Hydration — electrolytes, supplements, sports drinks, & performance effects [AMA 33 Sneak Peek]

hey everyone welcome to the drive podcast i'm your host peter etia all right nick we're we're back for another ama this is your second one so you survived the first one huh yeah i made it through the first one so we'll see how this one goes i don't know i think we've got uh some interesting topics on for today what do we have yeah we have a good amount of questions that came through around kind of hydration right all things that relate to that which i know as a topic you became a little more interested in in the recent weeks and months i'm sure people even if they haven't heard the sort stories might have seen the scars kind of on your face and some podcasts and things like that which are healing nicely so once you kind of give people a quick rundown of where this interest came from not that you weren't interested before but kind of where this additional focus yeah yeah it's definitely a renewed interest actually because um the story you're referring to was uh from the time of this recording several months ago um it was kind of a perfect storm of things uh so i on a tuesday gave a lot of blood about three units of blood and on the thursday so two days later hopped on a long flight from here down to brazil for the f1 race and of course anybody who's been on an airplane knows how dry they are and how dehydrated anybody gets on an airplane uh on top of that it was like an overnight flight so you know i mean i was basically asleep most of the time anyway so you know you sort of get to brazil it's friday morning i think and um so i was i think i was like i woke up in the morning when i was there and so it's between the giving the blood the being relatively dehydrated and then just i naturally have very low blood pressure anyway and at least once or twice a month when i stand up from bed i have to take a knee to just not fall but i'm it's not like i never lose consciousness or anything but anyway you can see where this is going got up in the morning and this time completely lost consciousness have no recollection of how it happened but just face planted into a table um and the only thing i remember was the sound of my neck cracking and then kind of waking up looking like there was a murder scene in the room um and it's funny at the time i didn't put two and two together i didn't understand why i could have such a horrible fall and truly lose consciousness and then of course after the fact putting two and two together and realizing actually you were profoundly dehydrated um so you know that kind of got me thinking well how can i mitigate this sort of thing from happening again and what does it say overall about my hydration status is that partly what may contribute to why i sometimes feel light-headed in the mornings yeah it's kind of funny when you think about it your biggest injury from racing an f1 came from travel to a race as opposed to in the race car itself that's right that is hands down my biggest injury that involves any racing that i've done or observed including in a minivan yes definitely the the minivan the biggest challenge is just the family screaming at you when you race well sometimes you know you just got to enjoy the ride they just got to sit back and enjoy where they're headed um well so kind of getting into this hydration thing i think one thing that would be interesting is oftentimes people and i've heard this before right which is like your body's 50 water your body's 70 water your body's 60 water you know you kind of hear over and over like your body is so much water and so um when you talk about like gaining weight losing weight you often hear the term water weight so you know just stepping back what does it even mean like that our body makes up anywhere from 50 to 70 of water do we know what percentage it is where is it located kind of maybe lay the groundwork there yeah this is a bit confusing because first of all it does change a little bit so infants have a higher percentage of their total body in in water than adults so i think using 60 is a reasonable number because that's about where adults are so what does that mean well you want to divide that into two categories broadly the first is water that is inside of cells and the second compartment is water that is outside of cells so obviously we're made up of trillions of cells so the water inside of cells is called not surprisingly intracellular fluid and that accounts for two-thirds of your water weight so if we're talking about you know sixty percent of your weight is um water then two-thirds of that sixty percent is within the cells themselves which of course implies that one-third of that weight is extracellular fluid or fluid that is outside of cells now this is where it gets a little more confusing because that extracellular fluid resides in different places now one of those places is pretty obvious which is the vasculature so when you know you take blood out of the vascular system obviously water is a non-trivial component of that and it turns out it's about 25 of the extracellular fluid is the plasma that makes up the blood right so blood is made up of cellular contents clotting factors things like that and then of course plasma and you'll notice this anytime you spin blood or see blood spun you know you see if a tube it's red you spin it and all of a sudden it gets very dark at the bottom that's like all the cellular contents predominantly what you're seeing is of course the platelets in the red blood cells which dominate everything else and then you see a sort of clearish yellow fraction depending on um you know how much lipids are in there and that's the that's the plasma which is effectively the water so 25 of the extracellular fluid resides in that space about two-thirds to 60 percent of the extracellular fluid resides in what's called the interstitial space so this is the space that is between cells but not in plasma this is very complicated this is a space that is under appreciated so when you have a cold or you're really really sick some people notice they actually might gain weight um and then they might notice that in the if they're really paying attention in the days after they're starting to get better not only are they losing weight again but they're peeing like crazy and that's because of the expansion of that interstitial space so when we're sick our blood vessels become very leaky and the reason for that is important that's where we have all the white blood cells and immune cells do something called extravazate from the vascular system so that they can go and reach the tissues but that leaking is what leads to this swelling so if you see a most a more extreme example this is somebody in the icu who's very sick they almost always look like a puffed up michelin man and that's the reason why so the remaining part of the extracellular fluid basically resides in the digestive tract the csf or you know other small fluid uh filled areas within you know epithelial line spaces so the way you can sort of put a bow on this is about 67 of your total body water is inside cells about 20 percent is in the interstitium this area that exists between everything and of course that can really expand when you're sick about eight percent is in the vascular system and about five percent or thereabouts is basically everything else including csf and things like that and do those percentages the overall percent of kind of uh water and someone's weight as well as the breakdown of percent does that change based on body types like if someone's lean if someone has more muscle if someone has more fat and maybe even a follow-up is like does that even matter right does it if you're 60 compared to 65 it's probably what your baseline is as opposed to where you are compared to someone else yeah no but it does change sure for sure so you know muscle is far higher water content than fat so fat tissue is about 10 water by weight we refer to that as being quote unquote anhydrous without water uh muscle is probably 75 water so right there you can see you take two individuals one of them is 12 body fat the other is 35 body fat there's absolutely going to be a difference in how much water that person is carrying the more muscular person has a higher amount of their body weight made up in water yeah so i mean bob kaplan he's probably what 80 90 percent water weight then with all the muscles he's rocking i think bob is pure water pure water just pure water it takes that uh who was it bruce leave like that this is water just takes it to a new extreme that's right well this is water of course was david foster wallace but i think bruce lee was oh move like yeah taking the form of water yeah yeah i got my water mixed up um so another term you hear a lot is tonicity when talking about kind of hydration water levels things of that nature um i thought it'd be good to just get an idea of kind of what that is how does that play into everything here yeah so tonicity basically refers to how the concentration of one solution compares to that of another and the way we think about this in human physiology is all relative to the concentration of a cell because the cell is the dominant source of water so if you ask the question and i think red blood cells are the easiest way to see this right so if you if you put a bunch of red blood cells into another fluid how would the water move between those two so let's start with the easiest example of this the easiest example is something that is isotonic so we have a figure that shows this right nick yeah yeah okay so um what you're looking at are a bunch of red blood cells in a solution where the surrounding solution has a different concentration of solutes in it relative to the red blood cell so in a moment i'll tell you what the concentration is of the red blood cell meaning i'll tell you what the concentration how much solute i. e you know electrolyte is dissolved within that but for the purpose of this discussion you just want to understand that there's an equilibrium so if you put those red blood cells into a solution that has the same tonicity as them there's a total balance between how much fluid goes from the outside solution to the cells and how much goes from the cells to the outside solution so the red blood cells don't really change in shape at all now what happens if you put the red blood cells into a very concentrated solution so we would call that hypertonic so if you did that you would have a net flow of water from the red blood cells into that solution why because just like water always rolls downhill water always moves in the direction of the concentration gradient right there's a natural equilibrium that's always trying to happen where water is trying to equate the concentration across the permeable membrane of the cell so in a hypertonic solution the cells would shrivel up as they lose water into the more concentrated surrounding solution and of course the opposite is true if you put water into a hypotonic solution there's going to be an influx of water into the cells and they'll eventually swell swell swell until they actually would rupture so does that make sense the difference between hypertonic hypotonic and isotonic because this is important if we don't get this right i think a lot of what we talk about today will be harder to follow yeah no i think that does make sense yeah and just as an aside like when we were you know anyone who's been in a hospital has seen someone getting intravenous fluids you've probably noticed you never give somebody water intravenously right even sterile water you couldn't give that intravenously because it doesn't have any tonicity so the uh the tonicity of pure water is essentially zero so if you just infused water into somebody's vascular system you would rupture all the cells in their body that would be a really bad thing to do so when we give fluids we have to give them relatively close to isotonic solutions now you don't they don't have to be always isotonic they can be a little hypertonic and that's something that you typically do in um with with people that have head injuries as you're trying to reduce the swelling in their brains you're actually trying to suck fluid out um and then you can also give slightly hypotonic solutions especially if a person already has too many electrolytes on board they have their sodium levels are getting too high and things like that but as a general rule you're starting from the baseline of giving an isotonic solution which is 0. 9 sodium chloride and then you can adjust up or down with how much sodium chloride is in there and also how much other minerals uh ions are in there along with things like glucose which contribute to tennis city as well got it so kind of on that realm then one of the follow-up questions we got was what are some of the most important solutes for determining the tonicity of blood so kind of how you know like are there certain things that are more important than others kind of how do you look at that thank you for listening to today's sneak peek ama episode of the drive if you're interested in hearing the complete version of this ama you'll want to become a member we created a membership program to bring you more in-depth exclusive content without relying on paid ads membership benefits are many and beyond the complete episodes of the ama each month they include the following ridiculously comprehensive podcast show notes that detail every topic paper person and thing we discuss on each episode of the drive access to our private podcast feed the qualis which are a super short podcast typically less than five minutes released every tuesday through friday which highlight the best questions topics and tactics discussed on previous episodes of the drive this particularly important for those of you who haven't heard all of the back episodes becomes a great way to go back and filter and decide which ones 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