many people came to me and said that they agreed. It led to starting Data Science 4  Everyone. I mean, it’s obviously hard to change education, but we are making baby steps and things are happening. But one of the challenges that we struggle with is that nobody can really agree on what data science even is. I have a vision of what data science is, and that’s a way of thinking, a way of being — not so much tool driven, but more how you approach problems. Other people think it’s different. They think it’s really about the programming and doing machine learning. And I don’t know what the right answer is, but as we try to create curriculum, we want to create the curriculum that people really need and want. And so to try to help make some headway on this problem, we’ve put together a survey and it’s up on our website, datascience4everyone.org. The words “data science,” the number “4,” the word “everyone,” dot org. And we just have a five-minute survey that we’d love interested people to take to try to give us an idea of what people would want from a K-12 data science curriculum.

LEVEY: Do you have to be a parent or student to participate in the survey?

LEVITT: We would love parents and students, but we want everyone. We are interested in the general thoughts on what’s useful in teaching data science. It’s obviously not a particularly scientific survey. We’re not trying to be representative. We did a survey like this back in that original Freakonomics Radio episode —

we had polled people and just asked them what kind of math they used in everyday life. And it was startling that real people in real jobs hardly ever use things like calculus or geometry, but they use Excel and they use data all the time. And in the same way that gathering those data helped motivate and direct what we were doing, we’re hoping that this survey will do the same.

LEVEY: Is there a deadline for the survey, Steve?

LEVITT: October 15th is when we close it. So, please, if you’re interested, make a visit before then.

LEVEY: Okay, great. We will put a link to the survey in our show notes, but listeners can also find it by going to datascience4everyone.org. That’s “data science,” the number “4,” the word “everyone,” dot org. If you have a question for us, our email is PIMA@freakonomics.com. That’s P-I-M-A@freakonomics.com. PIMA is an acronym for our show. Steve and I read every email that’s sent and we look forward to reading yours.

Next week, we’re back with an encore presentation of my conversation with artist Wendy MacNaughton. Of all the podcast episodes I’ve done, this is the one where our conversation surprised me the most. And in two weeks, we’ll have a brand new episode featuring Ken Ono. He’s a University of Virginia math professor who’s used his math expertise to transform elite swimming. As always, thanks for listening, and we’ll see you back soon.

*      *      *

People I (Mostly) Admire is part of the Freakonomics Radio Network, which also includes Freakonomics Radio, No Stupid Questions, and The Economics of Everyday Things. All our shows are produced by Stitcher and Renbud Radio. This episode was produced by Lyric Bowditch and Morgan Levey. It was mixed by Jasmin Klinger. We had research assistance from Daniel Moritz-Rabson. Our theme music was composed by Luis Guerra. We can be reached at pima@freakonomics.com, that’s P-I-M-A@freakonomics.com. Thanks for listening.

NESTOR: I’ve probably done 400 interviews. I literally have never been asked about half of these questions. 

LEVITT: Well, that’s good!

NESTOR: So, kudos to you.

LEVITT: Good, thank you—

NESTOR: I hate you, but I also thank you for getting my brain working.