Transcript for:
Understanding Lactate's Role in Performance

the science and practice of enhancing human performance for sport play and life Welcome to perform Hello friends I'm Dr Andy Galpin I'm a professor of Kinesiology in the center for sport performance at Cal State of Fullerton in today's show we're going to be talking about lactate or how many of you probably think of it lactic acid now I know when I say those words you immediately start thinking about things like exercise and muscle and fatigue soreness and and reducing exercise performance and that all is true kind of in fact as we're going to lay out the overwhelming perceptions and thoughts about what lactate or lactic acid really are and what they're doing are massively false in fact I'll spill the beans right now lactate is in no form or fashion cause of your muscle fatigue it actually does quite the opposite it preserves muscle performance we'll get into all that stuff later in fact I actually think that highlights why I wanted to have this conversation or do this episode is because it's high time we start really understanding what lactate truly is and how it's functioning in our body it has classically been thought of as this waste product something that you don't want to round uh something that you want to avoid at all cost or manage or mitigate whenever possible and the reality of it is it has a number of widespread benefits across your entire physiological landscape let me give you a couple examples of what I'm talking about lactate is known to stimulate a molecule called pgc1 Alpha this is involved in any metabolically active tissue and any part of your body and it is directly responsible for mitochondrial biogenesis this is another way of saying by increasing in utilizing more lactate you're going to be increasing and making more mitochondria this is a known response and this is obviously a positive thing for overall health and performance but it even goes beyond that let me give you a couple of other examples you may not realize for example did you know lactate targets LX cells which are responsible of course for testosterone in your body it has a number of other benefits such as bdnf so brain derived neurotropic Factor this works directly on the hippocampus to stimulate neurogenesis so the growing of new neurons particularly in your brain similar idea with a molecule called VF which is responsible for endothelial cells and then therefore promoting angiogenesis so the growing of new vasculature throughout your entire body grin which is associated with Hunger so lactate actually acts directly on the hypothalamus to regulate gin and one of the major benefits here is suppression of appetite I don't need to explain a lot to you there but very few people can do a high-intensity exercise spout where they generate a lot of lactate and then feel extremely hungry immediately afterwards so appetite suppression with high lactate is a pretty easy one to imagine I'm going to go even further though because there's so many more things lactate doing whether we're talking about the liver and the kidneys and increasing what's called gluconeogenesis so as you'll see later in our conversation the primary place that we're getting the molecule or precursors for gluconeogenesis is lactate another benefit is its ability to act on Osteo class and therefore play a role in bone remodeling now I could go on and on here and we're not quite done yet because I want to give you a handful of ones I'm going to Rapid Fire these ones but lactate again has been highly associated with positive adaptations across your brain uh it's heavily involved in memory and learning heart health dehydration in fact any of you that have ever used a ringer solution I know exactly what I'm talking about there cancer sep is insulin regulation traumatic brain injuries wound healing postsurgery recovery arthritis inflammation gut microbiome health and then finally overall metabolic flexibility my guess is you had no idea that many things were happening in response to lactate so in order to understand all these things what I would love to do is spend a little time today walking you through exactly what lactate really is how it's created how it's managed what role it's truly playing in your overall physiology and then of course at the end we will do our three eyes which is investigation how do I measure this stuff what should I be paying attention to two interpret how do I know if I'm good bad great terrible or world record and then three intervene how do I improve my body's ability to produce and clear lactate so that it can perform at its highest level regardless of the task I'm asking my body to perform to get us started on this journey we're going to go all the way back to the beginning when we initially discovered and began to understand the role of lactate in really all of biology but specifically in human exercise physiology the story really starts in 1708 when sheal found lactate in sour milk now the term he gave it actually roughly translates I think into milk acid but it really persisted in this idea of just general food space until nearly 30 years later in 1808 when a scientist bersus and I have tried to pronounce this at least 200 times but bersus really and this is a classic story in all exercise physiology Cycles he found that concentrations of lactate were much higher in hunted Stags so a deer-like creature in Europe and so it's very clear at this point that lactate is somehow associated with elevated stress or exercise and we didn't really know much past that but it seemed to be in all of physiology at this point so we had now crossed over from things um like food elements and bacteria into now human physiology so that was really a big step up in terms of our understanding of the relative importance of it for living creatures now bersus went on to do a whole bunch of other stuff in this field in fact he was directly responsible for the name that you all probably recognized as a catalyst U by studying lactate and trying to figure out what's going on he really came up with this idea that he called ferments now that sounds familiar because it is where we got fermentation from in fact you may be starting to make a connection in your brain which we'll do a little bit more directly later that really lactate and fermentation are almost one and the same in a human exercising muscle we call it anerobic g olsis and lactate production in food elements and in the food industry we call it fermentation not exactly the same but very very close and I'll maybe explain that a little bit more later we haven't really moved into the realm yet of exercise physiology there was no real understanding that this was happening as a byproduct of muscular contractions or anything like that at this time we were still at the level of understanding what happens when carbohydrates are used with and without oxygen so in fact we can be more direct here when we break down carbohydrates for a fuel source that's fermentation you do the same thing with protein you we call that thing putrification same thing happens with fat and you call it rancidification and so I fact you may have never made that connection before but you ferment carbohydrates fats go rancid and proteins are putrified so at this point in the story we're kind of into the mid 1800s in fact in 1843 shurter was the first to find lactate in the blood he actually was autopsying folks that had died from septics and fevers and infections and things like that and notice during these bouts of really high fever so we now know of course that's really high caloric expenditure really high need for energy high temperature etc etc you've gone through a lot of metabolism lactic concentrations were really high we hadn't really Associated this with muscle yet and certainly hadn't done it with exercise and we were actually at this point thinking it was something that happened to be associated with death the St Stags had been dying folks these folks had been dying or dead and that's all we knew at this point it was another 15 years or so at the late 1850s when they first started finding this in the blood of actual living people and this changed everything in fact for the next 50 years or so most of our breakthroughs were from a gentleman named Lou Pastor you're probably familiar with him and in fact all the stuff that we do with milk and we pasteurize it all this is from pastor's original work and so there was all these associations that were floating around and then really everything came to fruition with the very Classic series of papers in 1907 from a combination of folks one of them is the the authors Hopkins and Fletcher were really the first to identify that lactate was a byproduct of muscle contraction and then a handful of years go on and two very famous scientists both whom won Nobel prizes OT meerhoff and AV Hill put together what most people and certainly at the undergraduate or graduate exercise physiology level Now understand as basic lactate metabolism we are now understanding things like it's coming from car carbohydrates it's coming from muscular contraction there's an association between more metabolism more lacate production and all that fundamental stuff and while they certainly got many things wrong meerhoff and a hill are the ones most credited with our basic understanding of the differences between anerobic anerobic metabolism and lactate being a core Cog in that discussion in 1960 lactate analyzers came on board and the field exploded and one of the more fundamental things that happened was a paper published by waserman 1964 in which he outlined a concept called the anerobic threshold now what he was basically saying there is at some point when you're producing energy and you need more of it you switch from aerobic into anerobic metabolism and there's a threshold for everyone in which you can no longer produce energy aerobically and you have to switch to anerobic metabolism if I missed you with all that stuff and you don't really know what those terms are I promise I'm going to come back and walk you through that all in just one second but this concept of the anerobic threshold from 1964 persisted for a very long time however even waserman himself fairly recently and a series of letters has acknowledged that that was probably not the right concept and the real rationale here going all the way back to mehoff and AV Hill was the fundamental understanding or thought that lactate was produced as a result of insufficient oxygen in muscle and that's an incredibly important Point here so I'll say it one more time the idea at this point was you go through Anor robic metabolism of carbohydrates and again if you don't know what those terms are I will walk you through that in just one second but you go through that anerobic metabolism of carbohydrates and if you have enough oxygen you'll proceed and handle the carbohydrate just fine if you don't that's when you generate lactate and at remember at this point lactate was still thought of as a negative thing as a thought of as a cause of fatigue and so that's really kicked off at that point it wasn't until 1983 when a young scientist named George Brooks launched an idea called the lactate shuttle hypothesis now it took him almost 17 years to really outline the entire thing but by the 1990 or so he had fully explained the lactate shuttle since then the last 20 years he has just continued to dump more and more research in support of that such that the field generally recognized it as while we can continue to call this the lactate shuttle hypothesis it's very hard to refute at this point now before we go too much further I'd like to take a quick break and thank our sponsors because they make this show possible not only are they on this list because they offer great products and services but because I actually personally love them and use them myself today's episode is brought to you by momentus MST make 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and when you guys try it you will know what I mean after lots of research and development these David proin bars are releasing to the public in September of 2024 the macronutrients one more time are 28 g of protein 150 calories and 0o gram of sugar and they do this with excellent ingredients if you're interested in trying these bars for yourself you can go to david.com perform to purchase if possible or be notified when they're available again that's David protein.com perform to purchase if possible or be notified when they are available so to this point we really been dancing around this idea of what lactate is and I've been trying to argue that it's been misunderstood and so now at this point I think you're convinced and so it's time for me to actually explain to you what it really is and how it's working to get us going the very first thing we need to address is the name you've heard me continuously refer to it as lactate now and not lactic acid lactic acid is almost never existed in the human body see what the functional difference is this when you make a lactate molecule in human physiology at our temperature and pH it almost immediately disassociates into what's called a lactide anion so this is actually written as a capital l little a negative and that means it has a negative charge so it's a lactide anion with a hydrogen plus ion so one thing you really got to keep in mind physiology in in fact chemistry in general biochemistry will regulate charges I mean by that is a positive and a negative charge um dramatically in fact this is how all of chemistry works works right it's positive and negative Charges going back and forth and this is what determines how all molecules function and so you don't ever want a a situation in your body in which something is floating around with a positive or negative charge you almost always want to combine it so that they are neutralized and this is why when you take various um supplements that they have weird things attached to them citric acid is a very common one um salts a common one so they can balance charges so that they actually get into your system they don't get immediately broken down or metabolized or connected with something else you want so positive and neutral charges are are absolutely essential to understanding what's going on here and so you're never really going to see lactic acid in that form because it would require that hydrogen to be placed on top of it and it's going to immediately dissociate keep this in mind later as this is going to tell you the entire story of what we're going to talk about hydrogen itself is a H+ that is almost synonymous with proton so remember protons electrons negative charges positive charges right so if you have a free floating hydrogen anywhere that is going to be synonymous with acid in fact the term pH right so if you have a low PH you're acidic a high pH is alkaline so a lot of acid going around pH depending on who you want to pick stands for either potential hydrogen or power of hydrogen but the point is pH is simply a measure of how much free hydrogen is around more free hydrogen more acid that it's the same thing so that H+ is acid so anytime walking you through this this biochemistry here and you hear me say things like this results in a free hydrogen I might say a free hydrogen I might say proton I might say acid in your brain you can hear that all is the same thing right there's no other sources of acid than hydrogen so the opposite of pH is O negative and so an acid is a lot of H alkaline is a lot of O Negative you bring those together you take a acid you take a base you put them together and you make water that's how the whole system works great now lactate itself can come in two basic forms L lactate and D lactate in humans we're almost always talking about L lactate when we think about D we're typically thinking about the food industry so you're talking about sauerkraut and pickles and yogurt um sour milk like we talked about earlier beer Tomatoes uh apples wine etc etc almost all those have a combination of D and L lactate but they're functionally a little bit different Recent research is actually coming out on the role of deact in humans and particularly regarding the gut microbiome and so you can actually see you probably noticed something there's this connection here between fermentation fermentable Foods sauerkraut yogurts gut microbiome health and there is a strong relationship there in fact one of the things that's possibly probably potentially happening is when we ingest more fiber we know that this is generally good for gut microbiome Health but potentially and this is a strong potential again the research is very recent here and there's a ton to learn about the gut microbiome but that is aiding in the ability to ferment that fiber that is then producing high quality results like lactate and so one particular thought that's being espoused right now by Dr books and others is that maybe deact is a byproduct of some of the bacteria in your gut microbiome is increasing the amount of lactate in your system which is a good thing I told you go back to the beginning remember all the positive things lactate is associated with and so this could be one of the many reasons why a healthy gut microbiome is important for overall health and performance again very early but very interesting and the connection seems to make some sense we also can take a look at the research uh I know my group um lead author great giki we actually published a review article very recently on the changes in the gut microb with acute exercise there's a lot going on we have an additional study going on right now on the gut microbiome in female athletes and there seems to be a pronounced and positive Association there with the ability to work with lactate in various forms um there are changes in athletes uh in the again the bacteria associated with lactate production and clearance U and then it goes the other direction as well so a lot to learn in this area but there seems to be a very strong connection there with the ability to process clear generate and handle lactate through the gut microbiome through the blood as well as in physical activity so in fact because of all that there's some idea right now that deact could be an important biomarker for overall intestinal permeability more on that stuff later but an interesting idea nonetheless so like I said while that part of the field is growing and evolving what's extraordinarily clear is lactates role in regulating metabolic acidosis yeah that's right not contributing or causing in regulating it as in stopping it from happening or even reversing it now metabolic acidosis is the increase in acidic level of your blood in response to metabolism that's most simply its point but think about it this way your body regulates a number of things to keep you alive how much blood sugar you have your blood pressure to make sure you're moving blood throughout your system but over on top of all of that the single most important thing for your body to regulate at all times is your pH level if you become too acidic or too alkaline all the enzymes in your body for the most part stop working you'll die very quickly it's a huge problem and so making sure you're not either alkalic or acidotic getting too far outside those ranges is the single top priority of your body at all times and you've got to keep your brain alive number one and you've got to make sure your pH is on point and so when you get to a situation where you are are slightly acidic and it's not that much by the way the pH regulation and body is very tightly controlled uh especially relative to things even like lactate concentrations which can go up orders of magnitude you don't change pH very much under any circumstances so if you were to alter your pH um say at a baseline of somewhere in the neighbor we'll just make it like 7.1 7.4 pH and you were to go down to like five you're dead right so you're going to keep it way way way tighter than that right getting you would trust me if you got if your pH was below six or below seven into the sixes you would be feeling that um very very very much so metabolic acidosis that particular case again as when the pH or the concentration of acid gets too high and so just take for example one of the fastest ways that you could deal with that is to get an IV of lactate this is a very common thing in cases of dehydrations when folks are really really dehydrated we will use what's called a ringer solution so this is typically combination of fluids of course and then a bunch of salts right so you're talking sodium chloride sodium lactate potassium chloride a whole bunch of electrolytes to balance osmotic pressure to keep fluids in the system but really you're getting a ton of lactate because it can go to the liver immediately be converted in what's called bicarbonate and bicarbonate could then kind of eat up all the free pH all the free hydrogens rather that are floating around and now careful terminology and increase your pH meaning reduce acid level right higher pH means more alkaline so don't want to confuse you there but the point is you give somebody a bunch of lactate in that form you're going to make a bunch of bicarbonate and you're going to reduce uh you're going to alter what's happening at the kidney with urine secretion and you're going to make yourself more alkaline back to normal so this is a very any any of you in the medical field that are listening are like yeah yeah this is like very basic medical physiology 101 lactate will help with metabolic acidosis but if I really had to boil it down I would say the three primary roles of lactate in your body is number one it is the primary energy source of mitochondrial respiration two it is the primary precursor of gluconeogenesis and then three it is a signaling molecule or hormone in order to understand this we've got to talk about metabolism and learn how you actually produce cellular energy now in humans you've got two primary places you can go fats and carbohydrates and there are some pros and cons to each and in fact really the way to think about this is not such as like a one's better than the other one that's completely misunderstanding the point they are meant to be complimentary they want to give you options this is what metabolic flexibility means the ability to use fat or carbohydrates in the best possible situation this allows you to be most efficient as well as most productive create tons of energy when you need it and not waste any when you don't but the way in which we create energy from fats and carbohydrates is quite different and so from the highest onset fat has to use aerobic metabolism keep that in mind there are no ways in human physiology to anerobic metabolize fat carbohydrates though are particularly powerful because it can do both anerobic and aerobic metab metabolism what's that mean fun and this is not totally true but fundamentally I want you to think about when you hear the word aerobic associate that with mitocondria in other words saying we have to use oxygen and we have to have the mitochondria in play to go through aerobic metabolism I don't have to have that for anerobic oxygen can be around to do anerobic but it's not required either and so when you are imagin yourself as a little muscle cell and you need to create some energy and you're deciding what do I use fat or carbohydrate think about it this way way the benefit of fat as a fuel source is it's basically Unlimited in fact most people even fairly lean people have enough fat on their body to power 30 plus days of continuous exercise I don't mean working out every day I mean start running right now and don't stop for 30 straight days you probably still will have enough fat Supply on your body to stay alive it's effectively unlimited and unending why don't you just use all fat for fuel then well the problem is it's way too slow when you use fat as a fuel source for exercise it comes effectively from the entire body equally and so if your hamstring is Contracting so that you can run you're pulling fat from your forearm from your hamstring from your back from your fingers and anywhere else it's coming from the entire system which means it has to be broken down mobilized taken into muscle tissue muscle tissue then has to bring it into the mitochondria and then we can start producing energy the other part about it is molecule per molecule fat is less efficient as a fuel source than carbohydrate and so it's an unending Supply but it's slow and less efficient which means it's fantastic for times of low energy need it's great when I'm doing what I'm doing right now talking sitting walking low levels of exercise it can be used because I have plenty of time but anytime I need fuel faster or energy faster I need to switch to carbohydrate now remember carbohydrates start anerobic and finish a aerobically which means I can get going right now and I can get going and I can be used during really high intensity exercise when I don't have enough time to bring in and utilize oxygen and so again not fat is not better or worse than carbohydrate carbohydrate is much faster you get carbohydrate from a couple of places most specifically and initially it's coming from stored carbohydrates in the actual exercising muscle itself we call this muscle glycogen if you need it from somewhere else it's going to come from your blood we call this blood glucose if you need extra Supply from that you can get it from the liver which stores muscle glycogen it breaks the glycogen down puts it in the form of glucose puts that in your blood and then you can steal it that way and so in fact one of the classic things that happens when you initially start exercising is despite the fact that you are pulling in glucose into your muscle cells blood glucose levels rise and that's because of an anticipatory response the liver starts kicking a bunch into the blood because it knows you're going to take it and you don't want blood glucose levels to drop because then you're going to pass out because you don't have glucose for your brain in fact this is why if you see somebody like the end of an endurance race pass out one of the first things that the EMT staff and stuff will do is they'll come over and give them really fast absorbing sugars candies juices stuff like that to get blood sugar to come up really fast because I know blood sugar is very very low anyways back to the point so carbohydrates are fantastic because they are right there and so at this point we need to think about what is the actual chemistry of carbohydrates and how does that relate to lactate and actually really more importantly why is that than helpful to the brain to the heart to the liver to wound healing and all the other stuff we talked about earlier and then of course why is this actually helping me perform one of the things you're going to hear me talk about a little bit later is there's a strong association between better athletic performance when you can produce more lactate and that's because of what I said at the very beginning here remember it is a potent fuel it is a strong signal send the ability to go to your liver to make more glucose and it is a hormone it is a signal um it has many functions there and in fact more recent papers describe it as that lacto hormone which is a fun way of saying it can communicate with other cells in order to be called a hormone what this actually functionally means is one cell has the ability to communicate to another one and so what we'll say for lactate is it has both autocrine paracrine and endocrine um characteristics so autocrine meaning it can signal its own cell to do things paracrine meaning it can go to neighboring cells so you're talking other muscle fibers within the same exercising muscle or it can actually have an endocrine function which means it can get in the blood and go to any other tissue you're going to see this later because it's going to get in the blood and it's going to go to other muscle it's going to go to the liver it's going to go to the kidneys it's going to go to the brain it's going to go to the heart and a bunch of other plac it's going to go to the digestive tract and it's going to provide them with important signals um as well as be used as a direct fuel source okay so now going back uh to where we're at with overall metabolism when we said it has those three powerful UH responsibilities I quickly talked about it that third one right that's what I mean when I say it's a signaling molecule or mechanism or hormone the one above that when I said it is the primary precursor for gluconeogenesis lactate can go into the blood get sent then back back to your liver and even kidney and go through What's called the Corey cycle in this we can actually take lactate combine it together and make glucose so the way that I call this is it is a precursor to glucon neogenesis gluco meaning glucose Neo meaning new genesis meaning create so how you can create new glucose molecules out of non-glucose and so again all we really have to do and I'll explain this in a second is take two lactate molecules smoos them together and I've made myself glucose and so that's an important rule um as it's in in the precursor of gluconeogenesis the third one was it's being the primary fuel source for mitochondrial respiration now again I apologize I know I'm throwing lots of different terms around if you are in chemistry instead of saying monoch condal respiration you probably say aerobic metabolism they're not exactly interchangeable as I've discussed earlier fermentation is not the same as anerobic glycolysis again functional distinction there when you're talking about bacteria or food types of things we're going to call it fermentation when you're talking about in exercising muscle itself it's now anerobic glycolosis coming from mitochondria and so again trying to not throw you off in terminology but as you're reading or hearing other things that's really what we're talking about and so the ability um of lactate to be a primary fuel for mitochondri respiration is exactly how we started the show one of the primary things that lactate does is stimulate mitochondrial biogenesis it tells your body to make more and make bigger mitochondria and in fact it works together in this entire meshing network when we generally talk about mitochondria people kind of think about it as these independent units but more recent research is suggesting that is really truly a network effect you're probably familiar with mitochondria but is incredibly important for exercise performance and a number of overall Health and Longevity metrics and so people go out of their weight to try to stimulate and increase and uh have various protocols that they do to to enhance mitochondria and lactate is probably the best one and so that right there is explaining why you should be paying attention to it if you care about mitochondria it's the top place to go to increase it or improve its quality so to get get back to the biochemistry what's happening here remember fat as a fuel is coming from the entire body carbohydrate it's coming from the cell that is exercising itself fat has to go through aerobic metabolism which means it has to go into mitochondria but carbohydrates are going to start anerobic and finish aerobically or finish in the mitochondria so as a very quick reminder your muscle cells have two functionally different areas they've got What's called the cytoplasm or cytool which is kind of like this jelly filled thing that's all around the inside of your cells all your organel are inside of that and then in this particular case you've got mitochondria anerobic metabolism whether we're talking about creatine or in this case carbohydrate happens in that cytool if you want to then use aerobic metabolism We've Got to Now shift into the mitochondria and this is another reason why aerobic energy from either carbohydrates or fat just takes a little bit longer because we have to have that even even when we're in the muscle cell there's that additional step needed to get it into mitochondria to then really go through the metabolic processes there all right now last little back backgound before we really get into this story remember fat and carbohydrates are just functionally large chains of carbon so a fat is the case of a triglyceride is a glyceride which is a carbohydrate it is a glyceride three carbon molecule each one of those carbons has a long chain of carbons attached to it that we call a fatty acid so a tri glyceride is Three fatty acids attached to a glycerol backbone think of it this way it is a three carbon carbohydrate with three long chains of fatty acids and all those long chains of fatty acids are carbons depending on how many carbons are there we call it a different fatty acid steric acid or lenic acid or other things like that if they're perfectly bonded we call it saturated if it's has one missing Bond or two missing bonds we call it unsaturated polyunsaturated Etc but we're talking big long chains of carbon so when one molecule of fat comes in to a cell for energy we have a lot of Po IAL carbons however carbohydrates in the case of exercise remember it's coming from glucose that is a six carbon chain so it is much smaller so benefit of fat on ending and way more carbon per molecule carbohydrate way faster can go anerobic in the muscle but only six total carbons why this functionally matters here is all of metabolism summed up in about 5 Seconds you break off carbon you run it through a whole bunch of steps and processes to get rid of that that releases energy you use that energy to make a molecule called ATP you then get rid of carbon put it in your blood put it in your lungs and breathe it out so you breathe in oxygen you break up fat or carbohydrates by breaking those carbon chains you give off energy use that energy to make ATP the waste product is carbon you attach that to the oxygen to make carbon dioxide you breathe that out so the net result of all metabolism is three things and three things only ATP water and carbon dioxide now if you were in my laboratory I could put a little mask on you connect you to what's called a metabolic chamber and I could actually identify how much fat you're using for fuel or carbohydrates you're using for fuel a little bit of math that goes on there we can figure that out because of the different efficiencies between car hydrate and fat like I said earlier but the point is by simply measuring carbon dioxide I can measure and identify what you're burning for your fuel and one of the things that tells us when you start increasing lactate and you pass into these different areas of aerobic or anerobic metabolism is when the rate of carbon dioxide that you're making or exhaling starts to now be different than your rate of breathing and I can now tell okay wait a minute those things should be in lock step step but when they're not the rate of increase of carbon dioxide is different than the rate of ventilation I know you've switched ways you're getting energy that's the quick version of what's happening there right now while you are doing low levels of exercise or even all the way down to sleep it is advantageous for you to use fat as a fuel source again Unlimited Supply I don't have to run it out I have a limited supply of carbohydrates I can only store so much in muscle very very small amount typically like a couple of teaspoons total of glucose in my blood and then very small amounts in my liver remember the liver is like the football size thing relative to how much fat you could potentially have on your body that's unlimited and so carbohydrates are always meant to sort of be there for sustained living and high powerered exercise and fat is your backup tank it's your reserve right now when I start going through exercise the ideal situation would be to spare my glycogen spare my glucose spare my car carbohydrates okay all same thing here so now ideally you would use all fat for fuel that keep you nice and lean of course and we wouldn't be wasting our preserves and our concentrations of carbohydrate but because it's slow what effectively happens is at rest we have a value that's called rer or RQ so this is stands for Respiratory exchange ratio or respiratory quot typically 78 something like that in a a lot of people maybe a little bit lower if you're fit and that suggests that you're burning mostly carbohydrates but a decent percentage of fat as you increased exercise intensity that number will climb in fact a score of 1.0 literally means that you're burning 100% carbohydrate because I can't break down and utilize fat as a fuel source anerobic as soon as I cross that aerobic into anerobic space of exercise I now cross out of my ability to use fat as a fuel another way to say that once exercise intensity gets too high I can't use fat as a fuel and so from there I'm lowering the percentage of energy that's coming from fat and increasing the percentage of energy that's coming from carbohydrates such that when I get to truly high-intensity exercise that number becomes 100 and zero all my energy from carbs none of it from fat the opposite never exists you can never be in a situation where you're burning 100% fat in fact the highest you're going to probably get maybe 60% fat maybe 70% not much higher than that though maybe you could argue me 75 but that'd be sort of your Peak and so we are uniquely positioned as humans and all mammals really to burn carbohydrates that is the primary fuel source by a landslide basic physiology will tell us that doesn't mean we only want to use it in fact the idea of metabolic flexibility is I have strong capacity to go back and forth between utilizing fat and utilizing carbohydrates now a lot of folks u in the last couple of years have significantly misinterpreted and misdescribed what metabolic flexibility is perhaps we'll do an entire show on that maybe we should how to test it identify it improve it etc etc but metabolic flexibility does not stand for your ability to maximize fat burning that is not at all what it is it is exactly what I just said the ability to use both effectively if you hedge towards only fat burning or hedge towards only carbohydrate burning those are not metabolically flexible you want to do both more on that later perhaps if you all are interested so as I get to this high intensity of exercise in fact this is one of the ways um one of our metrics we use to identify whether or not you're at a V2 Max is do you cross a threshold of 1.1 on your re is the typical standard there which mathematicians are saying well wait a minute I thought 1.0 is 100 and it is and so anything above that actually represents you hyperventilating which again tells us kind of where you're at so I've actually seen um I'm myself pretty typically can get to like 1.35 1.4 I've seen plenty of athletes get up there um which means you are producing a significant amount of carbon dioxide as a waste product and you are in significant discomfort as well and so that's really what's happening right we're burning a lot of carbohydrates at high intensity um and the lower the intensity goes the lower um the more fat we're burning as a fuel why is that well this is exactly based on story geometry and chemistry of how we can get to energy so when we make when we use fat as a fuel source let's say we broke it down from our back of our arm or our face or whatever and we want to use it to power energy in our hamstring the fat has to get put into blood it's got to get transported on a protein it's got to get into our exercising muscle it's got to go through Transporters there it's got to then get transported into mitochondria that is limited by the amount of carnitine that's there some of you may have explored and use carnitine as a supplement that's exactly why that's the rate limiting step okay now the more mitochondria I have the more then I can bring in and the more carnitine I have on the mo on the mitochondria themselves the more I can bring in but I have to bring that in the problem is you have these giant long chains six 18 carbons they're too big they can't get into the mitochondria so what you do is you cut off two at a time and I know exercise physiologists I know biochemists I'm skipping a tremendous number of steps here but nonetheless you're going to cut off two carbons at a time this matters this matters to lactate hang one second and I'll tell you why when you cut off those two carbons at a time that is called beta oxidation you've used oxygen to do that and it's beta because you cut off one two of the carbons those two carbons can then get transported into the mitochondria those two carbons together like that are called acetal COA very important acetal COA that goes into the mitochondria can run through a thing called KB cycle by doing that you use these high intermediate exchanges with things like NAD which will come back to an fad you use that to shuttle protons hydrogen pluses and electrons around you send them to a thing called the electron transport chain all that is used to then create a bunch of ATP as a byproduct of that you burn off one two carbons and so you had a two carbon molecule go into the KB cycle it comes out as carbon dioxide ATP and water remember earlier final product of allall metabolism is those three molecules so now we have taken a carbo a fat rather taken it into our mitochondria and run all the carbons out I just continue to cut off two at a time two at a time two at a time until that entire fatty acid chain is metabolized highly effective process but slow limited by my ability to bring in oxygen get that oxygen into blood get that oxygen from the blood into my exercising tissue get that into mitochondria now in other episode we talked about V2 Max I believe that's in the cardiac or the heart episode I went through all of those things avo2 difference and limiting factors the central factors to Performance so you can see that episode for more there but that's effectively the problem right we thought for many years lactate was produced because of an insufficiency of oxygen in that mitochondria in other words it's limited by that we now know that's totally wrong in fact the evidence is not only clear it is uh Beyond reproach fuel through your muscle is never Limited by oxygen that's never going to be the limiting step for lactate specifically so lactate is created not because we're out of oxygen but for some other reasons so that's the quick story of fat metabolism understanding that let's transfer back over to figure out how these carbohydrates are broken down doesn't really matter for this story if we're starting with muscle glycogen if we're getting the glucose from the blood or if we're getting glucose that was glycogen in the liver put into blood and now broken in either way let's just stay with the place of glycogen in the muscle it's right there you start going for exercise I don't have to worry about mobilizing the fat and bringing in it I don't have to wait for oxygen to come in I can get bringing in energy right now and so in this particular case carbohydrate the chemical formula is C6 h126 what's that mean why does that matter that is six carbons attached to six H2O molecules folks that's what carbohydrate means it is a carbon that has been hydrated it is one carbon and one water in the case of glucose there are six of them now if you go to fructose or some other forms of sugar or carbohydrate they have different amounts of carbon but in this particular case you have six carbons attached to six Waters that is a carbohydrate so when that is inside the muscle cell the cytoplasm if you will sitting there and we've decided to not use phosphor as a fuel source which is the primary and fastest one and we want to use carbohydrates this initial step is what we call anerobic glycolysis again if you take that and put that into a bacteria you'd call that fermentation in your muscle we call it anerobic glycolysis lysis means to split or to break and gly meaning the glycogen or glucose so we're splitting and breaking this thing apart we're doing it without the use of oxygen and so it is anerobic and so if you can visualize this any of you watching this you've got six carbons that are all chained together now instead of breaking two off like we did in the case of beta oxidation and fat we split the entire molecule in half so we have two separate three carbon molecules we call that pyruvate so we have not lost any carbon in this exchange but we have broken a chemical bond this is given off some energy this itself gives us two ATP give you a little bit of an example if we go back to earlier when we take acetyl COA and take it through the C R cycle and you get 25 or 28 ATP in this particular process we make two so energy amount that we create from this process of anerobic glym is very low but it's not bad either okay we have actually made it with a little bit less oxygen and we made it really fast because we didn't have to wait here's the downside this process as many of the processes as we'll see later is limited by this molecule called NAD your ability to go through all the Met olism is determined by your ability to regulate PH meaning enzymes don't work in highly acidic or highly alkaline environments you won't let things go through if you can't balance positive and negative charges so what you do with naad is you shuttle hydrogens back and forth through molecules doesn't depending on what's Happening it could be going different ways but you're going to go from a molecule called NAD to a thing called nadh hydrogen and an H+ if you want to go the other direction you ship it back and so you were limited a large part by how much NAD you have because as soon as you run out of NAD you can't run these processes because you won't be able to handle all the hydrogens that are built up critical step in fact um in a second here this may me think of something else I'll explain to you why that helps you with hangovers really soon okay so that that's our our process so by doing that we split these this like or this glucose into two separate molecules called pyruvate and by doing that we've shuttled a couple of NAD nadh's across each other and made a couple of ATP and that's all well and dandy the perate itself is fine back to Anor robic threshold back to how I was taught in exercise physiology what we initially thought was this is the end of anerobic glycolysis we're done at pyruvate if we had oxygen we would then take the pyruvate break off one carbon each so the three carbon molecule pyate you cut off one carbon you make it a two carbon molecule and that's acetal COA that's gone into the mitochondria and it runs the exact same KB cycle or tricylic acid cycle as I described earlier with fat identical literally the same thing it is the exact same precursor it's the exact same substrate exact same process exact same amount of ATP created identical okay like I said carbohydrates start anerobic and always finish aerobically identical to Fat at this point if we run out of oxygen or don't have enough oxygen that pyate is then converted into lactate okay that was the original and that's how I was taught we now know that the end product of that pyate is always lactate and we know this from a lot of different areas of research um the the concentration you typically have something like 10 to 50 to one amount of lactate that you do py so it's almost never there which tells you lactate is very quickly being created out of pyruvate as soon as pyu is being created um that number can go up in order of a magnitude during exercise and so it doesn't make any sense to think that that you're stopping at pyu furthermore there has been an excellent research identifying Transporters specific to both pyruvate and lactate that get you into the mitochondria and so some pyruvate can be moved in mitochondria and a lot of lactate can as well we also know that those m CT uh is the the abbreviation for those Transporters or in a number of different cells throughout your body uh and so we can move it throughout and that's one of the reasons why we have this lactate shuttle um ability so here's what we think at this understanding right now and of course as research comes on board we learn more things we might change our opinion but according to the research right now the prevailing thought is the end product of anerobic metabolism is always lactate the majority of that is going to go into the mitochondria in the working cell some portion of it is going to leave muscle in fact what happens here is once your ability to process that lactate is exceeded by your lactate production in other words you're making more lactate than you can handle in that cell you begin to transport the lactate out of the cell we call that lactate efux you put it into the bloodstream and you ship it to a number of different areas the first place you ship it to are neighor neighboring muscle fibers that are not working or have a greater ability to process lactate now think about it this way anerobic metabolism is more common in your fast twitch fibers aerobic metabolism is more common in slow twitch fibers the amount of an enzyme called lactate dehydrogenase which is the enzyme that switches you back and forth between lactate and pyruvate is about 50% higher in slow twitch fibers and so we're creating it in fast twitch fibers and likely shipping it into slow twitch fibers so those slow twitch fibers got a pre-digested half broken down sugar molecule it's an insanely effective fuel source it didn't have to do anything didn't have to increase its acid concentration didn't have to run through any of its NAD and I got a pre-digested if you will fuel source at the same time the the fastro fiber benefits from being able to run through metabolism faster and not having to deal with the waste products so it's a win-win win win win if those muscles don't want it it can go again as I said earlier in the blood and can go to the kidney or liver for the gluconeogenesis it can go to the heart which absolutely loves lactate as a fuel source in fact the heart is the biggest consumer of lactate of any organ in the body it's actually the preferred fuel source over glucose especially during a schic or anytime oxygen concentrations get low in the heart it loves it it can go to the brain and the astrocytes actually which are like these star like neurons that are all or cells that are all across the central nervous system they prefer lactate as a fuel over glucose or anything else in fact this is also why um you see things like ketones and other noncarbohydrate fuel sources because we know we need that as fuel for asites and lactate is basically again pre-digested carbohydrate so it is adored across the entire physiological system as a lovely fuel source so not only is it grabbing on and holding on and making you less acidic is a phen phal signaling mechanism as well as a direct fuel source for almost every tissue in your body 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 that means ag1 provides a variety of vitamins minerals probiotics prebiotics and adaptogens in an easy to drink greens powder initially I was very skeptical of ag1 as I am with all supplement companies frankly but after months of discussions with their lead nutrition scientists and the team at ag1 I've been impressed by their commitment to sourcing the highest quality ingredients and rigorous testing to ensure that every single batch is free of banned substances allergens heavy metals microbes pesticides herbicides residual solvents and microt toxins it's even earned the prestigious NSF certified for sport third-party testing approval now ag1 is not a replacement for eating Whole Foods but it is a great way to fill in the gaps and it's been a big help pushing some of my clients just in the right direction for eating more high quality foods because it helps them with Cravings digestion and many other benefits now not everyone needs to consume greens powders but if you're going to do so you better make sure it actually includes the ingredients that it claims to and that those ingredients are of the best sourcing 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 today's episode is also brought to you by Renaissance periodization if you want to put on muscle through science-backed training programs look no further than Renaissance periodization 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this point we've covered how lactate is created and what it's doing and the different roles it's having in our body I want to move on to some other things but before I do that I got to go back to the promise I made earlier which is talking about alcohol now if you pay attention to beer or wine or spirits of any kind you probably are recognizing fermentation and so if I were to take barley or Hops and introduce some yeast or bacteria to them and ferment them if I did that long enough I would create ethanol well that's basically what I just described to you in your muscle anyways it's a very similar process in fact there's a high exchange here remember earlier when I was talking about the gut microbiome being able to create all kinds of awesome stuff with lactate um PR met fiber and stuff like that your body actually is thought to produce around 3 gram or so a day of your own ethanol through that exact same process it takes the carbohydrates does the same thing that that your favorite producers do when they make your beer or your bourbon or whatever the case is and your gut just does the exact same thing however you're able to clear it really fast so don't worry no one can smell the ethanol in your breast because your gut microbiome um babies do the same thing by the way it's happening in fetuses and all that stuff so it's it's a normal part of all physiology and so there is this very strong tie between these things now what you can actually do is is kind of go in reverse and so ethanol typically is associated with even things like methane um this is associated with fermentation and foul smelling gases in fact if that process is happening too much in your stomach then you can have some pretty significant GI distress and this is one of the reasons why carbohydrates are the primary cause of uh flatulence and overall gas but nonetheless what's really happening is you you've got your ethanol alcohol you've created it yourself or you've brought it in that's ethanol um etto if you're in my lab you'll see all the bottles with e on them that stands for ethanol we use that to clean surfaces and a bunch of different things in our action but if you were to have this in the form of an alcoholic drink or whatever um your body would bring this in and it runs almost identical to the pyu metabolism that I just talked about so you can take ethanol and the very first thing you're going to do is is convert that into a thing called acetal now that is highly toxic and primarily responsible for hangovers and so one of the things that's happening is when you bring in that ethanol again you're immediately digesting it as quickly as you can in your liver when you do that because it has to go through the liver for the most part because this is metabolism now you can think about that this as basic carbohydrate metabolism now when you increase carbohydrate metabolism you tend to decrease fat metabolism and the opposite right so these are kind of working back and forth so unlike earlier when we talked about the lactate shuttle and I said hey you should stop thinking about lactate um as this this negative byproduct you also need to really stop thinking about aerobic and anerobic Metabolism as a tug-of-war it's not good or bad it is more like a chain on a bicycle so that's that the chain is the lactate and turning of one gear turns the other one this is a fundamental rethinking of how we understand metabolism and energy production anerobic and aerobic metabolism are not at each other's throats they are productive and lactate is the signaling mechanism from one to the other one it is the precursor for mitochondrial biogenesis it is a precursor for gluconeogenesis it is the signaling mechanism it is this this as George Brooks called it in one of his more recent papers it is the Phoenix Rising again it is a restored understanding that this is a collective Cooperative relationship between aerobic and anerobic it is not a tug-of-war that is the absolutely wrong way to think about it so when we're in the liver here and we're handling this carbohydrate metabolism because the need to go through carbohydrate and anerobic glycolysis is so high it shuts down fat utilization why this is problematic is this is why high amounts of alcohol consumption is associated with fatty acid development in the liver this exactly what happens you're supposed to be metabolizing the fat there but you can't because you're too busy processing the alcohol and so that fat then becomes stored you shifted the burden it's also why um alcohol intake is associated with overall fat storage because again you're downregulating fat storage everywhere because you're upregulating the need to do the ethanol in your liver that fat then gets stored everywhere else now as long as your calories are equated it's a little bit different but alcohol typically comes in chloric excess and so then you got extra calories that need to be burned but you can't burn fat so they get stored so that ethanol then like I said is is supposed to be converted into um acetal alide acetal alahh is very easy to then convert into acetate which is then converted directly into acetyl COA so you're right back to where you started the ability to cruise back and forth between pyruvate acetal alahh and all the way up to ethanol is fairly quick to be totally honest with you and so you can Cruise back and forth between those things and so whether um you're a bacteria or in your own um system you're whether you're creating yourself you can create some um some acetate yourself you can go backwards up and down that chain but really you're you're talking one step away and so ethanol again acetal aldhy tons of that going through metabolism that concentration gets really high you get super hung over so what do you do about it well this is one of the reasons why getting a big sweat in the next day or going for a run or working out tends to help some of the symptoms not all of them there are many symptoms associated with The Hangover but one of the things that you're doing is you're increasing the demand for acetal koay doesn't matter if you're going aerobic or anerobic because remember acetyl KOA comes from the breakdown of fat or carbohydrates anerobic or aerobically it's going to get there and so you've increased your demand for acetyl COA so instead of leaving things in the form of acetyl alahh which again is really problematic you force it to converted into aceto Quay because you've increased the demand for that and so you can kind of think of it as like the old College you know I man I got to go burn out all the alcohol uh to get out of my system that's not exactly what's happening but it's also not super far off either you're really just using it as a fuel source now alcohol as a fuel source for exercise performance is not a good thing this is a very very slow and rate limited process in fact this is being limited heavily by NAD concentrations you're going to run out of them and so that process gets backed up very very very quickly um you can do a handful of things to potentially uh try to escalate that or keep that going faster but the reality of it is your liver is only so big it can certainly take a beating um it is one of the most regenerative tissues in all the body but that said you're going to only metabolize um alcohol so in fact some of you have probably heard of some people metabolize alcohol much faster than others and that's specifically because the acetyl alide dehydrogenase molecule the more that you have the faster you metabolize alcohol the slower the lower this is this is the red face flush and all those other things associated with low alcohol metabolism so alcohol metabolism fermentation anerobic exercise carbohydrate starches all this stuff very very similar fermented foods all this stuff can really come back to in some part lactate okay so to get us back on track here up to this point we've talked about what lactate really is and its role in physiology and then more specifically exercise physiology but if you're a curious mind you may be thinking to yourself a handful of things wait a minute so I'm confused at this point is more lactate good or bad you keep saying it's good Andy but I haven't quite made that connection and if so how is it really good what is it doing maybe go a step further if it's good is more better and what is mean more in the cell more getting out of the cell more in blood what really is going on here and so can you really just can you Andy can you bring it all together for me and help me truly understand the role of lactate what it's doing for my body and why it's positively affecting all these other organs outside of exercising muscle let's start off by just answering the question of well is more lactate better that's a little bit tricky to answer so remember lactate is created in exercising muscle and then at some point when that rate of production exceeds how much the mondri can handle it starts getting pushed into blood now in order for me to know how much lactate is actually going on in your muscle I'd have to go in and take a biopsy so that's really tricky the easier way to understand that is to measure it in Blood and so we can look at things like onset of blood lactate concentrations how much lactates in your plasma or whole blood overall and different things like that and kind of depending on which metric you look at you're going to get different values different terminology and so again admittedly that stuff can to be a little bit tricky I want to try to simplify it as much as I can for you right now give you just the overview of what I think the field is saying rather than all those individual details because it will get unnecessarily tricky at this point well there's research suggesting that higher level athletes those that have greater performance in endurance based events actually are able to handle more lactate at the same time there are plenty of anecdotes for folks like Michael Phelps who supposedly sustained extremely low concentrations of lactate I guess this really highlights a couple things one we don't really fully understand exercise biochemistry yet there's clearly some gaps in our understanding of what's really happening the second thing is that we probably have multiple Avenues to physical success you can imagine some individuals doing well because they can handle a lot more lactate others maybe doing particularly because they don't produce that much and so they don't have to deal with that I think it's pretty clear both of those Avenues are potential for success again particularly in endurance events at the same time look at the research on lactate supplementation now we know very effectively that sodium bicarbonate and other forms of supplementation that reduce acid buildup in tissue are quite effective this comes in a number of varieties so you can take a look at things like beta alanine supplementation this increases carnosine concentrations in muscle tissue and effectively acts as an acid buffer so it keeps it lower and so your muscular endurance and um whether shortterm or even moderate term exercise events tends to increase and it's not perfect but there's a lot of research behind that similarly you have things like sodium bicarbonate this is a different mechanism but same idea and you're bringing it in bicarbonate as I talked about earlier it's able to then absorb some of the free floating hydrogen protons which Rings your muscle ph up right less acidic more alkaline so then when you start producing excess hydrogen ions from exercise you're at a higher set point and so then again the pH or acidinduced fatigue is slow down again a lot of research on that the problem with sodium bicarbonate is sometimes can create GI distress and some other issues and so a way around that is a handful of different lotions or creams momentus for for example makes a thing called PR lotion which is a sodium bicarbonate thing that you can apply directly on muscle uh to again have the same effects of that lots of different ways around it momentus is one product but there's plenty of other ones on the market as well and so we know that works but what about then if you just take lactate we know lactate is another potential buffering mechanism we know what it can do it can hold on to those hydrogen protons for us help with NAD recirculation etc etc so will this allow me to continue to go through glycolysis since I continue to feed back NAD to that system which we know requires it to proceed well it's one of those disappointing aspects of science it should work makes all the sense in the world but it doesn't look like it does the evidence that's available today suggests minimal or no effect really of lactate supplements on exercise performance so if that's what you're looking for I would encourage you going through either the sodium bicarbonate either the powder supplementation pill or the lotion or something like a beta alanine um to buffer and improve performance at the same time there is much more room for Hope in application of lactate supplements for other outcomes in fact I know of multiple trials led by the legendary George Brooks who I've mentioned multiple times georgean as I mentioned is still active in this field actually he took on one of my master students Jose aralo a number of years ago who should be finishing his PhD up there but they've done a numerous trials looking at applications of lactate immediately after traumatic brain injuries concussions and other treatments so there's a lot of things to be excited about about lactate but from an exercise performance perspective where we focus most of our time in this show doesn't really seem to be super effective that said there's not a tremendous amount of research probably more is needed or warranted so if more comes on board and we get a different answer I'll be sure to update you when that time comes I'd like to take a quick break and thank our sponsors today's episode is brought to you by continuum Continuum is a membership only wellness club designed to help high performers reach their Fitness and performance goals Continuum just opened its Flagship Club in Manhattan quickly making it one of the most sought-after memberships in the city its location in Greenwich Village is incredible in fact it's stunning it's a 25,000 ft space with state-of-the-art equipment a beautiful design and everything you could possibly want in this unique mix of a gym Wellness Center and Social Club Continuum members start with a thorough Olympic grade assessment that results in a biometrically driven AI assisted wellness program that updates in real time and incorporates everything from personal training and physical therapy to Hyperbaric and IV therapies by bringing together true Fitness Experts best-in-class technology and proven Wellness services and amenities Continuum delivers the most comprehensive solution to Performance I've been involved with Continuum working as their head of performance science since their founding and I've been incredibly impressed by what the team there has built if you're interested in joining Continuum their team has agreed to give a select number of you the listeners here a fully waved onboarding which includes V2 max testing dexa scans blood panels sleep analysis and more all at their Fabulous New York City Flagship location to learn more visit continuum. club/ perform again that's Continuum with two 's. club/ perform I realize at this point now I've talked about Lac date and conven you that it's not a cause of muscle fatigue but I haven't explained to you what is so I didn't really plan to get on this in this episode and and in fact we may do an entire show on just fatigue management sometime down the road perhaps in season two or three we'll see and so but I I got to give you a teaser here and really to reiterate it's not lactate that causes a fatigue but pH can be a legitimate issue in our cardiac episodes and some of the other ones that we've done in this season on endurance I have talked about when you exercise fatigue is a global event there are what do we call Central reasons for fatigue so this is the central nervous system this is the heart and cardiovascular system and ability to move oxygen throughout the body etc etc and they're all peripheral issues more specific to muscle uptake and oxygen as I said the very beginning it is clear at this point lack of oxygen in muscle is not the cause of lactate production that part is extraordinarily clear I think it's also fair at this point while people are debating still whether or not fatigue is Central or perectly driven I think it's hard in my opinion to make a reasonable argument that it's not a combination of both there are excellent review papers on this that cover dozens of different explanations I would love to be able to explain to you in one or two words what the real culprit is that's just not the case easy examples if you change an alter pH with exercise I'm almost almost exclusively talking about more acidic could be more alkaline it would have really the same effect but really it's acidic you've made that pyate you've then tried to convert that into lactate or you have successfully converted into lactate either way you still have hydrogen floating around when you take ATP and you split it into ADP that requires that goes through a process called hydrolysis this still results in hydrogen production and so no matter how you slice it if you're Contracting muscle you're going to generate hydrogen that's going to make the environment more acidic enzymes all of the enzymes involved in Aerobic anerobic phosphocreatine muscle contraction all of those are going to have a problem in excessive acidic environments same thing with temperature changes we see alterations in things like calcium signaling so calcium is one of the important minerals required for muscle contraction that gets altered uh during muscle fatigue the little environment or organel inside your muscle called sarcoplasmic reticulum what holds and stores your calcium and releases it becomes problematic there are issues with magnesium magnesium then starts taking the place where calcium should be there and inhibiting it um so we see single muscle fiber contractile problems we see oxygen transportation problems we see other issues associated with um ATP pumps and sodium potassium pumps being disregulated and changed and altered so really the most fair and honest way way to explain to you why you're getting fatigued well I know it's not because of lactate buildup that's true and it's definitely not because of lactic acid and for that matter lactic acid is not even close to being responsible for your muscles being sore the next day that has nothing to do with the equation it's definitely not involved however you can still globally say acid buildup that's a reasonable thing to say it is more complicated than that but it is also true at the same time it's just probably most appropriate decision while there is an increased in acid buildup during muscular fatigue it's not lactate lactate is actually probably saving you from acid buildup if that wasn't there you'd have even more acidity but still you see how those two things are going to be highly Associated let's go back to the very beginning hunted Stags imagine you're running through a forest being hunted or not doesn't matter but you're exercising sprinting through there you're creating more metabolic waste more pH more acid rather you're feeling more fatigued at the same time you're having a higher lack to e-lux even if that is a positive thing for you those two things increasing fatigue and increasing lactate are going to be Associated and that's why for almost 200 years of lactate research we have Associated fatigue with lactate buildup so they do go hand inand but that is a classic example of correlation not causation now that we have a better understanding of what lactate really is it's time for us to discuss our three eyes such as how do I investigate in other words how do I measure my lactate or my lactate threshold number two how do I interpret it how much lactate should I have at rest and what should my lactate threshold be and what's the highest lactates we've ever seen and then three finally how do I intervene in other words how do I improve my lacti concentrations again at rest as well as during exercise and then how will that actually relate to my improvements in sport performance let's get started with the very beginning and that is investigate so a couple ways to think about this I slid in a term there I realize I've said it a few times but maybe not fully described and that is lactate threshold okay you can measure lactate concentrations in your blood that's the normal way to do it a biopsy is probably not really sick for many of you and honestly not necessary but I do want to acknowledge a couple of things there are a lot of lowcost lactate analyzers available on the market when I was a student you basically had to be an exercise physiology lab now these are consumer available for 20 to30 or $40 there is also research on these different devices and their accuracy and they're not all the same I wish I had a gold standard one I could say go buy this one it is the best unfortunately that's not the case honestly they measure them a little bit differently the techniques used the part of your blood that's used is a little bit different and so these values can be fairly squirly I would strongly encourage you to pick one and pick one of ones from the research that is known to be reliable and then use that for all of your metrics moving forward if you switch machines out and change standardizations and procedures you're going to get slightly different results I will give you one little Insider tip here behind the scenes if you're going to use something like a small finger stick or an earlobe stick which is the most common ways to do it that first drop of blood that comes out I would wipe it away and not use it it tends to give you really funky numbers it's going to tell you the lactate that is right there on that spot rather than circulating in the tissue so we always take the first couple drops wipe them off and then use the second ones you'll get much more reliable numbers if not you will see your lactate all over the place and you'll be like what the heck is going on I don't believe anything these people say about exercise physiology because these lactate numbers are totally screw so that's going to tell you how much lactate you have the other thing you probably want to pay attention to is what's called lactate threshold there are at least 25 different methods I have found in the literature for measuring lactate threshold there is clearly no succinct completely agreed upon method many of them are good in fact all 20 five of those have been validated but they are not measuring the same thing this gets extraordinarily complicated you thought that the biochemistry got complicated earlier this is potentially worse and it's not all measuring the same thing generally the field has moved past anob threshold you may have heard of that before for the reasons I've described we don't really talk about that one however there is lactate threshold and in fact there's multiple stages of lactate threshold there's stage one and stage two there's ventilatory threshold and that is very similar but it's not the same thing there are things like critical power um your maximum velocity at lactate threshold your ability to sustain just under lactate tal and a ton of different things to pay attention to here so what are you actually measuring is the first question and then secondarily again there are dozens of different free lowcost and all the way up to clinical research grade methods to assess lactate threshold I'm not going to go through all of them for you rather I want to arm you with the tool of saying if you care about learning something like your lactate threshold that's great but really pay attention to what your needs are so what sport are you in are you a distance Runner are a rower are you a a more Anor robic sport athlete what are you using and try to pick the test that is best for you in your situation and what do you care most about ventilatory threshold anerobic threshold do you want to know your race Pace that's probably the most common reason people get a lactate threshold test done is they want to know what pace to run at uh during their races or how fast they need to run to be in zone one or two or three or four how much time they should spend at each exercise intensity and things like that and so it is extremely context dependent going through lactate threshold I will give you a couple of examples here but I did need to make sure you understood depending upon where you look you can see wildly different numbers wildly different protocols and dozens of different free or in laboratory assessment methods for lactate threshold with that entire Preamble aside even me trying to describe to you what I mean by lactate threshold it's different for each one of these definitions quick example the general idea here is we're trying to figure out how fast can you run or how hard can you row or cycle or whatever you're doing before we see a different change in our slope of lactate what do I mean imagine you're sitting there at rest and you're producing a very marginal but small amount of lactate and now we start jogging and then we slowly over the course of say 10 to 30 minutes increase our speed of jogging okay as I increase my speed I'll increase my fatigue I'll get more tired but that's not not a linear increase it becomes exponential it is linear at the bottom and then at some point we have this sharp uptick and fatigue now that is what we're trying to identify as our lactate threshold what we're saying is if I know that and let me give you some numbers here let's say you can run at 20 miles per hour that's pretty darn fast it's not the fastest ever but that's pretty fast and we'll make numbers easy all right imagine you and I both run at 20 mph and let's imagine just make it even easier we have the same V2 Max so we both have a V2 Max of 100 that would be very very very high but I'm trying to make math nice and easy for you so you and I can both run 20 M hour and our V2 Max is 100 who's going to win the race well if we look at Classic exercise physiology literature there are three main predictors of endurance performance and again I really want you to think about Marathon running just as an easy example here your V2 Max your efficiency and your lactate Thresh what I've effectively saying is if you and I both have the same V2 Max and the same maximum running speed but you are slightly more efficient than I am you will have more energy to run that race so even though we can run as fast as each other you'll be able to run at a higher percentage of your max speed before you get tired this is classic Jack Daniels not the the whiskey the the famous running coach um has a ton of work in this area in fact a lot of people call him the greatest running coach of all time I'm not a runner so I don't know but he really laid this stuff out and said all right if it's not those two things it's your lactate threshold so if both of us can run at 20 miles per hour but you can run at 16 before your lactate really starts to increase and I can run at 15 that means in the race I have to run the race at 14.9 because if I go at 15 all of a sudden I have this massive increase in lactate and you get to go at 15.9 you get to run a whole mile hour faster than me even though our maximum speed is the same and our V2 Max is the same so lactate threshold is that way of saying what's the threshold how much work can I do how how many watts can I put out on my bike before I have this again excessive increase in in lactate buildup why that matters not that lactate is causing fatigue but that is clearly an association which you have overwhelmed mitochondria that's what it's telling you mitochondria can no longer keep up with lactate builds and now an e-lux happens and this e-lux happens really really fast easy easy examples to think about go on and do some exercise at 80% of your heart rate then do it at 85% and do it at 90% you're going to feel slight increases in fatigue go from 95% to 100 that 5% increase 95 to 100% will feel way worse than if You' gone from 50 to 55% in fact you will feel very little difference is in fatigue from 50 to 60 or 65% but a 10% increase going from 90 to 100 is way more fatiguing than going from 50 to 60 hopefully that makes sense and so fatigue is not linear like that what we lactate threshold we're trying to identify where do these breaking points or what a lot of times we'll call them as deflection points happen well again this is where lactate threshold gets complicated because people Define these things differently depending on the method you use and again there's there's over 25 of them there are excellent studies over the last 30 years where you can take the exact same report from the lab hand it to different exercise physiologists and get different lactate thresholds based on calculation not only because of like subjective decisions which can happen in the visual method but also just which calculation you're using which equation you're using which method you're using so a lot of the times um and I I'll get to this in one second but just since we're right here a lot of the times people can say things like this all right the visual method the most classic method of lactate threshold identification is you do a 30 to 60 Minute test and you slightly increase fatigue over time and what you're going to see is this slope of V2 so how much oxygen you're using go up but again that slope will have a big curve and there'll be these inflection or deflection points those points are then marked as lactate Threshold at the very beginning you tendency like an early one and then there's a second one later so some people say there's lactate threshold one and threshold too others will say I don't care about the first one I only care about the second one it doesn't matter it tends to be lactate um at and we would have covered this in one second but we'll do it now I guess since we're here at rest your lactate is typically something like 1 millimar maybe down to 0.5 millimar in that neighborhood and a lot of people will then say lactate threshold happens at two molar now you may be familiar with that because that is genely what people say as the thresh threshold for being in zone two training and that's exactly why one of the major reasons people are excited about zone two training is you're actually saying we specifically staying below that threshold which means we are not going to overwhelm mitochondria we're going to train them and work them but we're we're not going to let them off the hook because if we go too high we've bypassed that system we're now having to deal with so much lactate elux that we're using different fuels of energy production so we're going to stay right below that threshold to make sure we put the most pressure possible on mitochondria this should enhance your ability to use fat as a fuel source this should enhance mitochondria biogenesis and a bunch of other positive benefits associated with that type of training others are then going to say no lactate threshold happens at four millimolars it's a different thing but there is a very clear distinction between two and four and so in fact probably the most common way to establish lactate threshold in science is to just arbitrarily say what speed in the case of running or wattage in the case of cycling are you at when you hit four millimolars of lactate and so rather than defining it by the slope of that oxygen increase and I know this is a little bit Technical and wordy for some folks a lot of times you can just arbitrarily say it is four millimolar and where you're at when you cross that threshold is your lactate threshold scientifically you will see equal accuracy between both of those methods now if you don't have the ability to analyze lactate directly there are a number of different ways to estimate it I mentioned Jack Daniels earlier he has by far the most popular version called a v do this is a little bit of a play he actually initially I think he called it the pseudo V2 Max and they had this really cool conversion equation uh for this book's very very old but it's really cool and it allows you to say all right if you know your race pace so whether you've done a 400 meter dash 800 met Dash either way up to a marathon half marathon on 5Ks 10ks any one of these races you can actually look up your race score in it he's got all kinds of tables these are available all over the Internet and then you can look and predict your performance in any of those other races based on your V do which is really pretty cool actually and so you get an idea of how much time you should be spending in each training Zone according at least to to Dr Jack but that is is a nice way to do it is it perfect no is it scientifically validated yeah so pretty cool tool there if you want to know more about your race Pace if you have the data from one you can predict it and many others if you want you can go to the show notes and pull up the papers and these exact tables and look up your scores but I'll give you a couple just since we're here to have a little bit of fun let's take uh mile most people know their mile time and you probably think back to high school fact you should go run one right now and see where you're at I always think like once a year you should go run a mile and see where you're at uh okay so let's just pick a random score here let's say you ran a mile in 7 minutes and 38 seconds according to this table then you should be able to run a uh 10K in 53 minutes or so a half marathon in an hour and 58 minutes and a full marathon in 4 hours and 4 minutes if you've ever done any of those events that smells pretty good right you're running a 7 and a half minute 8 minute mile recreational Runners that go run a marathon probably going to do a 4-Hour Marathon those numbers again are pretty good if we want to have a little more fun for those of you faster out there let's say you have a V2 Max of 70 ml per kilogram per minute is um more specifically technically V Dot of 70 but those are somewhat interchangeable here this should mean you should be able to do a one M race in 4 minutes and 19 seconds which is cruising not elite elite but pretty Elite for most people also a 70 ml per kilogram per minute V2 Max is pretty Elite so that makes sense your 10K time would be 31 minutes your half marathon would be 1 hour and 8 minutes and your full Marathon would be 2 hours and 23 minutes again feels pretty darn good let's go even further all the way down let's just keep that same person just to do a couple more ones um if you wanted to do kind of uh interval pacing you'd run a 400 meter dash in 71 seconds which again feels about right and a 200 meter dash in 32 seconds and so there again you can look up any one of these and and there's bunch of them if you want to look up your marathon pace your easy uh running pace your threshold Pace your interval Pace your repetition Pace they're all available in these uh gez I don't know 30 40 50 year old charts at this point I can just tell you anecdotally spending many many years in exercise physiology Labs with a lot of endurance athletes though I'm not one myself and these numbers are pretty good I've yet to find anybody who's significantly off on them you'll have some people who are just a little bit unique but they're they're pretty darn good and pretty impressive uh to figure all this stuff out without the Advanced Technologies we have now I know we got a little bit off track there but to wrap up the investigation if you want to know your lactate levels a lactate analyzer is really the only way to do it but really pay attention get a high quality one and use the same one over and over if you want to know your lactate threshold you have dozens of ways to do it the gold standard is to go into a laboratory at this point it's somewhere usually between1 and $200 or so to find a lab that has a metabolic cart now not all offer a lactate threshold test but if they do that's probably what you're going to be looking at they tend to last something like 30 to 60 Minutes you're going to have to run for a long time and is a lot different than a V2 Max s so if you specifically want a lactate threshold test you need to ask for that not nearly as many Labs offer that as a VO2 max test in the VO2 max test some some will take your lactate but that's not a true lactate threshold test that's a very different thing um usually what we're looking at here is something like four to five minute stages where we slightly increase the velocity on the treadmill or something like that and we're going to take a a finger or ear stick and plot out your lactate every four minutes for like I said 30 to 60 minutes so that is the kind of the gold standard if you really want to know if not there are tons of ways there's concone test there are 30 minute run tests there are two mile tests there's Jack Daniels tables and a bunch of other ways you can just take a heart rate monitor at most at least a stopwatch go run a test come back with your numbers plug it in and get a good sense of your lactate threshold hopefully though in a few years we'll have a better answer for this I know of at least four companies at this point who are working on continuous lactate monitors these come in the form of watches as well as an eyepiece like a contact lens that can do that that technology is already available for things like like glucose monitoring and I know that many companies again are working on this for lactate I don't know exactly when they'll be on the market but I would imagine potentially by the time you're even listening to this they're available if not pretty soon after that I don't know the accuracy or validity of them of course that will come in time but it's reasonable to think it's not a particularly hard thing to measure it is needed in so many different areas even things like acute medicine and Trauma heart failure heart attacks other issues like that so I am pretty optimistic that within a few years there will be really highquality continuous lactate analyzers available to the masses I mentioned this just a second ago but it's worth repeating in terms of interpreting these data at rest something like one Millar of lactate is pretty normal maybe even down to 0.5 what I can tell you and this is just anecdote this is Andy's personal coaching belief you will not find extensive data to support this we know lactate at Baseline is a reflection of what's happening in your mitochondri and since you're not going through much physical activity there shouldn't be much now we don't want it to be zero because the lactate is beneficial it is good but I think my interpretation of it is this gives you tremendous insight about your metabolic flexibility if somebody has a resting lactate of 1.5 or even honestly in like 1.2 1.3 I have seen this often times associated with either short-term overtraining or overreaching excessive stress psychological or physiological other things going on in their blood work with hydration number of cortisol disregulation and things like that also could indicate a bias towards carbohydrate metabolism so this is actually something that is a little bit sneaky I don't want you to be to over interpret yourself there there is actually some data on what happens I know that least there's some case studies on individual athletes throughout the entire year of the season and when they're doing more lower intensity endurance work resting lactate levels come down and when they shift over to more power and speed and Peak Performance they start to go up this makes sense we know that physiological adaptations happen in the muscle when you bias towards different forms of energy production it's a good thing right and so that's actually one of the things I pay attention to as a idea of to see okay is this person struggling with fat utilization I should be able to use a lot of fat as a fuel source at rest and so therefore lactate production should be fairly minimal and so something to keep in mind like I said said once you get to two or so you probably feel different so if you're at that stage you may actually have something else going on that's medical diabetes or metabolic acidosis or something like that I don't know again I'm not a doctor don't use me for medical advice but the point is somewhere around one or so is normal at maximal exercise you will see people get as high as 20 to 25 I don't know what the highest number I've ever really seen is I know of some folks in medical situations uh like having metabolic acidosis It's associated with diabetes especially at altitude highest number I've seen in literature is like 47 millimar I know of a group of actually endurance athletes who supposedly maintained 10 millimolar for an hour straight which again folks some people will be peing at 10 Michael Phelps supposedly only got to eight even during world record um swim performances right fatiguing not the not the Sprint ones and so a lot of high level athletes 10 12 is enough some can get up to 20 25 and in that particular case that person was up to 47 which is extraordinarily High I don't know what the real numbers are for that but that gives you a little bit of context of where you're at at rest as well as maximal exercise in terms of lactate threshold typically happens around 70% or so of your V2 Max or maximum heart rate um for recreationally or lightly trained individuals as you become more physically fit and you're able to handle that e-lux better for a number of different reasons you're either better at creating lactate or you're better at clearing it then that number actually gets higher it's not uncommon to see folks high 70s 80s even up to 85% um we don't have a ton of data on male versus female but the stum that is available suggests it's slightly higher in women than it is in men but I wouldn't say that that is a complete slam dunk in the science um you will often also see this number to vary between highly successful individuals like I said earlier endurance events can have success in many different ways so you can have a higher V2 Max you can have a higher running economy or cycling or swimming economy or you can have a higher lactate threshold but at the same token that also means you can be really good with a lower lactate threshold so there's a lot of paths to victory in sports and endurance is no different so anything in that Stratosphere of kind of 80 85% uh would be normal for a moderate to decently train endurance athlete fun fact while we're on this point remember the heart itself needs metabolism so it is going through energy production it is then therefore generating lactate as a byproduct of its own endogenous energy production so the energy needed for the heart to contract now if you give a given second typically when your hard is Contracting that takes around 200 milliseconds and around 800 of the milliseconds then are left with the hardest not Contracting so it's filling back up with blood it's thought then that during that contraction time you're producing lactate during the relaxation time which is again four times as long it's clearing the lactate but once heart rate gets really really high and that goes from a 4 to one relax to contract ratio to 3:1 to 2:1 to 1: one or even more than that the heart doesn't actually have enough time to clear all of its own endogenous lactate production which is one of the reasons why you become fatigued which brings us to our final eye intervene a handful of ways you want to think about this number one you want to make sure you're metabolically flexible so that we're not creating too much lactate at rest and not too little as well we talked about possible supplementation directly of lactate and that doesn't seem to be panning out at this particular point maybe more hope for gels and creams but as a direct supplement doesn't seem to be super effective nutritionally well you might think about carbohydrates are important important and the primary place of which lactate created so then should I have lower carbohydrates or should I have more carbohydrates at this point I don't think there's any specific rationale to think as long as metabolic flexibility is appropriate that increasing or decreasing carbohydrates is going to play significant role in your quality of lactate management will it change production look anytime you have more carbohydrates especially directly prior to exercise you're going to bias carbohydrate metabolism which is a way of saying you will shift more of your energy coming from carbohydrates because more is acutely available so will that shift and alter lactate production potentially but is that making a meaningful impact on human performance well outside of the benefits of having carbohydrates in your system it's unclear at this point in terms of training then all we really have to think about is what's going to advance and increase mitochondrial Health quantity and size in the reality of it is you have a ton of options here we talked about this a lot in our other episodes on the heart and V2 Max and so I'll keep it brief here you can head over there for more detail but you have different options what about low intensity exercise what about zone two well let's run the whole gamut here starting off with low intensity exercise we know that zone one or zone two can enhance mitochondria quality this is almost by definition staying at 2 millimoles or lower so that's absolutely a strategy in fact many distance and endurance coaches are going to spend a lot if not most of their time in that area and for probably very good reasons if that also increases capillarization and we're able to then get out lactate of the muscle and get it spread across to the other tissue the heart the liver the kidneys the brain then that's going to be effective what about more moderate continuous exercise in the research we generally abbreviate this as miic so moderate intensity continuous training well that works too now you're probably in the neighborhood of 2 to four millars something like that and you're going to be doing it for a longer duration is it having the exact same effects no but has it been shown many many times to enhance mitochondria quality fuel utilization and waste removal absolutely continuing past that what about higher intensity stuff really now we're talking about a couple of things high-intensity intervals is a good way to do it and you can do these in long or short the short version would be something like 20 to 90 seconds of a burst followed by one: one or up to 3 to one rest so this could be as short as 30 seconds of rest up to even 3 minutes or more of rest also incredibly effective we know this increases VO2 max and certainly lactate threshold as well as overall economy so another possible strategy the longer duration intervals would be more like 2 3 4 up to 5 minutes with an equal or larger amount of rest this is a classic most well described one four minutes of allout work matched by 4 minutes of rest important to realize when I say things like that four minutes of all out work I really don't truly mean that you can't be at 100% of your V2 Max for 4 minutes typically high-intensity interval training is really honestly somewhere between 85 to 90 maybe up to 95% and so good but a slightly different mechanism the highest on the end here then past that is what we usually call S or Sprint interval training and now this is truly at 100 if not higher or super maximum allout exercise the duration here is far shorter sometimes as low as even like 10 to 15 second bursts matched by a lot of rest but now you got to repeat this many many times so instead of doing things like uh 30 seconds on 30 seconds off for say four attempts or five attempts or even your longer duration ones for again three or four you're doing many more maybe up to 20 repetitions if not more than that of these short bursts if you look at the research and the studies even the met analyses that have directly compared MCTS moderate intensity stuff with low intensity stuff maybe even high-intensity intervals and sits and there's lots of different combinations in the research here you're going to find slight differences I'll acknowledge that but all of them work do they have unique components to it I think so I don't think we have a ton of information to explicitly say that with confidence because again they all generally work now sometimes in some studies and some met analyses some work slightly better than others for different aspects and so to me the clear answer is you should probably have all of it in your program there should be plenty of time at low intensity steady state sub 2 millimolar sometime they'll probably not a ton but sometime in two to four millimolar range continuous submaximal stuff a decent amount of time in these higher 85 to 95% high-intensity interval ranges and then some small amount of time in the super maximal but the final Point here is this remember fatigue exists on a nonlinear curve and so if you can imagine all four of these paradigms on that curve if I'm in zone one or two and I double my work I go twice as fast I only have a small increase in fatigue as long as I'm still in that zone going from 40% to 55% is not much more fatiguing but as I go and I cross miic and I get into the high intense intervals now two three four 5% increases have huge increases in fatigue and now I get all the way up to Super maximal I have large increases in fatigue for very small increases in performance to me that suggests you should probably spend small amounts of time in the top end of the range some amount of time in the middle and then a lot or or most of your time in the low end of the range rationale not being low intensity is more effective it clearly is not I need to repeat that low intensity is not more effective at improving V2 Max it is not more effective at Fat Loss which we've talked about in other episodes it is not more effective at improving mitochondria it is however more recoverable at the same time it takes a long time and so the benefit B of going at moderate and high and even really high intensities is they're really really short I don't need to be running for 45 or 60 minutes and they are providing unique and potentially potentially more adaptations I just can't spend all my time doing that because I won't have the recovery necessary to keep it up for long enough to really get sustained adaptations so in my opinion whether you're in this for sport performance you want to run a Marathon you want to row in a race you want to do a Iron Man or whether you're in this for life you just want to improve your V2 Max you want to enhance your metabolic flexibility improve your overall mitochondrial Health have more energy throughout the day more Global recovery be better at utilizing all forms of fuel the answer at the end of the day is still the same you probably want to train over that full spectrum making sure we lower or at least keep our lactate production at Baseline moderate to low enhancing our lactate threshold enhancing our total ability to produce to generate and to handle and clear lactate once it's there appreciating all the benefit it's doing for our memory for our brain health for our cognition for our heart for our liver for our wound healing for our immune system for our digestive system and everything else that lactate is doing to make us a healthier happier and better performing human 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 fstar 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 if you have yet to sign up for our monthly newsletter you can do so at perform podcast.com our newsletter provides episode summaries with the key takeaways for each and every episode of the podcast this includes topics like how to improve your VO2 max how to build muscle mass and muscle strength how to optimize your sleep for high performance and much more to sign up just go to perform podcast.com click newsletter at the top of the screen and then enter your email address once you sign up you receive access to all of our newsletters 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