Ep 163: Are Lungs Outside the Body?

Biomechanist Katy Bowman talks with biologist Jeannette Loram about lung movement.

Katy and Jeannette debate whether the lung surfaces are actually outside the body, similar to the tubes of the gut, and discuss how lung movement is not only important for breathing but also for immunity. They discuss the anatomy of our lungs and the mechanics of lung movement and explain how our lungs, just like our hips, have a range of motion that they need to be moved through on a regular basis.

They discuss humans as endurance-adapted animals and explain how our ribcage anatomy is adapted for greater lung movement compared with non-endurance animals. They also discuss postural issues such as hyperkyphosis and forward shoulders that can limit our ability to take good breaths.

Finally, they touch on some unique breathing scenarios such as high-altitude and aquatic environments.

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Creators & Guests

Host

Jeannette Loram

Biologist, Yoga & Movement Teacher, Nutritious Movement® RES-CPT, Restore Your Core® Teacher

Host

Katy Bowman

Bestselling author, speaker, and a leader in the Movement movement, biomechanist Katy Bowman is changing the way we move and think about our need for movement.

Editor

Brock Armstrong

Brock is a podcast editor and producer (audio and video). Currently working on: The Resetter with Dr. Mindy Pelz, Better! with Dr. Stephanie Estima, Health Coach Radio, Move Your DNA with Katy Bowman, and Change Academy.

What is Move Your DNA with Katy Bowman?

Although the world is becoming mostly sedentary, our bodies still require a wide variety of daily movements in order to work well. Many of us struggle to get regular exercise, but even that can fall short of nourishing the body from head to toe. How can we move more—a lot more—when we have sore, stiff parts and overly busy lifestyles?

Join Katy Bowman M.S., biomechanist, author, and movement educator as she combines big-picture lessons on biomechanics, kinesiology, physiology, and natural human movement with simple and practical solutions and exercises to get all your body parts moving better. Katy’s lighthearted and funny approach helps us all put the movement back in our lives, and the joy back in our movement!

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This is the Move Your DNA podcast, a show where movement science meets your everyday life. To make sure you don't miss an episode and keep up to date with what's coming up, be sure to follow or subscribe to our podcast wherever you like to listen to audio. I'm Katy Bowman, biomechanist, author, and deep breather. And I'm Jeannette Loram, biologist, movement teacher, and breath listener. Every body is welcome here. Let's get started.

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KATY: Ok I just have a quick question.

JEANNETTE: Mm.

KATY: What is a breath listener?

JEANNETTE: Oh, well I think that for the past 15 years, at least, probably 16 years, I've been listening to people breathing from my newborns - you know when you're in that stage when you're always listening to how they're breathing - and then as a swim coach. So when I'm working with kids, then I'm listening to how they're working. Because some kids push themselves very hard and you might need to give them a little rest. Especially in the pool. And then, also I notice when I'm teaching adults, and I'm teaching something that might be challenging either physically or they're thinking about it, I can't hear any breath.

KATY: Oh interesting.

JEANNETTE: So I cue it and then they all exhale. And I'm like, there we go. That's what I want to hear.

KATY: Yeah. And for a movement teacher, we talk about breath as an alignment point to make sure it's sort of flowing and not being held. But the fact that you're monitoring this other, so-called, alignment point. That's pretty great.

JEANNETTE: Yes.

KATY: I thought you were - the person sleeping next to you at night was snoring.

JEANNETTE: No. Not so much. More in terms of as a movement teacher and a parent.

KATY: Yeah I like that. I listen to gait. Heavy footfall. Shuffling. Foot sliding.

JEANNETTE: Yes. Interesting. Yeah. Somehow I'm always drawn to breath.

KATY: All right well we're going to talk about lungs and breath today.

JEANNETTE: Yes. So one of my favorite bits in your latest book, My Perfect Movement Plan, is when you talk about lungs and the heart, actually, as being a bit like hips. And having a range of motion that they need to be moved through regularly. So we thought it would be great to do a whole episode on lungs and lung movement. Because I have questions.

KATY: And I have questions too. So this is going to be great. And originally we were going to try to do the full cardiovascular system, because in that section of the book, what I am trying to do is show - I'm trying to normalize the units. So range of motion is the way we think about - our knees, our shoulders, our hips have to go through their range of motion. And I see the heart and lungs in a similar way. But you don't often see them talked about in that way, if ever. But the heart and lungs are just too big to do in a single episode.

JEANNETTE: Right.

KATY: So we're going to do lungs in one and the heart in a subsequent episode. This is a meaty episode.

JEANNETTE: Right. It is a lot.

KATY: Why is there so much?

JEANNETTE: Well, the more you start thinking, the more questions pop up and the more avenues we can go down.

KATY: Yeah.

JEANNETTE: So how about we start with what the lungs are and then some of the roles of lungs and then movement?

KATY: Ok.

JEANNETTE: So, I think most people will know, broadly, what the lungs are. But they're a pair of organs that sit in your chest. Cone-shaped organs. And I like to think of them as trees. You start with this tube and then it branches out. And then you end up with these tiny tiny little tubes. And then at the end of each one, these air sacs. And that is one of the primary functions of the lungs - is in this exchange of gas. We need to take in oxygen for energy generation in our cells and we need to get rid of carbon dioxide. And these tiny little air sacs are where that happens.

KATY: Yeah, it kind of reminds me of trees. One of the reasons I love trees so much is because they're so fractal and they remind me of much of how our own anatomy is organized. But if you imagine the lungs, where they've got a trunk with air being pulled in through your nose or mouth, coming down this main tube, and then there are branches, and then there are twigs, and then there are leaves. And I always think of the leaves as the similar place to the sacs that you were talking about. That final place where it's interacting with the outside, or in this case the inside world. And that brings me to - I just got back from backpacking and camping so there's all this late-night talk amongst all the girls in their tents and their moms. We're all talking to each other because it's raining and we're all in there. And one of my daughter's friends said, "Walking with you is like walking with a textbook. A body textbook." Because I was always throwing out these little things to enliven a long day of walking. And one of the things I was throwing out there was this idea of the digestive system being outside the body. Have you ever come across that?

JEANNETTE: Yes. Yes for sure. Because I think it's not well understood that actually some contents of your gut never crossed into you body, it just goes straight through on the outside. So yeah, I think that is something that people don't appreciate.

KATY: Well, and I appreciate it because actually when I started thinking about the body as a series of surfaces that really helped me understand the function. So I think it was early on in my anatomy training at university, I think it was the anatomy T.A. had talked about what we're saying is, if you put something into your mouth, it's entering a tube that has an exit. You know when you go to the bathroom there's another exit there. So from mouth to anus is one tube. So if you imagine a donut hole, there's a hole going all the way through it. None of that hole is technically inside the bread of the donut. So when it comes to the body, it's all about barrier surfaces. Where are the barriers between inside and outside. So I was talking about that. And then one of the other parents was like, "Well then are the lungs outside the body too?"And I thought "That's a great question!" And I always think about the uterus , also being another outside the body, because it's that same - it's really exposed. It's surface - it has a surface that's really exposed to the outside of your body environment. There's no physical barrier there. But I had not thought of the lungs as being outside of the body. But yes, it meets that same condition.

What do you think about that?

JEANETTE: It's really interesting because before you brought it up I hadn't really thought about it in those terms, actually. But, I had always realized, just like the skin - the skin is in constant contact with the environment - and the same with the surfaces of the lungs. That's the whole point. You've got this massive massive area which is designed to interact with the air.

KATY: Yeah.

JEANNETTE: Which is brought inside but it's not you. But I really like that. And it's actually the largest surface area in the body, larger than your skin. I used to love this in biology. When they give you images. When you're pregnant and they say, "Your baby is now the size of a mango."

KATY: Or your DNA goes all the way to the moon.

JEANNETTE: Yes. So the same thing with the surfaces of alveoli which are the little air sacs at the end of those bron... the leaves.

KATY: The leaves of the tree.

JEANNETTE: To use your analogy. Which are also the size of...

KATY: Exactly.

JEANNETTE: It's the size of a tennis court. 17 meters square. So it's huge. And that's interacting with the outside. So I think it's a really valid question.

KATY: Yeah. And I just love this idea that you're bringing air into a specialized chamber that your body folds around outside air. But it is still, I don't know when we began and when we stop. But you are able to draw it in. You could fill that volume but it hasn't crossed over the barriers.

JEANNETTE: No.

KATY: Your external barriers. And I just thought it makes it even more beautiful. If you think about it. And it makes it easier to be "that's what we're doing." We're bringing in oxygen into tiny and tinier and tinier places in the same way in blood vessels you take the blood that's flowing through an artery and eventually get it to a capillary because it needs that thin layer to allow to cross over into the body.

JEANNETTE: Yes.

KATY: Our bodies, our walls are so robust in many places. And so in order for these exchanges to happen you need thinness. You need to get to the place where the barrier is more like a piece of tissue paper. And so the leaves are more like tissue paper.

JEANNETTE: And I think the lining of the alveoli are the thinnest in the human body. Nanometers.

KATY: Nanometers.

JEANNETTE: And I think they didn't really realize that until the electron microscope because you couldn't really sense that there was separation. So super thin. And covers this huge area. Pretty amazing.

KATY: Yeah. So one side of the lungs are outside of the body and one side of the lungs are inside the body.

JEANNETTE: I would think if the gut is... it's the same as the gut.

KATY: It's the same as the gut.

JEANNETTE: So I think it's valid.

KATY: Yeah.

JEANNETTE: Because it's - some of the contents of the gut crosses the barrier, obviously. You digest and assimilate food. Some contents of the air sac goes across but not all of it.

KATY: Mm-hmm.

JEANNETTE: And then it's expelled. I would say it's the same.

KATY: And I also really appreciate when I think of these parts and immunity. You know this idea that we have to have a very robust, let's just say defense system, soldiers, everywhere on our outward facing surfaces. So our skin certainly has those. But the lungs do as well.

JEANNETTE: Yes. And the gut.

KATY: And so does the gut. And so does the uterus.

JEANNETTE: Yeah.

KATY: We burn off our uterus lining once a month because it is so exposed to the outside environment because you're trying to keep pathogens, essentially, coming across. And mucus is such a way that we have of the defense on the outside of the body. And we'll talk about mucus (I'm doing air quotes) "inside" the lungs. But that mucus is similarly outside the body. Just like nose mucus. And any parts of our body that sort of drip and move things out. Those are outside of the body defenses.

JEANNETTE: That's right. So you have these - in the lungs there's lots of different types of defenses. Mucus being one of them. Physical barriers: you've got mucus. You've got this structure of the cells themselves. Then you've got movements. You've got these little projections called cilia which actually kind of beat and can clear things.

KATY: Like nose hairs.

JEANNETTE: Exactly. Like tiny tiny little nose hairs. And then there's also compounds that are secreted by the cells of the lungs. Things like enzymes, proteins that can digest bacteria. And cells that can engulf them. Engulf bacteria like amoeba. But then what's really fascinating was a paper that I had not come across. You shared with me about how the immune system or the immune response of the lungs is actually affected by breathing motions.

KATY: Yeah.

JEANNETTE: Which blew my mind.

KATY: Well that's in my wheelhouse, right? Because of the way we tend to frame movement: it's of the arms and the legs. But I think you and I had conversations years ago about movement is so protective of health in general. But why it's protective isn't always obvious. There's many levels upon which it's working. And this was, to me, oh yes, this is another level at which the anatomy of the lungs and all of those specialized cells and tissues, enzymes that you named, are still dependent on movement. It's not enough to do their work in a very still environment. Of course there's an efficiency in those systems being packaged in something that would naturally be getting a lot of movement. I think of the lymphatic system as something similar.

JEANNETTE: Yes.

KATY: It's got its job and we tend to think of its job in a vacuum, a very still vacuum. Oh and here's how it moves the waste out and shuttles the waste from place to place. But of course its job, its volume of job, its strength and force that it does in its job is dependent on what the musculoskeletal system is doing. Which means how you are interacting with your environment as an individual? How much labor does your life take? How much movement are you doing? And as these systems were evolving there was a lot more movement than there is now.

JEANNETTE: Right.

KATY: So we just tend to forget that movement is also a part of the anatomy. Or the anatomy depends on movement to work to its full capacity.

JEANNETTE: Right. So it's really the case that the lungs and movement of the lungs have biological effects beyond gas exchange.

KATY: Yes.

JEANNETTE: That's how I would put it. We just think about lungs as how we get air in and out. How we get oxygen but actually those movements have a cascade of different biological effects.

KATY: Right. And I'm always looking at that ecological picture. Lungs are this part that are really helping us get oxygen into our blood to ultimately feed the muscle. So there's the bare minimum of staying alive. But then there's also fueling the body with oxygen to be able to accomplish movement. And the things that you want to be able to do physically in your life is depending on these lungs doing this sort of specialized job that they have in the body which is bringing the oxygen in and letting other gasses out. Or keeping other gasses out, I guess.

JEANNETTE: Yeah. Getting rid of carbon dioxide. You need to get rid of that. So, when we're looking at lung movements, could we talk a little bit more about what it is? Do lungs have a range of motion?

KATY: Yeah.

JEANNETTE: Could you maybe explain that? What is their range of motion?

KATY: Well, right. And you were talking about the structure of the lungs and we have this beautiful tree picture. But I also think what's really helpful is that lungs have lobes. So they're not just - I'll back up. In the way that I explain it in My Perfect Movement Plan where we're breaking down what are the different movements that my body needs is lungs are essentially like a balloon. So when more oxygen - or when more air is going inside, the walls are stretched broader - farther away from each other. So if you are taking deep deep breaths or doing a lot of physical work, you would be taking your unfilled balloon and really stretching it big and then it would go back to being small. Stretching it big and then going back to being small. So it has that capacity. And we can talk about lungs’ capacity in a minute. But just to get a sense of what the range of motion is when you are sitting down and you're quiet at rest. Working on the computer, reading a book, sleeping. That lung motion is fairly small. You're only stretching the walls of the balloon barely enough to meet the oxygen demand of your body at rest which is very little because you're not moving. You are not requiring oxygen in that way. And then when you exert yourself or you take deep breaths on purpose then you are stretching the walls farther beyond that position. So you're ending up with a larger balloon - circumference isn't the right word because it's like a globe - but you're opening it a little bigger. And we tend to spend most of our time with our lungs really only going to that small balloon size. Now you don't really have one balloon. You've got these lobes. So on your left lung you have 2 lobes and on your right lung you have 3 lobes. And so this stretching is happening, you could say you have 5 balloons. Your lungs are actually 5 balloons. They all inflate about the same. You don't have the top one inflate fully while the bottom ones are sitting uninflated. It's just all of them are in this smaller balloon shape. And so the idea is to get the five balloons to all stretch their walls really far. Maybe this is a good place to talk about the difference between skeletal muscle and smooth muscle because lungs are muscle tissue.

JEANNETTE: Mm-hmm

KATY: But it's a different type. What's the easiest...

JEANNETTE: Smooth muscle, maybe like your gut has smooth muscle. So you don't have to actively contract your gut to move the contents through it. Like skeletal muscle can help but there are muscles (I'm holding up kind of, just in case you're not seeing this, a circular tube). There's smooth muscle that can contract the muscle and open it. And it's the same type of muscle that's in the lungs.

KATY: Mm-hmm. Yeah. So skeletal muscle, which we're used to modeling if you've read Move Your DNA. There are sarcomeres organized where everything when it contracts gets shorter or longer in a linear fashion. So contractile proteins are in series. They're a long line so things shorten. With smooth muscle, actinomycin which are the contractile proteins, they're organized differently. They're not in a chain. So the easiest way to think about it is if you imagine a big dinner plate and then you imagine a saucer, what smooth muscle does when it contracts is it changes the dinner plate down into a saucer. It's more of a surface area. But smooth muscle is arranged in different shapes. So in the arteries and veins like you were talking about it's more like it. But when you have that dinner plate to saucer motion, what happens is the tube shrinks or constricts.

JEANNETTE: Right.

KATY: And when it relaxes that surface area gets bigger. It allows that tube to dilate. The lungs are similar. Because remember we're talking about sheets. Imagine the rubber walls of a balloon it's just a sheet. And so when it stretches it goes to a dinner plate. Not the lung shape itself but the tissue that makes up the balloon. Rubber is being stretched broadly when you blow up a balloon. The walls are becoming longer. It's more like a dinner plate but when it's empty it goes back to shrinking down to that saucer. The walls are made of tons of saucers and then they go down and they shrink. And that's what is happening in smooth muscles. So it just contracts a little bit differently. And so when we think of the lungs as a tool for breath, I don't think the walls and what the walls are doing are that important. Right? Because you're concerned with volume. And there's a lot of concern about the volume in breathing spaces. And by breathing spaces I mean people studying breath and looking up the importance of breath. We're looking at what's the air flow? Because I think in the hierarchy of human needs, breath's right up there.

JEANNETTE: Right.

KATY: You can go a long time without food and water but you can't go long without breath at all. But what I find most fascinating about the lungs are all the other things that you were mentioning. Those functions, the snot of the lungs, the mucus, the enzymes, that's really because of that stretch of the wall. Those are processes that are really tethered directly to how the wall is behaving itself. The movement of the wall as it's changing shape is part of how a lot of those functions, biochemical functions...

JEANNETTE: Yeah, roles...

KATY: ... how they're mediated. It's because of this movement. So I love the smooth muscle landscape. Because again, movement colored glasses for Katy Bowman. So I'm just always thinking more about what are the movement and what is the function of the movement. Not so much the after effects. I mean I'm all here for oxygen. I love it.

JEANNETTE: Right.

KATY: But I think we miss a lot when we think about the lungs and not consider the actual organ and what it's doing.

JEANNETTE: In its entirety. And I think possibly a lot of that comes - there's sort of scales of knowledge. And I think, you know, lungs were just a breathing organ. And it's only recently that people have started even looking for these other roles that their lungs can play. So to back up a little bit, we have this movement of the smooth muscle. But that's not the only muscle that are important in moving the lungs.

KATY: Right.

JEANNETTE: Because we've actually got skeletal muscle that's responsible for a lot of the pull and push on the lungs. Like the diaphragm and the intercostal muscles and the abdominal muscles. So, again, we're now expanding our from the lungs a bit. But we have muscles that are important for the breathing motions and presumably as well the smooth ... So here's a question for you because I don't know too much about the smooth muscle. How does a movement of what I would call the skeletal breathing muscles, how does that movement impinge on the smooth muscle movement?

KATY: You mean how does it keep it from happening?

JEANNETTE: No. If the smooth muscle can do its contraction from dinner plate to saucer and back again, there are bigger movements presumably of that tissue of the lungs but exerted by muscles that are outside the lung tissue, like the diaphragm and the intercostals. So when we're talking about the range of motion of the lungs, it's the smooth muscle plus? Or am I misunderstanding?

KATY: I think that lungs have their own ranges of motion. But I think that their ranges of motion are in partnership with the chest cavity.

JEANNETTE: Ok.

KATY: What the chest cavity is doing is affecting the range of motion of the lungs. So right. When we think about the lungs, we again tend to think about them in a vacuum. That's lots of puns because so much of the way that they work is based on pressures. So the lungs are inside of a cavity of your body that's purely dense. Another difference between smooth muscle and skeletal muscle is skeletal muscle is more under our control. Where smooth muscle really isn't.

JEANNETTE: Sorry. I think it's a complicated question.

KATY: Well lungs have their function in a vacuum but they don't really function in a vacuum. They function in a chamber of the chest cavity. So bringing oxygen into the lungs is not done by the lung tissue.

JEANNETTE: Right.

KATY: I think that's a helpful distinction.

JEANNETTE: Yes. Like a sponge. The sponge itself doesn't do ...

KATY: It can't draw in. It's very much like a balloon in that way. There needs to be someone pushing air into the lungs. That someone is you. But it's not through your mouth blowing it in , it's through a series of contractions of skeletal muscle that change the shape of your thoracic cavity to make it bigger. So it's almost like you contract your body in a way that takes the walls of your thorax and it makes that open up like a balloon. And then that draws air in. And that air drawing in is like someone blowing into the balloon sacs of your lungs and they inflate. And then after you've done that, all of the muscle which has worked, skeletal muscle which has work and contracted to open and all of your saucers that have been stretched to dinner plates, that's like the elastic of a rubber band and it recoils and it all comes out when you're done. So let's just talk for a second about the thoracic cavity, or the chamber that is your chest where your lungs reside.

JEANNETTE: Mm-hmm

KATY: You think about the rib cage and you think, that's pretty stiff. And it is but you look at how little of it is actually stiff. You're given a little bit of rebar to sort of protect your tender vitals, but most of it is fleshy and shape shifting. And so you just have your - imagine your skeleton. You just have a spinal column and you've got this rib cage. But everything else is meat - soft flexible meat.

JEANNETTE: And even some of the ribs are softer. They're cartilage, not bone.

KATY: That's right. So you've got this really beautiful balance between something that can protect while also allowing it to change shape because it's the changing of the shape of the thoracic cavity or your chest cavity that contracts and opens on your command so that you can inflate your lungs balloons. And that's the relationship between lungs and the muscles of the thorax. If we were thinking about what your breathing muscles are, your diaphragm is the bottom of the chamber. That's a flexible room. It's the same as so much of your pelvis. There are flexible walls here. So you've got the flexible floor that is the diaphragm. In between each of these ridgid ribs, you've got your intercostal muscles. They're flexible and they're dynamic and so they can actually lift the ribs and increase the size of the room when you need them too. And they can also drop down and make the room very small again. And that motion of them being able to take the hard rigid parts and sort of move them out of the way temporarily that's a big part of why these balloons are able to fill. The same thing the diaphragm can come down and move out of the way and moves back up. And then we usually think about those as your primary breathing muscles. But then when you're in distress or sometimes just stress, you'll use accessory muscles and you'll create a bigger room by lifting the top of the room away from the bottom and bringing it back down. So you've got the top and bottom that can move away from each other, sides that can open up. So you've got this room that grows and shrinks. And its capability to do that is what takes the lung lobes and moves them into something bigger and smaller. And there's five of them, right? So your range of motion here, in all the places, is what is going to take you through your range of motion here. There's no real other way to do it.

JEANNETTE: Right.

KATY: You can't get the range of motion in through your lungs in regular use and stretching the walls, and remember the range of motion is not just for oxygen but it's for all of the other functions of the lung tissue, without all of these other hinges being mobile enough to change the shape of the chest room.

JEANNETTE: Right. Ok. Fantastic.

KATY: Ok podcast is over. Thanks everybody. (whistles theme song) Just kidding.

JEANNETTE: So that's great. We've got this basically canister of the thorax that can move and the muscles can make more space. One thing that I find really fascinating is comparative biology. Comparing humans to other creatures. In terms of our rib cage anatomy, we've actually got quite a lot of potential movement. More so than for instance our closest relative the chimpanzee. And there was a wonderful study that came out very recently comparing the ability for the ribs and the thorax to expand on running. And humans tend to be grouped in what's called cursorial mammals. So a cursorial mammal is one adapted for running. And there's too many to type so you've got your sprinters, like cheetahs which can run really fast and not huge lengths of time. And then you've got animals like horses, humans, dogs that can run at a sustained pace for a long time. And we can't beat many animal records.

KATY: No. No.

JEANNETTE: But the one thing we can do really well is kind of keep going for a long time.

KATY: Yeah.

JEANNETTE: So in this study, where they compared dogs and humans to goats. So goats are not an endurance runner. And then they compared those in how much the thoracic cavity expanded when they were going from rest to running to all out running. And they found that humans had this ability to move in both breath wise - so side to side - and front to back.

KATY: You mean their chest cavity.

JEANNETTE: The chest cavity. So their chest cavity could expand sideways and front to back. Goats hardly changed. And dogs were mainly front to back. They have these deep chests. And then the other thing they did in the study which is really interesting was to look at the structure of the rib bones and its joint. And what seems to be true is that when you compare sort of close relatives like humans to chimps or horses to maybe hippopotamus that kind of thing...

KATY: Oh a pause. A horse and a hippopotamus are...

JEANNETTE: Yeah, they're very closely related, I think.

KATY: Ok that's going to be my favorite of the podcast.

JEANNETTE: I think that's right. I'll have to check that. I might be wrong. Don't hold me to that.

KATY: OK, I won't.

JEANNETTE: I'd have to find the study and actually look at what they compared. But they found that animals who were not runners had much flatter ended ribs and less curved joint space.

KATY: Yep.

JEANNETTE: And then in running adapted species - those that are good at keeping going for a long time - it was more shape. More convexity and concavity to the bone and the joints.

KATY: Part of it is it has to hinge.

JEANNETTE: It has to be able to move.

KATY: Yeah, that curve of where the ribcage interacts with the spine essentially...

JEANNETTE: That's right.

KATY: ...it needs to be able to rotate. That's what allows the ribs to, we'll just say, flare.

JEANNETTE: Yes.

KATY: And I'd also be interested to know what else would affect the ... let's say the expandability of the chest besides rib cage mobility. The only thing I could think of would be cartilage content of the ribs and maybe the sternum. How flexible those pieces are. I can't think of what else.

JEANNETTE: That would definitely - and I think that's something with age that could change. The cartilage could become more fibrotic so they can stiffen. Oh and the shape of the spine would be another thing.

KATY: So that's something, yes, that we want to talk about.

JEANNETTE: Yeah, the degree of curvature.

KATY: Forward curve, yeah.

JEANNETTE: Because that will limit the articulations of the ribs.

KATY: Well I was just thinking in goats. There's not a lot of hyperkyphotic goats.

JEANNETTE: Yeah.

KATY: It hasn't gone that far yet.

JEANNETTE: Yeah so in terms of comparing animals, I think the shape of the rib cage is definitely a thing. We've got quite a barrel. Whereas chimps have a more triangular shape. So I think sometimes just the shape...

KATY: Right. That can be the actual resistance to the movement of the pieces.

JEANNETTE: Because I think chimps have a much more stable structure of the ribs. And then shoulder blade, I believe. And I think that's more of a hanging adaptation. It's less bending forces when you're hanging on one arm. So it seems to just be a more stable structure than ours.

KATY: Traded more hanging. Traded hanging locomotion for the rib cage adaptation that allowed over the ground locomotion.

JEANNETTE: Yeah.

KATY: Also we talked before - are humans natural swimmers? And are humans natural runners? And we're definitely endurance. Endurance and running are separate.

JEANNETTE: Yes.

KATY: But we are cursorial.

JEANNETTE: Biologists do categorize us in the cursorial category as we have long legs. And also we, I don't think there's any culture that doesn't run.

KATY: Yeah.

JEANNETTE: Swimming is one of those things that you might or might not see, but running is something that is - children do naturally.

KATY: Yeah.

JEANNETTE: But that being said, so do a lot of mammals.

KATY: Right. And there's a lot of people who don't run and who never run. And it seems to be - it's one of those things where clearly it's important to be able to do. But to be able to do it for a long period of time or a long period of the day is not necessary. So it's a peak. That's why I put it at the peak of the movement pyramid. It's essential and maybe important but it's not foundational.

JEANNETTE: Yeah. And there are these theories about endurance running and as one of really those evolutionary drivers for human beings. And there is this theory, it's called the endurance pursuit hypothesis.

KATY: Yep. Know it.

JEANNETTE: You've probably heard about it. It's this...

KATY: Leiberman is...

JEANNETTE: Yeah. And it had been around for a while. But what's interesting and just very briefly the hypothesis is that we became endurance, or we developed this endurance running capability really to pursue prey. We have lots and lots of attributes or features that allow us to run for a long distance, in particularly hot weather, that other animals can't do. They don't have the ability to thermoregulate like we do with our non-hairy skin. And our ability to sweat profusely. So there's this idea that you can outrun, even though you're not as fast as a prey animal, you can outrun it over a long endurance run. And I think the problems that people have had with that are that there aren't that many examples, currently, of people actually using that strategy.

KATY: Mm-hmm.

JEANNETTE: The idea that it seems not very efficient because it's a lot of energy to run for a long period of time. But actually recently there was a study that came out just very recently that actually suggests that there were a lot more cultures using that strategy before 1950. Which is sort of interesting.

KATY: Yeah.

JEANNETTE: But, again, all the examples were men.

KATY: Yeah.

JEANNETTE: And it probably would have been in probably certain scenarios where it would have been advantageous. So I still don't know whether you could use it as foundational.

KATY: Yeah. Or definitional.

JEANNETTE: Yes, or definitional.

KATY: It's interesting. I really think of humans and their different traits in a collection. There's always the idea of thinking about every person having sort of identical function. And there are certainly many things that we share but, it seems, when I think of bees or collections of bees, the specialization of function within a collection. I think that humans might have something similar. And I guess where I would probably look is for people who are doing endurance - big endurance not just like I can run a marathon or a 10K - but people really pushing into doing marathons daily. Do they have different anatomy than other people slightly that makes them more... and I've read this before where there actually - I think in general and you can correct me if I'm wrong here - our lungs are sort of, when you look at what our lungs can do, and what we do, it's like, wow. I think overbuilt is the word that's used.

JEANNETTE: Yes. That's the word that's used.

KATY: Overbuilt. It's like this is a very powerful tool that is really on most people. But when I think of other specialized animals or insects that might have a bit of anatomy that either they got a slightly different set of anatomy or through practice of whatever their particular role was developed that anatomy in a particular way. And then there's this so-called hypertripe. There's not hypertrophy to the lungs, we should talk about that.

JEANNETTE: Yes we need to get to that.

KATY: Oh my gosh, how long is this going to be? It'll be so great!

JEANNETTE: I think what is often neglected when we're looking at these hypotheses is that we are cooperative - a cooperative organism essentially. And I just look at my family to see we're kind of split 50/50. My eldest son and I are built for endurance. We can just keep going at a steady pace. And then my husband and my younger son, they're just built for strength. And they're strong. And they look at me like I'm pathetic. They're just like, "pick that up" and I'm like, "I can't. But I'll walk for you."

KATY: Exactly. And they're like, "I can't! It's too hot." And again to the Olympics, you can see that there's myriad strengths.

JEANNETTE: Yes.

KATY: Myriad ways of being fit.

JEANNETTE: And when you're reliant - when your success as a species relies on a group of people rather than just you, you Mr. Cheetah who has to do the same thing every day which is catch the prey, but you live in a network of people, you have to play to the strength. So I think it's a lot more complicated.

KATY: Yeah. I think probably there are some people for whom using their lungs to that more built capacity - it is maybe a peak number of people. Not so it's peak... I'm talking about my movement food pyramid from My Perfect Movement Plan. Even for the person who can do it, it's still going to be peak of their pyramid.

JEANNETTE: Yes.

KATY: It's not something to be done at high volume. But yet it's not to diminish the importance of that skill to the individual, to the community, to humanity.

JEANNETTE: Absolutely.

KATY: It's just that it might not be the prescription for everybody.

JEANNETTE: Mmm. Yes.

KATY: But, let's talk about or let's consider the fact that while lungs are over built, our current environments are really putting our lungs at risk because they are not taking ... I mean we're not even to the overbuilt part. We're not even utilizing them to low bar function.

JEANNETTE: Oh yeah. I just want to clarify overbuilt. The idea that the lungs are overbuilt has come about because there's always this residual capacity that even when we're exerting ourselves really hard, we don't get into it, unless maybe you're doing an ultra marathon every day. So most healthy people are just not using this bit. And added to that is this observation that lungs don't really morphologically change with exercise. Because you've already got this kind of buffer.

KATY: Yeah.

JEANNETTE: So to go back, you're saying that basically this is our capacity. I'm holding out kind of two hands about half a foot and we're using down here, a quarter. And we're not even getting close to this residual capacity.

KATY: Yeah. Or just to go with what you were saying. If we take the analogy of range of motion, for most joints of our body, for musculoskeletal muscle tissues sake, you want to use sort of that full range of motion. But with your lungs, you aren't necessarily going to that full range. You don't need to go to that full range of motion. There's always sort of an excessive amount. Imagine someone, like a circus performer, they're so bendy, and they're doing this thing with their arm and yes their arm can do it but it is a range of motion that is extra. Not going to be dipped into, I think even in super endurance runners. You can't even really touch this piece.

JEANNETTE: I wonder what that almost is for. Is it for if you're in an extreme environment? Like altitude which we haven't even got to yet. Is that for those kind of, because breathing is so critical, I wonder whether we have that bit of reserve for those extreme conditions. Like we're suddenly in extreme heat. I don't know. But it's just interesting.

KATY: If any part of our body needs to be overbuilt it would be the lungs. And you know you could really operate with lobes removed. A whole lung removed.

JEANNETTE: Right.

KATY: So there's this backup to it. It kind of reminds me of the space shuttle. There's a lot of redundancy. But it's not redundancy given maybe some particular situation that I can't imagine. Ok, so if that's full range of motion would be this overbuilt piece, you were gesturing with your hands a small amount. We are more like never doing the equivalent of picking our arms up over - you know our elbows never come above shoulder height. Our hips never really straighten up all the way out of a chair. There's such reduced motion of our lungs. And I just use that example of the arms and the shoulders to highlight what is happening to the lungs, but of course those two examples aren't even unrelated. They're directly tied together. It's because we rarely move our arms and our legs that our lungs can barely move. So you and I are going to step into, now, talking about all the things to do to change your mobility of your thoracic space. But I don't want people to focus so much on mobilizing the rib cage to miss the forest through the trees here, which is you have to move your whole body in ways where your lungs have to be stretched. You have to increase your oxygen demand. You have to go up the stairs. Up the hills. You have to do things a little faster. You have to lift a little heavier to get your oxygen demand point with your whole body such that the oxygen is pulled in.

JEANNETTE: Of course, your breath is a fantastic guide because if you're breathing harder, you're moving them more.

KATY: That's right. You've got this biofeedback tool. If you're sitting here with this quiet shallow breath, you did not take your lungs out and stretch them well throughout the day. And of course they're not something like a dog that can only be walked once for 20 minutes and then sit back.

JEANNETTE: Or like Coneys.

KATY: Yeah exactly or like my Heelers. They need to get out. They don't have to go out for a long time but they need a sprint. Maybe that's why - back to the overbuilt is - when we think of endurance that word means to hold it for a long period of time. But heart and lungs just a short little spike in coming up and down - it's like throwing a ball or throwing a stick for your dog. Big stretch and then go back to relaxing. So start to think about your lungs like a dog that needs to be walked.

JEANNETTE: Brilliant. So now shall we have a little conversation about the mobility of the part itself?

KATY: Yeah.

JEANNETTE: Which we alluded to a little bit by discussing the curve of the spine that might affect your ability to expand your rib cage and your lungs.

KATY: So let's say our goal here is to understand how to care for our lungs with movement.

JEANNETTE: Yes.

KATY: We don't usually think about that.

JEANNETTE: No.

KATY: We think of the lungs need to be there to serve the body. But it's really reciprocal. Right? Your body is caring for your lungs. You need to care for your lungs. And so to do that, like I said, you have to move your whole body in challenging ways. I think many people do that. But what can also impede on this ability to fully stretch and inflate is the state of your thoracic container. So we talked about this shape that we have that the ribs articulate with the spine. And the ability for the ribs to open up to the side. And really, I keep saying opening up to the side, but that opening up to the side is also opening up to the front.

JEANNETTE: Right.

KATY: It's really just the dinner plate - now we can use it in a different way. When your rib cage is at rest it's more like the saucer. And when you take a deep breath, the ribs open and everything kind of moves out and bigger and it ends up looking more like a dinner plate. The circumference of your entire rib cage is larger when you get that inhale. But spinal vertebrae - the position of your spinal column - affects how much those ribs can rotate. And hyperkyphosis, that is an excessive curvature to your upper back, makes it so that those ribs can't rotate. So if you are wondering is working on my posture, the alignment of my upper ...

JEANNETTE: As you said that I'm like...

KATY: I know. Standing up. As you think about the importance of it, that upper spinal curvature really can hinder the function of the lungs themselves. That's probably why outside of bone density and fractures in the spine, the impact hyperkyphosis has, that extra forward slump, has on the lungs is probably the most taxing. I mean it's the most dangerous if you will.

JEANNETTE: Right.

KATY: It's your greatest liability in that case. And so working on thoracic upper back spine mobility and alignment, lateral bending of the spine, rotations of the spine - you want to keep that spinal column as supple as possible because your lungs inflation is going to be dependent on those pieces. And I think that's, when I see this younger generation with their phones and that forward-slumping posture that is so extreme, unlike anything. Imagine if, I want to write a whole piece on how quickly we've integrated this shape in forming bones. It'll be really interesting to see what the shape is on forming bones and then what the lung issues will be coming out the other side. So if you're wanting a reason to ditch some of that forward curve posture, again, it's for better lung care. Because those balloons can only inflate as much as the ribs and the diaphragm can move themselves.

JEANNETTE: And along with that phone posture and the curved spine, you've got the forward shoulders and chest tightness.

KATY: Yes. Which can affect the front from expanding.

JEANNETTE: Yeah.

KATY: It's just a lot of pressure. We're creating a lot of resistance to breathing just through our posture. Now because we're such shallow breathers because we don't do that much movement, it's not really showing up as affecting our day to day.

JEANNETTE: Right.

KATY: Right? Because if you get rid of the movement, you're not recognizing how difficult it is. But it becomes a problem when you want it to go move. And I do think that for people new to exercise or movement, they'll say "I can't catch my breath."

JEANNETTE: "Catch my breath"

KATY: And again we briefly mentioned it but lungs don't adapt like other tissue or muscle. It's not like you have stronger lungs really when you're an exerciser. You develop better pathways of getting that oxygen to your blood...

JEANNETTE: Yes.

KATY: ... that's the adaptation.

JEANNETTE: It's more cardiovascular. It's more capillary development.

KATY: Yes. Right. But one thing that it could be is not being able to take a full breath because these parts don't move. So in that case, it is sort of - it's not an adaptation to the lungs itself, but it is a resistance that you're having in your body to those lungs inflating.

JEANNETTE: Interesting. So I have a question. What about a stitch? I would find, if I had run for a while, I could get a stitch on one side. And I'm wondering is that partly - does the diaphragm become stressed because the other parts are not moving so well?

KATY: Yeah, I have no idea. I remember when I was in graduate school we were talking about this a lot and I don't think "cramps" are really clear. There are different types. Cramps is a big category. People would say it's electrolyte-based.

JEANNETTE: Yes. Because you can get that.

KATY: If you're missing something that you need uptake for release, yeah exactly. But this we are often at the onset, or... where were the other things? You just ate and your blood is going to digesting your food. There are all these different theories for it. I would love, if anyone knows, send us a note.

JEANNETTE: Yeah let us know. Posturally or related to the thorax that could limit taking that good breath?

KATY: Yes. One thing that you don't hear as often is the impact of core strength on breathing. To be able to deploy. I think that people will underestimate the importance of core strength to being able to take a deep breath. The reasons are sort of tricky to explain, I would say verbally. But one, many people might be aware that the ribcage is sort of lifted. The hips are forward, stomach is pushed forward. Ribcage is lifted forward. Imagine you've been standing for a long time and you let your hips and your chest all go forward because it's an easier place to stand. That position you lose - Your ribcage is not really strongly connected to your pelvis. So if you, you know, were to pick up something heavy, you probably would pick it up in that relaxed position. You would bring your rib cage down and you would create a girdle effect through your musculature. When you have that girdle effect, it holds your rib cage in a particular alignment to make sure that you're not impinging on the space for the ribs to move behind you. Because when you thrust forward you kind of scrunch up your back behind you.

JEANNETTE: Right.

KATY: And then also when you're really anchored through your - When your ribcage is really anchored to your pelvis, through that core work, it allows more work to be done in the intercostals. The work is harder but it's the same thing if you're trying to bend your arm, sometimes to be able to feel the muscle you need to add more weight into your hands so that you can really generate more force and anchoring the rib cage down in this way allows those intercostals to generate more work and lift things up. Yeah.

JEANNETTE: Interesting.

KATY: All right. So what do we know so far? Hopefully the thing that I wanted to get across with this episode is, lungs need care. They need to be taken out on regular walks. Hopefully this is saying something than everyone needs to exercise and the benefits - just think about the lungs themselves. They need to be taken out. It's not just for your general health. It's not for physical performance. It affects overall immunity. We didn't even talk about mood and oxygen. We'll leave that for another episode. And then also as far as the alignment and those micronutrients, it's really the effect of stiff shoulders. Stiff Spines. And core. All affect your ability to take your lungs out on a walk fully. Everyone can take their lungs out for a walk without having to worry about all those things but these are also things that could be considered. What are other things about the lungs that interest you?

JEANNETTE: I definitely think, as a swimmer, we talked about last week. That interests me because you're in a different situation. You've got higher pressure in the water. And you're in a different position. And I think it is now well understood that there's a little bit more work to breathe. Another way that you could take your lungs and your chest through a different movement walk ...

KATY: Take your lungs for a swim.

JEANNETTE: ... take them for a swim.

KATY: When I said a walk - a walk can be anything that just...

JEANNETTE: And it's also a time you can practice your breath holding a little bit. A way to get your lungs under different challenges. So I find that interesting. Altitude is definitely interesting.

KATY: Oh, I love it.

JEANNETTE: I know you have a background of pilots in your family.

KATY: Yeah.

JEANNETTE: I have a good story here for you and your likeness. So the rest of my family are into rugby. And there was recently a league, it's called the URC, and our team, Glasgow Warriors, got into the final. Which was in Pretoria. They didn't know they were going to get into the finals. But Pretoria is at 1,350 meters above sea level. And Glasgow is not. So there was a bit, oh how are they going to cope with the altitude. And across the changing rooms for the opposing team at the Pretoria Bowl Stadium is a sign that says, “Altitude 1,300 Meters. It matters." I thought you would like that.

KATY: Yeah, I love it.

JEANNETTE: Altitude matters. And they won. Actually Glasgow won, but they did a lot of breathing training. Hypoxic training. So they would hold their breath and then sprint. So they had to adapt. So I thought that's a pretty neat story.

KATY: Yeah, there's so much we could talk about. Some of the morphology of high altitude living that shows up in people.

JEANNETTE: Yeah. You've got populations that are much higher than Pretoria. 4,000 meters. And they do have quite distinct characteristics; differences in chest depth and volume and ability to expand their chest. So yeah this would be unique in adaptations.

KATY: And some differences in lungs. Although in babies...

JEANNETTE: Yes. I believe...

KATY: They were adapted in the womb. It was not genetic change. It was just adaptation in the womb. That's amazing.

JEANNETTE: That's right. It must have been hypoxia in utero essentially.

KATY: Yeah.

JEANNETTE: And the lungs have what they call greater compliance which means for a given amount of pressure there's a bigger volume change.

KATY: Yeah, and we didn't even talk about compliance of lungs and the disease states that create more resistance within the lungs themselves. We pretty much talked about lungs as if they're equally compliant. But there are changes in compliance with fibrosis. You can get so much stiffness where that could be something that would limit the ability. It would be like a very stiff rubber balloon.

JEANNETTE: Take your thickest resistance band.

KATY: And then on the opposite side of that is emphysema. Things that make it like a ...

JEANNETTE: Grocery bag.

KATY: Yeah like a plastic bag. And the problem in that case is not inflation. It's that it doesn't - the exhale, that recoil, does not happen easily so it's harder to get air out. Which, of course, translates into not getting the air in. But difficulty breathing can be mechanically different. You just have to know what you're dealing with. We could do another whole lung episode. If you love this episode, let us know.

JEANNETTE: I know. When I started to just think about lungs -it's just phenomenal.

KATY: There are so many more things. But hopefully, now listeners have a different appreciation for the lungs and go out and take a deep breath. We didn't talk about smoking. We didn't talk about sitting by fires - cultures that live and what is sitting on the - it's outside their body but it is affecting all the other air trying to get into the body.

JEANNETTE: And create cellular changes.

KATY: Absolutely.

JEANNETTE: Outside the body but it's creating internal effects.

KATY: Same thing with changes to your skin. They're still outside your body, but, exposure to the outside. All right. Thank you so much!

JEANNETTE: Thank you. That was great.

KATY: I love it. (takes a deep breath and laughs)

(Theme Music)

Hi, my name is Marcia from Australia. This has been Move Your DNA with Katy Bowman, a podcast about movement. We hope you find the general information in this podcast informative and helpful but it is not intended to replace medical advice and should not be used as such. Our theme music was performed by Dan MacCormack. This podcast is produced by Brock Armstrong. And is transcribed by Annette Yen. Make sure to subscribe to this podcast wherever you listen to audio and find out more about Katy, her books, and her movement programs at NutritiousMovement.com

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