the science and practice of enhancing human performance for sport play and life Welcome to perform I'm Andy Galpin a professor of Kinesiology in the center for sport performance at Cal State Fullerton in today's episode we're going to be talking about the heart and I'd like to start with a very simple question and that is why do you breathe now that may have caught you off guard and so I'll let you think about it for a quick second why is it that you breathe the first couple of answers probably rushing to your head are something like well if I don't breathe I'll die and yes that's true but why why is it that if you don't breathe you'll die with that prompt and you're now probably thinking about well I've got to get oxygen into my system because oxygen is needed as a fuel for metabolism to produce energy and to keep my cells and heart and brain alive well that's not exactly the right answer of course oxygen is critically important and you will die without it but there are many other things going on that determine how you breathe why you breathe how often you breathe and why that's vital to both your health and performance given that the focus of this show is to discuss the science and physiology of maximizing performance I think it's pretty prudent of us to then spend a little bit of time learning more about how and why your heart functions in order to do that we're going to cover what I call the three eyes the first being investigate another way of saying how do I understand and analyze whether or not my heart is functioning at the highest level possible the second eye is interpretation how do I value those numbers is that great terrible amazing best in world history Etc and then the third one is intervene which is a way to say what do I do about it how do I improve various markers how do I reduce others so that I can maximize my overall functionality and performance of my cardiovascular tissue or in other words your heart in order to do that we're going to have to expand our conversation past just the heart itself this is going to include things like respiratory rate in fact I opened up the conversation here by asking you why you breathe and so we're going to take a look at not only the cardiac function itself say your resting heart rate maximum heart rate cardiac output V2 Max and things like that but we'll also get into other important and relative metrics like your heart rate variability your respiratory rate CO2 tolerance and other things that you need to understand to fully appreciate and then therefore improve Pro function of your cardiovascular system before we get started with all that though we need to take a quick step back and go through really what the heart is how it functions what it's made of and that will then give us insights and understanding about how to measure it interpret it and then therefore improve it now before we go too much further I'd like to take a quick break and thank our sponsors because they make this show 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necessarily appreciate in fact I directly said that the heart was not nearly as important as your skeletal muscle I've come since to learn that that was the wrong approach and I I'll tell you more why even if you're into those types of activities you should care deeply about the functionality of your heart and how that can absolutely improve your performance even in situations and scenarios like that okay so as a quick reminder here remember your body has three main types of muscles smooth cardiac and skeletal now there's a number of structural and functional differences between these three and just very quickly smooth muscle lacks contract off properties and so some of the things we're going to get into later the micro anatomy of smooth muscle it doesn't have and so it lacks the ability again to contract it can isometrically hold in place and so this is really something you don't have cognitive control over it's the stuff that regulates kind of um your your background physiology digestion things like that cardiac tissue again when I say that think the heart and skeletal muscle think everything else so the muscles you can actively control whether they be small muscles like in your fingers eyes or toes large muscles like your hamstrings or glutes spinal Erectors and things like that so kind of everything else is a skeletal muscle now there's a lot of similarities between skeletal and cardiac muscle which I'll talk about a little bit later but there's also some major differences and that actually is going to explain a lot about how you need to approach these interpret diagnose and then actually train these things differently and so I didn't appreciate that earlier in my career I kind of gave all of the credit to skeletal muscle and and didn't understand how important and vital something like my respiratory rate is in terms of performance as well as tracking and monitoring ongoing progress and then particularly signs of things like nonfunctional overreaching or overtraining or general fatigue so I hope that suffices as a small apology for all of you heart experts and efficient AOS out there okay so let me wind the story back just a little bit so I can set the stage appropriately and you'll understand why I felt the way I did coming out of high school I knew I was interested in sport performance and so I actually wanted to go to college to learn more about the physiology and science of performance but those programs really didn't exist and so I remember being taken on recruiting visits and they would ask kind of about your academic interests and I would say that and they would say well we have an athletic training program which is really injury prevention and treatment and management and stuff like that or we've got Premed and I didn't want to do that and really the only kind of exercise physiology programs involved exercise but it was really more Public Health disease prevention treatment management and stuff like that and so I never really found a home academically at least initially so I remember going through school and again while the exercise was a part of that it was really from the perspective of oh yeah you know athletes do that and then there's kind of exercise you should park your car in the end of the parking lot you should get more steps in and you can go upstairs and it was kind of that public health message which is awesome stuff and Incredibly important it just wasn't my passion so I kind of remember almost feeling like I didn't really have much of a home academically and I would learn stuff and I was excited about learning the human body and that stuff fascinated me and still does so from the the cardiov ascar perspective I just really didn't care that much about that stuff until we got into doing things like testing the V2 Max I'll tell you what that is a little bit later and we'll walk through it but that got my attention right because it's like hey this is a maximal exercise test and it was something we could do for athletics to see uh who's the most fit who had the best endurance and if you look at the research on sport performance there are some clear associations in fact some of them are very highly tied to success in sports in your V2 Max now classically you would think of something maybe like an endurance Runner a marathon runner per se and while the V2 Max is not the only thing at all that predicts performance clearly it is higher in those individuals relative to athletes in say baseball or golf or something like that so some sports didn't mattered a lot in others it didn't and there was a way that we could assess and test and identify performance and it all made sense to me and I grasped it but what I never did was make that connection across to basic physiology and I don't blame myself because no one else did either now what's funny about that is it really didn't come into my purview until really close to 2010 or so and I was fortunate enough to as a graduate student to have a gentleman by the name of Jonathan Myers a legendary physiologist out of the University actually of Stanford and he came and visited uh our laboratory and he gave a wonderful talk about the relationship between VO2 max and mortality and I was stunned and now you're talking about and I I'll give some actual studies later but you're talking about uh research and papers that used you 10,000 subjects 100,000 subjects just massive databases and they're finding incredibly strong predictions of your V2 Max and how long you're going to live and my eyes just exploded and I went that that that's it oh my gosh being healthy performing physically at your best is almost the same thing so now I got really excited about this metric and said hey man I want to know what this stuff looks like what is this is Jonathan the only guy that found this out well learning more about the history of exercise physiology and going back and and I realized we actually had known this since the late 1980s so there's another legendary physiologist who unfortunately very recently passed away named Steven Blair and he spent the vast majority of his career running these giant studies the first one most iconic one came out in a journal called jamama so Journal of American Medical Association one of the preeminent journals in in all of Science and Physiology and Medicine in 1989 and in that initial study he was really the first one that said hey when we look at V2 Max and we compare that to say smoking or cardiovascular disease it's as strong if not a stronger predictor of how long you're going to live than any of these other metrics and then actually if you look at you you you'll see study after study and you could pull up meta analyses and and and this has really caught actually attention the Lexicon and last say five or so years people have really jumped on board and it's it's really warmed my heart actually for that to happen because I felt like it was something that Us in the exercise scientist World a strength and conditioning folks and again scientists of exercise have been screaming from the top of our lungs for 20 years and no one really paid attention to or cared about and then people found this stuff out and started talking about it as if it was a new finding and us again in our world we're saying oh my gosh we've been telling you this for 20 plus years so that's okay it's a free pass I'll give you that I apologize to you I will accept your apology for ignoring us exercise scientists for so long but I think it really highlights another theme of this entire show which is the importance of understanding what maximum performance looks like if you want to be a better athlete that's great it's my personal interest but that doesn't have to be yours but the value that creates to the rest of society is unmatched V2 Max is one of those examples I will share with you many many more of those in in another episodes but that is to me one of the best examples of when we stop looking at health and performance differently and start looking at it as hey if your physiology performs at the highest level possible you're going to be healthy right Bill Bowerman if you have a body you're an athlete and so I just want your physiology to be functioning at the highest level that can you can then choose to use those skills however you'd like to be better at playing golf or basketball or or riding mountain bikes I don't really care whether you want to have more energy more recovery better sleep throughout the day something like a VO2 max is going to be intricately involved in all of those things now for those of you that absolutely love numbers I I'll give you some but please don't get too specific and particular about these couple of studies I'm going to go over think of them just as really highlights of the overall field depending on which population is studied in a certain setting or or database these numbers will VAR VAR slightly but again this is going to represent what you would generally find across dozens if not hundreds of similar studies that looked at V2 Max and overall health and wellness quick point of clarification when we say Fitness scientifically we're referring to V2 Max in the actual strength conditioning and performance settings you might have a different definition of it that's absolutely fine but scientifically those terms are pretty synonymous so Fitness means we've tested your V2 Max in almost every scientific uh situation so let's start off with that first seminal Steven Blair paper from 1989 in jamama in that they had about 10,000 men and about 3,000 women or so and what's actually interesting about this study and many others like it they typically follow the individuals for years I believe in this actual study it was something like nine years and within that several hundred people actually died and so it's a bit moreid I understand but it makes the science incredibly compelling because we can look at a number of people wait for several of them to die and then come back and say what actually was different between those people who died at Baseline versus those who didn't die you know again at Baseline and after that and so we can get really strong insights about what predicted death now what they found in this initial study and this is directly from the paper itself was after age adjustment so again they they would kind of factor in their age and say let's take that out of the equation so after age adjusted all cause mortality meaning died for any reason declined directly across Fitness levels so as you reduced your Fitness you increased your all cause mortality risk and it went from a number of what is referred to as 64 so 64 deaths per 10,000 people that was the highest rate there it reduced from that to about 18.6 and so again if you're looking at that saying all right if I go from the least fit category to the most fit my risk goes from 64 death per 10,000 people down to 18 death per 10,000 people if that part is confused you just run the 18 versus the 64 so another way to think about that is if my risk of dying is 18 and now it all a sudden goes up to 64 it's a huge increase in your risk of dying and and nobody wants that similar story for the women the numbers there actually went from the risk per 10,000 was 39.5 and reduced all the way to 8.5 and so again clear evidence that this thing was happening and what's also interesting here just because someone will ask I'm sure this was true once they factored out things like again as I mentioned age but also smoking habits cholesterol levels systolic blood pressure fasting blood glucose levels parental history of coronary artery disease and then followup and other metrics so what they're basically saying is even if you take those things into account you still see this massive reduction in health when we have a reduction in cardiovascular fitness now I realize following numbers like that is sometimes difficult if you're only listening to this in the audio version so we will have this paper in the show notes the actual title of the paper is physical fitness and all cause mortality a prospective study of healthy men and women and again first author Steven Blair from 1989 so if you Cruise onto table two of that paper you're going to see that they actually ran the analysis and split up the men and women into uh quintiles so this would mean the lowest 20% of Fitness the next 20 next 20 next 20 next 20 so take everyone across the Spectrum lowest to highest and split them up top 20% etc etc all the way down and what I will read off to you is the relative risk and again this is risk of dying as we go from the most fit 20 percentile to the next most fit to the middle kind of 20% to the second to last 20% all the way to the bottom 20% that's a way to to view this so if you start at the highest level of fitness and we put that as just a number of one .0 right so this is saying okay you're at a 1.0 if I go from the top 20 percentile to the next 20 percentile so think of this as like 60 to 80th per if you will my risk goes from 1 to 1.7 this is a 177% increase in Risk if I go to the next one down it's gone from 1 to 1.7 to 1.46 the next after that 1.36 and then here's where it explodes so again think of this as if you are somewhere between the 20th to 40th percentile 100 being the best zero being the absolute worst so just being the second to last category your risk is 1.37 you go from that category to the body 20th percental so just one category below your risk goes from 1.37 to 3.44 and this is why people will highlight you don't have to necessarily be the fittest on the planet from a health and cardiovascular perspective but you cannot be the lowest the magnitude of improvement you see from going from the least fit people around to just a second least fit is almost half to three times the risk reduction so massive improvements you'll see the exact same thing in the women in in the study so uh to not run you through everything but we're really talking about improvements as you go from the healthiest or most fit kind of going all the way down to the bottom 20 percentile that risk factor is 2.42 and then the lowest goes from 2.42 all the way up to 4.65 so similar message between the men and the women just being the bottom of that category is incredibly dangerous and problematic for your health so if you can just do a little bit to bump up one level that's going to do a lot for you now again there's a ton of studies you could pull from here the numbers again I don't want you to be super specific on that because they will differ depending upon the population a little a bit of context on that I grabbed another study for you also in jamama far more recently called The Association of cardiorespiratory Fitness with long-term mortality among adults undergoing exercise treadmill testing and this is actually going to tell you a similar story U but wanted to show you how even the studies that are a little bit different are are going to have the same take-home message in this particular analysis now they've got over 122,000 patients so okay great maybe there was something unique about Blair and his little population of 15,000 people or so what about if we 10ax that number roughly do we see the same basic results and the answer is effectively yes so in this almost 14,000 people died throughout the course of the study so we're getting same kind of idea pretty healthy people some are going to die but what does it really look like in terms of the folks that stayed alive and those that did not I'll Zoom you all the way down to the end to not make it so painstaking as the previous one but similar stuff here uh in fact it's even more jarring because they're able to do more uh in-depth analysis here of some of those other co-actors which is what I want to highlight so you know directly from the paper again here the increase in all cause mortality is associated with reduced cardiorespiratory Fitness which was comparable to or greater than traditional clinical risk factors such as coronary artery disease smoking and diabetes now I am certainly not trying to tell you that as long as you're in shapee that it's okay if you smoke or do anything else again just from this one particular study really profound there right the cardiovascular fitness again V2 Max was more predictive than traditional risk factors like coronary AR disease smoking and diabetes right so I I'll put numbers behind this because it gets even more interesting the cardiorespiratory Fitness is inversely associated with long-term mortality and not observed to be an limit what that also means is there doesn't seem to be any reduction in the benefit by continuing to increase your V2 Max so in other words the higher your V2 Max goes the more it seems to preserve all cause mortality risk so there doesn't appear to be in this study in fact you'd see the same thing if you looked at almost any other study in this area there seems to be no upper limit and so there's just really not a rationale of saying well I'm good enough here I'm okay this is enough if I get any better it won't really help that much you actually do see that in sport performance so a classic example here is in the sport of mixed martial arts if you to examine the V2 Maxes of the athletes in that you would see that it's kind of on an average of about 55 milliliters per kilogram per minute and if you get past that the benefits of performance continue to go up but even but slightly and once you really start getting past north of 65 it seems to be really no more association between improved performance by by that I mean winning fights doesn't mean it is detrimental of course or not advantageous to be in better Fitness prior to a mixed martial art fight but we're just saying the rate of increase in performance against the rate of increase in V2 Max starts to taper off we don't see a similar thing with cardiovascular health I'd like to take a quick break and thank our sponsors today's episode is brought to you by ag1 ag1 is a foundational nutrition greens supplement what's that mean it means that ag1 provides a comprehensive variety of vitamins minerals probiotics prebiotics and adaptogens in an easy to drink greens powder getting your nutritional right is hard for many people I certainly know that I have clients who really struggle for whatever reason to get the proper nutrients from whole food sources now ag1 is not a replacement for eating highquality Whole Foods but it is a great foundational supplement for filling in the gaps where needed I've also personally found that with many of my clients ag1 helps move them just in the right direction for eating more high quality Foods because it helps them with Cravings digestion and many other benefits I especially personally like taking ag1 when I'm on vacation or traveling because it helps me just sort of stay on track with my nutrition I know that missing a few days of getting the proper vitamins and minerals and other micronutrients is not a big deal at all that's not really how those things work but for me again I just like knowing that I'm kind of staying somewhat on track when I'm definitely not making the best nutrition and food choices of my life if if you'd like to try ag1 you can go to drink a1.com perform to receive five free travel packs plus a year supply of vitamin D3 plus K2 again that's drink a1.com perform to receive five free travel packs plus a year supply of vitamin D3 plus K2 okay so hopefully I've made my point here about the importance of V2 Max but in case I haven't just one more final study that I thought was of Interest here to to bring this point home even more actually this is one of Jonathan Meers more recent papers called cardiorespiratory Fitness and mortality risk across the spectrum of age race and sex published in the last couple of years here this is actually in 750,000 US veterans uh between the ages of 30 and 95 and I like this paper because the sample size is enormous again it takes into account things like race as well as age look at that Spectrum right almost a 65e spectrum um and within that 175,000 people or so died so if it held up against 15,000 then it held up against 150,000 and now it's holding up against 750,000 I just don't know how much more evidence one would need to see uh to believe not only in this as a actual finding but the relative risk ratio seems to be lining up across all these studies as pretty similar and so what they found in this again same idea they found no reduced benefit of Extreme Fitness in other words the higher the V2 Max just the higher the risk reduction there seemed to be no upper limit there and in addition what they found was a couple of metrics so if you take into account what are called the comorbidities and so you look at things like diabetes diabetes in this particular study took their risk factor from one to 1.34 so that's a big deal however going from the highest Fitness level to the next highest Fitness level represented an increase of risk of 1.66 so again I'm not saying that diabetes is okay or anything like that again I'm not a medical doctor and I don't do really anything with disease but just look how staging this is and in fact if you run this all the way out examples in this paper and here I'm looking at a figure two by the way if in case you want to go look yourself you're talking about uh the addition of age represented uh a 1.06 increase in risk factor hypertension smoking arterial fibrillation Cancer all these things are plotted you can see how much they increased risk and all of those the highest one was chronic kidney disease which represented 1.49 when you look into the V2 Max numbers the lowest risk factor was 1.39 and then it just escalates from there to 1.66 to 2.1 to 2.9 again with the least fit people having a 4X higher risk of mortality that's how important your heart is and so it's hard for me to make a cogent argument that even as athletes who are interested in say again dunking a basketball or these anerobic high power low fatigue Sports very difficult to say your heart is not playing a big role in your Global health and that that isn't going to limit your performan and somehow so at this point if I haven't convinced you of the importance of your VO2 max I don't think I can so let's go ahead and move on regardless now you're probably interested to know how do I assess that how do I value that then do something about it and we're going to cover that a little bit later I promise I'll give you a full breakdown of how to know whether your V2 Max is good based on whether you're male or female your age and where that puts you in the categories and percentiles we'll cover all those data and have of course plenty of links directly to tables in the show notes but I think before we do that we actually need to talk more about what makes the cardiac tissue so special and unique I'm going to talk a lot about skeletal muscle in other episodes and so what I want to do here is really focus on what is unique and special about the muscle fibers in the heart as this is going to explain a lot about how we interpret it what we do about it and how actually there's more things to pay attention to than just your V2 Max to get us started here I'd like to actually ask you a question that is you ever thought about why your heart never gets sore I mean as I said at the beginning you've got three types of muscle right smooth muscle which doesn't have contractile properties and it's not important or relevant to force production or human movement you've got skeletal muscle which is everything else it's your arms legs neck shoulders things like that and then cardiac muscle your heart now you know when you exercise really hard or do something unique and novel train over a larger range of motion do more Ecentric work and all these other things your muscles get sore but why does your heart ever get sore if you went out right now and you have an exercised in years and you ran a V2 Max test you would get extremely tired but you would not wake up the next day with a sore heart your intercostals or your ribs or your low back or something might be sore but not your heart well why is that well actually the answer to that tells us a lot about how we should assess the functionality of our cardiovascular system as well as how we need to think about training it differently than we train skeletal muscle you see it always comes back to physiology right so there's a reason we're going to walk you through how the heart is set up the structure of the fibers why it TRS the way it does because again this gives us insights into why we need to totally change our mindset about how we're going to train and improve it relative to how we talked about and we'll talk about training our skeleton muscle so the heart is made up of really four unique areas and we call these Chambers it's got two at the top called your Atria your left and right and two at the bottom called your ventricles and really the idea is you take blood from the Atria you squeeze and contract the Atria that pushes blood into the ventricles the ventricles in squeeze and that pushes blood out of your heart and into your system there's a lot more detail in there but that's close enough for now of primary interest is the left ventricle that's actually the reason why when you see a heart it isn't that perfect unique symmetrical shape that you envision when your 5-year-old daughter draws it it's actually slightly tilted to the left a little bit and that's because the left ventricle itself is larger than the right ventricle primarily because the right ventricle just needs to pump blood to the other side of the heart but the left ventricle pumps it out of your heart in throughout the entire rest of your body down to the tip of your toes and then all the way back up into your heart so it has to have enough Force to have all of that blood movement Up Against Gravity fighting through muscular contractions to get blood all the way to return now you have some ways that you can help that blood return along the way but primarily that's what the left ventricle has to be able to do and so because it is asked to have a higher function and know in other words produce more force it actually is larger there is an association at all times between muscle size and muscle strength though that is not linear and we'll discuss that in other episodes and so globally the left ventricle is larger what's also unique about the heart is that the way that the muscle fibers themselves are made up and so you see your heart like any muscle is just a composite of many hundreds if not thousands of individual muscle fibers and we will talk again about the nature of those in the skeletal muscle episodes but for now we need to think that they are actually quite different and so while you think of muscle your biceps muscles or hamstrings muscles or quadriceps muscles they are meant to have specific functionality a term that we're going to use in muscle science all the time is structure equals function so the structure the way that it is built equals the functionality so as a quick example your hamstring muscles are primarily meant for explosive movements to run Sprint jump stuff like that and so the way that they are built the way that they contract and oriented and attached to the B are different than say your spinal Erectors your low back muscles that are meant to just keep you up in vertical all day they're not really meant to be exploded or contract with a lot of force they want to be on and contracted mildly to keep you vertical and direct with that nice great posture when we go to the cardiac side then we need to start thinking okay what is the actual need and demand of the heart and so why we want to be able to turn skeletal muscle on and off a lot and to have really specific and precise movement that's not the role of the heart and fact we need to hedge towards something else we just want the heart to contract we don't need it to contract in different ways we don't need High Precision we need a full contraction and in fact more importantly we need to hedge against the possibility of not having a contraction if your hamstrings don't fire appropriately or you think your glutes are turned off or they're not as strong as you'd like that's not going to really change your ability to live if your heart fails to contract even one time you have serious problems if it fails to do that for you just a couple of minutes you're dead and so the demand is quite different it needs to be very consistent and it needs to basically do the same thing every time and it needs to have fail saves so some problem exists it can still contract and so the nature of the fibers in your heart are quite different in muscle they are very very long so you'll see them up to you know five to six inches in length of a single muscle fiber in say your quadriceps they are short and thick in the heart the diameter cross-sectional area is roughly the same you're talking about something like 4 to 5,000 micrometers squared in terms of a cross-sectional area but the length is very very short now you're talking about something like 0.1 cm in length and the reason we want that or the reason that's actually is happening is because the fibers themselves are what are called single nucleated and so this differs significantly from skeletal muscle that has know thousands of nuclei in the cell the nuclei as a quick reminder are the place in which you hold your DNA it is the control center of the cell it determines how the cell responds to external stimuli recovers repairs goes through protein synthesis or adds more mitochondria delet s or whatever the case may be this is being run by the nuclei and so by having more of them in skeletal muscle it allows it to be extremely plastic and adaptable and responsive to exercise or interventions or lack of exercise or anything else going on on I don't need that in cardiac tissue fact I don't need it to be growing and shrinking and dying really quickly what I needed to be doing is extremely consistent with both its Activation so its contraction and the force applied in that contraction so the fact you've got a single nuclei in the cardiac tissue tells you its primary role is not actually adaptation in fact depending on the study you look at you're going to see that the muscle fibers in your heart heart are going to turn over somewhere between 50 to maybe up to 70% throughout your lifetime meaning many of the fibers in your heart that you have as a child especially past puberty are going to be there the rest of your life there isn't a huge turnover now that differs considerably if you look at something like the skin that's probably going to turn over you will have all new skin cells every you know 30 to 50 days or something like that red blood cells you know may be more like every 120 days and you know skeleton muscle can actually have a a lifespan of maybe a decade or something like that maybe a little bit longer but your heart tissue is going to very rarely turn over it's not meant to be hyperplastic that does not mean it doesn't respond and adapt and change to stimuli like high blood pressure like exercise it absolutely does but it happens much slower that's not the primary job so the fibers themselves are shorter they are nice and thick and they have a single nuclei but they have a couple of actual specially unique advantages that skeletal muscle does not have for example they are connected to each other through what are called intercalated discs now these are specific and unique to cardiac tissue and what actually allows to happen is for there to be what's called Gap Junctions so there's almost little entry points from one of the fibers to the next one and what that does is it gives the ability for an action potential which is the electrical voltage that goes into the fiber that causes it to contract it allows that voltage to leak from one fiber to the next you wouldn't want this in your skeletal muscle because that means when you contract one fiber or set of fibers you might accidentally contract other ones not good remember we want High precision and control of movement in skeletal muscle with cardiac tissue we just want it all to go and so the fact that we have these these open Gates um through these intercalated discs and through these Gap Junctions that it says hey if for some reason we struggle to get intervention or activation of an action potential as long as we get it into one of the cells it'll be able to leak into the rest of them as well so in this case we want to hedge guaranteed contraction Over Control now on a similar point if you go to skeletal muscle it exists in what are called motor units so you might have several hundred to even many thousands of muscle fibers all inated or controlled by one basic nerve is the way to think about that okay this allows you again to upregulate how many of your muscle fibers in your muscle are Contracting at a given time by turning on or off more total motor units the heart doesn't have any there's no motor unit in the heart we don't want to have the consequences of what if a nerve fails or is blocked or dies and now we can't contract those fibers and so in fact the heart is not dependent upon nervous system activation to contract now I'll say that again the heart does not require any nervous system activation to contract and this explains exactly why you can do really awesome and interesting things like in the movie Indiana Jones Temple of Doom where the gentleman reaches into the guy's heart and he pulls it directly out of it and he stares at that man's heart that's in his hand and it still continues to beat this happens because again unlike skeletal muscle which requires nervous system activation the cardiac tissue does not it has it own intricate rate and can spontaneously uh produce the electricity needed to contract independent of the nervous system now that does not mean the nervous system does not have a role in your heart it absolutely does and we're going to talk a lot about that in fact it's incredibly important to understand that as a way to monitor Global fatigue Readiness performance and overall nervous system activation another thing that differentiates the skeletal from the cardiac tissue is how and how long they contract in skeleton muscle we actually want the ability to do what's called summation to reach tetany and so what happens is the muscle fibers in say your biceps brachi will contract with that electrical potential and then actually almost before it gets all the way back to Baseline it will contract again and then it'll contract again it contract again and so those those Min contractions start to stack on top of each other or summate and in fact if you do that long enough you can reach what is called Full tetany think of this as a muscle cramp so this is the muscle fibers themselves Contracting permanently instead of doing this kind of on off on off Rhythm cardiac tissue doesn't do that and I think you could probably imagine why it would be a very bad thing for you to reach tetany of your heart remember when we first started talking about the anatomy of the heart the primary job of the heart is to move blood from the Atria or the top of the heart to the ventricles and the bottom and then move that out to the body so if this thing were to reach tetney blood wouldn't move anywhere you wouldn't be able to circulate any blood throughout your body and of course you would die so while it's okay to have a cramp in your calf and it's painful and it's annoying and it's all those things having a cramp in your heart would be far worse and so your body Hedges against that and what it says is all right if I have this extremely fast what's called refractory time in skeletal muscle it's the ability to kind of contract multiple times with then a single muscle fiber I want to extend the time of contraction in the cardiac tissue so that I don't have that repeat and summation so in addition to not wanting tetany you also need to allow time for blood to fill up the ventricles remember this we're going to come back to this later in the episode when we talk about determinance of V2 Max what to improve in some of these these other numbers and why that relates to your resting heart rate your maximum heart rate why that's not trainable why there's no difference in maximum heart rate between highly fit people and unfit people and things like that so the ability of your heart to fill back up with blood is critical so it's got to contract allow enough time for blood to fill back into the Atri or ventricle and then contract again so big long smooth contractions not a lot of plasticity in the tissue itself we want to hedge against having lots of fine motor control we want consistency over specificity here so another way to build on top of that is going back to what I said a second ago how does it produce a contraction independent of the nervous system I gave you the potentially little bit crude example from uh the Indiana Jones movie but another way to think about this is how can my heartbeat if I'm unconscious right if I've got the brain turned offline well it will continue to do that because it has this intrinsic rate you've got four what are called Pacemakers in your heart the one I want to cover and talk about the most is the SA node so the Ceno atrial node this is in the right Atria and it controls for the most part your heart rate now you've got other ones like the AV node penji fibers and uh bundles of his and things like that but those are really backup systems so in case the SA node fails it'll go to the next one go to the next one and all the way down there so we've got various fail safes that give us the ability to say all right if we have a problem we're still going to get contraction because remember all we've got to do is get one chunk to Fire and it'll spread through those Gap Junctions and get everything else to contract in the appropriate fashion and so we want to have that in position this is also why if you have something like a heart attack and several of your tissue in your heart die you can still survive because you can get contraction of everything else but it is complicates the process right because we start to lose electrical impulse through the parts of the tissue that are dead now the essay note itself is actually a bit of a Marvel you could sort of think about this and actually remember in school being told that we have no idea it's one of the modern Mysteries of the world of how the essay note intrinsically develops this pace well that's not exactly true I think my teach they didn't know the answer or was just trying to hypee me up a little bit we know a lot more about what controls it in fact there's a number of things that go into that it does have a little bit of Wonder I don't want to steal that we don't know exactly how or why this thing beats the way it does why it's similar between almost every human and how it can just spontaneously create these Action potentials that is regulated by a number of things including uh various endocrine or pericine um these hormones that are circulating in your system blood pressure the strength of your contraction the amount of blood that comes back into your heart called preload and various other factors so it's actually a fairly complicated millu that go into it I'm actually still okay with you thinking about it as this modern mystery that has just this magical property where it contracts and causes electrial stimulation and action potentials out of nothing I'm cool with that too what we do know more about though is how this regulates the rest of your body so when we talk about skeletal muscle we know specifically there's a neurotransmitter called acetylcholine that is required for muscle Activation so the reality of it is your nerves are actually not directly attached to skeletal muscle there's a little space in between them what happens is acetylcholine is on the pre synaptic nerve so this is the nerve that comes in there it gets released into this little space in between actually attaches to little Lian Gates on the muscle itself they open up they let sodium and into the tissue and they cause a whole series of electrical things we call this an electrical to a chemical backr electrical signal way you transfer an electrical signal down your nerves into a chemical signal back into an electrical signal that allows muscle contraction so once again acetyl choline is the primary neurotransmitter that excites or activates skeleton muscle but shocking enough if you put acetylcholine onto the heart it slows it down yeah it does the exact opposite and so you have a number of nerves that are coming in probably the most famous is the Vagas nerve now this is is a v a not a v gas like the city so the Vegas nerve and several others are what are known as parasympathetic drivers and so the autonomic nervous system is split up into two large branches the first one is the parasympathetic this is rest and digest this is relaxed sleepy depressed chilled all those things over there right the other side of the equation and it is more complicated than this but this is all we need to know for right now is the sympathetic this is fight or flight this is freeze this is action anxiety aware aroused and all kinds of things like that we want both of these they are critically important for everyday life we need these for high performance we need these for health we need these to just be alive and so we want to be able to fluctuate back and forth between these two states appropriately they are not onoff switch they are more like a gradient or a toggle they're they're a dimmer switch more so than they are you know again flipped on or flipped off so what happens is the intrinsic rate of that SA node is probably higher than your resting heart rate in fact it probably wants to beat more like 100 to 120 beats per minute most people's resting heart rate is more like 60 to 80 beats per minute so you kind of have this vagus nerve that is constantly applying this drip of aceto choline to naturally slow your heart rate down now this is actually really cool mechanism because what allows you to do is if you want to increase your heart rate the very first thing you have to do is not necessarily turn on sympathetic drive it's just to reduce parasympathetic drive another way to say that is imagine you're driving downhill say you're in San Francisco or some place that has a ton of hills and you're going at 60 mes hour and you decide you want to go faster well the initial instinct is to maybe hit the accelerator or hit the gas think of that as the sympathetic nervous system well you don't actually have to do that the first step is just to make sure your foot isn't on the brake the parasympathetic nervous system so kind of what's happening is at all times when you're driving the Vagas nerve is slowly keeping its foot just a little bit on that brake to keep you relaxed now it's doing that again so that if you want to go faster really quickly all we have to do rather than giving out additional resources like epinephrine or adrenaline all I actually have to do is stop us from slowing you down it's kind of one of those classic double negatives right so if I inhibit the inhibitor I can actually go faster so if I remove my foot from that break my heart rate will increase to again somewhere in that 100 to 100 20 beats per minute range plus or minus here without us doing anything if I want to continue to accelerate past that so now I'm going down that Hill I was going 60 M an hour I've removed my foot from The Brak now I'm going 80 M an hour or 100 miles an hour but that's not fast enough I want to go 150 now I can hit the accelerator now I can push down on the sympathetic nervous system increase adrenaline turn on a faster rate and pump my heart even more to produce more work more energy or whatever I'm trying to accomplish great now that we've got that down let's go back and answer our question why doesn't the heart get sore well let's think about it what are the reasons that cause skeletal muscle to get sore remember all skeletal muscle with the exception of one and I wonder if you know that which one that is by the way all skeleton with the exception of one is connected to Bone via tendons and so when we contract muscle connects pulls on the connective tissue pulls on the bone to get you movement our cardiovascular our heart is not that it is not connected to Bone that's not the point we're not trying to cause movement it is really just connected to itself so because of that we can't ask it to go over any additional range of motion so that factor gets thrown out the only thing we can possibly do is put more blood back into the heart which puts it on an Ecentric stretch that's our only mode here now Ecentric exercise does lead to excessive soreness if done especially heavy or in a novel fashion with traditional exercise and so Ecentric exercise is something to pay attention to but the fact is we don't have the ability to overload the heart more than the maximum amount of blood we already have in our system so there's no novelty we can add to it that it's not already used to by the way to answer your question what's the only muscle not directly attached to Bone I give you a hint you can see it on me right now and if you were my 5-year-old you would love to show it to me all the time it's your tongue pretty cool right all right going back to business here so it's not range of motion it's not the Ecentric training other things that cause soreness are higher intensity not really applicable here again if you're used to Contracting at a maximum heart rate we're not going to be able to go past that more volume well we could do that but more volume tends to mean more exercise over more range of motion your heart beats all day it is not subject to that much change in volume if you looked at the total amount of heart beats that you go through throughout the day a little bit of exercise is not changing that volume too much so it's really difficult to add much volume relative to the standard or Baseline there and so as you just continue to go down all the other factors that influence muscle soreness and you see they don't really apply to muscle again that's not its primary role and so while you may get fatigued from exercise especially endurance-based exercise the heart itself is not really subject to fatigue in fact the heart rarely gets tired it has far more mitochondria in it than skeletal muscle we used to refer to this as the ultimate slow twitch muscle it is not meant for force of contraction going back to motor units we actually can't alter force of contraction in the muscle fibers themselves in the heart we can only do it by changing the stretch on the tissue same thing in your skeletal muscle but in that case you've got both options right change stretch or strange contractile properties we really can't change the contractile properties in the heart especially acutely what we can do is put it on more stretch this means more blood back into the system again preload we'll talk about that a little bit later afterload is another way but if if we put more back into it we put the muscle on a bigger stretch and this allows it to then respond I think about like a rubber band if I pull it a little bit it snaps back if I pull it a lot it snaps back harder that's all we can really do but it is not meant uh to be regulating Force up and down we don't even have motor units it's an all or none thing ideally and so we've got a lot of mitochondria in there we are phenomenal at aerobic metabolism again specifically within the contractile properties we're not talking about aerobic metabolism of your entire system or heart we're talking about about the capillaries surrounding the heart itself the ability to get blood into the tissue of the heart not the blood actually in the chambers that you're using to send the rest of your body remember your heart has its own blood supply not the stuff it's trying to give out to everybody else um think of this like as Halloween where you've you're sitting in the house and you've got this giant bucket of candy and the candy you're giving out to the rest of the world you're not eating that candy as well you've got another supply of candy in your back pocket and in your house and you're pulling out of that candy if you will okay so the hardest self is meant to be incredibly robust against fatigue against damage against soreness and against changing any of that's an inherent contractile or ionotropic is what the cardiovascular folks would probably call it properties that said it does respond somewhat similar to skeletal muscle with exercise adaptation so just like in skeletal muscle where you can add quality contraction force and speed and power and you can add quantity muscle size the same thing actually happens in the heart the heart can get physically stronger this would result in you pumping out more blood per pump again the fibers themselves won't necessarily change their inert properties but the heart can contract with more Force we'll talk about that a little bit later that's going to be referred to as ejection fraction and stroke volume it can also get larger and in this particular case typically what you'll see in response to exercise or healthy lifestyle behavioral changes the enlargement in your heart you'll see will be primarily in the left ventricle again this is the one that's going to have to deal with the pressure of the aorta getting that blood out the rest of your body and what will ideally happen is the amount or size of that chamber so the the inside the amount the space that can be filled by Blood will either stay the same or even get slightly bigger but what you'll basically do is you'll pack on tissue to the outside of the ventricle so it gets bigger allows it to produce more Force but it doesn't compromise the size of the chamber so again think about the left ventricle as a balloon if that balloon gets smaller and you can feel less blood in it that's going to be a problem we don't want it to necessarily be extremely large either and so if the back end grows but the chamber size the balloon size stays the same then we're going to be able to contract with more force and not compromise our total blood flow if you achieved an adaptation like that and it allowed you to pump out more blood per pump that number is called stroke volume so the volume of blood that comes out per stroke or per contraction the percentage of the blood that gets emptied out of that ventricle is called your ejection fraction so let's just say there was 100 milliliters of blood in your left ventricle and you contracted and 50% or 50 milliliters was left in The ventricle your ejection fraction would be 50 and so we would like to see high ejection fractions so that we're not wasting our time Contracting and blood's still sitting in a ventricle if you improve either of those things and I'm going to really focus mostly on stroke volume here that will allow your heart rate to drop and so one of the classic adaptations we see of any type of physical training but think more specifically endurance type training is a reduction or a drop in resting heart rate see at rest right now as you're sitting here listening the amount of oxygen required is the same whether you're fit or unfit it doesn't necessarily matter there's a minimum amount of oxygen based on your body size and other factors that don't really matter your Fitness level and so we call that your cardiac output okay so what that is is it's the stroke volume multiplied by your heart rate so how much is coming out per pump and how many times are you pumping in a given minute you multiply those together and you get a cardiac output let's just say that number is 5 lers per minute it's a very standard resting cardiac output if if you are fit and we improve your stroke volume since the total demand again the back end of this equation is still five lers per minute but I've increased one of the numbers that allows me to decrease the other number and so your heart rate as I said the ESS node is paying attention to many things and one of them is that preload so how much blood is coming back in and how much is going back out and various other factors so it knows if I'm getting say this 100 milliters of Blood Out per pump I don't have to pump as often so increase the acetylcholine drive slow the heart rate down and let's chill out in fact we we'll cover some of these numbers later about uh what a good heart rate is what the best we've ever seen why you don't want to be too high or too low and stuff like that but that's basically what's happening and so we can identify whether or not we're struggling in either the stroke volume portion the cardiac output side of the equation or heart rate just based on that understanding of how the heart works that will then tell us what style and type of training we need to do to make the most efficient improvements and not only our heart rate but more importantly our V2 Max now your heart rate again how many beats per minute you're using at rest or during exercise is incredibly telling as I mentioned earlier it doesn't actually change though in response to exercise training at its maximum the only really thing that matters in this particular case is your age and we know that maximum heart rate goes down as you get older but it doesn't alter that much with Fitness and so what it can tell you though are things like your heart rate variability and so let's just use the example of a heart rate of 60 beats per minute so one would think and assume that if my heart rate is 60 beats per minute that means I'm having 60 beats in 60 seconds that would be one beat per second and if you calculated the total amount of Beats you had over the course of the minute you would in fact achieve 60 that's what that number means but it doesn't necessarily mean it's on the exact same Rhythm so it would not be like on a metronome your heart would not be beating every second on the second there is a variability in the space between heart beats so while you again you would achieve the same number by the end of the minute in this case 60 it might do two or three fast ones in a row have a little bit of a pause have a little bit of a pause a fast one five fast ones Etc so there's a variability in that rate now it's not very long it's actually so small that you won't even be able to perceive it but we can measure this with a number of different Technologies this is called heart rate variability you may have heard of it before it's been around for over 60 years and there's extensive evidence and research on this originally most of the work there again came from these disease and health models HRV has been associated with cardiovascular Health mortality mental health depression anxiety but more importantly for me was when HRV started coming along for things like athlete Readiness recovery sleep and performance and so as always the case physiology is physiology friends if it's dysfunctional it's dysfunctional if you're leading that to long-term Health implications if that's leading to short-term performance detriment it's really the same thing right so understanding the role of HRV is something we're going to have to get into a lot later in future episodes I would love to talk to you more about that there's a lot of nuance and interesting things we can pull there but globally something we want to pay attention to so as we go into our next section here where we cover those three eyes right how do I investigate my current cardiovascular fitness how do I interpret how good that is and then how do I intervene what do I do about it I want to make the point that just looking at your video to Max is not enough just looking at your resting heart rate wouldn't be enough you would also want to pay tremendous attention to your HRV and then various other factors like your respiratory rate again I'll do respiratory rate in a future episode I would love to talk to you for many hours about that I would actually tell you right now a little bit of a spoiler alert I think that is the most underappreciated of all these metrics I think it should be considered a Vital sign and is potentially the most important thing that you can measure for overall fitness and health and quite honestly it's the thing I pay the most attention to on a day-to-day basis of all of these metrics more on that later you're gonna have to wait for now though I'd like to take a quick break and thank our sponsors today's episode is brought to you by momentus momentus makes safe highquality supplements now I naturally despise and frankly don't trust most supplement companies and for good reason in fact I recently co-authored a review article that was published in 2023 in which we found that the amount of adulterations which accidental contaminants or deliberate spiking like adding stimulants or anabolic or other agents which are not supposed to be in the product or mislabeling in which the supplement contains either a far greater or lower concentration than is being reported on the label is shockingly high so I actually honestly spent literally years vetting both momentus and their leadership team before deciding to officially partner with them last year bringing them on as a sponsor for the show was this a natural ution of our partnership now I did all that because of their dedication to cleaning up the supplement industry and I've seen them do that with their pocketbook first every single momentous product is third- 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now at the part of our conversation where I can answer the question we started off with which is why do you breathe and we talked about how it's oxygen and we need that well oxygen is not really a fuel for metabolism it's needed to go through aerobic metabolism but the fuel is coming from your fat and carbohydrates I only need oxygen during aerobic metabolism but I'm very effective at anerobic which means I can produce energy without the need of oxygen but to finish those processes I've got to have the oxygen around and so it's a little bit of a Twist here this is also explaining why even if you're an anerobic athlete you still care deeply about your Aerobic System because this is what allows you to recover to completely metabolize your carbohydrates to finish that process and restore yourself back to homeostasis the faster you can do that the faster you can repeat your Anor robic processes you can recover you can get back to training get back to competition the more you practice the better you get the better you perform and so what's actually fully happening is this when you take a breath in and you inhale you're bringing in amongst other things but primarily oxygen when you take a breath out you're breathing out CO2 the oxygen you bring in is primarily there to regulate metabolic processes but the CO2 you're exhaling is regulating your pH now there's a handful of things your body will regulate almost anything else one of them is your pH it does not like to mess with this if you were to look at other markers like say your blood glucose you realize that that's highly variable it can be as low as you know 70 milligram per deciliter as high as 150 during exercise or something like that and so you can see it all double or maybe even triple the amount in the blood you would never do that with ph it has an extremely tight window that it will not move out of that's because all the enzymes that are required for you to go through any metabolic process need to be in a certain PH range if it gets out of that becomes too acidic or too alkalic they can't function you can't create energy you're going to die very very quickly so pH is insanely important to hold into a tight window and so what happens is you don't feel that air hunger or that desire to breathe because oxygen starts getting low remember especially at rest or even during exercise you can produce energy anob so when you start getting low on oxygen you'll just switch to anerobic catm it's not necessarily a reason for you to panic to stress or to change your behavior increases in CO2 though will do that and so remember your muscle is whether it's using fat as a fuel or carbohydrates as a fuel it's trying to generate a molecule called ATP this is the energy currency in all of biology and it doesn't matter what you use that ATP for by the way it doesn't matter if we're talking about skeletal muscle we're talking about cardiac muscle or anything else so whether you're using this for exercise to power your brain to recover to digest food it's irrelevant here right we're going to use carbohydrates or fat as a fuel we're going to make ATP and then at the end the final B product of all metabolism is going to be water CO2 and ATP so the CO2 concentration increases as metabolic rate increases as a result of that you start then moving CO2 from your tissue into the blood concentrations of CO2 then in blood go up you've got chemo receptors in your brain stem and various other places that are going to be paying extreme attention to the amount of CO2 in your blood if CO2 gets really really high we call this hyper Capia if it gets low it's called hypo Capia remember those terms so hypercapnea increases in CO2 concentration actually signal your red blood cells to drop the oxygen on them making it easier for your muscle to extract and absorb the oxygen effectively think about it this way if CO2 is high in the blood your body is under the assumption you're going through a lot of metabolism so it's under the assumption that we want to use and need a lot of oxygen so it reduces that affinity and this is called the bore effect if you get hypocapnic again too low of CO2 it does the opposite now this is going to be counterintuitive when we talk about things like CO2 tolerance and respiratory rate in in future episodes as to why you could potentially have problems with hyperventilation or over breathing so what's happening in this context is those signals are being sent to your brain and that is interpreting it as saying CO2 is too high let's reduce that the way you reduce CO2 concentration in your blood is to Exhale and so this would cause you to increase your respiratory rate and to start either mildly or excessively hyperventilating and this is why as you exercise your respiratory rate again the amount of breaths you're taking goes up it is in part to increase and bring in oxygen of course but when we're doing it Anor robic we're not using oxygen anyways so the real reason we're breathing so hard and we're panting and and all that stuff is we're getting harder and harder of our exercise is because we're trying to dump and get rid of all that CO2 buildup remember excess CO2 is altering pH this is making us more acidic this becomes an extreme problem so another way to think about this is when you inhale that's actually a sympathetic driver and so your heart rate increases during inhalation when you exhale it is parasympathetic and it drops so effectively what's happening is your body is sort of saying oh you're inhaling we're assuming then you're bringing in oxygen let's get prepared to deliver this oxygen throughout the system when you're exhaling it's the opposite I don't want to be in a situ situation where I'm hyperventilating I don't need to be breathing too much because if again that CO2 gets too low instead of being acidic we are now in respiratory alkalosis so the opposite direction right we're too basic and so it slows the heart rate down so every time you take a breath in your heart rate jumps up a little bit every time you take a breath out it goes down a little bit so if I'm altering my respiratory rate I'm then altering my heart rate and this is why things like HRV are so intrinsically tied to things like respiratory rate I can't let us move off this point without saying one final thing I know we want to get to our three eyes here in one second but a lot of people are aware and in the coaching world people use HRV very often and there's a lot of data to support this there's a lot of critical information we can get for assessing say exercise volume fatigue Readiness and things like that tons of value there but I don't think enough people are paying attention to respiratory rate this is really highlighted in a paper that just came out in the last few months and so I'd like to bring this to your attention what they did is looked at College age students and they simply measured their respiratory rate and one of the things that they found that's interesting is for every breath per minute that increase so if a respiratory rate went from 15 breaths per minute to 16 breaths per minute they increased their likelihood of experienc stress by 1.25x and what I found particularly interesting about this is they found that irrespective of changes in things like HRV total hours of sleep sleep efficiency sleep onset and various other things that are typically the metrics used to measure overall stress and autonomic nervous system functionality and things like that and so what we're what we're going over here is not to say that HRV or sleep are not good metrics to take they clearly are it's just that you're going to find things in the respiratory rate that you're not necessarily going to see in other places that give you great clues about overall stress so strongly encourage you to pay attention to respiratory rate and we'll talk about that plenty in the future so at this point we've now got a much better understanding of why our cardiovascular system matters to both performance and health we know a little bit more about how it contracts with some of the unique properties that exist within it that differentiates it from some of our other tissue like skeletal muscle and then of course we've learned why we breathe and how that relegates many other functions like our sleep recovery and of course overall performance using all that we can now discuss the three eyes which are how do I investigate how do I interpret and then how do I intervene on improving my cardiovascular fitness let's start with the first eye investigate now depending on the metric you're interested in something like a heart rate can be done with no technology whatsoever you can simply put your fingers up to your neck count your heart rate divide that by the time domain and get your heart rate easy example there most classic one we teach is start a stopwatch count how many times your heart beats in 15 seconds multiply that by four and then you'll understand how many beats you're taking per minute you could also simply just measure it for one minute count those numbers and that's fine but in reality most of you probably have some sort of Fitness technology app or watch or something of that sort that's going to tell you that number already as far as things like HRV and respiratory rate we're going to have to cover those in their own IND idual episodes as you've got a lot of options and there's some context there I will tell you again most Fitness technologies will give you some insight of that whether directly on the app or something you can get if you dive in to the data a little bit further HRV is really challenging though because there's a lot of ways to measure it's not standardized and there's just a lot more context we have time to get into right now so unfortunately we're going to have to take a little bit of a pass on that respiratory rate is actually quite simple you probably want to focus at least initially on respiratory rate over night rather than during the day but both are acceptable as well and again probably already coming in any of the technologies that you may be using to track your sleep recovery or performance or anything else so I'd like to focus most of our attention here on the cardiovascular stuff that we spent most of our time in our conversation with and get into some of those details right now the gold standard to measure your V2 Max is going to be in a laboratory with a metabolic cart you can get this stuff in various equations you you can use any of your Fitness Technologies I will strongly encourage you though that if you care about this number if it's possible and it may not be spend a couple of hundred dollars and get this actually tested in a laboratory the data are quite clear at this point I have not yet seen really any standard over-the-counter Fitness technology that gets an accurate number of your V2 Max when the number gets high and particularly for people who are already fairly fit if you're V is really low it might give you a decent number but for folks that are kind of moderate to highly trained it's just really challenging to get an appropriate estimate from a watch or a ring or things like that perhaps those will improve in the future in fact I quite expect them too but as of now the margin of error is a little bit too high for me to be comfortable with when you care about accuracy if you're trying to just get a global sense they're fine um in fact if you want to do that you can use any number of absolutely free estimate equations examples of this would include something like a 2-minute step test where you would take your heart rate step up and down on a very small box say 12 in or so you do that cons continuously for 2 minutes and then measure your heart rate at the end you can enter that score into uh an equation and get an estimate of your V2 Max those are scientifically validated methodologies uh the 12-minute test ends up being something like a mile and a half run so you could simply in fact you can do this if you'd like as well run a mile and a half as fast as you can take that time enter it into equation and get an estimate if you have that time as well as your heart rate you can enter it in as well and get a more accurate picture and so again all of these are close we call these submaximal estimates because they are that they are not the direct measure so I would encourage you again if at all possible to actually go into a laboratory and get this measured in addition if you do something like that you can get a bunch of other metrics you can't get with some some of these estimate equations like what percentage of fat versus carbohydrate you're using your Anor robic and lactate thresholds your maximum ventilation so how much total air you can bring in and out and a bunch of other stuff that we talked about in the show and we'll get into in a second again if you don't have access to any of that that's fine use any of those other free or extremely lowcost options and you'll get yourself pretty close our next eye is interpretation so sticking with heart rate and V2 Max as I mentioned a little bit earlier resting heart rate will go down as you improve Fitness but your maximum heart rate will not really change in fact if anything it will be reduced because you're a little bit older and so to State it one more time there's no real association between highly fit people and their maximum heart rate and unfit people so it's not a metric that we should be overly concerned about of you know where is your maximum heart rate it is relevant to again your stroke volume but the heart rate itself is not going to tell you that much so not something to be concerned about your resting heart heart rate though or your heart rate at any given intensity is very important so if you're going to be running say at a standard Pace say 7 mil hour and your heart rate at 7 miles per hour was 150 beats per minute and now a couple of months later your heart rate at the exact same speed is now 115 bits per minute that would represent a significant Improvement in cardiovascular fitness stroke volume would be much higher and because of that that allows your heart rate to come down right justing heart rate is a similar story giving you a little bit of context here and the reason this is top of mine is because there's a hummingbird that lives in my backyard and my wife and kids look at it every single day and they get so excited they call her mom's Little Helper they named it squirt actually and so they get really excited when this little hummingbird is flying back there because it's super fast hummingbirds have a resting heart rate of something like 1,200 beats per minute it's absolutely insane so you're talking about putting an order of magnitude on top of almost a human mag maximum heart rate you contrast that to a larger animal like a giraffe an elephant or a blue whale and you're talking about a heart rate of something like five to six beats per minute and so humans of course are are somewhere in between if you were technically to Google this you might see something like a normal resting heart rate is 60 to 100 beats per minute I I am here to tell you I I cannot fathom a situation in which somebody's resting heart rate is over 80 beats per minute and they are healthy and I absolutely would not think that that would happen to somebody who is performing at their Max Maxum in fact I even will tell you this is off the record this is not the science this is me and my professional opinion even a resling heart rate of 60 or so particularly in a man is that's catching my eye I would like to see most folks probably in the 40s to 50s somewhere in the range again you might be fine at 60 but getting a much above 60 is quite a bit high I can also personally tell you I've worked with plenty of athletes specifically in this case uh several UFC fighters whose resting heart rates were in the low 40s if not high 30s so 37 38 40 things like this and so that's the lowest I have personally seen that said there are classic stories of plenty of endurance athletes you're talking about Elite cyclists and cross country skiers and marathon runners and such who are in the low 30s lowest I'm aware of is the the legendary cyclist Mel induran having a resting heart R of 28 beats per minute as far as I can tell that's the lowest ever reported in this scientific literature though please if you've seen any lower uh let me know I'm sure there are plenty of stories of anecdotes of people uh in personal training records and stuff who think they're lower but if you've ever seen anything verified scientifically I would love to see that interpreting your V2 Max is more interesting in my opinion because there's a lot of components to it and so in order to truly understand this let's talk about how we calculate V2 Max to begin with the easiest way in my opinion is to think about V2 Max equals your cardiac output multiplied by what's called your av2 difference now as I've stated cardiac output is simply your stroke volume multiplied by our heart rate so if we were to combine this entire thing we would say your heart rate multiplied by your stroke volume which says okay how much blood am I getting out per pump how many pumps am I getting and I multiply that by what's called your av2 difference now the a stands for arterial v stands for Venus and the O2 is oxygen so what literally this means is what's the difference in oxygen concentrations between the arterial side and the Venus side remember arteries generally go away from your heart which means they're going to exercising tissue and veins come back and so what we're really looking at is saying okay how much blood how much Oxygen's in the blood when it leaves the heart this is going to be the highest concentration of oxygen possible and how much is in the blood when it comes back having passed through muscle this then directly tells you how much oxygen your tissue extracted in the process so to give you some numbers here to make this easy these are not accurate just representing the math here if you had a 100 molecules of oxygen that left your heart and went into your quadriceps and then once it's gone through the capillaries that surround all the muscles and tissues and fibers in your quadriceps and it went in as 100 and then it came back out the other side and went back to the heart and lungs to be re oxygenated if it went in at 100 and came out at 75 the difference between the arterial and the Venus side is 100 minus 75 which would give you a score of 25 now what that means and I'm again I'm using those round numbers to make this simple you've extracted now 25% of the oxygen that came in your system you only got 25% of it out that's not a very good score you want that number because it's a multiplier to be as high as possible so if 100 goes in I don't want 75 coming out I want zero coming out let's say maybe you got 10 out so now 100 went in 10 came out you extracted 90% of the oxygen that was available to you and got to bring it into muscle and use it for everything we talked about earlier and so now your avo2 difference is 90 much higher than 25 so we get to multiply that by our cardiac output which brings our V2 Max even higher the easiest way to think about V2 Max is to use What's called the FI equation VO2 max according to the FI equation is your heart rate now there how many beats per minute multiplied by your stroke volume how much blood coming out per pump multiplied by what's called your avo2 difference to be perfectly honest with you the av2 difference numbers are difficult to convey over Audio Only so I'm going to spend most of our time on the other side of the equation when it comes time to interpreting your VO2 max numbers there's a lot of charts and papers you can use we'll provide some of those in the show notes for you for you I want to give you some numbers though to give you rough context typically we think about V2 Max in what's called a relative term now scientists and people that are more advanced in this field might like to use the absolute versions uh depending on the scenario that make more more sense but for now let's just stick to the relative what that means is how many milliliters of oxygen are you using per kilogram of body weight per minute so you'll see them expressed as things like your V2 Max is 50 milliliters per Kil per minute so 50 m of oxygen per kilogram of body weight per minute you can kind of think about V2 Max almost on a scale of 0 to 100 and so the average person that would kind of say walk out of my classroom somewhat moderately trained male or female that's you know in the neighborhood of 170 lbs or 70 kilos something like that is probably going to have a V2 Max around you know 35 to 45 milliliters per kilogram per minute something in that range if you fall below 8 18 milliliters per kilogram per minute you're probably Crossing below the threshold of what we call Independence for women that's about 15 or 16 which means it's very difficult to live independently and by yourself because your Fitness is so low going through basic activities of daily living become challenging so what I'd like to share with you is not only the normative values but also the highest we've ever seen in terms of V2 Max cardiac output and stroke volume now there's so much data on V2 Max we can actually break this this down by age and by sex in really specific numbers so uh if you know your exact age you can go ahead and look these up and these this charge but I'll give you a couple again just to give you Paul Park let's say you were a female between 40 and 49 years old and your V2 Max was 28 that would put you as what we consider to be below average if you wanted to go from below average to average you'd have to go into the 32 to 36 milliliters per kilog range if you wanted to go all the way to Elite tell me what's the best ever you'd be needing to surpass the mark of 47 milliliters per kilogram per minute any of you that are maybe older let's go ahead and jump way down uh let's say you are 71 years old again talking about a 71y old female here below 18 you know you're still above that line of Independence but it would still be considered low you would really want to be looking at something like 22 to 24 to be considered above average and then really over 36 to be considered Elite now I know uh my friend Peter AA likes to tell people he wants them to be considered Elite in at least the decade before their actual age if not two decades before and that's a phenomenal way to think about it so just as that example if you were that incredibly ambitious and vigorous 71-year-old Elite for you would be 36 milliliters per kilogram per minute the decade before again 60 to 69 that would be 40 but if you wanted to be that extra person and get that double gold stamp from from Peter you'd want to be above 46 so the difference is going from 36 to 46 would give you that Elite category for two decades younger than you for the men it's a similar story you just add a little bit of the numbers to it so a male who is say between 50 and 59 years old above average would be 36 to 40 milliliters per kilogram per minute and you need to be above 50 to be considered Elite at that age now in my personal opinion I kind of like to say there's no excuse to be under 50 unless you're over 50 meaning you have no reason to be having a video to Max of lower than 50 unless you're over 50 years old and even then 50 to 60 I don't want you anywhere near below 50 so that's a nice number to go after uh we'll also talk about in a second how changeable that is and how much it responds to various types of training and so it's going to give you a little bit of hope you have some room to move there and it will respond to your training and so there's some at the end of the tunnel if you're looking at those numbers and you've had a V2 Max done recently and you're thinking oh my gosh I am way below what Andy said there that's fine you still have within your capabilities to change that now while I said that those are technically Elite and would probably put you in the 99th percentile they aren't necessarily the highest we've ever seen in fact it is very common to be much much higher than the scores I just described so as always I'd love to share with you what the best in the world are it's important for us to reset our standards and recognize and challenge what we think is possible and to not accept just being in the 99th percentile let's see what is absolutely possible in human physiology and those no numbers and scores go far higher than that 55 and 60 I just described so for many many years in history the highest documented V2 Max that we would you know acknowledge scientifically was from an Austrian CrossCountry skier now this study was was actually published about 4 years prior to him then winning a gold medal in the Olympics and so he was obviously a very high profile and highly successful athlete he came in if you know these values if not that's okay with a hemoglobin concentration uh up around 16.8 which is outrageous most folks are going to be 14 or 15 or something like that uh hemoglobin is the molecule that carries oxygen around on your red blood cells so innately he's got a huge ability to do that his V2 Max was reported to be 9 .6 MERS per kilogram per minute which is incredible so that actually stood around for a very long time and people thought that that's basically it again there had been talks of people in the 92s 93s and stuff like that but nothing had really been independently verified whether you think that's important or not hard to know right until a few years later and this is one of the most miraculous and cool stories I ever remember being a part of in fact I remember when this happened live and it was fun for me getting prepared for this show to go back and read the updates on this individual cuz it was such a stark and massive change it's it was one of those LeBron James or Tiger Woods moments uh for the endurance and exercise physiology worlds uh the guy came on the scene was an absolute Phenom what I'm talking about of course is the story of the legendary Norwegian cyclist Oscar senson Oscar came on as an 18-year-old and I remember hearing these murmurs coming and people were saying some kid some 18-year-old just hit a 100 on a V2 Max score and everyone was like no way again we've heard all these stories before may or may not be true and everyone was basically like okay prove it prove it you've got to do it in a verified way we got to send some independent scientists out there in fact they sent the manufacturers for the the metabolic heart company out to the facility that says you need to be here you need to verify this thing is accurate nobody really believed it not the first time we had heard stories like that and so of course um actually the the team out there that was coaching him connected with a guy named Mike Joiner Mike is a legendary exercise physiologist at the male clinic um one of these people actually who's probably potentially published more in this area did a lot when we were considering uh in the early 2000s whether or not a two-hour Marathon was even physiologically possible Mike did a lot of these calculations so really involved in the field they connected with Mike they published this paper and it turns out that they were actually able to verify um that Oscar was able to hit a V2 Max of 96.7 ml per kilogram per minute if you're more familiar with absolute terms that' be an absolute of 7.4 lers per minute just phenomenal phenomenal record what's also really interesting about this story is he actually retired just a few years later at the age of 21 or 22 I think he had some success in competitive cycling but perhaps not as much as one would think given his VO2 max was so extraordinary I think this is also an interesting message right it tells you this is one of the reasons why we love sport it's just because you have some physiological parameter you you're tall or have some skill that doesn't necessarily mean you're always going to win endurance events are based on more than just V2 Max and Sports in general have a lot of things going on in them besides just physiology I love physiology I'm obsessed with it but it's also why I love watching sports because you never know what's actually going to happen the world record for VO2 max for females is also phenomenally impressive this belongs to of course the iconic Paula Radcliffe she had a VO2 max reportedly about 75 milliliters per kilogram per minute if you're unfamiliar with Paula multiple time world record holder in the marathon again iconic is maybe even not enough to describe how successful and talented Paula was she reportedly ran somewhere in the distance of 140 to 160 miles per week and this is actually really cool because this is a a document that you can go look up she had a a very well respected and known exercise physiologist Andy Jones he was actually one of the gentlemen probably most responsible for bringing beetroot juice and Arginine and things like that onto the scene uh from a supplementation and nutrition perspective but Andy worked with her for I believe almost 20 years and was able to document her training and her uh performance and metrics and things like that so was able to take her through a bunch of world records and so has this stuff as something you can go download and take a look at before we move into our final category of intervention I think it's important to give you some context I realize many of you are probably familiar with a vertical jump test a 40- yard dash maybe your One max bench press those numbers kind of make sense perhaps these ones they they have less context for you it's hard to grasp how impressive they are outside of seeing how much bigger or higher these numbers are for world champions relative to the rest of us the numbers don't make a lot of sense so what I've done is is I've made a couple of quick calculations here to give you a little bit of context of what it means physiologically to have a V2 Maxis High uh what that means in terms of how much you're pumping throughout your system how efficient your muscles are at getting that in and so just as a couple of examples want to hit you with some fun numbers here as we talked about earlier a standard cardiac output at rest is something like 5 lers per minute and remember cardiac output is heart rate multiplied by stroke volume so if we assume a resting heart rate of say 60 beats per minute and we wanted to get to that number of call it 5 liters per minute that would mean your stroke volume would need to be somewhere in the area of about 80 to 90 milliliters all right now for some of you depending on where you're at milliliters make complete sense uh those here in America maybe not and so I've converted that at something in the neighborhood of like you know just under 3 ounces and so while you're sitting here resting every time your heart is beating it's kicking out about 3 ounces of blood every time watch how high this number gets when we get to maximal exercise in the case of these phenomenal athletes like Paula or Oscar we don't actually know their stroke volume but we can run some quick calculations and get a pretty close estimate Oscar would have had to be in the neighborhood of about 225 milliliters at his max to reach the cardiac output of around 40 to 45 lers to give him a V2 Max uh in the 100 or so milliliters per kilogram per minute again I know I'm moving from liters to milliliters so run the math yourself if you want to challenge that number on the back end as I said avo2 difference is really kind of complicated so most people are probably in the neighborhood of about 70% extraction rate so of all the going into tissue they're able to get about 70 of it higher trained athletes though are looking something more like 93 94 95% and so the ability to extract get it into tissue Which is far higher than the average person in that 70 to 80% range coming backwards into stroke volume if we assume that he or or she is in that neighborhood of like you know 200 to 20 25 milliters or so um this is what that math would look like so if we said Oscar was call him 20 years old to make math a little bit easier his predicted maximum heart rate would be about 200 beats per minute if you're not familiar with that equation if you take 220 subtract your age that gives you a very rough and please this is just a rough estimate of your maximal heart rate but a a maximum heart rate of 200 beats per minute is is maybe a little higher than what you'd really see but not out of the question so if we took 200 and multiplied that by 225 that stroke volume so the heart rate multiplied by the stroke volume that would put us right near that 45 L per minute Mark again that's the highest I've ever seen in terms of cardiac output perhaps there's some conditioning and endurance coaches out there that have seen higher but but that's that's phenomenally high in fact again many of the the best performing endurance athletes ever are still in 40 42 lers per minute and so Oscar would have had to again be able to get at least up to 200 beasts per minute and if not if he could only say get to 190 his stroke volume would have had to been even higher than 225 what that functionally represents for those you know not familiar with the metric system 45 L per minute is just under 12 gallons of blood pumped per minute throughout your body I'll say that one more time 12 gallons of blood being pumped throughout your entire body every single minute another way to think about that that 225 milliliters is around 7.5 7 .6 o so if we go back to earlier remember when I said you're kicking out you know something like under 3 o per contraction now you've over doubled that number right so you're giving you know half a bottle of water out per pump but you're pumping three times per second remember your heart rate's no longer at 60 beats per minute as in one beat per second it's over triple that so you're beating 3.3 or so times per minute so you're not getting out 7.6 ounces per second you're getting that out per pump but what you're really getting out is closer to like 25 or 26 ounces per second like a general water bottle is 12 to 16 ounces a large one is 20 you're doing that entire thing every second that you're exercising and that your heart is beating if you were then to extend that throughout the entire minute it would mean you've pumped over 1,500 oz in a single minute through your heart I don't know if and how any of that information actually helps your life but me personally find it just endlessly fascinating to think about not only the performance side of this equation right how fast can I run a marathon and things like that and that's really awesome and cool but what's the physiology behind it what does my body have to do to enable something like that to occur and thinking about the fact that man I'm going to have to pump 12 gallons of blood through my body per minute to be able to execute on something like that to me that's that's maybe even a bigger Joy than seeing somebody perform a race at a certain time both equally impressive and fun but love to see the physiology behind that to round this entire story out let's move on to our third and final eye which is intervention in other words what can you do about these things how much do they change and what do I have to do to see improvements in them if we work backwards through this V2 Max equation as we've talked about can we see improvements in our avo2 difference absolutely how so we're primarily looking for a couple of things one increase in capillarization so the amount of capillaries in our exercising muscle and or some sort of combination of improved mitochondrial size or content if you do those things you'll be better at extracting the oxygen that's coming in into the tissue as well as utilizing it to go through aerobic and anerobic Recovery metabolism back off of that we now have stroke volume and in fact one of the things that makes this interesting is as we go towards maximum exercise and start improving our stroke volume we start to run into a little bit of a problem you see if our heart rate is too high we don't have enough time to fill the ventricles and the arteries back up with blood and so we start actually reducing our stroke volume and so this is one of the reasons why you would not actually want to have your heart rate continue to increase as a training adaptation it's now at the point somewhere around 200 beats per minute or so where it's compromising what's called filling time if you don't have enough time there we can't get enough blood in so while you have extremely strong tissue and you can pump a lot of the blood out of there per pump your ejection fraction is massive right you're getting all the blood in the left ventricle out of there every single time you contract you've got to have some physical time to actually fill it up and so you will see adaptations in the the heart tissue itself in fact if you look at the actual size of the left ventricle kind of an average number to things about there is like 150 g or so in a non-athlete where maybe you know upwards of 200 in an athlete is something that we see respond and is generally Associated as a positive adaptation to exercise and so we know we need to increase the strength of the left ventricle as a starting place if we do that that will allow or actually produce and result in an increase in stroke volume so what does that mean for training well fundamentally outside of things like exercise technique and timing and nutrition and all that other stuff if we're just talking about the background physiology we have two Avenues or areas to push on to improve our V2 Max we have our stroke volume and our av2 difference so there's a lot of ways we go about improving both of them I am of the opinion that you need to train across a wide spectrum of exercise intensities to optimize both factors if you in fact look at Classic training logs of endurance athletes uh going back to even what we know about Oscars training they are typically going to spend something like 70% or so of their time at a low intensity what's that mean exactly depends on the athlete but you're probably talking about something like between 60 to 80 maybe up to 82% of their heart rate Peak most of their time is there I'll explain why in a second then you've got another additional maybe 20 to 25% of your time being spent at a moderate intensity and typically something like again 82 to 90 or so per of your heart rate Peak and then three to maybe 6% of the time at the remaining higher heart rate so this is 92 93% or so plus the reason I'm giving you kind of rough guidelines there is every scientific paper has those zones if you will a little bit differently all kinds of different endurance coaches historically have set different landmarks and so there's no exact numbers there and so as a very guideline I think it is very safe to assume some split like that should be highly effective at improving your V2 Max what's that mean in terms of exercises well actually it's entirely up to you V2 Max is remember depending upon how many milliliters of oxygen per kilogram of muscle per minute which means the more muscles you utilize the higher the V2 Maxes uh if you were to go to get a VO2 max test done and let's say you were not specifically trained Tred on like a bike if you were to get that same exact test done on a bicycle versus a treadmill where you're running versus cycling the score on the treadmill is going to be about 10% or so higher than it is on the bike and that's simply because there's a small increasing the amount of muscles involved when it comes to running versus cycling now if you were specifically trained on the bike and you cycle a lot that may not actually be the case and in fact highly endurance strained folks ony cyclists rather will score higher on a V2 Max test on the bike than they will on a tread mode but that really is now coming down to test specificity efficiency and like other things that are that's not what we're trying to talk about here and so generally the more muscles involved the more oxygen being utilized the higher that V2 Max so when it comes to training we want to think about the same thing the exercise mode I don't want to say it doesn't matter it is relevant but you have unlimited options if you want a bike or swim or cycle or row that's great if you don't like any of those traditional modalities and you want to use something like an assault bike or pull a sled run up hill drag something those are also incredibly viable options it's not the exercise per se that determines the adaptation it's the application of the exercise right the Body Works and Physiology works on a principle called the said principle which stands Sid which stands for specific adaptation to imposed demand so you put a demand on a tissue to bring in and utilize oxygen at a high rate it will adapt that specific demand so challenging your muscles continuously to bring in and utilize oxygen at a rapid rate is all fundamentally that needs to happen for you andove that and so again the mode of the exercise is not that big of a deal if you are new to exercise I would generally recommend you being careful of exercises that involve a lot of Ecentric action so jumping Landing because you're going to get really sore really fast but if not feel free to choose whatever exercise modality or combination of them switch it up a little bit do some cycling do some running uphill jump in the pool really up to you the intensity which you do that is more like what I just explained as I apologized at the beginning of the program I earlier in my life grossly underappreciated the cardiovascular system as a whole and I certainly underappreciated the importance of low intensity exercise I'll also be candid with you here I am not as fond of Zone 2 exercise as some other folks are I don't certainly don't think it's bad it is good for you I just don't think you need to be that worried about what exact Zone you're in you want to be something probably in that lower intensity 60 to 80ish per of your heart rate I don't really care where your millimolars are in any of those low intensities you're going to be challenging the ability to bring in and utilize oxygen over a long period period of time look at any amount of research on that it is very clear steady state lower intensity exercise especially over time 6 months to a year is generally going to improve VO2 max probably upwards of 5 to 10% depending on the person the training history and other contexts like that so it's very very effective and something I have absolutely Incorporated more and more into my both my life personally as well as my coaching practice so really important to do that stuff on the other end of the equation you can do things at an extremely high intensity for a short bout depending on the study you want to pull here you can see things like high-intensity intervals this could be a combination of 30 seconds of maximal exercise resting 30 seconds and repeating that anywhere between like four and 12 times can equally improve V2 max if not greater and more so than your steady state exercise there's a lot more context that go into that it's not necessarily meaning High intensity is better there are some significant downsides and concerns with only doing high-intensity exercise another thing I've changed my opinion on and so I think we want to use high-intensity exercise there's clear benefit there it's fundamentally different though than low intensity exercise so we're challenging a different part of the system which is why I'm am going to argue you should be incorporating both most of the time doesn't have to be always in all of your training but you wouldn't want to leave either either one of these things entirely off if the pure goal here is to maximize V2 reason is when you do something at a higher intensity the point of failure in the tissue becomes different so extending my ability to move at a lower or moderate intensity for a long period of time is challenging different aspects than it is when I ask it to introduce a tremendous amount of fatigue so I'm now into Anor robic metabolism when I'm going really hard and really fast I can't use oxygen so I'm building up a ton of byproducts pH is being disturbed potential damage is happening other things are occurring CO2 is getting extremely high and so enhancing my ability to deal with that is a similar thing in terms of increasing mitochondria biogenesis so more mitochondria higher functioning mitochondria larger mitochondria increasing aerobic capacity all of these same things occur and so again I don't want to make the arent that one Higher intensity or low intensity is better than another I think you should do both I will make the same argument for moderate intensity while that isn't as specific and precise in terms of what it's challenging it's reasonable to build some of that into your equation as well another thing you're going to find commonly in the research is a longer bout of intervals this is described in a lot of different ways a good friend of mine and an expert in endurance physiology Joel Jameson has talked a lot about high-intensity continuous training hi if you're not familiar with that stuff I would encourage you to look it up it's very very effective lots of different things and tools we can pull out here one example would be something like let's go uh what a classic Runner would do is something more like one M repeats so run a mile as fast as you can this is going to take most folks you know six to eight or n minutes or so however long it takes you to run that mile rest that same amount of time so it's say one to one work to rest ratio so 6 minutes of running 6 minutes of rest and then you repeat that again for a total of two or three or perhaps four repetitions that's a very long workout the average person would not not be able to do that but those of you that are not average and are that are good to high to strong performers listening right now that's absolutely within your capabilities and fact you've probably done it before it doesn't have to be that extreme you could use shorter durations say 2 minutes 3 minutes 4 minutes is a very very common one you'll find in research so four minutes of allout exercise four minutes of recovery repeat it again two to four times what's critical to understand here is these work when you're actually achieving a maximum in that time domain so you can't do four minutes at 70% rest for 4 minutes and do that again that's going to burn you some calories and has other benefits of just making you feel better today and some other stuff like that but in terms of VO2 max that's probably not the most efficient thing you can do so to summarize all of that stuff spend a good amount of time at a lower intensity that's going to drive efficiency common adaptation there since it's going to be the highest activity you can do to maximize utilizing fat for fuel you're still going to be burning primarily carbohydrates don't get that confused but that's the best way to burn some fat so this is typically associated with higher metabolic efficiency getting better at using fat as a fuel source and things like that it's also easy to recover from it's not going to change your autonomic nervous system that much so you typically don't see uh big drops in uh HRV scores we don't really see as much overtraining or non-functional overreaching elevations in respiratory heart rate other signs of hunger fatigue not wanting to train things like that doesn't really happen when we spend time at lower intensities higher intensities are phenomenal really really really time efficient but they've got consequences as well they're going to be entirely or mostly anerobic which is okay too because you'll still use the aerobic side of the equation to recover from that so super important but there's a price to be paid there people can run into problems and you you will you're more likely to see issues with those metrics I just described if you're doing too much intensity too often especially if you're combining this with a normal stressful life so you're doing this kind of exercise then you're going right back into your your day job uh you're having difficult meetings even if they're exciting and happy meetings you're thinking hard you're working you're getting back and forth and you're in a kind of a long high stress environment all day really really challenging on the on the system to be in that high of a stress at all times so other ways you can mitigate that we can talk about those in future episodes but just wanted to say while high-intensity exercise is very time efficient it's not necessarily a free pass either low intensity is not a free pass either it's going to leave things on the table that you're missing so to round all that up again I would recommend a combination of lower intensity moderate intensity and high intensity training the mode of the exercise in terms of the the what you choose bicycle kettle bells circuit training it's entirely up to you spin class whatever you'd like to do frequency can be as high or as low as you'd like there are plenty of studies showing kind of the higher intensity stuff done two to three times per week can improve VO2 max but you can also do the lower intensity stuff every day or combination so really you can modify this based on your lifestyle and what's going on and finally rest enals they're not incredibly applicable here in fact we've already baked them in if you're not doing intervals then there is no rest interval if you are um we typically look for something like a one to one work to rest ratio but you're welcome to do 2: one 1:2 or any combination of that if you train appropriately and of course you've got all the other factors like your nutrition and sleep and Stress Management under control it's not unrealistic to expect a 30 to 50% Improvement in V2 Max after 6 to 12 months you'll find plenty of studies that land in that ballpark the rate of increase obviously goes down as you become more and more trained now candidly you don't have the ability to improve your V to Max probably as much as you do something like your strength but you can improve it significantly nonetheless you will find plenty of studies showing even a 10 to 20% increase in highly trained individuals after a year in untrained folks that probably takes about half that time so 10 to 20% Improvement in four to 6 months or so so if you know where you're at right now you train appropriately fairly consistently again those are reasonable numbers to expect after a half a year or so of training and as we understand it the biggest limiting factor at this point is probably the time needed to fill the ventricles back up with blood I know we covered a lot of ground in this episode and I hope you had as much fun listening to it as I did talking about it but before we walk out of here let's quickly recap what we discussed most importantly we talked about why you actually breathe how you can pull a heart out of a living animal and it can continue to beat on its own and while your heart unlike any of the rest of your muscles never gets sore along the way of course we talked about what your heart is why that tissue is special and unique and how it functions we talked specifically about your V2 Max how to test that score uh how to know where you are that spectrum of good great ter Elite and then really what to do about it at the end in covering that stuff we also gave some hints about things like CO2 tolerance how that influences sleep and Recovery respiratory rate HRV and a number of other factors that are not directly but highly associated with overall cardiovascular health if you were of my opinion when I first started my full rate IND ex physiology and you didn't really give cardiovascular health and performance the credit it deserved I hope that I've changed your mind a little bit and warmed you up to it if you're the opposite direction coming in being a champion of the cardiovascular system I hope I just gave music to your ears and let you double or triple down on your joy and biases towards the heart and its importance in overall health and physical performance thank you for joining for today's episode our goal is to share exciting scientific Insight that helps you perform at your absolute best if the show resonates with you and you want to help ensure this information remains free and accessible to anyone in the world there are a few ways that you can support first you can subscribe to the show on YouTube Spotify and apple and on Apple and Spotify you can leave up to a five-star review given that we're a new podcast subscribing and leaving a review really does help us a lot second please check out our sponsors the show would not exist without them and they really are exceptional products and services and then finally you can share today's episode with a friend who you think would enjoy it if you have any content questions or suggestions please put those in the comment section on YouTube I really do try to read these and see what you have to say I use my Instagram and Twitter also exclusively for scientific communication so those are great places to follow along for more learning my handle is Dr Andy Galpin on both platforms thank you for listening and never forget in the famous words of Bill Bowerman if you have a body you're an athlete