VO2 Max from the Muscle’s Perspective: Building Endurance from the Inside Out

The nervous system is kind of the puppet or the puppeteer in all of these sorts of things, right? And you've got to have that puppeteer that's manipulating and moving ⁓ the rest of the body. And if that puppeteer is not

able to kind of move the body forward,

then it's not gonna be any good, right? And I think you get that by making sure there's sort of a holistic practice around you from good circadian rhythm, sleep, recovery, social interactions.

good nutrition.

Hello and welcome to the Athletes Compass podcast where we navigate training, fitness and health for everyday athletes. Today we're continuing our series on VO2 max, the key marker of aerobic performance by shifting our focus from the heart and lungs to the muscles, blood, blood vessels and cells. While many of us focus on our cardiovascular system to boost endurance, what happens at the muscular level can be just as important. We're diving into the role of

capillaries, mitochondria, enzymes, I think we're going to get this deep, and muscle fiber types in determining how much oxygen your muscles can actually use because it turns out that delivering oxygen to the muscles isn't maybe just enough. So Paul, we know that VO2 max is about how much oxygen the body can use during exercise. Can you explain how the muscles themselves might limit VO2 max even if the heart and lungs are doing their job?

Yeah, well, I guess the muscles are gonna be potentially limiting your via 2 max if they don't have enough mitochondria, which are the little organelles that are sitting in the cells that are used to actually burn that fuel. Remember, the fuel that they're burning are the food that you eat. Those eventually turn into ⁓ carbohydrates, fats, and proteins, and then those get.

those get cycled into those mitochondria and under the presence of oxygen, can burn. Again, we used the analogy last time of ⁓ my open, or not open, but closed fire ⁓ sauna that I love to go into and it always kind of makes me remind that I've got to keep the oxygen level going in right, I've got to keep the fuel going in and I need heat as well, right? So these are, we're actually looking for a chemical reaction that occurs within that muscle cell.

And that is dictated ultimately by the number of ⁓ mitochondria that you have within there. Because their job is to burn that fuel. yeah, it'll be a limiter. It could be limiter at the capillary level first and foremost when we're looking at that periphery. So if you had actually used a, what do they call those, those cat-soo devices, right?

where they kind of, they put a pressure and actually put a resistance against the blood flow that's getting into the local area, right? And you can have, but usually when we're training, the capillary level around, the capillaries, remember, they're wrapped around the muscle cells. That actually couples and becomes similar in terms of increases relative to the number.

of mitochondria. In fact, even at the research level, usually researchers, they'll, you know, they might kind of measure one thing or the other because they know they're so tightly coupled. So if they have the ability to measure capillary density, that's usually enough. They won't kind of also measure a marker of mitochondrial upregulation, which is usually some of the enzymes Paul was talking about, like citrate synthase. ⁓ So, and yes, cinase.

dehydrogenase, these are the enzymes that are around, indicative that you're increasing the mitochondrial level. So I'm geeking out a bit, but Paul warned you. But yeah, so that's ultimately what can limit you, the number of mitochondria that you've got in the working muscles, those, you know, the organelles that are there to burn the fuels, burn the food that you eat and make you move faster, convert the chemical energy to mechanical energy.

So what kind of training do I need to do to increase capillary density or mitochondrial density?

Yeah,

really simply, great question MJ, but really simply you need repeated contractions of the muscle cells and the muscle groups that are doing the activity, right? So you just got back from a swim, we know you've got the goggle marks on there, you're trying to hide them, but we know. So you were swimming and stimulating those, you know, the muscles around your shoulders, predominantly whole body exercise as well, but like predominantly the main movers.

where your latissimus dorsi, when you're kind of pulling down and you were actually creating the signal, an actual chemical signal in those muscles. And that signal is used to tell your muscles, they're a little fatigued actually, right? Like you're feeling like the shoulders should be a little heavy. And that signal is saying to the body, hey, next time,

I'd like a few more mitochondria here so I'm a little bit less fatigue resistant or more fatigue resistant and that's what happens. So then you go and you refuel and you know, all of the, mostly the protein kind of goes back into there and the amino acids go back and they build up and they make more of those mitochondria. The capillaries widen as well so that at the delivery level, those were actually getting more ⁓

Hmm.

more fatigue resistant. And that could be in both slow twitch muscle fibers, which you predominantly used when you were swimming duration. But also if you did any sprints and you engaged some of the fast twitch muscle fibers in those groups, well those get a little bit of help too in terms of their mitochondrial density and their fatigue resistance. So that's, yeah, that's what you can kind of do about it is it's the training. The training, ⁓ appropriate training gives the signal.

to make more of those mitochondria so you're more fatigue resistant the next time.

Can I just take us to a rabbit hole here? So when people start their, let's say, I want to run half marathon this year and they are basically coming from couch and you know, like zone two is nearly non-existent.

Yeah, let's go there. Let's go.

you you start walking fine, but then you start running and your heart rate just jumps straight to like a zone three, zone four.

Is that indicative that there is not enough capillary density or mitochondria?

Mm-hmm.

Yes, it is. It's basically, ⁓ so it's probably a number of issues, but that is certainly one of those. it's like, ⁓ yeah, there's like a, yeah, it's a really good example, right? Like the system at the peripheral level, we're talking about, right now we're really focusing on the periphery in terms of that. ⁓

Hmm.

you

you know, the limitation of VO2 max. And that is almost, yeah, it's clamped down because, and it's so just like we talked about where we're providing the signal with that consistent training, like you just did MJ. ⁓ if that doesn't happen, then the signal goes away and the mitochondria, they basically get, they get cleaned up via apoptosis and like basically there's no need for it, right? I'm not getting the signal that we need that mitochondria anymore.

Mm-hmm.

So why would we waste the energy to build those things? That's pointless. So the organism just retreats because it's going back to sort of saving energy. So if you don't give your body the signal to do those things, then exactly. And then you have to start again. Like when we're going couch to half marathon, we got to get back into the process again and we need to give that repeated cell signaling to build back those mitochondria.

to build the system to be a good fat burner again, to process the oxygen, burn the fat at the same time, then with, of course, as you know, when you're doing your coaching, eventually you get to the point where that heart rate no longer needs to go and soar into zone three and four because fat is taking up and it's burning appropriately.

at those lower exercise intensities, it's doing its job, you've developed your bass training. So this is, and here is the importance of that bass training first and foremost, is just to create that basement layer.

Mm-hmm.

So weekend warriors, they crash and burn, do double days of hard training and then they don't do anything for five days. They're basically just jamming in the one spot and never get better because they don't have that frequency of cell signaling. And that's why we have often like running training plans, lots of, almost every day of running.

Correct. Yes, yes.

Yep. Totally,

totally. Context is everything, right? Like we had a really good velocity session this morning ⁓ on, on Athletica with MJ and we were talking to SoCal there as a regular, ⁓ you know, ⁓ a regular rider with us. And he was saying now, you he's really, he's kind of on the bit, he's in his taper. He really needed a day off, right? So in that sort of situation, the guy's been training so consistently and almost it's, he does need a day off in that.

in that context, right? So because the other thing that we always have to keep in mind of is the central nervous system, right? There's sort of two players, like there's the signals that you're making along on all the muscles to make them adapt and become ⁓ more fatigue resistant and with the mitochondria we're talking about, but at the same time, there's this whole body systemic, ⁓ you know, central nervous system that we've got to take care of as well. And in that case,

And in Sokal's situation, we've got to take ⁓ a little bit of time off and it's a really good thing in that point. I have to admit, I took a day off as well this weekend and I tell you, it was so needed. So there's a context for everything here, but in general, yes, you want that consistency of your training day in and day out.

How do you know or how can an everyday endurance athlete know if their performance is limited more by muscular factors versus heart and lungs? is it a guess we should do everything all at the same time? What's your call on that?

Yeah, you know, it's a good question, Paul. You know, I don't have a ⁓ solid answer for you on that because as we often say, there's a lot of centers that are kind of popping up and they're called integrative physiological, integrative physiology centers, right? So there's just an integration. Everything is sort of important, right? You do any sort of training and every one of these sorts of, you know, areas is...

you the pinch points that we've talked about from lungs, heart, blood, to periphery, they're all engaged and they're all sort of making these changes. ⁓ And, you know, you wanna kind of address all of them. ⁓ You know, I think probably MJ gave the best example there right off the bat, right? If you've got, ⁓ if your heart is just soaring when you're doing your zone two training, you've probably got a...

Mm-mm.

The main issue you've got is the peripheral issue and you're probably not a great fat burner and you probably don't have plentiful levels of mitochondria. So you need to kind of get back into that zone two based training sort of first and foremost. And then when we get more towards the higher end athlete, we kind of go back to more the, we can start to look at VO2 max training like we talked about before with a

where the heart is more involved. ⁓ So have a good base, now do your via2max training where you're really gonna engage the heart, but then you're ⁓ also engaging the lungs and then the really one percenters, we can start to do respiratory ⁓ breath training work to strengthen the respiratory muscles like we spoke about ⁓ two episodes ago.

So now everybody's going to go and start with the respiratory training. And forget about the long poor, what? Yeah, everybody wants to know the 1%. Right?

That's right. We went in the wrong order, didn't we? We went in the wrong order.

Yeah.

Yes. Yes. Yeah, for

you

⁓ to ⁓ tell them to make more mitochondria within those fibers too. And again, the coolest thing that happens, ⁓ so again, the story with the muscle fibers is you've got the smaller slow twitch muscle fibers, slower to contract but fatigue resistant, they'll go on and on and on, right? Think of your soleus muscle in your...

just below your gastroc in your calf, right? Like that is where we have the most ⁓ slow twitch muscle fibers. You can walk for days, right? And that's because we've been kind of ⁓ created to have that sort of But again, the gastroc, which is predominantly more fast twitch, you can still engage that and make that more fatigue resistant too and get more mitochondria in it. So the gastroc now, we have larger muscle fibers.

way more powerful. Think of, you know, now you're going to slam dunk a ball, right? So now you're going to engage those, that gastroc a lot more to jump really high. Well, if you contract that gastroc, that's, you know, a little bit more of a fast twitch kind of, kind of muscle, you're going to, and you do that repeatedly, you still tell that muscle to make more mitochondria, develop more capillaries around it and, ⁓ and alleviate the, I guess the fatigue in that.

Larger muscle fiber kind of group. Okay, so both are sort of possible and it's just like balancing at all

So here comes the strength question from me. What ⁓ role does strength training or low cadence work play in the peripheral factors?

Thank

Hmm. What an

awesome question. We don't actually know. Um, but, um, Dayo Sanders in the training science podcast was on and it, here's a guy who is like, uh, so any of us Grenadiers, if you follow tour de France, Paul will know any of us Grenadiers, right? Like they're pretty top. He's a top coach slash, uh, sports scientists for them. And he provided a really.

Really good overview of how he uses strength endurance. I guess training within his, within his team, his, ⁓ and they're pretty tough, tough guys. ⁓ but they're, yeah, that he believes that that low cadence, high torque, ⁓ you know, like between 40 and 60 RPMs on the bike, sort of, ⁓ more, you know, between like we do between zone three, a and zone four.

just really grinding functional strength training session, that that's actually a stimulus for the larger motor units to again become more fatigue resistant and develop more mitochondria, become more slow twitch like, but maintain their function as powerful muscle fibers. that's again, the data is, ⁓ it isn't sort of laboratory based in textbook, but there's a,

you

a good hunch and there's a lot of, you know, it always happens in the field first, but with the coaches and those winning, because it has to, right? Like, you know, they're paid to do that and that's their observations and that's what their practice is that to do that. And just anecdotal, ⁓ you know, benefit from coaches. And it's why we have those, that's what we did this morning, MJ. You led that session, which was great.

you

Mm-hmm.

Mm-hmm. Mm-hmm.

Yeah, one of my favorites. ⁓

So let's switch gears into the fourth limiter, blood in the circulatory system. Let's talk about that. How is your blood in circulatory system a limiter to your VO2 max?

Mm-hmm. Yeah, great one. And we have in fact those that follow the athletes compass podcast You already have this information Available to you somewhat when we looked back at the heat lecture. Really we're talking about your blood volume So in your blood as you probably know you have both a water component like your plasma and you also have the red blood cells right which contain the hemoglobin the protein that transports all of the

oxygen to deliver it into the periphery of all your cells. So I guess the, how could we legally, oops, sorry. How could we legally actually get more red blood cells into us? That's the million dollar question, right? Of course, you know the illegally, illegal ways to do that. that's, blood doping, EPO use, those sorts of things. That's why, I mean,

We know it works, right? Because there's, WADA monitors these sorts of things. Blood transfusions, ⁓ taking your own blood out and then putting it back, EPO use, these are, so the blood itself is very important. And if you have more of that blood, it's going to deliver more oxygen to the periphery and the periphery will take that up. So what can you do about it? Well, there's the two big ones that,

that we use is altitude and heat. Those are the big ones that you can do something about. We know that we get a blood volume and training in itself actually. Like actually just even exercise training. will, you wind up diluting, no sorry, you actually enhance your plasma volume ⁓ by making more of the water component, the plasma part. And again, the...

at the kidney level, it detects this and it says, hmm, I think we need more red blood cells. then the, yeah, the kidney creates, it tells the blood, tells the bones to make more of the red blood cells. So yeah, and then the same sort of thing happens. We spoke about this in the heat lecture, and we know that heat is poor man's altitude.

And the same sort of thing happens there as well, right? There's a kickback. The body senses that there is a dilution from this enhanced plasma volume and it kicks back, it makes more red blood cells. So heat, training, altitude are the key things you can do to enhance your blood volume.

Anything else that we can do?

To enhance our VO2 max? Well, let's go. Let's review them all. Is that okay if I just kind of review, start back from the beginning? Because we're kind of at the end, right? So first and foremost, any sort of training movement is going to be key, right? ⁓ MJ mentioned it already on this one. If we're couch potato, there's no stimulus to actually enhance the... ⁓

I was.

Thank

Yes.

maximum volume of oxygen uptake. And conversely, and that's why you're doing your exercise training, because you're telling your body, hey, this is important. Why is this whole issue important? Because we know from Peter Ortiz's outlive and all of the studies that he references that VO2 max is probably the number one key indicator of your health and longevity. So this this topic is very important. Now starting where we started, we started with the one percenter.

We know that when we take up oxygen from the atmosphere, and especially when we're towards VO2 max, we have to hyperventilate. We have to ventilate the lungs so that they can diffuse the oxygen into the blood that's perfusing them. And then ⁓ number two, and we also learned that you can actually train the muscles that do that job.

And if you ever do exercise at VO2 max, you will actually feel that your lungs are tired, right? You can actually feel that you're, you do repeated 30 30s with MJ on velocity, you'll feel your respiratory muscles, they're tired. Then at the same time, the heart is ⁓ the next one that we covered. It's probably the number one most important factor that's going to enhance your VO2 max. And yeah, that's just ultimately the delivery aspect.

And we learned about cardiac output. We learned that cardiac output is the amount of blood that's delivered around the whole body in a given minute, which can go as high as 40 liters a minute in elite athletes. ⁓ most of us, know, ⁓ weekend warriors were kind of sitting around 25 on average. But yeah, you want to sort of enhance that. And there's a one-to-one relationship with your VO2 max and your cardiac output delivery.

stroke volume times heart rate. And then, you can enhance that by training at VIA2Max, but don't forget you have to have the base stuff first. Then we talked today about the periphery, and that is really where the base training comes into play. Both are important, both the base training, the 80 % and the 20 % of the high intensity stuff. That's important too in terms of giving the muscles the signal to make more mitochondria.

make more capillaries, the density of those capillaries that surround the muscles, all really important for enhancing that delivery of oxygen into those muscle cells that need it to convert the chemical energy into mechanical energy. And last but not least today, we spoke about the importance of the blood. there's lots of ways that you can, well, there's a few ways that you can enhance the red blood cell volume.

of your bloodstream and the main ones that we've covered in previous episodes include the heat training, also altitude training, and then training itself. Anything that causes for an acute reduction in that, or acute reduction in blood volume, then a re-kickback of the plasma volume, and then ⁓ that little trick where it thinks is you need more red blood cells, and so you're, ⁓

your bones kick in and they start to create more red blood cells for you, which are handy. So those are the four key ways, the four key pillars of VO2Max and the various different pinch points or limiters. ⁓ What do you think, guys?

Nutrition, hemoglobin, red blood cells. Let's dive in there. How can you improve like your, like if you're anemic, like if you have low ferritin or hemoglobin, any little hill that used to be easy now is horribly terrible. So how does nutrition play a role in, you know, improving

Yeah.

your oxygen carrying capacity.

⁓

What a fantastic question. That's definitely one that we missed. You can think about it, because we just left off on this last point with the blood. If we don't have the ⁓ material that the cells need to become red blood cells.

then you're going to be really challenged to actually produce those red blood cells, right? And thinking about that, that'll be things like the, you know, vitamin B12. We often hear about that and, you know, so, and heme iron as well, right? So those are probably the two key components. Well, where do you get those? You get those from meat, right? And certainly ⁓ you can get them from...

you know, lot of ⁓ spinach, but the volume of spinach that you need is pretty substantial relative to the amount and the bioavailability that you get within your, you know, good old cow. know, beef and liver, very plentiful in that regard.

Yeah, I mean, the number of times that I've sort of seen the reversal of that anemia in individuals that are presenting with that when, and often they have not had sort of sources of red meat for a long time. And then all of sudden they get that and, and it makes a world of difference. So if you are feeling like you're suffering from an anemia and, you can get your head around having meat, then it's certainly, ⁓ usually very effective.

Okay.

Great question.

Yeah,

yeah, awesome. No, because I know I've been anemic before and it's not a great feeling. Like if you can't put one and two together, it's just like why I can't move faster. It's just like a mystery until you go get your blood work done and then you're like, ⁓ my pharygine is low, my hemoglobin is low.

Yep. Yeah. So if you are feeling that way, like MJ's talking about, that's the first thing to do, right? Is, yeah, go get it measured and find out what all those various different levels are sitting at. Get a, know, a CBC, Chem 20 and, you know, all the things that the doctor will get to, you know, find out what your red blood cell and...

and you'll get the white cells as well, usually you'll be concerned about the red cell counts if you're feeling that fatigue.

Last year you had a good tip for people who don't like to liver. It was like liver pate and then you cut it in small pieces or you froze it and then cut it in small pieces and you just, yeah.

Hahahaha ⁓

Yes, correct.

Correct. And so a lot of people can't stomach the liver, but we know that beef liver tends to be the most plentiful level of, you know, the sources of, you know, everything that we're talking about here from the heme iron to the vitamin B12s and the most bioavailability as well. So what you can do is, you know, you take a liver or a frozen liver if you don't want to handle it too much.

because it is kind of jelly and all that if you haven't played around with liver before, and cut it into pill-like pieces that are frozen. And you just basically, yeah, swallow those like pills. And that sort of a pill is going to be far more effective than an iron tablet, say, for example, right? Where, you know, I don't know what the stats are on the iron tablets, but I think, you know, some of the reports where it's less than

you less than 30 % of your, are you actually getting when you ingest the iron tablets and these sorts of things. Plus they are very, they tend to make you constipated as well, which isn't great. So, so yeah, that's a, that's a super great tip. If you can get your head around having ⁓ frozen liver pills, it's the bomb. You're going to feel a whole lot better.

So in order to improve our VO2 max, which is what we're looking to do, we need to endurance miles, VO2 max, and strength training. Then there's heat and altitude to improve our blood plus good nutrition to make sure we're getting enough iron. What else can we or should we add to that list or is that enough for the everyday athlete to be able to

improve or at least stop the decline in their VO2 max.

I think that's probably those are the big rocks. The other ones are just kind of like the whole holistic sort of stuff and just make sure that stress is at bay, control your stress. And, ⁓ you know, because if you're not able to control your stress, we're back to the, you know, the nervous system. The nervous system is kind of the puppet or the puppeteer in all of these sorts of things, right? And you've got to have that puppeteer that's manipulating and moving ⁓ the rest of the body. And if that puppeteer is not

able to kind of move the body forward, then it's not gonna be any good, right? And I think you get that by making sure there's sort of a holistic practice around you from good circadian rhythm, sleep, recovery, social interactions.

and good nutrition. And ⁓ these sorts of things are going to be the foundation of allowing all the things that we just sort of spoke about to happen. And again, we wanna do this consistently for life as long as we can so that we maintain our health span and wellness.

But Prof, those are all the boring things. We want the 1%. Come on, Prof. We want the 1%. We don't want the big rocks. We want the exciting stuff.

you

Hahaha.

Well, the problem, as you know, right, sometimes you meet people and you see people and they're missing that, just the basics first, right? So just check in that you've got the basics first and then, I mean, ⁓ you know, have to plug good old Athletica, right? We've got a good solid training program there and a system that can really help, you know, enhance the VO2 max from there on. if you've got your...

Mm-hmm.

If you got your big rocks and your basics down, then jump on Athletica and grab all the one percenters because we got them ready to go for you.

Thanks for exploring the path to peak performance with us today on the Athletes Compass podcast. When you subscribe, you'll ensure that you're always tuned in for our next journey into endurance mindset and performance. And when you share this episode with a friend, teammate or coach, you'll be helping them discover new ways to level up their training and life. Take a moment now, subscribe, share, and let's keep navigating this endurance adventure together.

For more information or to schedule a consultation with Paul, Marjaana or me, check the links in the show notes. For Marjaana Rakai and Dr. Paul Laursen I'm Paul Warlosky and this has been the Athletes Compass podcast. Thank you so much for listening.