Sodium Supplementation for Ultrarunning with Alan McCubbin PhD | Koopcast Episode 159

trail and ultra runners what is going on what's happening welcome to another episode of the KoopCast as always i'm your humble host coach Jason Koop and on the podcast today we try to answer one of the most long-standing and misunderstood issues in ultra running today and that is sodium supplementation this is an area of ultra marathon nutrition where i see coaches and athletes constantly screwing it up and that is for very good reason sodium balance is a complex interplay where you need three starting variables you're starting blood sodium how much you're sweating and the sodium concentration of that sweat to determine how much fluid and sodium you're actually going to replace it is not as simple as take one salt pill per hour which is what you will see on many of the nutrition products out there today fortunately today's guest repeat offender dr alan mccubbin out of monash university and the founder of next level nutrition he sharpened up his graphing calculator and algebra skills just enough to present a new model of how and under what conditions we should be supplementing with sodium his new paper which you can find in the

european journal of sports science is titled modeling sodium requirements of athletes across a variety of exercise scenario and variety of exercise scenarios is actually really important in ultra running identifying when to test and target or season to taste a link to that paper is going to be in the show notes this is a pragmatic view of the entire complexity of the problem after speaking with alan and during this podcast one thing struck out to me more than any other and that is because of the duration of most ultra running races we can supplement during those races drastically different than what we do in training and this fundamentally breaks the don't do anything new on race day paradigm that we are so accustomed to i want each of you listening to think about that as we discuss alan's model additionally i have a treat for all you listeners at the end of this podcast i pulled together a group of our coaches and we discussed exactly what this means for each of our athletes and each of you listening and we did this just like we would do in one of our typical coach education round tables this is a request that i have been belabored with since the inception of this podcast and if i'm being honest i've been reluctant to pull it into form oftentimes our continuing education sessions they either contain sensitive athlete information which we can't broadcast to the public or the context is just a little bit too much inside baseball

it's just not the right format to bring to a wider audience but i thought that this topic in particular was nuanced enough and important enough to use our coach continuing format to give it additional context so stick around after alan and i's discussion where coaches duncan callahan ryan anderson nicole rasmussen and frederick saboteur pastor all of which who have made previous appearances on the podcast and in fred's case he was actually a guest where we talked about some of his research we have an unfiltered coach round table that honestly it's pretty much exactly how we would do it if the mics weren't rolling and i thought it was pretty cool so let me know what you think about that particular format after you listen to it in its entirety all right that's enough that's too long of an intro for now i'm getting right out of the way here's my conversation with alan mccubbin and a subsequent conversation with our coaches all about sodium supplementation i'm always excited to do podcasts like this because i i firmly believe in the people that have kind of followed my content and also the the our coaching staff will they'll definitely back me up on this comment i've always thought that fluid and hydration and sodium the confluence of all of those is one of the biggest drivers of ultra marathon performance and you combine that with the fact that it's very dynamic in the in the sport application that we have because we have a huge temperature range that can

happen with any within any one competition not just one competition to the next like if you look at the olympics they all know it's going to be hot on the olympic marathon course like before because they can look at the average temperature ranges and things like that but if you look at ultra marathon and especially the longer ultra marathons you go through this huge range of temperatures so that adds in another point of complexity to this whole fluid balance equation and then you have this history which you're very well aware of where we look at you know the drink to thirst versus drink on a schedule wars or battles or even the position statements right that the acsm has uh has put out you combine that with this with the kind of the cultural sodium supplementation that has gone on within the ultra marathon uh world specifically and it just creates this like incomprehensible kind of goulash of of of of factors that athletes and coaches have to weed through and i think those two things combined the fact that it has such a such a huge implication on performance and the the dynamic of how fluid and sodium supplementation uh plays out during an ultra marathon race you combine those two things uh you combine those things together and i really think that we can't talk about this enough as coaches and and and and athletes out there so i'm always really excited to to to bring you on board whether whether we end up muddying those waters even more and confusing people more or adding a little bit of

clarity i think remains to be seen but not but nonetheless i always like talking about it because i do think that every time we chip away at better answers um and and i've experienced that during the course of my coaching career where initially we thought we had good answers and five years later we revise those in five years after that some other wrinkle gets added to it and then five years after that another wrinkle gets to it what i appreciate about your paper that we're going to talk about and uh what i mentioned what i mentioned off air is that this is math that i think everybody has wanted to do but nobody's taken a crack at it so yeah so kudos to you for taking a crack at it yeah it's it's interesting like the genesis of i guess me having a crack at that was you're doing some work in the lab with athletes and you know looking at sodium replacement there and getting these values and going well then you know even when we're not giving them sodium their blood sodium concentrations are going up and you know we know that if you don't drink anything that will happen but these guys were drinking stuff and their blood sodium was still going up even before we gave them any sodium and then it was sort of going back and going okay well how do we you know and then i tried to come up with sort of models of okay well how much sodium do we need to replace during exercise clearly it's not 100 because we're you know we're just sending their their plasma sodium through the roof but you know how much is it is it zero percent is it 50 is it 100 and how do we define that you know numerically and and so that's what sort of brought me out of the lab and i guess during

covid when we couldn't do research it kind of helped as well to to look at the mathematics of it and i guess the first thing i'd say is that you know the equations here are not my own work um this is taking equations that have existed since 2003 uh originally come from clinical medicine but then they were validated during exercise by the guys at the gatorade sports science institute but they were doing it to predict people's blood sodium at the end of exercise given the fluid ins and outs and the sodium ins and outs whereas i just used some high school algebra to flip that equation so the thing on the left of the equal sign is the sodium intake part rather than the final blood sodium so it basically says well if we want our blood sodium at the end of exercise to be the same as it is at the start and we've got a certain amount of fluid ins and outs and a certain amount of sodium loss and there's potassium in that equation as well but it makes a pretty small difference to the the overall result how much sodium do you need to achieve that result and so yeah it's just taking an existing equation and looking at it in a different way to answer a practical question it's amazing how far high school algebra will take you in these scenarios exactly right i had to think back a bit to uh work it all out uh hi it's a shout out to all the high school uh algebra teachers mine was gail nobles i remember her very very fondly but yeah those tools those tools go a long way okay so the paper that the paper that we're talking about there'll be a link in the show notes for listeners to go and reference this if you want to it's it's not a it's not a bad paper to read it's open access right because i have a copy of this or did you send me the copy of i think i sent it to you yeah i don't think it is open okay so it might not be it

might not be open access but the paper if you want to look at it the title of it is is modeling sodium requirements of athletes across and i'm going to emphasize this intentionally a variety of exercise scenarios and i think that that point is particularly taking with the ultramarathon audience because that is one of the scenarios that you modeled across and i think one of the strengths of all the math that you applied because it shows it really demonstrates how dynamic or how different the the strategy that you can deploy actually is depending upon the the inputs all of the inputs of one of which is an ultramarathon uh scenario so that's the title of paper the links to that will be in the show notes but we're going to start out by going for the jugular so the uh the audience might precipitously drop off after this next couple of minutes because we're going to give everybody not the answer but we're going to give them the major themes to start out with and then back into the caveats and the details behind those themes behind it to really arm the athletes with okay because you are going to have to come up with this is what i'm going to do on race day based on all of these scenarios but i want to start out with that just to start to paint the picture of really what is what are we talking about and what is realistic and what are these general kind of guiding principles so we're going to focus in initially on the ultramarathon side of things yeah so describe to the listeners this context that you started to put around that you started

to put around how much sodium supplementation is actually needed or necessary in most of those situations yeah well the first part i guess when we try and work out you know how much sodium do you need during exercise and that's been a huge gap in our guidelines you know there's been a lot of research working on how to work out exactly how much you lose but very little in terms of well okay once you quantify that how much of that should you replace i i guess i sort of went back to square one and said well why are we replacing sodium what are we actually trying to achieve by doing that and so you go through and look at all the different reasons that people have given historically for why you want to take sodium during exercise and it might be around fluid absorption although the literature suggests that it has very little impact on that across the entire gut you look at things like cramping and the literature suggests that you know sodium may play a very minor role but probably it's not the major role for most people can you repeat that can you repeat that again yeah so so cramping is is a really i think where our understanding has sort of come to now is it's a very complex multifactorial similar to gut issues during exercise there's lots of different causes they're probably different causes for different people they can be more than one cause happening in the same person at the same time and so by eliminating one thing at a time you don't actually figure out what's going on um and sodium plays a very tiny part in that much bigger picture okay i just wanted to emphasize that point since it is always a even though like when we're in the field we don't think it's that

contentious anymore but it's wednesday i do this ask me anything on instagram on wednesday i still get that question every single week yeah and i'll continue to get that for the next two or three years so anyway yeah okay continue continue yes so so there's some of the reasons that people give of why you replace sodium and then you get to the you know managing blood sodium concentration so you know hyper or hyponatremia so hyper meaning high high blood sodium hyponatremia meaning low blood sodium now hyponatremia i guess is the one that's kind of brought up as the big scary thing that people are really worried about could put you in the medical tent or hospital potentially in some cases although that is relatively rare thankfully the issue with hyponatremia is usually excessive fluid because it's the fluid build up in the lungs and in the brain that actually you know hyponatremia the low blood sodium drives the fluid into our cells but you've got to have the fluid in the cells to cause the problem so low blood sodium without a fluid excess seems to be not so much the issue you have to have the fluid excess as well to have that sort of clinical condition that that we see in in some events so and then i guess the final thing is sort of flavor fatigue you know that just getting sick of sweet things all the time and you know having sodium to drive thirst to make you want to drink more or just because it tastes better and you're more likely to consume you your sources of carbohydrate and things so they're kind of the reasons that you might want to replace sodium during exercise and then i guess then the next stage is to look at okay well which of those actually requires a specific amount that you might want to go and test for work out your losses and then replace

whatever we'll get into that shortly how much of that you need to replace and really you know obviously the taste side of things is like all that season to taste it's based on your personal preference it's got nothing to do with your sweat losses so you don't need to do a sweat test to work out whether a drink tastes good or not likewise in terms of you know driving thirst maybe a little bit but probably not so much so it's really around managing the blood sodium concentration it seems to be the one where actually testing your sodium losses and then replacing a certain amount in some situations might be worthwhile and so that's i guess the genesis of this paper and i guess if we skip straight to the conclusion from that i guess the main thing is that sodium replacement is really about balancing fluid replacement and it's having those two things in sync that seems to be important and so it's very difficult you really can't plan the sodium replacement based on a sweat sodium test unless you know what you're doing with your fluid replacement because it's the mismatch between those two that causes the problem rather than a deficit in one or the other per se as far as sodium is concerned and this is what makes it this is why i call it dynamic right because it's not just one single variable that you're controlling for you're really controlling for for three variables all at the same time all of which well some of which change depending upon the environment that you're that you're that you're actually experiencing but the the picture that you portrayed not only in the paper but in

some of the accompanying slides that you sent me earlier is that i'm gonna i want to make sure i get my vocabulary right so please forgive so please correct me if i if if i'm misstating here that sodium supplementation is only critical and i'm emphasizing that word intentionally because i want to distinguish between critical and and impossibly ergogenic or at least mitigating performance decline might be a better way to might be a lot of better way to put it if you have large sweat losses in the four to five liter range that's a lot that's a couple you know a couple hours three hours worth of activity for normal people normal circumstance you can replace most of it and you have an above average sweat sodium concentration if you meet all three of those and you've hit like the loser lottery so to speak meaning you have like this this like trifecta of things going on that that begins the conversation of we need to supplement with sodium outside of that meaning if you do not have large sweat losses and you can replace a lot of it or you do not have an above average sweat sodium concentration there's likely little or no need to replace any any sodium that you lost or supplement with sodium and the example in one of the tables in the uh uh in the in the paper that that kind of struck out to me the most is your ultramarathon example where you have a certain combination of those variables and i'll let you explain that where that athlete running a hundred mile ultramarathon

needs no additional sodium to avoid getting to a critical level which is actually possible i mean you go back in literature and you can find this it's wouldn't be a unicorn of a person or a unicorn of a situation it'd actually be not relatively common but you could find it in in a group of individuals so describe that more in detail because there are going to be a lot of athletes that are sitting on the other end of this podcast going but wait a minute you know i see salt supplements on every single table at every single aid station and all i've been told is is i have to replace the salt that i actually lose and you're kind of turning that off on its head and saying no it's only underneath these conditions yeah yeah and i think this comes back to i guess again why we're replacing the sodium and what we're trying to achieve by doing that so i guess people have traditionally thought of sodium i think almost like glycogen or what glycogen in a way like you lose a certain amount of it during exercise and therefore it needs to be replaced because if we lose too much something bad is going to happen kind of thing whereas you know sodium exists as a concentration within our fluid in the body and that has really big implications obviously with hyponatremia that's one example of where where that goes wrong um but you know it's it stimulates or not the kidneys to either pee out fluid or to retain it it stimulates or not our sense of thirst and our desire to drink it also controls the shift of fluid between the inside of ourselves and the outside of ourselves so if we are just trying to sort of

quote unquote prevent like a whole body sodium deficit in that way that we kind of think of glycogen but we ignore its relationship with water then we can start to get into trouble because we can over over supplement sodium or completely under supplement sodium and the balance between our water replacement and our sodium replacement gets out of whack and then that has all those sort of implications in terms of over or under hydration or you know fluid shifts into or out of the cells during exercise so yeah that's i guess the the main sort of crux of it but yeah i think people still get nervous going well but my test says i have you know a 1500 milligram per hour sodium loss and it's like well yeah you might and yes you are losing a lot of sodium the problem is if you're not replacing enough fluid to require sodium replacement and you take that sodium to chase that loss but not the fluid loss you end up with a sky high blood sodium concentration you're going to feel awful you're going to be terribly thirsty you might get nauseous and you're not going to be in a great state so a lot of people when they argue oh but i i take sodium during my exercise and i feel so much better therefore it must be important i would probably say well maybe because it's also then you know stimulating your thirst and actually making you drink more and it's actually you know being better hydrated that's having a big impact on that that feeling of feeling better during exercise just to give you a bit of an example of what that looks like because i know people get really skeptical about this when they kind of

first hear it right and this was an example i did this is an iron man example but it could be the same for ultra running so it was a 10 hour example and you have someone with a 1200 mils per hour sweat rate a very high sweat sodium concentration 60 millimoles per liter is high for a whole body value and you drink about 80 percent of that water back again but you go out and go well but i lost all this sodium i'm going to replace 100 of my sodium losses so over the 10 hours you lose about 16 and a half thousand milligrams over that total which is about probably 20 to 25 percent of all the sodium in your body has gone and then you've lost about 12 liters of fluid 1200 mils an hour obviously over 10 hours which if you drank nothing would be a 17 body mass loss now clearly you are going to drink something so that's never actually going to happen but that's what would happen so then you go out and you drink as i said you know 80 percent of your fluid loss is back again so you end up in about a 3.6 body mass deficit which is pretty reasonable i think for an iron man type event but you've replaced 80 of the water but you've replaced 100 of the sodium because you did this sweat test and said i need to hit this number so you take all of that you don't end up with any total body sodium deficit but your blood sodium concentration which started exercise at 140 millimoles per liter which is kind of in the middle of the normal range is now 155 millimoles per liter because what you've done is

you've lost water and sodium in your sweat you've replaced some of the water but all of the sodium you've over replaced the sodium during exercise and he like okay brilliant example and i'm going to tack on to that with practically how this actually how this actually unfolds it's completely rooted in the fact that fluid is harder to take in than sodium because it compromises more volume right you're talking about somebody trying to replace 70 percent of 180 of of one point would you say 1.2 uh liters 1.8 liters 1.2 yeah that's a lot of that's a lot of freaking fluid that's hard to take in with everything else that you're taking in all the food and carbohydrates and things like that sodium per unit volume right little pill right little pill you can take in you can get a couple hundred milligrams and it doesn't take it doesn't take a lot i guess is what i'm saying and so the balance that most that that most people go through and this happens a lot in the ultramarathon world is since it is so hard to take in fluid because they're because of the volume dependency of what you are trying of the percentage that you are trying to replace i'm trying to be really careful here with my language you can't you can't guess is just is just so much larger and so much like more like literally more difficult to ingest than the small amount of volume that you're trying to replace on the sodium side it's very easy to get to to get out of balance yeah and the other problem is that you know when we produce sweat in our sweat

glands obviously there's the fluid in there and then there's the sodium component and a few other bits and pieces in much smaller quantities but our sweat glands have the ability to reabsorb some of that sodium back into the body so when the sweat is first made at the base of the sweat gland it basically reflects what's floating around in the blood and what we call the interstitial fluid which is the fluid that's sort of in the space between the cells and our blood vessels and so that's at 135 to 145 millimoles per litre and so the initial sweat that's produced at the base of the gland is that sort of concentration but as the sweat goes up the sweat gland some of the sodium and the chloride gets reabsorbed back into the body and so the final sweat sodium concentration on the skin surface for a whole body because it's different in in different parts of the body is typically between about 20 and maybe 70 75 millimoles per litre so what that basically means is from that initial sweat that was produced somewhere between sort of 45 and 85 percent of that sodium is actually kept or you know restored back into the body and it never actually leaves the body but all of that fluid leaves so you're losing yes you're losing water yes you're losing sodium but you're losing proportionally more water compared to sodium and that's why when we exercise if we don't take anything at all no drinks no sodium no nothing our blood sodium concentration will go up because yes we're losing both but we're losing more water relative to sodium and and from you know a physiological point of view that makes sense because when that goes up we get thirstier so we want to drink to replace that fluid and that'll bring it

back down so it's a perfectly normal kind of well-designed mechanism for an evolutionary point of view but it then means that yeah if you're replacing the fluid you know relative to sodium it's it's going to be much greater in terms of importance well here's how this is going to practically practically work out i did not plan this this way by by the way for the audience this just sprung up upon me so if you guys think that this is like some sort of master plan it was not now you can back me up because this is not not in our outline but there are going to be for those of you that are watching the youtube version there are going to be wearables that start to come out i just happen to have one on my desk right now this is a nix patch it's one of the new players on the market it looks like one of the continuous glucose monitors you slap it on your arm and it tells you within a reasonable degree of accuracy your sweat rate and your electrolyte concentration which we can kind of extrapolate to to sodium concentration my fear is the tendency is going to be to look at that and say one for one everything and what what alan just went through and what this paper very very elegantly although with a lot of math manhandling demonstrates is that you still need to apply some sort of thought to the thought process and the biggest one is is how much fluid are you actually replacing to make sure that everything is in balance that's my fear with that's my fear in general with the wearables is that we're taking them as a one-to-one for whatever it is glucose sodium hydration or whatever it is and usually there's

another variable that's that's that that this is not capturing or you're trying to capture in another different mechanism i was just reminded that their app actually asks you to to to input how much fluid you're taking in but my point of it is is you can't just take that information and say just like you know glycogen as your example was earlier say i'm just going to replace things one-to-one because you have there are other variables in the equation totally and i mean from a fluid point of view this is where i think it gets interesting and then it will kind of further go on to relate to the sodium replacement but from a fluid point of view if we think about traditionally how we think about hydration you know we're trying to prevent a you know a certain percentage of body mass loss and you can argue all day long whether that should be one percent two percent five percent whatever it is um you could probably put an argument that you know the the longer uh like slightly lower intensity events maybe you can get away with a bigger percentage body mass loss but that's almost impossible to study so we don't really have an answer it's more of a hypothesis but i guess if if i give an example of that if we calculated someone's percentage body mass loss and we were trying to limit them to a a total body mass loss of two kilos so rather than doing a percentage just two kilos of body mass loss so let's imagine two scenarios one someone goes and runs a half marathon and it's pretty warm day obviously half marathon the pace is pretty high so your sweat rate is going to be high because you're producing a lot of body heat and so over the half marathon you know hour hour and a half whatever it is

you lose two liters of fluid so you lose your two kilos so how much fluid do you need to consume to limit your body mass loss to two kilos or zero because you only lost two kilos so you need zero percent fluid replacement in that scenario now let's go to the other extreme an ultra marathon so let's use 20 hours as a neat kind of a number so you oh sorry 20 liters of fluid loss as a neat number so you lose 20 liters of fluid over the course of your ultra marathon and you're trying to limit your body mass loss to two kilos so how much fluid do you need to replace all 18 kilos or 18 liters so you still got the same deficit overall same you know hydration wise your total body water deficit is the same in both scenarios but in one you've replaced zero percent of your fluid losses in the other one it was 18 out of the 20 liters so that's 90 percent fluid replacement so i guess the key thing here is the greater the cumulative sweat loss and it doesn't matter whether it's because of duration because of sweat rate or the combination of those two factors the more total sweat in liters you lose the closer to 100 replacement you need to go now you never actually get to 100 but you get closer and if you plot the curve you see a steep rise for the first sort of three four five kilos or liters of sweat loss and then it sort of almost plateaus out but just gets inches ever closer to that 100 mark and how much you need to replace in an ultra marathon situation relative to the total has been

the subject of of many many debates i talked about on your podcast and we'll link that up i don't think we quite know the answer to that you know i think we could say it's not a hundred right because we know there are there are non you know uh non-water losses or non-body water losses that that occur and you certainly don't want to don't want to replace more than that but outside of this is a little bit of a guessing game and some of it comes back to where on the ergogenic versus trying to stay out of a critical situation are you actually are you are you actually sitting and i don't want to talk about that a little bit because a lot of your paper in the accompanying slides talk talks about staying out of this critical blood sodium range right so you're you're kind of preventing people from going to the hospital having some sort of some sort of uh some sort of catastrophe why did you why did you tend why did you intentionally tend to frame it like that as opposed to here's how we can like optimize performance with this very specific blood sodium concentration that we can aim at because you can certainly aim the math at that specific point so why did you choose choose to do that yeah so i guess there's two parts to that the paper kind of does look a little bit at both because when it models the fluid replacement in the three different exercise scenarios it models fluid at around that two percent body mass loss and when i say two percent body mass loss it's not literally the body mass before and after it's a fluid loss specifically fluid loss equivalent to two percent of body mass as you

said obviously in ultra there's other body mass losses that you have to account for um and so the sodium is aimed at maintaining a stable blood sodium concentration for i guess what we would consider the ideal fluid replacement whatever that is however we'd want to define that and as you said that's still controversial and particularly in ultra we don't really have a good grasp on that and so that that's kind of how that the sodium side of it was built i mean we don't have any suggestion or any evidence or ideas or suggestions that a particular blood sodium concentration is going to be more ergogenic than another as long as it's within the normal range and so all of that modeling data was basically looking at the start and end blood sodium being 140 millimoles per liter which is like smack bang in the middle of quote unquote the normal clinical range and that's what i was kind of getting at is we don't know that is it slightly more optimal to be at 145 or 135 or whatever there's no data to indicate that any of that is any better than the other and i've always taken that as a cue when you don't know that is you just get it close right whenever you're doing your real application sports modeling and you have this kind of range of this this range that you can be in of whatever you're trying to target it's not worth slicing that hair any finer you just get it close from a pragmatic standpoint and then call it good and then realize that performance is multifactorial there's going to be other things that get thrown into the mix yeah and i think if we look at the data that has been done to date on sodium and performance and

none of it is in the ultra space just because it's so difficult to do you know in a lab setting or in a real world setting you know there's too many variables going on that might influence that but i guess if you look at those studies this probably what you see out of them is that the fluid replacement and the hydration status will influence performance but the sodium doesn't it's about the total amount of water that's sitting around in the blood or the total body water and really the sodium is just there to balance whatever that fluid replacement needs to be to optimize performance assuming that it needs to be there can you go over for the audience some of like the physiological underpinnings or some of the theories as to why that actually is why that why that total body water matters so much when other components don't seem to yeah so it's a tricky one from a mechanistic point of view i don't think we still really fully grasp why what it is about hydration or dehydration if you like that impacts negatively on performance uh what we tend to see in those studies so you know those classic hydration studies where they give everyone like a hundred percent fluid replacement or they don't let them drink anything which is kind of the classic dichotomy that you see in most of those studies and of course they're not blinded because how do you blind whether you drank fluid or not apart from i think there's three nasogastric tube studies where they actually gave the fluid through a tube to to blind it or the idea i've seen that in a couple of studies yeah yeah exactly and they do that beforehand yeah um and so in those situations what you tend to see in the people

who didn't have any fluid is their perception of effort was higher so it feels harder to work at the same pace um or they they work to the same perception of effort if it's like a time trial but they're going slower for that same perception of effort you know it's kind of a flip side to that um generally if it's again if it's a fixed intensity of exercise their heart rate will be higher so that sort of cardiac drift classic that you see with dehydration um and their body temperature tends to be a little bit higher as well although it's actually not that much but it is a bit higher now which of those things i mean that gets into the whole like what causes fatigue is it central is it like that's an old have an old can of worms that would take another four podcasts probably to unpack so we won't go there um but yeah one of the interesting things that one of the things i'm interested in is you know is it the total body water that's important that influences all those things or is it the actual plasma volume like the volume of fluid within the blood vessels it does it not matter about the rest of the body and again i don't think we've fully unpacked that i think from a body temperature point of view it seems to be probably the total body water that's more important and there has been some suggestions as well that in fact you know the higher heart rate and things isn't actually to do with a lower blood volume which sort of physiologically makes sense but actually maybe something about that dehydration impacts on the the endocrine system so your hormones your stress hormones your cortisol your adrenals and all those sorts of things and that then goes on and has other impacts throughout the body but you know human biology biology is so complex that

i think we're a long way from fully unpacking all of that which is crazy it's water right at the end of the day and we're still a long way from unpacking it as you just mentioned yep um i want to i want to move to something that's a lot more practical and kind of like down to earth for the everyday athletes that are going to go out there and train maybe they're running right now with their headphones or whether they're going to go train a session tomorrow because we've been talking a lot about about ultra marathon race situation which we're going to i'm going to revisit at the end um i want to specifically point to this is alan slide number uh 16 in the ones that you sent me that is it necessary physically possible and practically achievable uh if you want to cue this up and and and share your screen the the youtube uh viewers can actually uh see see this if you're tuning into that version but we're going to walk through this flow chart so to speak that alan's prepared and i think this is a really practical represents a representation of what you can do from a training perspective to start to plan out your fluid and sodium leads or lack or lack thereof because it literally walks you through if this scenario not this if that scenario not that and then the title of this of this slide in particular which i think is i think really gets to the heart of them the heart of the matter of how we try to solve all problems in sort in sports science is it necessary is it a problem that we actually need to solve which you have to cross that line first right because sometimes we're we're trying to solve for things that really aren't that material second thing is it practically possible meaning is the

solution that you want to put in place even feasible some and sometimes it's not and the second in the third piece of it is it actually achievable meaning do you have kind of the resources and the faculty and the the the kind of the wherewithal to actually put implement the the the plan into place so alan i want you to walk through that um do you want me to share my screen on my side because i don't i don't see it popped up quite yet yes disabled at my end you have to enable that oh okay never mind i will do that really quick hold on sweet there we go yep beautiful all right so yeah so as you said it's it's that kind of three-step process about you know is it necessary is it physically possible and is it practically achievable so we start off i guess with the um and i'll get to that flow chart in a sec but i thought this might be handy that first question and the 70 percent here we'll probably get to that a little bit later that seems to be the tipping point where actually replacing sodium starts to become necessary is when you're replacing more than about 70 percent of your fluid losses so you're drinking relative to sweat rate um so is that likely to be beneficial for you and this is what we were sort of talking about before that you know obviously the the greater the total sweat loss the closer to 100 you have to go to replace that fluid to whether it's a one percent two percent three percent whatever kind of body mass loss percentage you're kind of aiming for in that scenario so the red line there is the 70 so essentially when you go uh north of that line is when that um 70 is crossed and

when sodium replacement might be beneficial so you can see obviously the longer the event the more likely that is um and there's just an example of like different body weights of athletes so if you're 50 kilos versus 90 how that moves that line so it moves it a little bit but not you know the overall pattern stays pretty much the same so this is just that so the second question is it physically possible and what i mean here is from a gut tolerance point of view and being able to drink it without choking on it and the example i've used here is elite marathon running because in an elite marathon obviously if you're going at kipchoge pace you know 21 k's or an hour or whatever it is firstly you know you need to be able to drink that volume of fluid without choking on it when you're breathing that heavily i mean he's what putting out a vo2 or probably 60 mils per kilo per minute um just to maintain that kind of pace maybe even more higher closer to 70 or something like that you know sort of 85 90 percent of his vo2 max which is higher than the rest of us anyway so just being able to you know breathe and drink that volume at that pace and i was talking to um an australian olympic marathoner the other day and it was something that she really struggled with early on in her career as well so you've got to be able to do that but you've also then got to have the gut tolerance to be able to consume that volume of fluid and keep it down as well and so that becomes the second factor that might physically stop you from being able to actually consume that much fluid to meet whatever percentage body mass

loss you're trying to achieve and then the third one oh sorry i was just an example here you know if your sweat rate is greater than about 1.8 liters an hour you're probably going to have well to hit that 70 you're going to have to drink more than 1.3 liters an hour and as you said before that's very difficult for the vast majority of people um either to physically access that amount of fluid or just to keep it down physically particularly when you're running at the sort of pace that someone might keep choking you'll be running at like there's no way he would be able to drink 1.3 liters an hour of fluid i suspect yeah just from a practical perspective like the soft flasks in most people's bottles those are half a liter so you normally care carry two up front right one on each you know side of your chest that's more than that every single hour every single person out here listening to this will say no i definitely don't drink that much one liter per hour on any on any normal training run excited you know with the exception of people out in arizona and california that are like baking during the summer yeah exactly and i mean in an ultra generally your sweat rate would be lower than that because the intensity is a lot lower than that and we'll come to that with the flow chart as well to help people kind of make that decision then the third part which kind of gets to what you're just talking about there is it actually practically achievable and the example i mean this wasn't a sports specific um session that i was giving was soccer because you know you have 90 minute halves and during that this continuous play there is no access to fluid and so it's before the game at halftime and after the game that's pretty much the only chances you get with rare exceptions in hot environments

sometimes they modify the rules for drinks and things but generally speaking unless you're the goalkeeper that's all the chances that you get to drink and so you know you might think that replacing 80 percent of your fluid losses is important you might be able to tolerate it but if the fluid physically isn't there and you can't access it within the rules of your competition then what's the point what are you going to do yeah exactly right so you really have to satisfy all three of those scenarios before you're going to cross that 70 percent and then and you know we'll get into it and maybe look at the graph shortly that's when you know replacing sodium seems to be necessary for the for the average person so that gets to i think this is the one that you were talking about is this kind of little flow chart here so i guess the way i tend to think about it is start off with exercise duration and as a general rule if your exercise is less than four hours you're very unlikely to sort of cross that sort of four or five liter cumulatively sweat loss mark that actually aggressively replacing fluid would be important or you're going to be in a situation like the kibchoge where you're not going to be able to physically drink at the rate required to do that anyway because the intensity is so much higher the duration is so much shorter and so in that case for the majority of people if it's less than four hours you know i just say season to taste in other words choose your sodium based on taste preferences rather than trying to hit a specific amount because you're just not drinking to drink enough fluid realistically to need to replace a certain amount of sodium but if it's over four

hours then i tend to look at the hourly sweat rate and again you know using 1800 mils an hour is probably a good rule of thumb because again if your sweat rate is greater than that you're going to be needing to drink sort of 1.3 liters an hour plus of fluid to actually need sodium to stop your sodium blood sodium from falling and so if that's the case it's going to be very unrealistic in most scenarios that people could actually do that so again seizing to taste and i think this is the one that probably challenges people a lot because the traditional thinking is high sweat rate therefore i'm losing a lot of sodium therefore i have to replace it much more aggressively but the point is if you can't replace your fluid aggressively and that's aggressive relative to the sweat rate not aggressive in general then you don't need to replace the sodium aggressively either but if your sweat rate is less than that this is kind of just a general guideline so if it's over four hours your sweat rate is less than 1800 mils an hour which both of those scenarios are pretty much universal for ultra running and then looking at well are you likely for other reasons to replace you know more or less than 70 percent of your fluid losses and if the answer is no because of gut issues because of fluid availability whatever it is then again there's probably not going to be a need to go out and do a sweat test and work out specifically what your sodium loss is and replace it but if it is and in most scenarios that would probably be beneficial then that's when you might proceed to sweat sodium testing so that's really the only scenario where you would go and do that and then depending on the result

of that test you know if it's less than sort of 40 millimoles per liter which is about the average if you look at um you know gatorade have done a lot of studies with thousands of people where they've published all the data and the average sits around 35 40 millimoles per liter so if you're sort of average or below again you probably don't need you probably need some sodium but not very much you can probably just you know your normal foods and fluids are going to give you some sodium anyway and that'll probably be adequate it's not until you get into those sort of higher sweat sodium concentrations that replacing more than that might actually be of use to stop your blood sodium falling and the the only caveat on that i've got in the the far left there is if you're replacing more than 90 percent of your fluid losses which is not that common but it can happen in the really long stuff then you know you might have to go a little bit higher than these values a lot a lot of runners will identify this kind of a training situation and before we before we get to that for the people that are listening to the podcast and trying to envision this this flow chart that uh uh that that alan is presenting can i have access to this can i link this into the show notes as well yeah all right put you on the spot there thank you i encourage you guys to go and look at this because i think it very eloquently just describes the situation but the the way that i follow this cascade of events is kind of down the left-hand column of this which the only re the only time you're going to have to really pay attention to replacing your sodium i'm starting at the bottom right the bottom left hand corner essentially

is if your exercise duration is over four hours and if your hourly sweat rate is is great why am i getting confused on the greater than less than on the 1800 million years 1800 million years an hour here yeah so it's less than yeah if it if it's less than 1800 million years an hour and if you are going to replace greater than 70 of it and if your sweat sodium testing indicates that you are a salty sweater we're not going to get into the middle moles that's kind of the only practical situation where you really have to from a training almost from a training perspective not from a like a long ultramarathon perspective where you really have to pay attention to supplementing with sodium or replacing a large part of the sodium losses yeah yeah and i guess you know that the right hand side there where it says season to taste it's not saying you should avoid sodium completely it's just saying that you don't need to have a specific amount to you know stop changes in your blood sodium concentration because in all of those scenarios it's going up anyway so taking more sodium will only exacerbate what's already happening so in those scenarios it's about having sodium based on your personal taste preferences and what feels good to you rather than and you don't need a sweat test to tell you that okay if this goes back to one of the themes that i just keep seeing in product development and support science is in a lot of ways we are getting overly specific for the practical recommendations that athletes need to take in i'm

not just picking on nutrition i'm picking on kind of like everybody most most the time and most reasonable and i mean this is an extreme situation right greater than four hours you're working out hard and things like that but even when we take it to that you only need to be really specific in a in certain situations yep exactly right oh man everybody's going to be throwing away their salt tablets after this alan and what are we going to do about that well if you well not so much the tablets but i guess if you're putting you know dissolvable tablets in your drinks and you like the taste of it there's no reason to necessarily get rid of it if you like it but there's i guess no reason to have a specific amount but many people i guess what i'm getting at is there's nothing wrong with that but many people view it as necessary right and i'm emphasizing that word intentional like i have to do this otherwise my performance is going to deteriorate or something like really deleterious is going to happen yeah and as i said before like people that swear black and blue that that's exactly what happened to them and they just had sodium and it solved all their problems i suspect what's happened is it's actually you know yes they've had more sodium but they've also had a lot more fluid because if they just took all the extra sodium and had the same amount of fluid replacement as before either before they're becoming hypernatremic and the sodium was necessary or they just weren't drinking enough and now they are and that's the big part of the big reason that they're feeling better yeah but in addition to that there's a huge placebo effect and you and i both recognize this that we've been in like there's a

large part of the population that's kind of been ingrained with this with this fact that if you are feeling bad and or you're having cramps sodium is your pathway out of that and you take that and then there's a psychological boost there's a there's a rush of endorphins and you think that you're going to magically be cured and a lot of times that profile that that prophecy actually fulfills but here what you're saying physiologically is there's not a lot of basis for that action for that phenomenon actually happening yeah yeah and i think what's interesting here is if you know going back to what you said at the start and you know the guidelines around uh sodium replacement and i guess that the two that sort of dichotomous schools of thought of you know you need to be aggressive with your sodium replacement or no you're not this kind of sits in the middle of that because it's saying well you do need to be aggressive but only in certain situations and others you don't need to worry about it so i think if we compare it to those two camps you know the people that are you know testing sweat sodium on a one hour training run and you know getting really particular about replacing that or in team sports that are only go for 90 minutes or something like that and and this suggests that that's completely unnecessary but on the other hand in the ultra scene a lot of it is like just do whatever you don't need any sodium and it's like well yes you can get away with that and not get hyponatremia but you have to progressively dial down the amount of fluid you replace as a percentage of your losses and eventually that'll get to the point where it's going to impact on performance or potentially health if it's too extreme well and so i started out with a podcast i started out the

podcast kind of presenting that this situation is extremely dynamic and it's difficult to pin down because of that dynamic nature and i'm going to kind of come back to that one of the one of the reasons that it's hard to pin down is because what you do what you can do in training and you just you just presented this in this flow chart might be drastically different than what you do on race day depending upon the duration of that race and this is one of those infinitely difficult complexities within ultra marathon not only around sodium but around a lot of areas because the diff because the time duration of a singular training activity is so much smaller than the time duration of the actual event that in a lot of situations you are doing things different in the race as opposed to training which is like the quintessential no-no that we've all been that we've all been taught to do yeah that's the kind of the like not not that you can't do it in training it's just not necessary nor is it or is it ergogenic so that just adds to the complexity i guess is what i'm getting at yeah totally yeah okay let's move on to the i want to add a little bit of clarification around the 70 percent number because a lot of people are going to fixate on that whether they're whether they're going to read the paper or they're listening to that and they're going to think oh i only need to replace 70 percent of the fluid losses give some context around that before we have people come and yell and scream at

us afterwards island because they'll definitely do that if we just leave it at that yeah so i guess the 70 percent comes from not so much how much fluid you need to replace during exercise but at what point in your fluid replacement does sodium come into the picture so i'll just i'll tee up the slide for that which i'll start off with some some real life data from real life participants and then look at you know what the modeling shows which kind of mirrors that so i guess this comes back to managing blood sodium concentration and so in the ultra sense you know really hypernatremia prevention in a way and so this particular study was from the gatorade sports science institute so you know people might have preconceived ideas about what that means or not but this was actually the original study that validated the equation that i then used in my modeling and in this particular study it's only a two hour run in 30 degrees 70 percent of vo2 max intervals with a couple of minute rest throughout and then there was a performance test at the end but i'm pretty sure this data is just from that the two hours before the performance test and what's interesting in this study is that they've given them sodium replacement they've actually done it in milligrams per liter of fluid consumed or in this case per 100 mil so you've got zero sodium the white bars the gray bars are 37 milligrams per 100 mils it says 18 because it's 18 millimoles and then 69 milligrams per 100 mils of fluid consumed so per 100 mils probably how people might think

about it in terms of looking on food labels of their sports drinks or something and seeing how much is in there but what you can see here is that you've got three different levels of sodium replacement but then you've also got four different levels of fluid replacement so you've got scenarios where they gave people enough fluid on the far left to only lose four or to lose four percent of their body mass so they're becoming relatively dehydrated to lose two percent of their body mass so sort of getting around those sort of guidelines zero percent so they didn't lose any body mass or actually over hydrated so they've gained two percent of their body mass through fluid intake and then you've given them those three different levels of sodium so i think what becomes clear here is that firstly that the fluid intake has far more impact on the sodium concentration which is the vertical axis on this graph so the s is serum so serum sodium concentration and the delta means the change in so did it go up the bars go up if did it go down the bars go down and by how much and so you can see there that the sodium had much less impact than the fluid replacement did on whether the blood sodium went up or down now this would be used as an argument so that's kind of the water effect between the highest fluid and the lowest fluid intake and then that's the sodium effect between the highest and lowest sodium replacement now this was actually used then by tim noakes in his book waterlogged in a publication to argue that sodium was irrelevant and it's all about the fluid and you know to some degree that is probably true what i would say here is that the differences between the lowest and the

highest fluid intake here are very extreme you know four percent body mass loss versus two percent body mass gain that's a big difference very aggressive versus very not aggressive the differences in sodium intake here are definitely not from the low zero is obviously the lowest possible but this is nowhere near the highest possible sodium intake that someone could take during exercise i mean 690 milligrams per liter that's a regular commercial sports drink right i mean that's a run-of-the-mill middle-of-the-road commercial sports drink yeah yeah so you could go double triple that quite easily and and tolerate that just fine so i think in some ways it's probably a little bit of an unfair comparison because you're comparing the extremes of water intake between a much smaller range of sodium intake and if you had you know instead of 30 millimoles per liter which is that black bar you had you know 60 millimoles per liter 80 millimoles per liter that sodium effect would be a lot larger as well probably still not as large as the water effect but a lot larger here and so i don't know if i'd say that this has been cherry-picked but i think it's certainly been potentially misinterpreted a little bit or just over-emphasized i'll say cherry-picked because it's tim and i don't mind uh i i definitely i definitely don't i definitely don't mind uh saying saying that about him he he and i don't see eye to eye a lot of things um that's another story but i think once again a good like outside of the sodium stuff this is actually a really good example of how you can spin a study to fit your narrative depending upon

the angle that you are looking at it and how you are not interpreting the data but how you're presenting the effects of the of the effects of the change that you're seeing in the actual research yep and certainly tim's not the only one to have have sort of made that kind of a statement so you know i wouldn't say it's specific to him necessarily but i think what was interesting for me and and this kind of bears out in the model is if we're aiming to maintain a stable blood sodium concentrations at what point does it stop going up on the left there and start going down on the right because when it goes down that having sodium is going to help lower that fall if you like and so somewhere something i guess what we're saying here is that there's some important role for sodium but water seems to be more important but again that might be a little bit um because of the design of the study but somewhere between here and here is where the crossover point comes where the bars stop going up and start going down and that's when sodium replacement would start to theoretically lower the extent to which it falls which is obviously a black bar compared to the white bar in the blue circle there so that's where the modeling gets to that 70 mark which was the question that you asked so um that's just the equation i'll just skip through that quickly this is the results of that equation so this is very similar to what we just saw but this is theoretical data rather than actual data and here we've got different levels of fluid replacement but now it's in the percentages of fluid loss so this scenario is 1500 mils an hour of sweat rate and then you're replacing 50 60 70 80 or 90 percent of

that and you can see that the fluid intake volumes underneath and then you've got four different sweat sodium concentrations which pretty much span from the the least saltiest sweater to the most saltiest sweater and then you've got again on the vertical axis the change in blood sodium concentration is going up down and by how much and what you see is that the crossover point seems to happen for the majority of people with normal kind of sweat sodium concentrations around that 40 millimoles per liter or maybe slightly above that is happening at around that sort of 70 you know just above 70 percent fluid replacement mark so that's where that 70 percent comes from but you can see if you are an unusually salty sweater 80 millimoles i've actually never seen that in my career i think the highest i've seen is about 72 73 um yeah that crossover point comes at about 50 to 60 70 replacement and if you're a very low salt sweater it doesn't really come in until about 85 90 replacement so it does vary a little bit but i guess that 70 rule i'll put there is it would cover the vast majority of people with normal and quote unquote sweat sodiums so don't take 70 as a do this don't do that you're using as a reference point to where sodium supplementation is going to start to play in effect or where you actually have to start to think about it yeah yeah exactly and if you've got extremely salty sweat maybe lower that value a little bit if you've got very unsalty sweat maybe you can um you know not not worry about it so much until you're sort of 80 plus okay we're so

we're gonna leave that we're gonna leave the athletes with this since you just talked about salty sweat how can an athlete get a fix on that because that's the end of the that's like the end of your waterfall the very final linchpin is is do you have salty sweat or not to where it actually really becomes impactful on where you need to actually start to pay attention to this and in some scenarios those are all my caveats yeah how can you how can you get how can you get a fix on it let's kind of run through the range of scenarios that people can that people can practically go through yeah so obviously to to work out how much salt is in your sweat you're going to have to have a sample of that sweat and there's been different ways historically over the years to collect that the gold standard is considered what's called a whole body wash down which basically boils down to exercising in a plastic giant plastic bag uh it generally has to be done on a bike because you can't use a motorized treadmill in there because as i'll describe in a minute you would destroy your treadmill um you want to do it in as little clothing as possible so when they do these studies they just wear like almost like running shorts or you're not usually cycling nicks because that can absorb too much in the chamois um and then just topless no shoes no socks no nothing and then you do your exercise you're obviously sweating some of that stays on the skin surface some of that drips off onto the frame of the bike or onto the floor with the bottom of this plastic bag and then at the end of it they get either deionized water or some other chemical solution and they basically shower you in it so you know

liters of the stuff pours all over you to wash all the sweat off your body they do the same to the bike to wash all the sweat that's stuck on the bike and the minerals off into the bottom of the bag and then you get out you take all your clothes off and leave them in the bag and you get out start naked and then you go and get washed up and changed and then you end up with this giant plastic bag which has the wash bike and all your dirty clothes in it uh and this lovely soup of sweat and chemicals basically and they take the bag and they kind of swirl it around to mix all the the liquid together at the base of the bag and then they take a sample of that and because they know how much they've used in the shower they can work out basically how much sodium is in the the sweat that you lost during that period of time obviously very impractical very unrealistic you're going to destroy your you know your motorized treadmill if you try to do that for a runner so because of that it's very rarely done except in certain research labs that are well set up kind of to do that and the other problem is you can't simulate you know airflow in terms of fans and things you can't simulate you know you get incredibly humid in that kind of environment so yeah very unrealistic but it's good to actually understand the physiological mechanisms in the lab so what happens instead is we try and take samples from the skin surface and that's where that sort of patch testing comes in and that's what's been historically used is like a cotton patch with a waterproof dressing over it basically like wound dressings they use in hospitals is typically what's used you put them onto the skin surface for

a period of time the cotton bit absorbs some of that sweat as you're sweating and then you can take that off and there's a couple of different ways to extract the sweat from that and then you can measure the sodium concentration now these days there's you know the wearables you showed one before where we're trying to do this in a way that we can reuse that mechanism and also we don't need skilled technicians to clean down the site apply the patch take it off you centrifuge the patch to extract the sweat and all of and then you know then measure it on lab equipment so we're trying to remove all of those steps to be able to do it at home with a wearable i guess the one thing with both the patches and the wearable devices is and i've mentioned this a couple of times already is that the sodium concentration in your sweat varies at different parts of your body and it's probably to do with the density of sweat glands and all you know clothing that you wear and and all sorts of different things and so you take the sweat sodium concentration you get and on a forearm which is probably the most commonly used patch patch site generally speaking that the number you get there will be higher than what it would be across the whole body if you did that whole body wash down that i mentioned before and so there has been some research to come up with equations now that you can predict or estimate the whole body value based on the value at certain sort of standardized patch sites where they're actually done both simultaneously in the lab so what the people are now wondering is is i don't have access to any of this stuff right now i don't know where to get a patch there's few commercially

available and you can go on the internet we're not going to endorse one or the other is it good enough to say hey i've got a lot of salt on my shirt or on my hat because at the end of the day you're getting you're giving people you know in your in your uh scenario you're giving people like a high medium low category can people realistically go and do that yeah it's a good point because sweat sodium does vary probably 15 from day to day even if you're doing exactly the same thing um it changes whether your diet changes which is something i looked at in my PhD so if you load up on salt the two or three days before a race for example thinking i need to load up on salt in fact the kidneys will flush 95 of that out anyway um but but it will actually make your salt uh your sweat more salty on race today not by a huge amount i found three days doesn't have a massive difference if you did it for a week maybe more substantial um but yeah in in terms of actually then you know using salt on your skin i guess the thing i would say with that is that you know triathletes for example if you got out of the ocean did that salt come from your sweat or from the ocean for a start um one of the big issues the other issue there is you know i go oh i've got really salt you know big salt crust on my clothes today i didn't last week well was that because you wore a white t-shirt last week and a black t-shirt this week um they're the sort of things you need to bear in mind yeah exactly and and again you know the total amount of salt there is about the total sweat loss so it's going to be

duration dependent as well the longer you go the more sweat you've lost onto the clothes or the skin or whatever and then as the water bit evaporates the salt is left behind and so sometimes it might be more of a function of duration than it is a function of sweat sodium concentration so it's a difficult one i mean if you're doing the same two hour ride or run or whatever it is and you've changed your diet or something and you notice this salt the salt crust is worse than one and then the other but everything else is pretty much the same yeah maybe it is an indication of sweat sodium concentration but i don't think it's enough to just go i've got a salty crust i must be a salty sweater that's what i kind of keep coming back to too i know because everybody thinks that they have like salty sweat you kind of ask them and it's definitely not proportional to any of the bell curves that the gssi have put out or anything i keep having hope that the very and i i'm i'm the most skeptical person of the wearable industry so everybody who's listening to this you can take this into the context of this next statement i keep hoping that the wearables will come back with a reliable way to do it and the reason that i'm hopeful for that is because in the scope of everything that the wearables are trying to measure this is like the simplest molecule that you can measure sodium it's electrolyte it's not that complex it's small yeah it's we know the charge of it it's not like measuring something in the blood right which what you're trying to do you're trying to measure on the skin so i guess what i'm saying is is with all due respect to the people that are trying to solve this problem

they'll probably yell at me due to the complexities of all this now and you you're more familiar with this than i am what i'm saying is on balance in terms of the things that you are trying to solve this is one of the more impactful ones and then actually being able to solve it in real time with a wearable is actually one of the more simple things that you can actually start to look at and then you compare it with the ridiculous situation that you just mentioned of how very few labs but some labs actually do it with this whole di deionized water bath afterwards it's just totally preposterous like anybody who has ever seen that done you just look at it like this is the most ridiculous setup ever and i have seen it i've seen some photos i didn't see it live and i don't know if you have i think they might have done it at kona one year they actually had people like like these like kitty pools with like the plastic bag in the bottom of it and then like a bike set up on a trainer in the kitty pool and then yeah there's pictures of people like having water doused over their head at the end of the session oh my god totally ridiculous all right alan thanks for coming on the podcast this is um enlightening uh to say the least i have a little bit of a different perspective on how we're going to apply some of this with athletes it's going to be something that i literally start using and implementing tomorrow i mean that's i there are very few conversations where in very few pieces of research where i can where i can say that where i can look at it and go i'm going to look at this differently tomorrow than i did yesterday because normally it just takes so much to like turn that titanic of practice around this is something where it's practical it makes a lot of

sense it's something that we've all been theorizing for a lot of years and finally you you know crunched the numbers behind it so so thank you for doing that um as i mentioned to you offline there's going to be an accompanying piece to this podcast where we're going to discuss this amongst our coaching group and at the time i'm recording this right now i don't know if it's going to be at the very end of this podcast or it's going to be in a separate podcast so y'all are just going to have to wait until the outro to actually to actually listen to this but i think that the reason that i mentioned that right now is it's it's emblematic of how impactful i think this is is i think it's worth doing a two-parter with our with our coaching staff to discuss so thank you is there anything else that you want to is there anything else you want to leave the listeners with how can they get a hold of you where can they learn more about this yeah i mean i guess the first thing before i get into that would be just to say obviously this is theoretical data based on a mathematical model so it may turn out that it's not quite perfect in the real world but i think what it does allow us to do is conceptualize the basics of how this is going to play out and as you said like you know you're trying to hit a moving target throughout an event where you don't have even feedback on whether you're hitting that target or not and the target's moving simultaneously so it's never going to be precise anyway so well we've talked about kind of precise numbers today they never will be in the real world and if the model turns out to be five percent out or ten percent it probably doesn't matter anyway it just gives you that conceptual framework i think to to how to kind of look at all of this and how to

put it together in terms of contacting me i work from monash university that's sort of where i do teaching and research so if you just google my name and monash university you'll find that you know researcher pages and you know as universities like to do they'll put your email address up there whether you like it or not so you can contact me that way if you ever want to find a researcher just google them and the name of the university they work at and guaranteed you'll find their email address because there are no pain points associated with that is what you're trying to say none at all yeah yeah yeah um the uh i guess on social media so my twitter handle is next so this is from my private practice next level nutrition so it's n-e-x-t-l-v-l-n-u-t um or the the podcast that you mentioned before so we have a twitter handle for that but also i'm pretty active on instagram now as well is the long munch and so that's the both the twitter and the instagram handle and we've got the long munch.com is we've got the website it's it's not built yet but it's coming next year and that's going to have a whole bunch of sort of written resources and things that accompany the podcast that we that we've been doing for a couple of years now links to all that will be in the show notes once again thanks for coming on the podcast alan no worries pleasure i wanted to treat this more like a continuing ed so maybe we can just like start there right and go through the points of confusion and then start to work back into the reality i did not

have an outline for this but since ryan just brought up it so what other after you guys read alan's paper looked at looked at his slides and listened to the interview that i did with him what other points of confusion exists and exist in terms of i want to know more about this in order to apply it to my athletes i think one thing is when all of this content comes about i try to think of it of like how are my athletes going to come to me and ask questions and so listen to the recording um yesterday that will be released later and then i go back to podcast with dr hydration podcast with andy blow that like it's saying this and and when you listen to these things or read that article we want to latch on to one thing and then that sticks with us and we forget everything else and so i think when you're listening to this and anything like you want to zoom out and and taking everything because there's one point in that recording coop that it's like okay let's stop right there this is what people are going to latch on to but let's clarify that um so i think yeah there's a lot of information out there for better and worse um and also for better and worse you have to do a lot of parsing through it um to get through it so this is yet another set of information that has similar themes to dr hydration um andy blow and just like keep consuming more um pun with sodium and water

dr hydration being stavros cavaros which i'll link it's okay no it's all good it's all he has a he has a he has a very difficult name to pronounce and i probably just butchered it which he'll forgive me for i'll link that up in the show notes as well so anybody else with points of confusion before we kind of start to plow forward i don't necessarily yeah go ahead nicole sorry oh i was gonna say i think you know as you take it all in and try to conceptualize it i come back to i wonder you know like yeah we want to match you know know your fluid loss know how much you're replacing but like is there any harm in just moving forward with the recommendation you know like do we have evidence that consuming 450 milligrams per liter ingested you know what i mean like maybe maybe we don't need that much it seems it seems like from the math you don't need that much but like is there harm or evidence in following that recommendation to continue to get as close as we can and guess if athletes don't know their sweat rate and don't know how salty of a sweater they are right so i try to get through this with some of the conversation with andy is is we're trying to parse out the difference between deleterious and critical right and a lot of times when we talk about hyponatremia research we're talking about not falling below a certain level to reach some sort of critical state which would you know instigate some sort of hospital event where we've got to immediately replace those those that sodium loss somehow with some drastic uh some drastic type of intervention um and that's a

hard in this area that is a hard line to to to actually determine and as we wrapped up with i don't think we know i do want to nicole you bring up one really important point that i want you guys and all of our coaches and the people that are listening to this to kind of understand that andy mentioned this during the podcast is this is a model right this is a model based on math we're not putting humans on a treadmill or doing some sort of intervention study or actually like testing this with like a real person this is a mathematical model and a lot of times you have to start out that way in order to conceptually understand what type what types of interventions are you going to use how much fluid you want to prescribe somebody to take in i i brought up during the podcast the example of of the nix pod right so they are going to offer up an athlete recommendations right based on the inputs that they have which is the duration of the intensity the amount of fluid that they're losing and the the electrolyte composition of the sweat that the unit is detecting that might not be the right recommendation because of what what we just learned you're going to recommend something completely different based off of a five liter of of sweat loss per scenario which is four hour run right it's pretty realistic versus a 10 hour run scenario where you might lose 15 liters right those two recommendations in terms of the rate in the amount to replenish could be completely different and that's that's what i want

a lot of the listeners to to kind of come away with is we i think that we are well served to try to simplify recommendations as much as we can and try to weed through the nuance to come up with this is exactly what you need to do but this is one of those areas where i think we we are best served to add a little bit of complication to it and start to look at these kind of like graded scenarios of short run medium run long run race or something like something like that because the recommendations are going to be completely different across those scenarios yeah i i would just bring up i i don't know if this is a point of confusion but just like the broader view is that you know like the podcast was saying that alan was saying that you know up to four hours replenishment not as necessary yeah you know if you can't replenish 70 or don't replenish 70 or more your fluid less necessary knowing your sodium sweat concentration uh if you don't know that not necessary and that just highlighted to me that you know most athletes are training less than four hours most athletes when they train don't have as much access or any access to replenishment and most athletes do not know their sodium concentration and so no wonder you'll know anything well exactly so no wonder when we go into a 50 mile race 100 mile race and the time scale becomes so much greater and the environmental conditions become so much greater

uh the duration obviously is more that's when we start having issues and so the big big takeaway is we need to have as athletes and as coaches coaching our athletes we need to have more experience in those runs of four hours six hours eight hours and beyond and we need to have more experience with replenishment during those training runs yeah to to illustrate the easy math and i know a lot of people are not going to take the time to go and like view these slides that i'm going to put up in the show notes and a failure of audio is is trying to just trying to describe these things in words which don't really do it justice but i think the simplest way to think about is a normal dude i'm i hate to bias this towards men i'm sorry nicole but it's it's the easiest way for my feeble brain to to to work it out it's going to be about 70 kilograms two percent of 70 kilograms is 1.4 kilograms right if you want to talk about a two percent body water loss that's almost we'll just round it up to one and a half liters right if we're saying that one and a half liters is two percent and below two percent is where we want to start that's what we want to start to avoid that's a reasonable amount of fluid loss it's not a lot but you go out and run on something that's not an extremely hot day it's winter here everywhere and especially in color especially in colorado i ran at five degrees this morning it's going to take me a long time it might take me three or four hours to lose 1.5 liters of

fluid and so when when you kind of like when when you kind of look at that i think it just starts to paint the picture of now we want to layer on what the sodium that you would want to replace on top of that and it becomes a scenario where most people are going to be like oh wow i it's like i don't need to worry about this until far longer than i originally thought it's just a lot of fluid it's kind of what i'm what i'm getting at so don't get to your point i want to talk i really want to work through this initially because we are we're trying to give guidance to athletes on fluid and sodium replacement based off of three variables that are at best difficult to acquire and at worst we're just totally guessing so and we don't have good mechanisms of getting it right because you have to know the starting starting serum sodium concentration you have to know the electrolyte or the sodium composition of the sweat and you have to know how much fluid you're losing right those aren't easy things and you can split the middle you know and just try to like kind of like average it for people but i'm wondering after you guys thought of this what reasonable ways outside of going to a lab and getting a deionized water bath after you exercise on a after you exercise on a on an ergometer isn't that just a completely asinine way of doing it right like what other way what other

ways can you like go about getting this like what like an athlete's like okay i know what to do but i don't know how to get the variables in order to tell me how much to take in i'll jump in does nobody want to yeah go ahead nicole no you're right so you said three variables these are difficult right maybe we won't have the sodium concentration of the sweat maybe we won't have the electrolyte composition of a sweat sweat loss was the third variable you said so like we can test that pretty easily with athletes right and this is a normal practice that we'll do um is you have an athlete go out and weigh themselves before they run you know nude weight go to the bathroom beforehand go run for an hour try not to ingest anything while you're out there and then you weigh yourself after right and you get an idea of how much weight you lost and convert it to right like one kilogram is a liter right am i right yeah um so like we can get this estimate of your sweat loss and ideally we would do this across a variety of environments right because your sweat rate is going to be greater on a hot day versus a cold day so sometimes we'll send athletes out right for maybe three different temperatures so they have an idea of their range of where what their sweat rate is on across across that spectrum um but i think the thing that's interesting that we come to after reading through this is that you know like we we've always given this recommendation like the the longer duration

that you're going to be out there the closer to 100 we're trying to get right to match your sweat rate but that this paper kind of presents this you know like spectrum of percentages that you replace right so we may not know if you're a salty sweater we may not know the concentration but like if you know how much you're sweating and then you're starting to pay attention to how much you're consuming on an average four hour run and six hour run like you can at least get to where you now have a percentage replaced right this is like a new concept for me like that's and i think if you can get there like well what do i have on an average what am i replenishing that can give you an idea of how much sodium will be required so you're mentioning the sweat test quick show of hands how many of you have actually had like had your athletes do this like the weight yeah okay so that's good you guys now everybody's showing hands for those of you listening to the podcast version once again failure of audio here it's not as easy as it's described to create that entire portfolio that nicole just mentioned right because you have first the biggest thing is the environment so you're kind of talking about a whole year that you have to do this across like you could do like one every quarter to like balance out all of the different all of the different temperature ranges so it'll get it you're absolutely right nicole it'll get it close probably not precise because the error in those measurements is you know kind of who knows don't you know duncan's

been doing ultra marathons for long enough that you could probably remember the days of when the races used to use body weight as part of like the medical check-in at aid stations so you'd roll into an aid station and they weigh you and they'd use that as you know part of the kind of medical evaluation to determine if you are fit or fit or not fit or not to continue and so my point with all that is is it gets really problematic when you're when you're when you're doing in the field but i think the thing is is you can kind of just get it close right and and the the the reason that i like that tool honestly is to demonstrate to the athlete how different it usually is not not not always is but it usually is across those temperature ranges because most people have this kind of like static view of i need to take in one bottle an hour right irrespective of the conditions maybe it's one and a quarter if it's really hot but really it could be like three or four full difference from one temperature range to the other temperature the range and that's even excluding like that very edges of very edges of the bell curve i guess so i guess what my point with that is is the i think that the highlight of that tool yes you can start to get the like the exact fluid losses but it's i use it more as an education tool to to to demonstrate how uh how different it is at the different temperature ranges so that they can kind of apply those so they can apply the correct like course uh correct magnitude of course correction as they go through a race with that same variance in temperature and this is why

ultra is a great uh playground for this you take any reasonably length ultra marathon 8 10 12 20 hours or whatever you're going to go through a huge temperature range especially for the ones that start in the wee hours in the morning leadville trail 100 duncan you know that starts at you know 4 a.m and it's 20 degrees outside and then all of a sudden you know 10 hours later you're baking in the sun at 10 000 feet and it's 75 degrees that's a big environmental range to try to to to try to nail uh a hydration strategy down with because it is so dynamic and you're not just describing leadville like you're describing almost any mountainous hundred right it's the same issue yeah i'm just picking on duncan because he's a leadville winner and he doesn't like to he doesn't like to bring it up but it's just my way to pick on him well i was gonna say i mean that that's the big one most athletes if i if i have an athlete doing a three hour four hour type training run they're doing it at five in the morning six in the morning they're done by eight or nine in the morning that's the vast majority of their training so a lot of athletes don't hit that noon one two four p.m time slot in terms of their training in particular after eight hours of running already or 12 hours of running already and so the more we can train an athlete in that context i think you know the more information they're gonna have yeah this might be one of those areas where you actually do do something differently in racing as compared to training and you kind of got to be okay with it like if you don't

have a lot of experience trying to replace fluids at a temperature range that you're not training in first off the air would be you got to train in that temperature range at some point just to kind of like teach it but you know it's not practical for a lot of people who have real lives and they've got a narrow window of time to train and things like that and so we've got it like in in some cases i do think you you have to break the old adage of you have to do something different in a race as compared to what you did in training and that difference is we're going to take in more fluid at this rate and with this type of electrolyte composition within that that fluid and kind of everything else intake and you can come up with ways to model that right by extrapolating you know what they're doing in normal training to a different temperature range or using you know alan's model that that he mentioned here but at the end of the day they're doing it sometimes it's drastically different sometimes it's like double or triple instead of one bottle an hour it's like two or three bottles an hour and so like wrapping people's heads around that i think is a is a difficult challenge and also you're gonna have to slow down to do that because of the volume of fluid right yeah and like duration of intensity the temperature's going up like yeah you don't get to that one two o'clock time frame where it's kind of the hottest part of the day in training your your four hour less long runs you can pace those very evenly and then on race day you're going way longer for four hours so from the get-go you got to dial it back a bit and then

realize whenever i'm going to try this new thing on race day with fluid and sodium consumption i'm going to do myself a favor and also back off a little bit to to compensate for that as nobody wants to hear that slow down some people look at it for an excuse maybe uh ingesting the fluids is actually excuse go ahead fred i can see you chopping at the bit there yeah so one thing that i was thinking when you were saying all of that and also want to listen to the other recording is that i i wasn't about this idea of like doing things different in competition compared to compared to training and i think that it is true although like if you are ever planning to do that in training maybe even if it's just for like a one hour run yeah you should go like drinking a lot or like drinking a lot from the minute when you get out to like get used to that like whatever it is the slashing feeling of the water in the stomach and not come to competition like probably not a problem for someone who has a lot of experience in 100 milers because like they know they know it already and what it feels like it's like oh yeah i don't want this to be the next thing that that's like the new thing that is happening to me or to the athlete on race day so it's like i think it's this idea that like it's something you need to train for but still what you were saying like it's something that you probably don't need to train for as much or you just need to train it as practice for the race but not as something that you need for training itself yeah i mean you're trying to you have to figure out kind of what that tolerance is and you really don't know it until you test it

and even then when you test it it's a little bit of a dice roll you know come around race day like can you take into two liters of fluid in an hour i mean everybody out there they you know that's four bottles that's four soft flax worth of fluid you might be able to do that for your one hour run it might not feel that good you'll kind of suck it up and just you know deal with your you know bloated belly at the end of it but doing that in the middle of some sort of ultra marathon that is a completely different proposition because of all of the other stressors that uh that are going on so you're absolutely right fred i mean you do have tools to do that to kind of fake it right fake and see what that tolerance is during during training but i do think you have to realize the limitations of those when you're practically implementing them with athletes you they they probably are not going to convert one to one but if you want to use it as a learning lesson to see how hey this is how we could do it great the other thing that sorry i've got a little bit of a cold today so i'm sniffling um the other thing that's extremely interesting with this is that i think it also brings up the the concept of where your calories coming from so if you're using a fluid ingestion rate that's higher than what you are using in training and you're using a commercial electrolyte replacement beverage that has some level of calories in it you have to recognize that you might throw your total calorie balance out of whack because of these fluids that you're taking in that you didn't prepare for and i see this all the time

with athletes that are trying to use like even like a six or eight percent carbohydrate solution you know and and that and that's not that much i mean that's not like one of the rock tain or or or or scratch labs uh what's the name of that product i'm like it yeah the super fuel product right that's not even up to that level i mean that's going to be you know 120 calories in a in a soft flask just to bring it back down to back down to practical terms if you think about going through three of those in an hour that's a liter and a half that's 120 times three that's 360 calories most athletes can't tolerate that should they be able to that's a different question but a lot of athletes just from a carbohydrate absorption perspective aren't going to be able to handle that so now you've compounded this a couple of different ways because what most athletes will do will either dilute that drink which dilutes the electrolyte concentration or switch over to just plain water which you know fun which functionally dilutes all of the electrolytes that you're taking in and so back to the complexity piece right think about this is what i encourage athletes to do when you have this big temperature range think about the complexity piece of it because it it is going to be a more complicated math problem than take one sodium pill an hour it's going to vary based on the temperature range of the race and then how long the race actually is the good thing that's going for us before anybody jumps in too quick is that the training the in the intensity of the training conditions that we're normally in are very close to the race so i think that the like this intensity

component of yeah you can you're going to sweat more as the race is more intense like the lea kipchoge example right he's trying to run a two-hour marathon that complexity is kind of thrown out the window because everybody's running like endurance or recovery run pace out in training for most of their training and they're going to do that same intensity during the race so you actually do have a decent playground to start to figure these things out from that perspective yeah i keep coming back to the the idea of are you able to replenish right and so during training the issue is either no or the issue is yes but at a lesser rate than i would during a race and then we get into a race you have all this access to fluid all of a sudden and that to me becomes the variable that is least accounted for when you come to a race situation so i don't know if we can riff on that for a little bit and how to coach an athlete best through that scenario yeah i mean what do you guys think duncan are you saying in training you're going to have less access to fluid and then in on race day you're going to have more access for fluid and how do i count for that correct because i think that's where we're having these issues in a race for some people is all of a sudden i'm ingesting twice the amount of fluid and i'm not as cognizant of the sodium level of that fluid that i'm ingesting um you know so so an example is uh you know over the years in particular this past year or two i've gotten much more focused on

coaching athletes through doing loop training you know two hours back to the car three hour loop back you know whatever whatever the duration might be so they can resupply in their key training runs you know i didn't i never really worked with athletes in that regard before i would say yeah do the cool loop you want to do and you know but now i think it's uh it's a little more important to be focused on that so i don't know if anyone else does that yeah that's what i was going to say you got to do the the car aid station loop right yeah and then like what's nice throw all your wrappers down when you get there do some math right then get a jump start on your nutrition report card but yeah you've got to loop it to to make it simple because you go for your long run in the mountains maybe that streams out of water you know then then there's too many variables to account for i do think to to duncan's point as a coach here's where we can kind of come in with our expertise because we realize that there you not only have this kind of more like social situation you know for lack of a better word where now you have access to aid stations and pacers and you know i guess pacers you should only be taking fluid off of them if it's leadville to bring up that race again but you have this you have this like social situation where you just have more access to fluid as compared to just the fluid you can kind of carry carry on your back and that just presents more opportunities to to take in fluid that you might not need depending upon the temperature range that you're actually in or sodium that you might not need depending upon how much fluid you need to replace and how much fluid that um uh that

that you've lost and you combine that with what i mentioned earlier is we're working with this equation where it's hard to get the variables so one of the ways that we can kind of come in as coaches is make reasonable estimates and i think one of the things we can take from alan's work is is that if you make reasonable estimates you can kind of get it close and at least try to avoid something that is what i would say extremely performance deleterious like you have like a 10 decline in performance or something like that from the intervention that you give you always try to avoid those things and or just catastrophic from a extremely low blood sodium uh perspective i do think that you can reasonably do that in most cases as long as those athletes sweat sodium concentrations aren't on the edges of the bell curve when you have the athletes that are and i actually i just had one that texted me last last night about this so i'm a little bit hesitant to say everybody fits in this model because they don't but when you have athletes that are kind of in the middle of that sweat sodium bell curve you can there's tolerance there right there's tolerance there and as long as you're not i think as long as you're not like egregiously overdoing it one way or the other which has kind of been the trend to be honest with you your body will compensate to a certain extent and it can we know it can also tolerate losses you know we don't know what those are in an ultra marathon setting it's probably not two percent it's probably more than that i don't want to guess it how much more than that but it's

probably you know we probably don't need to focus on two percent body water loss as this like magic threshold for a hundred mile ultra marathon that you don't want to exceed because there's going to be more body mass losses that aren't associated with like the functional hydration piece of things but i guess my point with that is is is for a lot of people that are kind of hitting in the middle of the bell curve you can even if you don't have access to lab equipment to a wearable and things like that you can get it reasonably close and your body can kind of like compensate for for some of the tolerance as long as you're not epically screwing it up yeah like a calories as a as an example of that we're not talking calories today but you know if we avoid the extremes generally we know what works so if if an athlete's not going out in a completely fasted state and running in a fasted state that's an extreme that's going to cause issues if an athlete has no practice with gi tolerance is trying to get four to five hundred calories per hour that becomes an issue so at that middle spot if an athlete is attempting to get 250 calories per hour 300 calories maybe per hour they're probably going to be doing okay and i think the same with sodium you know as long as they're not going zero as long as they have an awareness that they need some sodium per unit of of fluid we're going to hit most problems uh i don't know yeah well because here's the other thing right like i've seen a lot of athletes do this uh both sweat sodium testing and sweat uh rate loss testing in like environmental chambers right so go in just like

we're we we were discussing you know with the stupid uh example with a bike you can do it on a treadmill in another format and use you know absorbent patches and squeeze the sweat out of the patch they use that in like team sports and stuff like that you can do that but i think one in ultra marathon especially especially for races like western states and uh bad water if you go through a heat training intervention using sauna or hot water bath that changes or if you just start training the heat right we know that your sweat rate changes at any temperature range and also the composition uh the electrolyte composition of that sweat can change as well at those you know at whatever output that you're um uh that you're actually performing in and so you might actually be trying to get as precise as possible but if you're going to go through a heat training intervention once again this is where coaching comes in you have to realize how that is malleable right how that's going to adapt these previous equations that you have or these previous loss rates that you have are going to adapt after you have gone through that intervention because that's kind of the point of some of the interventions is to sweat earlier and to sweat more and so if you're underneath that condition and you're working with kind of like previous variables once again this is another thing that that kind of complicates it that that that makes it that makes it extremely difficult so anyway i i i just thought of that and i thought i thought i would bring it up because there are a lot of athletes that want to get this dialed in i don't think now is the time to dial it in i think it's kind of like closer to the

race once you've gone through all of your training because even training can do that to be honest with you um once you've gone through all your training to really to really really get it close go ahead fred i was going to say about what you were saying right now like before when you were saying about the uh you you have to test almost virtually like my thought was like whenever i've done this or asked someone to do it was always close to the competition because this is actually when it is relevant like a more or less i don't care what is your sweat rate right now like if you want to know it for the sake of curiosity or because you want to like be on top of your hydration throughout the day and like no though i lost this much water i should drink more or less during the day because i'm feeling sluggish or something like that i mean absolutely yes but like for performance purposes yes that and then also like if you're doing any kind of heat training intervention what matters is and basically what really matters is what is your sweat rate on race day right so you want to measure as close to that like you cannot measure it on race day you can probably not do it the day before maybe you can do it a week before but not before not a month before when you're going to do your last three interventions trying to target that one race right yeah i i think that that's a money uh piece of advice there fred is you want to know your sweat rate on race day in and i'll add in in those conditions that the race day is actually going to actually going to present you can do all the testing that you want like you know pre it's not like it's not like we do like physiological testing right so we do lactate threshold vo2 max testing or do a field testing whatever you try to orchestrate those like once a quarter depending upon you know the

the athlete it's not like that because you're not marking like quote-unquote progress right you kind of you really don't care about this except for the race yeah you care about it in training but those sessions as we discussed earlier are rel are most of the time shorter and so the the pressure right that like ergogenic pressure right of getting this right is just less in that type of uh in that type of training situation as opposed to the race yeah and then like your body through the thirst mechanism really it will self-regulate so like for tomorrow's session like if you were thirstier at the end of the race or more dehydrated you will have drunk more you're not going to get chronically dehydrated like more and more dehydrated if you're drinking less because you will just be a bit more thirsty yeah so then from day to day it's not as important it is that what you were saying like close to competition yeah i still come come back to the theme is is you can use thirst to up to a few hours because once again it almost doesn't matter at that point right i mean not it doesn't matter but like you've got taller your body has enough reserves to to tolerate things but after that and especially in extreme environments cold altitude heat kind of whatever ultra marathons kind of serve up your your mechanism for thirst just you know gets foobarred i was going to throw in the real f word there but i held myself back it just gets foobarred because because of all of these different kind of all these different factors and so you can use it as an in as an indicator but not as the sole indicator i

kind of what i come back to but i do like like i do like this paper a lot because it's like the conversation that we're having because it's giving us two sides of something like this is very complicated and there are so many variables that we don't know and then on the slides that uh that you got from the podcast yesterday like there is this one uh like there's a decision tree which i really like how it simplifies it because like for like out of one two three four six options four of them are seasoned to taste right so it's like it's very complicated but like doesn't matter that much unless it's in these two specific scenarios yeah right i mean which is like at the very extreme yeah of it which i love it it's like oh like this thing that looks so complicated like we can probably summarize it and look at it in this way i agree but when you go down to the century pretty much every ultra marathon is going to end up in the lower left hand corner where you have to make that complicated decision and almost every piece of training is going to end up on the right hand side where it doesn't matter that it that now that i'm thinking about it fred that there you go that's why it's so complicated it it's related to my earlier point is you're doing something different in racing than you are in training or at least the the decision tree is telling you to do something different in a race scenario as is compared to a a training scenario for for almost all of them and you don't get a chance to like you know if there are at least the pressure the ergogenic pressure as i mentioned earlier isn't there in a training scenario to get all those things right and then you asked that question about like

can we know by like the sweat or like the salt how salty is your t-shirt after like can you know like it's like we cannot know but i i kept wondering like is there anything that can tell me this like it's not going to give you a concentration but are you like either medium high because basically if i remember correctly it's like everyone that is average would be in the season to taste one yeah and then like it would be only those that are above average so like do you tend to be uh i i keep wondering is there going to be something i know that there's at least one hydration company that claims to tell you with a test and then they send you one of the patch tests as well as well but like they there's one that has a questioner i have no idea how good that questioner is and of course they didn't provide any validation for it yeah oh go ahead fred sorry keep going no no about that like it's like can we know can we get a an idea or actually can we learn that from experience like can you do one of those long runs in like one way and the other and then from that try to guess estimate if you're a salty sweater or not yeah i don't know i mean it's one of those things it's still a dice roll you can probably get it right the majority of the time just from those observations the scientific community would poo poo on that because you're getting like seven out of ten people instead of nine or ten out of ten people but the company that you mentioned i had them on my podcast earlier is andy blow with precision hydration so and they will use they will use sweat testing and like a resting setting right so they'll draw the sweat out of the uh gland

electrically and and analyze and tell you what your electrolyte composition is uh based off of that and then they put you into a high medium low kind of category and i just happen to have one on my desk right here uh and i i use this product i have athletes that that use that product i think that my opinion is that i think that that's a decent level of granularity to go about it and but you have to understand that sorry let me let me kind of back up a little bit so fred your um um your statement about they use a questionnaire they're doing that as a surrogate for the actual sweat for the actual sweat testing so actually looking at the sweat determining the electrolyte composition and things like that and what they're doing is is they're taking this observational piece that they've seen and they have thousands of tests like this they're taking those tests and comparing it to those those athletes observations and designing a questionnaire for people who don't have access to this type of test because it's a big machine you know it's the size of a i'm looking at my soundboard here nobody actually knows what it actually looks like but it's the size of a big laptop if you want to think about it like that and it's not my point with that is is is you can't just go to best buy and go find it right you have to find somebody who has one of these machines and go and get the test or they've got to come to you or whatever so in lieu of that based on all the tests they have and all the observations that they've made they've designed this questionnaire which probably gets it close and they'd be

transparent about this i've always found them to be very open and honest about what they can do and what they can't do in my interactions with them but it'll probably get it close for most people who have an honest assertation of their themselves which you know you can say some people don't know i'm taking the test right i don't even know how to answer it yeah like i've taken it numerous times yeah yeah so you don't know or it might be different you might like because it's your observation right and your biases are going to go into it it might be one thing one day and another day but i guess my point with that is is dividing it up into this like high medium low piece i i think that that's a reasonable degree of granularity i think if you get any more granular than that like you're trying to find electrolyte replacement beverage that's like within you know five millimoles per liter or something like that it just kind of misses the point because the the other inputs that you have to use our earlier example right don't aren't going to lead to that quite of a precise of an uh of an answer so i don't know i think i think even with that though like one of the things that you can kind of take take away i keep coming back to this is your body has a lot of tolerance and we don't need to replace everything not even close we've been using that 70 threshold in a lot of cases to stay above this two percent body water loss and i do think that a lot of athletes have taken that as they need to replace 98 of their body water loss starting at

ounce one and that's just not the case right you don't need to it's it's the total that you need to realize over long periods of time and you might not even get to 98 97 of your initial starting uh body weight for a two or three hour run you know and that's not to say that taking in fluids is bad right especially at those at those levels but it's just not i don't think it's i don't think it's less uh extremely argogenic nor even necessary well and i one thing i really liked about alan's work that pulls this out you know if you look at both extremes the saltiest of sweaters and the least saltiest of sweaters along what's the graph you put up it said how much sodium do i need yeah yep right so you have your like 80 millimole those are your saltiest sweaters your 20 millimole the least saltiest so like you're looking at the extremes of the bell curve even if your saltiest sweaters are able to replace 90 of their fluid like help me make sure i'm reading this chart right because he's that's that would be 84 of sodium losses required to maintain your stable sodium plasma levels right right yep and and the least of salty sweaters are even if they replaced 90 of their loss they're at 38 yep right like it's just i think it just gives people a lot of like grace that there's yeah yeah it's not as extreme and as precise yeah well and one one of the things that's kind of led to this and

like nicole what what you're kind of getting at is is there there does seem to be a uh uh kind of like a culture i mean and i picked that word very deliberately a culture of over sodium supplementation and those of us that have been in the ultra running game for a long period of time we've seen this transition to where people would down those salt pill down salt pills they would be on you know you would have uh races that uh had sponsors right with uh with sodium pills and they just have every aid station just a little bowl of them people would just take them out by the fistful and eat them like chicklets um but we we we have had a culture of over sodium supplementation that has kind of gradually gotten course corrected um uh over the years and that can be problematic i mean we initially started to recognize this just from a medical perspective right where people were just coming in with just you know they were bloated and just had way too much uh sodium on on on board because of this and so i think to your point nicole i hope something that something that people take away is yeah you do have a little bit of grace you don't need to take in a salt pill every single hour nor is the time dependency piece of the the biggest thing that you need to the that you need to that you need to worry about and interestingly enough i still think this is showing my disdain for exogenous sodium supplementation i still think that that's the recommended use on most of those bottles do you guys

know like the and what i mean by that is is take one of these for every x unit of time when you see the direction not per volume yeah yeah i think that's i i've said that for years don't can back me up on this you've known me the longest in this group i agree i mean that that is uh one of the biggest takeaways it's not per unit time it's per unit fluid volume consumed yeah and if you're going to look at it that way i'll leave the door open that there may be some time dependency on it but it's certainly not the heavier hitters in the room it's certainly not the main ones the main ones are going to be how much fluid are you losing how much are you taking in what's the composition of those two things right that's what we've been that's what we've been talking about and it has always befuddled me and i bang my freaking head on the table when i see that recommendation because what it's really doing they're just trying to sell more pills right because they're trying to sell it per unit time so people go out for a two-hour run they expect people to take two salt pills that's i mean that's there's no other there's no other in my opinion there's no other logical origin of that recommendation and stamping it on because they could do whatever they want to the supplement industry right they can put whatever they want to on their labels so they're choosing to do it as a time dependency and essentially to to to to get consumers to to to consume more of them to get athletes to consume i would say to give them the benefit of the doubt i would say it they may be also just trying to simplify it for the consumer yeah okay where if if we're already saying x amount of calories per

hour x amount of water per hour okay x amount of salt tabs per hour you know maybe it's just a simplistic thing but i don't know it causes problems causes problems i don't know i think that's disingenuous because the consumer should be smarter than that right actually i think that taking into account that most cyclists use basically half a liter bottles and so soft flux plasks are actually half a liter bottles like the calculation would not be like it's one every two bottles if it's one per liter or like one every four bottles if it's one per two liter so yeah i think we'd so Duncan just sees the best in every one i know you know i mean i work has good motives i i coach people that sell these that sell these sodium supplement products right and they're gonna listen to this and throw an egg at me or cancel me or something like that so i mean if anybody wants to come on my podcast and explain that to me or just do it privately like you're more than welcome to but i've always had an issue with that but the take-home message just kind of drive this back to the athletes i think you take the take-home message here is is when you're thinking about your sodium supplementation you should think about it across these three variables and not necessarily and certainly not predominantly and maybe not at all across a time variable and more than anything else that just messes with people because they're used to doing everything else by time when am i going to get to the next aid station when do i get my next gel when right being the key the key word there am i going to do x y or z and this the win is not the determining factor right there's other things kind of like coming into play and

i just think that that switch a lot of people just they just can't like for whatever reason like get out of that ingrained thought because it's easy it's easy that way you don't have to be easy you don't have to do math while running i know when it whenever um uh whenever i've had to explain this at our camps so uh duncan will know this as we kind of go through this nutrition talk and we bring it along four points calories fluid and sodium and calories and fluid are always per unit time right x amount of calories for this amount for an hour x amount of fluid and it's a big range it's like double right to go on our earlier point per time and then when i get to the sodium piece i presented in per unit of fluid volume that you are taking in right and i always have to be very deliberate and slow and make sure that i'm emphasizing how i'm describing the units with that because you've gone through two maybe you should flip this around to be honest with you because i've always gone from easiest to most complex maybe i should just flip it around just to like start out with the hard one or whatever but but anyway my point with that is is just based on experience if i don't do that people will just like ignore the units and just think that and just assume that it's per unit time and i've had people go out on a run and say hey i took in 500 milligrams per hour i hit you know i hit the range exactly as you told me to and i was i'm like

no wait a minute like you totally missed it i did not explain this correctly because it's not per hour but at the same time when you're explaining that really what you're saying is like liquid is per hour yeah and then this is per liquid so then like in the end it's a multiplication of one thing and the other so like if they are strict with the liquid if they should get right right yeah but then like if something changes with the liquid then like or if they are not using the same part of the range like the top range or the bottom of the range yeah so what what we do at our camps is is just a an exercise that ryan uh described earlier is we have everybody go out they keep their trash not that they would like throw it out on the trails anywhere but they're very deliberate about like keeping all their trash and we dump their trash on a table and we just log it and the hardest part of all of that is this is how much fluid i consumed and this is the sodium from all of those things all of the gels the rice balls the crackers and cookies and sandwiches and the electrolyte actually in the drink itself and then we divide that by the total amount of fluid that was consumed whether that fluid was from an electrolyte drink or from water or from even like a like a coke or something like that and you can argue how that changes you know the composition of everything but we're just trying to get kind of a fundamental uh basis point overview yeah and the range that we're trying to get in is 600 to 800 milliliters of sodium per liter of fluid and once again it's a split the middle difference right and we're

not saying that you have to replace 100 of that we're just saying that the rate of ingestion as long as you're getting the rate uh as long as you're matching that correctly with the rate of output not one to one correctly with the rate of output that's going to keep you in the right serum sodium range if you're if you're doing that especially over long like long periods of time now this might add a little bit of a nuance to it where maybe it's not that high maybe it's 500 milliliters per there are 500 milligrams per liter or something like that 300 but but the point is is you've got to kind of like get it reasonable especially when you're looking at at long duration activities okay we're gonna wrap it up i want to hear duncan just left he like quit what happened to duncan he's mad at me yeah yeah go ahead for it yeah yeah yeah so there is one thing that like we have been looking at all of these variables and then one thing that you have been mentioning a lot is like how cool is the tolerance of the body for the different ranges right but one thing that i looked at in the paper like well i i built a calculator so like i built the model in excel and then like one thing that i was seeing when i was doing is that what it is trying to do is always keeping the sodium the plasma sodium concentration at 140 and this one thing that you said in the in the other audio file that is like do we know if the optimum is like 140 or is it 135 or 150 especially what i was wondering is because i don't know what

the normal range i know that 140 is right in the middle because it's what alan said on the other audio but it's like yeah like what is the range because even then like what is the tolerance that we have because i have my calculator and like well if i actually want to get it instead of 140 if i want to get it to as low as 125 how much more how much less do i have to take or like how much more can i take and it not be a problem because i will not be above range or how much less can i take and it not be a problem because i will still not be so i i will look at that one i'll try to make that calculator actually i will maybe even try to convert it to ounces if i oh man dude wait for do you doing all the americans a favor now fred's in spain right now for the listeners i started i started making it and i i started making it because i wanted to understand the model and then it was like well yeah i could probably share this with everyone i will have to make it pretty but right now i don't know if anyone yeah understand it like can i create a calculator that we can all have and then say like okay yeah so then is it going to be a problem or not what is the acceptable range that we have like what should i give my athlete or do it i mean we pass that around the coaching department if we can make it public in some format i could do it on my you know website and we can kind of cross-reference it with alan get some sign off there i think that'd be great he can check all of my calculations so i didn't screw it up yeah so far the numbers are the same ones that he has on the paper so yeah so i

wanted i wanted to you gave me a good lead in here right because i wanted to wrap off wrap up with like one thing you either learned or you're going to do differently or was re-emphasized to you um and mine was just that fred is the is that most likely when we're thinking about what most likely when we're thinking about serum sodium concentration which is just what you mentioned right how are we going to keep it in the right range there's probably not an ergogenic like optimal range like optimal way to do it if you're within this range it's potato potato you go outside of it and we know that there are complications right we have to send people a hospital you know all those other things but within there at the very most we're not certain and you know who knows 10 or 15 years now this might be proven wrong but i honestly don't think that one way or the other it's going to matter all that all that much i do think that there's obviously a critical there are critical levels there that we need to that we need to watch out for but who knows that was one thing that was re-emphasized to me is that we're talking about all this and we're still not sure if there is an ergogenically optimal level of sodium sodium serum sodium and if there is what is it is it 140 right we're kind of picking this from a medical perspective in terms of how to prevent catastrophe but a lot of times in sports we're trying to optimize it so anyway that was one thing that was re-emphasized to me that i brought up with alan he kind of gave the same answer is like we don't know so we'll go around the room duncan you get

to go first since you're on the left hand side of my screen i'm going to go clockwise that means nicole you're next uh so you can prepare your thoughts as as uh and get them ready so duncan what what did you either learn or are you going to kind of like do differently or re-emphasize with your athletes yeah big re-emphasis is again just on the importance of uh over the course of a year or six month window or or build up getting more runs greater than four hours getting more runs greater than four hours with fluid replacement as an option or as a as a more uh significant option and then attempting to get in sodium you know this is something we talk about all the time but hey sodium is important but it's per unit of fluid uh volume not per unit time really hitting that home i think uh is important and then just getting athletes into a range of environmental conditions you know i think i think of myself as an anecdote you know i run at 6 a.m every morning in the summer in gunnison it's 41.3 degrees when i start it's 57.6 degrees when i end every morning no rain no humidity it's always the same i'm not out of my comfort zone enough and so i think that's important for athletes to to run at different times of the day if they can run longer when they can and replenish more when they can yeah very dynamic right going back to our earlier point like that the fluid losses are extreme way more dynamic than most people appreciate when you go up and down that

temperature gradient all right nicole yeah i think this really drives home the importance of uh developing your hydration status first or your hydration strategy first right that you know we can like really dial in on the nitty-gritty of my milligrams per sip of sodium but like before you even do that like you have to understand your sweat rate right and understand enter a variety conditions like duncan said you have to have your hydration plan in place and experiment with that through your training and then the calories follow and then sodium intake follows right and we can easily correct if we get into a whole um caloric wise it doesn't take that long you can easily correct if you do get into a hole if you get behind on sodium we can do that quickly if you get behind on hydration that takes hours to correct and so figure that out first um and then the rest will follow right like that has to be the piece that's that's really critical i think one other piece that's worth taking home is i came away with this feeling like you know most athletic populations don't need to worry about sodium i think ultra runners like this is a good use case for doing a sweat test like using the patch like i i do like i used to tell athletes maybe that's not as important but i think for a lot of people there's a benefit there in knowing

your sodium loss so yeah i i think that this is something i told meredith when i meredith is ceo of nicks um when i saw her at the running event it's like you're gonna have a lot of team sports athletes that want this it's probably not very useful for them i hate to tell you that because it's a huge market for your business but you know when you go out and you're practicing you're in the weight room for an hour probably not that important and at the very most like even even you take uh alan brought up this example in the uh in in the podcast in some sports there's just no opportunity you've got a soccer match and you're out there for 90 minutes you can't like go to the sideline and you know start to rehydrate so anyway so the so even if you did know it it's like okay your intervention is now limited to halftime right or whenever that break is quarters in a basketball game or periods in a hockey match or something like that so anyway that nicole that that that point is is is really really well taken of ultra marathon might be the best and in some cases maybe the only kind of use case for this just because the duration of our activities are so long right certainly iron man and some stage race cycling gets it gets into this area as well but it's certain ultra ultra is certainly the best one because we see the whole range from training to racing that can be just an hour to days right all right right uh re-emphasized of just keep it simple and you're always practicing this

you're not going to hit the extreme temperatures of race day in your training runs so be prepared have an empty soft flask on you so you can fill up that extra bottle take the bladder um just just be prepared and slow down like i think yeah practice it in training and then on race day like oh yeah it's gonna be pretty hot it's gonna be mid 80s upper 80s i never ran in that so i don't know how much more i'm going to drink but i'm going to be capable rather than being that person that is parched and people are passing like do you have any water on you like just be prepared be prepared and slow down so you can so you can compensate for temperatures going up my body needs more research sources to thermoregulate so i need to slow down to counteract that we have one of our coaches you wrote an article about this on our blog that that screwed up that extrapolation and got heat stroke right cliff oh yeah and and i'll i'll link up that i'll link up uh i'll put the link to that blog in in the in the show notes as well but i think it goes to demonstrate that even when you're trying to make that extrapolation it's still hard and it's easy to lose in kind of like the field of battle so to speak with all these other things going on i do think ryan to your point that extrapolation of your training conditions to your race conditions when you don't have the opportunity or don't create

the opportunity to actually experience it that is one of the trickiest things about this and when you're working with normal athletes that don't travel all around the world to their race venues and stuff like that that happens a lot and it's just a reality that we have to recognize and i think all of us including me can do a much better job of paying attention to that extrapolation and making it a point in training and then also when we're coming up with the race plans all right fred you're next i would say my takeaway is that we should like practice and measure and then create a strategy ryan said before something like we don't want to be doing math while running which is absolutely true especially like at hour 15 of an ultra marathon like during the night or in the middle of the day so like do that math beforehand or like either you or your coach or whatever it is so like practice it measure it what you were saying before about dumping everything all the wrappers on the table and knowing what it is and then knowing like having like this strategy like okay like if it is this hot then i will have to drink more and then like this means like this much more sodium and like having some that like simple rules on your strategy that is like a flexible strategy that will help you on race day yeah you know i struggle with that a lot because i want to get the race day strategy as precise as possible but i realize that there's there has to be some sort of flexibility because you're not perfect at predicting things i kind of give myself like a 90 rule like if we can get a 90 there and then take

90 of the thinking out of it i'm like i'm good with that and i've seen that workout with athletes where it's like you know they come in and they have like one more gel in their pack like okay like you had eight gels and you took seven instead of eight i'm kind of okay with that that's not exactly 90 i know that but like i'm kind of okay with that you know like you you leave with three flax and there's just a little bit left in the third one when they come back in like i'm okay with that i think we've got that like we've got that close and the bigger advantage to your point fred is just not doing the math and not thinking about it because i tell you what that's energy like the the that is absolute that absolutely is a cost when you're out on a race course and you're trying to maximize performance it's just like putting on an extra couple kilograms or dragging a rock behind you or you know kind of however else you can think about handicapping yourself having to think a lot is absolutely a performance detriment and the more that we can plan for it in advance to take the thinking out of it that will that enables our athletes more crews can do that as well right we're going to take the thinking out of it out of it just take everything that we give you trust us that's a big part of it trust us and then then go and that i've seen that play out in so many different so many different situations where the athletes who just aren't thinking they're going to typically overperform because they've taken that burden off

of themselves awesome folks thanks thanks for being the guinea pigs thanks that's good i didn't even use my calculator i'm disappointed yeah i kind of bummed i am like craving something salty though we've got to go get a snack next time next time next time we will do it all right folks there you have it there you go much thanks to alan for coming back on the podcast links to his work as well as next level nutrition as well as his podcast the long munch go and check it out he just had a fantastic conversation with one of the legends in endurance asker jukendroop and that one will absolutely blow your mind thank you to the coaches for coming together for a roundtable and a little bit of an experimental format to try to make sense out of it all let me know what you thought about this podcast as i mentioned during the intro it is a little bit of a different format and that different format is driven by a lot of the feedback that i have gotten in the community that they want to hear more from our coaches and more about how we take some of this research and bring it to our athletes in a very practical way what we are doing day to day with our athletes so that you all you all the audience can learn how to better inform your training so let me know what you think i can do anything with this podcast i can make it an hour i can make it three hours i can make it 20 minutes if i want to that is one of the great things about not trying to monetize it not

taking on any sponsors is i can be malleable and do whatever i want because i don't care if it drives a hundred eyeballs or a hundred thousand eyeballs all i care is that you all enjoy the product and are informed by the end product that is produced once it hits your ears so let me know what you think as always you guys i appreciate the heck out of each and every one of you and as always we will see you out on the trails