The History of Sports Drinks with Dr. Robert Kenefick

We talk with one of the world’s top hydration experts about the evolution of hydration science and how it has changed our sports drinks over the decades.

FT EP 289 history of sports drinks with Robert Kenefick

In 1965, Robert Cade, a doctor employed by the Florida Gators college football team, was tasked with finding a solution to the frequent heat stroke they were seeing in their players—a problem all football teams were dealing with. Cade knew the problem was dehydration and electrolyte loss. To address this, he created a drink that contained a carefully portioned mix of water, salt, sugar, and a little bit of lemon juice to give it flavor. And with that simple drink, Gatorade and the modern sports drink industry were invented.  

Nearly 60 years later that basic ingredient list has changed surprisingly little in most major sports drinks. What’s been refined are the types of sugars and the exact ratios of water to electrolytes to carbohydrates. What’s also changed is that Gatorade and the original sports drinks were designed as an isotonic drink, meaning they mimicked the ratios in our blood. Since then, drink mix companies have experimented with both hypertonic and hypotonic mixes. Hypotonic drinks, such as Skratch and Osmo—which have less sugar—have been winning out.  

One area of debate in sports since long before the invention of Gatorade is just how much athletes need to rehydrate during activity. In fact, in 1900 the recommendation was that athletes should not hydrate at all. By the 1990s, sports experts had completely flipped and were recommending athletes replace all losses. Both recommendations proved to be dangerous. Now, most scientists say that a 2% fluid loss is acceptable, but still, even that is debated.  

Here to join us on today’s episode is Dr. Robert Kenefick, the Senior Vice President of Research and Development at Entrinsic Health Solutions. A top expert on hydration science, he’ll walk us through the history of sports drinks and how this area of science has changed over the last 100 years.  

RELATED: Episode 263—Geeking Out on Dr. Paul Laursen’s HIIT Research 

Along with Dr. Kenefick, we’ll hear from Dr. Brad Petek and Dr. Timothy Churchill—two cardiologists at Harvard. We’ll also hear from Dr. William Adams, the Associate Director of Sports Medicine Research for the U.S. Olympic and Paralympic Committee; owner of Sharp Coaching, Jennifer Sharp; CTS coach Lindsay Golich; and well-known researcher and physiologist Dr. Timothy Noakes.  

So, make sure you’re appropriately hydrated, and let’s make you fast! 

Episode Transcript

Rob Pickels  00:04

Hello, and welcome to Fast Talk, your source for the science of endurance performance. I’m your host, Rob Pickels here with Coach Connor.

Rob Pickels  00:13

Today we’re discussing the history of hydration, and if this were the early 1900s, we wouldn’t have much to discuss because up to that point, athletes were discouraged from hydrating during their events. That all changed in 1965 when Dr. Robert Cade was approached by the Florida Gators football staff to solve a big problem. Their players weren’t urinating during practices, and it’s reported they were losing up to 18 pounds during a three hour football game. Cade knew the problem was dehydration, and worked with the team to formulate a mix of water, electrolytes, sugar, and eventually a little bit of lemon juice to stop it from tasting like toilet water.

Rob Pickels  00:55

With that drink Gatorade and an emphasis on hydration were born. Now, this isn’t a Gatorade commercial, it’s just that 60 years later, and most major hydration drinks are following a surprisingly similar formula. What’s been refined are the types of sugars and the ratio of water, electrolytes, and carbohydrates. We’ve also updated recommendations from no hydration at the turn of the century, to a full replacement at the end of it. But both ends of that spectrum can be dangerous. Now, many experts have settled on a 2% body mass loss for optimal performance, but that’s also debated.

Rob Pickels  01:33

On today’s episode, we have Dr. Robert Kenefick, the Senior Vice President of Research and Development at Entrinsic Health Solutions. He’s a top expert on hydration science and he’ll walk us through the history of sports drinks over the last 100 years. Along with Dr. Kenefick, we’ll also hear from researcher and physiologist Dr. Timothy Noakes, Harvard cardiologist, Dr. Brad Pedic, and Dr. Timothy Churchill. We’ll also hear from Dr. William Adams, the Associate Director of Sports Medicine Research for the US Olympic and Paralympic Committee, Jennifer Sharper of Sharp Coaching, and CTS coach Lindsay Goldrich. So let’s stop for a pee break, and then let’s make you fast.

Trevor Connor  02:16

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Trevor Connor  02:40

Well, Dr. Kenefick Welcome back to the show. We’re excited to have you.

Dr. Robert Kenefick  02:44

Thank you for inviting me again. And it’s pleasure to be here.

Trevor Connor  02:46

Yeah. So I gotta say, I’ve researched for a whole lot of episodes, this might have been one of the most fun episodes to prepare for, because we are talking about the history of hydration. And even though I was there researching physiology for a lot of it, I’m sure you were long before I was, it’s kind of neat to go back and look at the history and go Oh, that’s right. That’s what we’re doing in the 2000s. That’s what we’re doing in the 90s. It was really fun to see, I don’t know, if you had the same experience.

Dr. Robert Kenefick  03:18

Oh, definitely, especially when I was student going back. And then, you know, you’ve touched base here, because in your outline, you provided a number of things that have changed. And I’ve lived through that, and 90s in the 2000s of some controversies that happened. And then we’re still there’s still controversy today. So it is an ongoing Hot Topic

Rob Pickels  03:37

is nutrition and is hydration. Is this the most controversial of the physiology in the training topics?

Dr. Robert Kenefick  03:45

That’s good question. You know, when you get into these subdomains, there’s always some kind of controversy, you know that some of them are pretty subtle, but you know, you have experts in a particular area. And sometimes they have their own research, which leads them to believe certain things, and they get pretty, they can be entrenched, they have their own beliefs. So I think every area is kind of has their their area of controversy, but this hydration is definitely one of them. Yeah. Well,

Trevor Connor  04:11

I would say to me, the biggest controversy right now in sports, nutrition is the carbohydrates versus should you be keto, and how much carbohydrates but I would say Drake mixes are right in the center of that debate. Yeah. And you look at some of the strongest opinions on it. They’ve done Drake mix research.

Rob Pickels  04:29

Well, and I think the other thing, and this is where and I’m going to maybe preface the entire episode by saying this, when I’m working with athletes, I oftentimes have to separate the conversation and say, Hey, this is what we know from research from science from anecdotal experience, but I don’t know if that’s going to work for you because there are some people that just say, hate the taste of orange, and they can’t have a single orange hydration product or they’re going to vomit, right and people are just like that. And so there really is There’s so much of this personal effect that goes into hydration and nutrition strategies for people that as much as I tried to be guided by science, and I hate the word, the science, but as much as I try to be guided by our knowledge, sometimes you just have to play the individual as well.

Trevor Connor  05:17

So we have a lot to get through. So I’m going to move ahead. But the one thing I’m going to say to this that I think is a theme you touched on that you should bear in mind going through this whole conversation, there was a study where they took all the popular sports drinks of the time and compare them in terms of performance. And the conclusion of the study was the best sports drink was the one you like the most. Because if you like it, you drink. And I was studying up in Canada, and this study came out and I always loved to have my teacher put it, they said, very Canadian, Moose urine could be the best performance hats are out there. But it wouldn’t matter because nobody would drink it.

Rob Pickels  05:54

You were studying before all the maple based products started coming out. So I feel like you miss your best buy opportunity. All right, so

Trevor Connor  06:03

let’s, let’s move ahead. And Dr. Cat, if I gotta ask you to explain a couple of things that I think there’s a few terms, a few concepts that are really important for people to understand. The first one is osmotic pressure. What does that mean?

Dr. Robert Kenefick  06:17

So we probably need to talk about osmolality. First, and what actually that is, so I was a professor for a number of years. And however it explained to my students, if you look the osmolality, the strict definition of it is the concentration of solute in a fluid. So a great example might be seawater. So seawater has an osmolality in it, and that osmolality can change based on the concentration of what’s in seawater, by added more salt or added more constituent and could then have to be salt, I could raise the osmolality, I could raise the osmotic pressure. Or if I had a more just pure water to that seawater, I can dilute it more, and that would change the osmolality and decrease the osmotic pressure. So if you think about your blood, and it’s true with any any fluid, it could be blood could be your urine. But if we just think about your blood, right now, the liquid portion of your blood, the plasma has constituents in it, like sodium, like electrolytes, like glucose, like amino acids, etc. And all of those constituents exerted osmotic pressure. And if you dilute the amount of of your plasma, you actually can change your osmolality, you can make it lower and decrease the osmotic pressure. Or if I take water out of my plasma, let’s say I’m sweating, and that’s where a lot of that fluid comes from, I would increase the osmotic pressure are the osmolality of my plasma. So you bring up a very important concept that has a lot to do with triggering thirst, triggering fluid retention, and even triggering other aspects like when you might urinate too. So this all plays a role. There’s these systems are very intricate. And they’re also tied in not just to osmolality, but also to pressure or volume itself. So the volume that is in your vasculature. And that changes to when you drink fluid, or when you become dehydrated,

Trevor Connor  08:13

do you touched on what I think is a second very important point, which is our bodies can’t sense weight, like you always read the recommendation saying if you’ve lost two, three pounds and body water, you’re replaced that your body doesn’t know your body can’t weigh itself. So the only way your body knows if it’s losing fluid is by changes and osmolality,

Dr. Robert Kenefick  08:35

changes and osmolality and changes in volume. So and this all gets into fluid regulatory systems, there’s a number of hormones and factors that play a role. So we can talk about changes in osmolality. So how I usually would explain this, let’s say you go out for a run or you’re, you’re riding a bike, or whatever, it’s a warm day and you begin to sweat. Now that fluid that comes out of your sweat is hypotonic. It has some sodium, and other electrolytes and other things in it, but not as much as what’s in the plasma of your blood. So you can think of this situation now I’m sweating, I’m losing fluid, that water portion of my plasma is coming out in the sweat. And what’s happening to my plasma is all of those constituents are getting more concentrated. The osmolality is going up that osmotic pressure that osmolality is sensed by your pituitary or posterior pituitary gland that makes your brain and that releases a number of factors that ultimately lead to the release of what’s called antidiuretic hormone, which is its common name or angel vasopressin. And what that does is it tells your kidneys, hey, all that urine you’re making because you’re constantly making urine when you’re making urine. Let’s kind of concentrate that more all the water portion that’s going in that urine. Let’s hang on to that. Let’s not put it in into the bladder. Let’s keep it in the bloodstream. And the result of that when you look at your urine is more concentrated, and it is usually more yellow and usually has more constituents in it. So that’s one of the effects of osmolality. When it goes up, it triggers this hormonal cascade which causes you to retain fluid at the side of the kidney. The other part of this is when the volume goes down, because you’re losing fluid right from that consuming fluid, when I’m exercising, and I’m sweating, the plasma portion actually decreases. So I have a change in plasma volume itself that actually goes down. And so the juxtaglomerular cells, so these are the cells in your kidney actually sense this change in pressure, which is related to a change in volume. And then it in turn also sends another redundant system. This is the Rena angiotensin aldosterone system. And that system also plays a role of releasing hormones and other factors that cause the retention of electrolytes. And you have to remember, wherever sodium goes, water follows. So that tells the kidney, hey, sodium, that you’re going to put in the urine and other electrolyte let’s pull those back into the bloodstream. And by doing that, it pulls more water in, so you have the osmotic portion. And then you have the volume portion, that both drive fluid retention, when you are doing something like exercise and losing fluid by sweating and not replacing it.

Trevor Connor  11:15

And I think you just touched on what is the third important point, which is water as a follower. And that’s important, particularly when you think about these Drake mixes, because if there’s some electrolytes in that drink mix, when your body absorbs that sodium, the potassium, it’s mostly sodium, the water is going to follow it. So aids absorption.

Dr. Robert Kenefick  11:36

Yes, and the other important part of this is that the water follows sodium but in the gut itself, and this is a lot of the work I’m doing now, there are particular carriers as GLT one which is a glucose transporter that carries glucose across from the inside the your intestine and the intestinal lumen right inside your intestine, across your epithelial cells, the intestine into your bloodstream. So stLt, one that carrier pulls glucose that you’ve consumed or across into the blood, and that glucose can carry, typically two sodium molecules. And that in turn carries a certain amount of water. So you leverage glucose, sodium co transport is the name of it. But it also is principally responsible for pulling fluid in, there’s another mechanism, I can get super into the weeds here, I’m probably not going to there’s another carrier that is the primary carrier of just pulling sodium across to another protein in your gut, another transporter, and that one transports sodium directly from the lumen into your bloodstream. And that just pulls water in as well. And then there’s another and you’ve actually, in your outline, you mentioned something called solvent tracks. So if you’re thinking about the cells in your gut in your GI tract that’s transporting sodium glucose and water into your bloodstream, is doing that through the cell, okay, so it’s the fluid, and electrolyte and constituents that go through the cell into your bloodstream. But remember, in your gut, the cells are actually right next to each other, right. And there’s a space in between them. And that’s called a pure cellular space, and that space can open up. And when glucose is present, has space opens up a little bit. And it creates another channel for fluid and other things to get through, depending on their size. So when we’re talking about solvent check, that’s another way that’s No, that’s not an act of transport. That’s a passive transport. That just means it does it on its own. But you’re having this act of transport when this fluid and electrolyte actually goes across the cell itself, because those are active transporters that are pulling the glucose pulling sodium and pulling water.

Trevor Connor  13:44

And so let’s quickly define three terms because we want to get to the history here. But I think these are the things people need to know what do we mean by hypertonic, isotonic, and hypotonic? And just give us the one sentence definition. Yeah, so

Dr. Robert Kenefick  13:56

typically, these are put in relationship to something usually that’s your blood or the plasma portion of your blood. So if it’s hypertonic, it means that it has a high tonicity or it’s high in concentration of constituents. A lot of times that’s electrolyte, when you’re talking sports drinks, that is almost always electrolyte. So something that’s hypertonic is typically has a higher electrolyte concentration or higher constituents and what would be in your blood. isotonic is actually matches what your plasma is, right? So that tonicity matches the tendency of your plasma. And then hypotonic is actually a lower tonicity. So it has less typically less electrolyte, less constituent compared to your plasma.

Rob Pickels  14:38

The question that I want to ask now we’ve been talking a lot about osmolality and how electrolytes play in that situation. But real quickly, is there a difference in contribution have electrolytes and say the carbohydrate in beverages? Does one have more of an impact on osmolality than the other?

Dr. Robert Kenefick  14:56

Yes, not that glucose doesn’t play a role. It does it it can show refutes sodium, when you measure it in your blood, sodium is one of the principal components that drives it. You know, I forget the actual percentage, but it’s probably an 80 to 90% range that’s driving the total osmolality.

Trevor Connor  15:13

So let’s dive into the fun part. Let’s get to the history here. And I’m going to start we’re going to talk about the turn of the century, not to 1000s. But 1900s. turn of the century. Yeah, just to give an idea of how far this has come. Because right around 1900, the belief in sports was what was called Neil by mouth, meaning don’t drink. It’s bad for you. And I’ve got a quote here from James E. Sullivan, who is the head of the US Amateur Athletic Union. And he said, Don’t get in the habit of drinking and eating in a marathon race. Some prominent runners do it, but it is not beneficial. Or there’s another quote, I remember reading a few years ago from a prominent person at the Tour de France, who basically said, you will feel this desire to drink, don’t do it, basically toughen up. I was gonna say

Rob Pickels  16:07

that, that proves that you’re tough. And that proves that you’re good at performance. It’s funny, we’re laughing about this. But, Trevor, if you remember, in a couple episodes ago, we talked to keel and Alex, and they’re in the pro peloton, now, and some race directors are also like, you shouldn’t eat too much, it’s going to slow down your performance. So it’s still a pervasive thought for 120 years of don’t sleep in a room with

Trevor Connor  16:31

plants, they suck up the oxygen.

Dr. Robert Kenefick  16:34

Yeah, and we are laughing about it. And it is interesting. And you know, a lot of that attitude carried his way through, you know, because I worked for the US Army, during research principally in their hydration, you know, up until after World War Two, this was the predominant belief is that you didn’t want to consume water, you could actually adapt to not consuming fluid. And so generals like General Patton used to harden the troops, so to speak, by not giving them water. And so we talked about heat, acclimatization, acclamation is a real thing, right? It’s you will naturally adapt to exposure to heat that happens either through training, or just seasonal exposure. So there are physiological adaptations that occur. But the belief was, and some actually still think this is that you can have physiological adaptations to dehydration, and there are acute changes that happen, but we’re not talking about actual changes to the restriction of fluids. So by not consuming fluid, you become better able to not want to consume fluid. And that is absolutely not true. And, you know, just a side story. You know, my, my family, my father fought in World War Two, an uncle also fought in World War Two, and he was in the tank command of General Patton. And I remember, as a young man, having seen that movie and talking to my uncle about it and saying, you know, you served with Pat, and what did you think of me, it was a great man. And he said, No, Patton was ambassador, he never let us drink ever. And we were so thirsty in the tanks and we sweated so much, and but he would never let us have water. And remember, they were in deserts in North Africa. You know, you’re looking at this, this concept and sport that also got transferred into the military all the way through World War Two. And it isn’t until after World War Two, you start to see this change in this concept through some of the research that was done, that began to show the importance of hydration, and then began to show the importance of hydration related to performance. Well, none

Trevor Connor  18:33

of us would ever recommend going back to the nil by mouth approach. Here’s coach and physiologist Lindsey Goldrich, making the point that elite athletes can learn to tolerate higher levels of dehydration.

Dr. Timothy Churchill  18:44

Hydration is really interesting is that you can train the body to work in a hydrated state. And you could also train it to work in a dehydrated state. I think the most important thing that I have found is that you have to understand what the ramifications are from a hydration status. So we know we can take some of our marathon runners not our but marathon runners throughout the world is that there’s been some research out there that during the course of a marathon of an elite male they can lose up to 10% of their body weight. Well, when we look at scientific research, it shows through that much of a decrease in hydration status is clinically unsafe. However, in a one off situation, it might be tolerable if an athlete can train and that’s what they’ve been doing not that that’s advised, but the body can still do pretty amazing things in a dehydrated state, rather than when we’re looking at an athlete doing day to day training or multiple training sessions in a day to hydrate hydration stache becomes critical for recovery and being able to, you know, again, recover from one training session to the next on the same day or even back to back sessions, you know, intense sessions from day to day. You know, hydrate So I find is actually something that’s pretty easy, you know, just doing pre and post bodyweight before and after training sessions, to understand what your individual hydration statuses and what you need to do to replenish that throughout the day. Not very difficult. Most people have a scale that they could, they could do that. But I find a lot of people don’t do it very often. And it’s something that’s pretty simple and can really impact performance. The other thing with hydration is that if you know that you’re not a good drinker, when you’re doing training or racing, and you feel that you gotta flush the belly or different things, it’s important to know that the gut can be trained. Our dietitians really work with athletes on this saying, Yes, we’re not going to just go from zero to hero in our hydration intake throughout a training session and be ready for race day is that just like our day to day training sessions on the bike or running with to do the same thing with hydration, so we have to work on increasing small amounts of hydration throughout a training session, so everybody can utilize it. And it doesn’t sit in our in our GI and flush around. And I think that’s important too, is that you can’t just make these changes overnight, that you have to take some time and do a little bit of investment. But it is definitely well worth it on the back end.

Trevor Connor  21:18

First of all, we should mention in the 1930s, you saw some of the first kind of sports nutrition research this was coming out of Sweden, it was a doctor born Aalborg and Jonas Bergstrom who are starting to research muscle glycogen and how you can improve the resist this of muscle glycogen. And that research led to I think, what is the pivotal moment. So this is the first big moment in history that we’ll talk about what you’re leading to, which is the invention to Gatorade,

Dr. Robert Kenefick  21:47

there’s a little stuff to get through before we even get to gate are one of the concepts when you’re talking about glycogen. And glucose is the idea of fuel, which is obviously important when you’re doing work, right. And principally, it’s glucose, blood glucose, but we can talk about proteins and other things that also can can play a role as well. So you’re really looking at delivery systems, so fuel delivery systems, and you can do that with a lot of things you could actually eat, you can eat food itself, right, that’s one way of doing it have a banana, or you can have something that’s more like a gel or a goo which is you know, popular now, or you can drink it. So one of the issues that actually makes us more confusing is that you look at this concept of hydration. And you look at the concept of fuel. My colleague and I, Sam shabam wrote a paper about this a couple of years ago, because you can’t really divorce these two things, they interact with one another. So you are actually delivering fuel by using hydration. And there are certain circumstances and this gets really into the weeds, there are certain situations where you may not actually need to drink fluid. If you were doing a 400 S, you don’t need to drink for that. But if it’s an event that might be very high intensity, of relative duration, you may need some glucose to fuel that you may not necessarily need to be hydrated may not be necessary, but you’re going to drink anyway because you need to fuel. So, you know, you look at a company like Gatorade, what they call themselves now is a fuel delivery system. They understand the hydration aspect, because I know they’re scientists, but they’re pervasive idea, their primary sources, hey, we’re a fuel company. And so now you’re you’re seeing this idea where hydration becomes important. After World War Two, research begins to be done. This is before informed consent. So a lot of these are volunteers, Army volunteers, individuals, college students. And so the big area of research happened in the 40s, a scientist named Edward ate off who was at Rochester University did a lot of his work, along with some other colleagues and published a number of very classic classic studies. And the classic book in this area called man in the desert, and that was 1947. And so he did a number of different experiments, lab experiments, they didn’t have environmental chambers at the time, he would go on on the roof and set up bicycles in the heat and have students go up and do exercise. So he’s measuring a lot of these things relate to hydration. And then he also went out into the Mojave Desert, him and other colleagues went out and they took students out. And they began to do experiments, very practical field experiments. And then there’s some other experiments that are in men in the desert, that look at survival at sea and dehydration by actually putting individuals in a raft and putting them into the ocean and tethering them, and then let them not giving them fluid and studying them as well. So this from that research, we began to see, one of the classic experiments that ate off did is he took a number of students and he gave them fluid, and he sent them on a hike. And based on the amount of fluid that he gave them. He saw a how far can they actually hike and that was also relative to temperature too. So you’re looking at situations like if I don’t give you a lot of fluid and it’s really hot, you don’t want So far, or if it’s very hot, and I give you a good amount of fluid, you can actually hike further. It seems very intuitive to us now. But this is some of the earliest research that’s begin to show this relationship between performance. However, you’re going to measure it hiking, biking, or even work to because they can also talk a little bit about work that was being done in in mines in the early 30s, and 40s, where a climatization to heat and hydration becomes important because individuals are having issues in the minds where it’s hot, and they’re working hard. And that was about productivity, which is another measure of performance. So this is the the era where this concept begins to change, you know, through the 40s, through the publication of man in the desert, leading into 1950, where individuals are saying, hey, hydration is actually important. We’re seeing how important it is relative to work productivity, athletic performance. So this is something that we need to think about.

Trevor Connor  26:00

So I think you’re now getting to a pivotal moment because this really sparked the whole modern sports drink industry, is this invention of Gatorade. And this was a scientist who came up with it, it was a gentleman named Robert Cade, who was working with the Florida Gators at the time football teams had huge problems with football players suffering from dehydration and having to go to the hospital. So they were trying to address this. And he was kind of piggyback and as you said, off of all this research from the last few decades ahead of him,

Dr. Robert Kenefick  26:35

yeah, I mean, so in the 1950s, and the early 50s. The idea the transporter that I mentioned earlier, stLt, one, this glucose, sodium co transport was discovered. And then that led to the invention of oral rehydration solutions. And that was also in the 60s. So an oral rehydration solution is principle used, a lot of times, it’s used in this country, but in the third world for individuals who have diarrhea or vomiting. And it is hailed as in the 20th century as one of the greatest medical advances of its time and save millions and millions of children’s lives. So that whole concept there that discovery, you begin to see this idea that, hey, if I have glucose in a beverage, I can move sodium, and then I can move water. And then you’re seeing the situation too, with the invention of Gatorade is putting all those concepts together of mixing glucose and electrolyte into water to create a beverage to address hydration. And again, to leverage this particular carrier leveraging glucose as a transporter of electrolyte and of fluid itself. So that’s really the whole concept behind it. That’s the concept behind pretty much every sport beverage that contains glucose, you’re leveraging glucose, you can leverage other things we could talk about a later and work that I’ve been doing of late. And that’s the use of amino acids that actually have carriers and actually carry sodium as well. So they carry sodium, they carry water. So there are other ways to carry electrolyte and get water into your bloodstream without using glucose. That’s a very new concept. But relative to history and the invention of Gatorade. That’s really the genesis of what becomes the modern day sports drink. And now you see so many tweaks on it. But that’s really what was done. And if my memory serves, and I was doing some research here talking to some of my colleagues, we’re not certain about this. But we believe that the concentration of electrolyte at the time it was invented at UF, the electrolyte was very high. So the concept was, we’re really going to try to match what you’re losing and sweat. And so you’re really talking if you’re talking about sodium, it’s a variable in your sweat, if you look into the the research, but they’re typically about 45 million equivalents. If you have a beverage like that it is pretty salty and pretty rough to drink. And you see, you know, a modern day oral rehydration solutions, things like Pedialyte and there’s a number of other ones. Things that contain a lot of sodium are tough to drink. A lot of times they put a lot of sugar in it to kind of mask that

Trevor Connor  29:10

stuff that I love reading about the history of Gatorade, it’s exactly what you’re saying compared to the modern Gatorade. It was much lower in sugar and higher and sodium. And it was the the rumor is or the urban legend is that Robert Cates wife tried it and said This tastes awful and told him to add lemon juice to it because otherwise nobody will drink it.

Dr. Robert Kenefick  29:32

Yeah, it’s interesting things that contain other flavorings. So citric acid is something that’s in almost all these beverages that actually drives thirst and by driving thirst itself you actually consume more fluids. So you know you’re also leveraging you know, your other physiological mechanisms to derive fluid intake as well.

Rob Pickels  29:51

And now something to point out real quick Gatorade wasn’t necessarily the first product on the market right there was a product called Luke is a that had come out Prior to that 39 to 27. Yeah, and something to really point out is we’re talking right now about how much sodium was in Gatorade. If I remember correctly, Lucozade had no sodium or electrolytes whatsoever, and was primarily based on on table sugar, right? Yep.

Dr. Robert Kenefick  30:16

Yeah, look, I say it’s still around. I mean, it’s a huge brands in the EU and other other areas of the world in and what’s interesting, too, there’s a cultural aspect to this as well. There are other beverages, if you look, you know, even now or even, you know, when I was starting this, almost 30 years ago, there are beverages on Japan’s a great example that are faring very salty, have very high sodium contents that are wildly popular, because culturally, that is something that they liked the consumer likes and the consumer will drink and things that at least in this country, would be considered unpalatable. But you can see now with the talk about modern beverages, the electrolyte concentrations are being changed all over the place. We can talk about that later. But you are starting to see with the advent of electrolyte and changing it around and adding flavorings that like like citric acid, or in this case, you know, something that’s like akin to lemon lime, you’re starting to see the birth of this science, because now the people are starting to study. Okay, how much sugar should we put in there? Should we changed the kinds of sugars? Should we change our electrolytes and what other factors play a role in getting the fluid and electrolyte and ultimately the glucose to into the bloodstream? Because there are factors that you need to think about. And now you’re seeing a lot of these concepts come through a lot of being driven by performance, to say, how can we study this? And how can we take our learnings and then adjust the beverages so we can try to get more performance. So

Trevor Connor  31:50

let’s stay in the historical context. Before we get into how it’s done. Now, let’s go back to the the 60s, the 70s 80s, and 90s. And I think what Gatorade set up was the and this was what Robert Cade was going for, was this concept of an isotonic drink mix. So the Gatorade that was originally sold was around a 6% carbohydrate solution, and about 400 to 500 milligrams per liter of sodium. And that kind of set the standard and they were basically trying to match what was in our blood. So talk a little bit about that. And the reasoning for the the isotonic mix.

Dr. Robert Kenefick  32:32

Well, I mean, that’s exactly the idea is matching what’s in your blood. The concept, though, is that your sweat is hypotonic compared to your plasma. So the amount of electrolytes lost in your sweat is not what is in in your blood, it’s lower. But ultimately, the idea is you want to be replacing losses. So one of the the concept is that you’re becoming volume depleted, right, we talked about sweating and coming out of your plasma, and you’re losing electrolyte as well, to a degree now, depending on the activity, and how long those all need to be replaced. But how much do you need to replace actually is totally dependent on the activity and a number of other factors. But that was the general concept of okay, we should match what your blood is. So that’s what you should be drinking. But you’re not really losing that when you talk about what is lost in sweat itself.

Trevor Connor  33:26

Before we go down this road. Let’s hear from two Harvard professors talking about the dangers of trying too hard to rehydrate.

Dr. Timothy Churchill  33:33

Hydration is of paramount importance. We both work in endurance races in the medical tent, marathons and other races. And we see athletes all the time that are dehydrated, and or may not choose the right source of hydration. So it’s really important. If you are dehydrated, it’s plausible that you would decrease your plasma volume, and that your cardiac output would be lower, and you may not be able to confer that fitness. And also, it’s really important to work with your trainers and coaches to make sure you’re you’re gaining the right type of nutrition. A lot of amateur young athletes will go out there and just drink water the entire time and we see them after the race. And their sodium levels can be low at a dangerous level because they haven’t taken enough salt during the race. So what we’ll do is actually we’ll be behind the quarter, pouring packets of salt into Gatorade or other hydration juices and having them drink them to make sure we can get them hydrated with the right type of nutrition which is of paramount importance.

Dr. Bradley Petek  34:33

I think the only thing that’s worth just adding briefly is as much of the for instance in the marathon setting as much as the danger of under hydration. There’s an also an important danger of over hydration with yet which gets at what Brad was talking about as well, which is that overhydration particularly with the wrong things can sort of throw off the Bloods, biochemical balance and can can lead to really important dangerous situations. So that’s an important consideration. And that’s why I think it’s the same message is about listening to your body and paying attention to the amount that in sort of matching the amount that you’re drinking to the conditions and to the, to the work that you’re doing, making them become important.

Trevor Connor  35:12

But I think this drove something that we could potentially say is a little bit dangerous. And I kind of want to go down this road and hear what you think you really saw with the rise of these, these modern sports drinks, you know, we talked about at the turn of the century was nil by mouth, don’t drink, you know, that’s bad for you, too, by the 1990s. You saw the complete reversal of that. So a 96, the American College of Sports Medicine, hears their position stand on hydration, during exercise, athletes should start drinking early and at regular intervals in attempt to consume fluids at a rate sufficient to replace all the water loss through sweating, or consumed the maximal amount that can be tolerated. So it was all about get as much in as you can don’t lose any fluid, immediately. 10 years later, they changed their stance a little bit to the goal of drinking during exercise is to prevent excessive dehydration, greater than 2% of body weight loss, and excessive changes in electrolyte balance to avert compromised performance. But he really saw in the 90s, in the 2000s, it was all about you got to replace everything or you’re in trouble. And like I said, I think that ended up causing some dangerous issues. And you might want to talk a little bit about the the issues with hyponatremia.

Dr. Robert Kenefick  36:31

Yeah, hyponatremia. And you’re right, this is that the time of a number of hyponatremia tests, a lot of them occurring and marathons, people are over consuming hypotonic fluids, so the water or something without solute and something without electrolyte in it. And what happens is you actually dilute your blood sodium down to dangerously low levels. And then ultimately, people will actually, you know, have good central nervous system failure, so, and a number of people died because of this. So, and this has become a huge area of controversy, I hope less so. And there were a number of camps at the time talking about sports drink companies pushing this concept of drinking as much as possible, and the American College of Sports Medicine in that position, Stan, one thing I can say about that position, standard 96 Is that part of the controversy happened because you guys read scientific papers, we have the paper, there’s an abstract, right. And so that’s just usually 250 words of a summation of what is there. And so that position, Stan had an abstract that talked about what you just mentioned, if you go actually into the body of the position stand, it doesn’t really say that same thing. It is a more measured approach. But the issue and it should have been caught that the abstract said what it said, and but people didn’t go and repass the abstract into the body and the actual position stamp. So that message was pushed forward, that you know, drink as much as possible, etc. And so there were a lot there was a lot of blame put out either to the position stand by certain individuals or certain groups.

Trevor Connor  38:06

One researcher who’s often at the center of these debates, and was certainly at the heart of this hydration controversy was Dr. Timothy Noakes, who took the stand that we just need to drink the thirst. Let’s hear from Dr. Noakes himself.

Dr. Timothy Noakes  38:17

Yeah, well, I read a book called waterlogged, which was my 30 year investigation of hydration policies and practices and what we were told to do. And I discovered again, that industry had distorted the message and there is only one message drink when you’re thirsty. And that’s it. As long as you do that, you will be healthy. What they tried to do was to medicalize, the so called dehydration, and they made it the disease. And the real reason was that industry wanted anyone who went to the gym to be drinking the instant they started. And they kind of argued that if you didn’t, if you lost one drop of sweat, and you didn’t replace it with a sports drink, you’re going to die of heatstroke. And I spent 30 years disproving that that’s absolute nonsense. All the advice that we got that you must drink ahead of thirst all that achieved was a couple of billion dollars spent on sports drinks, and the deaths of a number of people, particularly marathon runners, triathletes, particular people in the military, adventure races and so on, because they were told that you must drink to excess and the body doesn’t work like that. We have a reason We’re thirsty and the thirst tells you everything and all the current evidence shows that if you ask people just drink to thirst during competition, they will perform optimally and the very best athletes are the ones who become the most dehydrated during exercise. They’re not the ones who drink the most and are the least dehydrated. So as a few years ago, when the marathon runner Haile Gebrselassie set the world record, he finished the race 10% dehydrated he lost five kilograms. But he was running faster in the last mile or two then he had in the middle. So was he fatigued? gotten tired and dehydrated now, he lost five kilograms. I mean, what’s amazing? Imagine running the last 10 K’s of the race five kilograms lighter, you’re going to that’s going to be a huge advantage. And the same in cycling. You know, you watch the cyclists in the Tour de France. As they come to the bottom of outdoors, they throw the bottle away. They know that 500 grams of water in the bottle is going to slow them going dark going up outdoors. They know that so why would you want to drink to excess? Are you carrying an extra three or four kilograms in your body because you’ve, you’ve drunk too drunk ahead of thirst. So the advice and I read the book waterlogged, it explains everything. I looked at all the research, and disproved the whole nonsense about bad hydration and exercise. The body is very clever. As we’ve discussed, just drink to thirst.

Trevor Connor  40:52

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Dr. Robert Kenefick  41:19

So it wasn’t until 2007, where the American College of Sports Medicine reconvened a panel of scientists to address what was going on, and they revise the statement to maintain hydration, or to avoid a 2% change in body weight biomass of level of dehydration. So, and I’ve written a number of papers in this area, along with some colleagues kind of parsing this idea about when you can be dehydrated to a degree. And we do use this threshold of 2% by weight loss. So this is how much sweat you’d be losing during an event. And that’s kind of that’s most research shows that this is the line at which performance begins to suffer. But there’s a lot of caveats here. Everybody thinks Oh, it’s 2%. But if it’s 2%, in a cold environment, it has less of an impact. There’s a number of factors that play a role here. And we can get into a deep dive on that. But yeah, so I mean, I think now, the idea of hyponatremia, it’s still happens, it’s still out there, I think there’s better education. Now that people are understanding particularly and really long events, this is usually where you see it, you’ll have to drink an appreciable amount of hypotonic fluid. So the event tends to have to be very long. So you know, a marathon, especially for individuals who are slow, because they have more time to drink, and drink water, because they’re out there longer. ultra endurance events are quite common. I’ve done a few of these. So if you’re racing for 24 hours or a number of days, this can be an issue as well. But most of the individuals, at least that I know who were doing these events, there’s a lot of information out there now that individuals who are jumping into these things have heard about this, they know what to do and you’re taking in food during these events. It’s definitely one of those things. This is one way you can have that electrolyte replaced and avoid hypotension.

Trevor Connor  43:15

Just a quick side note, if anybody’s interested because you brought up this 2% dehydration, I think that’s one of those important debates. In episode 263. Rob, and I actually talked a while about a great study that Dr. Paul Larson did, were they using intravenous methods so that people didn’t know what they were drinking, intentionally dehydrated athletes to different levels to see the impact on the performance. So what they found was 2% had basically no impact on performance that you could go further than that. So if anybody’s interested, we talked a little bit about that.

Dr. Robert Kenefick  43:51

Yeah, I mean, this is a whole, you can do a podcast just on this, and I’ve written about it. And, you know, the point at which performance begins to suffer depends on a number of different factors. It also depends on how the study was done, you know, in a laboratory conditions, sometimes you do or don’t see this threshold for for performance. And, you know, environment plays a big role, too. And exercise intensity plays a big role. So there’s a lot of different factors that come into play here. And I’ve written a few things that kind of taking, I’m going to say more of a middle approach. I think, in one of my publications, I lay all this out, saying, Look, hydration for an individual just depends on a number of factors. So environment, as I’ve said, exercise intensity, as I said, performance duration. So I mean, if you’re looking at an events that’s relatively short, even maybe an hour or less, and it’s not particularly hot, it’s possible that you’re not going to reach 2% dehydration within that hour. You could conceivably not drink any fluid at all because you are not going to approach you know your sweat losses are going to be on a minimal side and you want to approach 2% within those conditions, as poss well to that some individuals who sweat a lot, and who may be in a hot environment, or doing some very high intensity work may get to that 2% earlier in the hour, and they may need to drink some fluid. So you have to take all these factors into consideration when you get over an hour, and then you’re approaching this 2% level, then you really need to be thinking about, Okay, should I be taking in fluid, so I don’t get there, because I still have more event to go through. So there’s a lot to consider there. And ultimately, I think, to its how important is performance to you? I mean, some individuals, you know, are very, very performance oriented. And one of the things that I put forward is that you need to know a number of things about yourself, how much do I sweat? What environment? Am I going to be doing this activity? And how fast am I going to do it? And what is my plan to avoid getting to 2% in an event? And how am I going to incorporate that plan in because I’m concerned about performance. And just as an aside, when was it 2012 2013, I qualified before that for Boston in I worked a couple of years to do this. And for those of your listeners, or maybe yourselves it’s qualifying for Boston is, is can be hard to do depending on your age group, even for any age group. So I’m a very, very heavy sweater, I sweat a lot. And I couldn’t take in enough fluid under my training runs. And I did a number of other marathons to try to qualify. And I didn’t make it out, I was relatively close. But I was always very well dehydrated. So I took what I knew. And I said I need to find an event that’s going to be in a cooler condition. So I did a qualifying race in December, and where I knew it was cool. And it was down by the ocean down in Rehoboth Beach. So I knew there would be some breeze, and that would help. And I had a fluid plant too. And so I leveraged all that so I could try to maintain performance or try to preserve it. And I did qualify. So you know, individuals who are going to try to do a particular thing need to understand these things about themselves, so that they can put together a plan. And and that’s really what I’ve written about. But again, you know, if it’s less than an hour, and you’re not going that fast, or performance isn’t a concern, or you don’t achieve 2%, dehydration, that time, you could not drink at all, and you would be fine.

Trevor Connor  47:15

So let’s switch gears here a little bit. And we’re going to come back to these isotonic drink mixes. But we’re gonna stick with the timeline here. So first, it’s important to mention that Gatorade in 1985 started the Gatorade Sports Science Institute where a lot of the research on hydration came from. And that’s relevant because and I don’t know the exact date these were introduced. But one of the next big innovations in sports drinks that we might very well say was kind of an oops, was this four to one carbohydrate to protein ratio. So there was research coming out of GSSI, saying that athletes seem to perform a little better if you not only put carbohydrates in the Drake mix, but you add a little bit of protein. But there was issues with that research, it’s very interesting to point out that Gatorade never got on board, even though this was coming out of their Sports Science Institute. They said we don’t buy it, we’re not making a drink mix with this.

Dr. Robert Kenefick  48:17

There’s a lot of factors that come into play. And so this is about the time I began studying this student, the Gatorade Sports Science Institute was known for putting out some good research at the time and still does. One of the individuals was Carl just off the at the University of Iowa, I believe. And he was doing a lot of this work for Gatorade. And he pioneered a number of techniques. And a lot of what he studied led to a lot of these changes, some of the concepts that you’ve talked about, that I think are important understand, you know, ultimately, what you’re trying to do is to get fluid and fuel into your bloodstream. That’s where it’s needed. But you do have to go through the stomach itself. And there’s a concept called gastric emptying. So how do these fluids how do these things leave your stomach and get into your test and where they’re going to be absorbed? There are things that can change how fast or how slow something leaves your stomach and gets into your intestine. So things typically we’re looking at the caloric content of a beverage can slow gastric emptying, the volume itself can either increase it or decrease it, the type of glucose and different types of glucose. Now you’re starting to see these different polymer chains or glucose and fructose put together which is what you’ll see a lot of now we’re changing the concentration down from like a higher, like a 6% even sees highest 7% down to like a 4% solution, which is what most sports drinks have now as far as sugars or carbohydrate go. So it’s that time that GSSI Carl just saw the principally in some of the other directors who I know you know, I’m thinking of Bob Murray, who was also one of the directors at the time, another great scientist was Doing a lot of this work and taking this information and starting to change the beverage itself, to get it to speed, how fast you can get it from your stomach, into your bloodstream. So in the incorporation of protein is another one of those factors, too. So you’re seeing that because, you know, proteins at the time, you’re looking at protein that can actually be used for energy. So this is another idea that you’re including that, and we’re gonna talk about other things when you’re talking about recovery beverages, why proteins are important. But that’s that is the idea behind the other issues of putting proteins into the beverages is that they can be difficult to put into the solution itself. And so this is my job now. And we do a lot of work in certain types of beverages and utilizing amino acids for this. There are things that are difficult to put in, especially certain types of proteins. So this becomes more of a formulaic concept, how you do what proteins can go in? What forms and so you’re seeing, I think, you know, that this time, I think, was it exceed or Excel accelerated? Yeah, I don’t know. If you were Did you ever drink that?

Trevor Connor  51:07

I was religious with it for years,

Rob Pickels  51:09

really, I won’t lie. I was religious with it for about a month before it gave me stomach cramps, and I couldn’t drink. I

Trevor Connor  51:15

loved it. I loved the taste.

Dr. Robert Kenefick  51:16

So but if you remember, it was kind of like it was is a little bit chalky, if I recall, right. And, you know, those are the issues you get into when you’re trying to put things like protein into a beverage, they can do it better today, but those are the issues that you ran into in manufacture. You know, it’s so I’ve learned I’ve learned a lot more in my present job, just manufacturing beverages, and what you can and can’t do. Science may point to some things. But then when you go into manufacture, some things can’t do, you can’t do very well. And you have technical challenges of actually, how do you deliver this.

Trevor Connor  51:48

So I also think another thing to point out about these Drake mixes is what they found in that initial research was, they would have athletes do a time trial to exhaustion, where they a straight isotonic carbohydrate mix. And then with one of these four to one carbohydrate to protein mixes. And what they found was the athletes taking the protein carbohydrate mix, were lasting a little longer. And so there was a belief that this is this is a better mix. But somebody actually went back and looked at that research and said, there’s an issue here, there’s also more calories in the protein carbohydrate mix, because all you’re doing is taking that carbohydrate mix, adding protein to it. And so when they repeated the studies, and match them for calories, the improvements went away. Yeah,

Dr. Robert Kenefick  52:36

an excellent point, you know, when you’re talking about, especially at time travel to exhaustion, that’s high intensity work. And that’s where you’re going to be burning a lot of a lot of ATP resynthesis, and there’s going to be a lot of glucose glycogen burned up, you know, so fuel is critically important for that.

Trevor Connor  52:53

So we’re now at a point in the history where as you see, with all developments, a whole bunch of companies are coming up with a whole bunch of products. So it kind of gets hard to cover all of them. But what I would say is, there’s two main things that you saw these companies playing with, and maybe you could talk about both of these, one was tonicity, playing with the different electrolytes increase in the decrease in them trying different mixes of electrolytes. I think the other thing that you’ve seen a lot more experimentation with is the types of sugar so Gatorade originally, it never was it just glucose or sucrose that they had in the original Gatorade should have been sucrose, the original, probably sucrose. But now you’re seeing maltodextrins You’re seeing a whole bunch of different sugars that they’re experimenting with. So maybe we just have this big conversation about these different trends and your thoughts on this. Well, sure.

Dr. Robert Kenefick  53:48

Why don’t we could probably start with the different types of sugars. I mean, you could do a whole podcast on just that. Yep. But just to kind of generalize, you know, a lot of that research that we talked about from GSSI, and others around the world began to look at the types of sugars that how again, how do we get them to leave the stomach? What types of sugars or combinations of sugars like glucose, fructose, sucrose, that actually can speed gastric emptying. So then you’re starting to see a change at one of those companies that begins to move to that change. Then the other piece too is, you know, what kind of sugars? How well are they transported? How well they metabolize? And then what kind of concentrations are we talking about? You know, are we going from a 6% or 4% solution? How much do you really need, and again, it really depends on how much you’re oxidizing. And doing a very intense exercise, you can oxidize a high amount of carbohydrate or glucose per minute. And so that can be very difficult to supply. So you’re seeing this advent of experimentation of the combination of different types of sugars, to try to leverage ultimately, again, you want to get it into the bloodstream, get it to working muscle, so that it can be used in benefit performance. So now you’re tweaking a lot of things to leverage that with all of these things, you have to take into consideration like leaving the stomach, like it, getting it through these various carriers. And then, and then metabolizing them, you know, through metabolic pathways within yourself. So this is the time that you know, a lot of lots of research is going out. And companies are tweaking what they’re doing, instead of a lot of us based in science. And I have to say some of this also based on marketing, too. But that’s

Trevor Connor  55:32

always good to ask how much of this now is marketing versus really seeing performance benefits? How much of this is a new sports streaming company comes into the market and says, I need to differentiate somehow. I will say, I think one of the worst examples I’ve ever seen of this, and I don’t think they’re in business anymore, was a sports drink that came out that had lactic acid in the sports drink. Because if you’re consuming lactic acid, you’re going to teach your body how to buffer it.

Rob Pickels  55:58

Sport, legs man, whole pill based system based on lack.

Dr. Robert Kenefick  56:03

I’m curious as to how that tasted. Yeah, I mean, I think now, again, my job now is working in this area. There is a lot of puffery, there is a lot of marketing aspect, like you said, How do I differentiate, there are companies, beverage companies, we are one of them coming out with with beverages. And we have some other beverages coming out in the area of oral rehydration solution that are totally based on science were science based company, there are other science based companies as well. There are some clever companies that have taken existing science and trademarked it to be their own very cleverly, I’ll leave those companies names out, but they were very smart to do so. And so they’re leveraging existing science. And then they’re the ones who are just basically using science or existing science and putting twists on it. But they don’t really have anything, I don’t want to call any brands, you know, when we’re talking about pH waters, and things like that, and there are some papers that have been written in this area, it’s unclear to me, at least on the science side with the benefit of these are these from a physiological point of view. But again, it’s big market, people like five talk to people all the time, they swear by these types of waters. And so companies come out, and then they say, Well, you know, so and so’s beverage has certain pH show and is doing very well. So we should probably do the same thing. There may be no basis for or very little basis.

Trevor Connor  57:25

So we touched on sugars, I think something that is important in the research, and you’ve touched on this, there are multiple transporters in our gut for different types of sugars. So I think it’s been shown pretty conclusively, that if you have a drink mix, that’s just glucose that might not perform as well as something that has a mix of sugars, because then you’re taking advantage of multiple transporters that are not only going to increase the caloric intake, but also because water is going to follow, it’s going to increase the drop of water into your system.

Dr. Robert Kenefick  57:58

Yeah, you’re exactly right. And there, there are multiple transporters within the gut. And just like I said, you know, stLt, one is one of them. There’s multiple carriers that have been discovered since the 50s. And even then, when I started out, and more of these transporters were being discovered, and again, now you’re looking at companies that are saying, I’m going to, you know, ultimately, what’s the objective get fuel and fluid into the vasculature as soon as possible? What can I leverage? What do I understand in the gut itself, that I can actually use to try to speed the uptake. And so now you’re seeing another reason for these multiple types of sugars, and is to try to leverage these multiple carriers. And, you know, we’re, again, plugging from our company, we’re doing the same thing. You know, as a science based company. We’re just not using glucose. We’re leveraging amino acid carriers that carry sodium, some amino acids care even more so it can carry even more water. So aside from glucose transporters, there’s amino acid transporters as well. So you can actually go to this next, what we’re thinking is the next area of of hydration without you using glucose at all, so leveraging leveraging the science for hydration, and there’s still things to be learned.

Rob Pickels  59:12

Dr. Kenefick, can I ask from just my own information, we talked previously about how glucose utilizes in SGL T one transporter and it’s co transported with sodium and and that helps water flux across you know, from the lumen of the gut into the bloodstream. The other big sugar that is out there on the market right now is were talking about multiple transport carbohydrates is fructose. And for the most part that’s going to go through what glute five, is there with the transport of fructose? Is there any hydration pathway that’s occurring? Like we saw with the glucose transport? It was that just purely from like getting a carbohydrate into the bloodstream to oxidize later issue?

Dr. Robert Kenefick  59:56

This is on the tip of my brain.

Rob Pickels  59:59

I stumped him i did it I did a good job.

Dr. Robert Kenefick  1:00:02

So I know that I think it carries less sodium or not or not any. So it’s one of those two. We just made a slide of this the other day, but you’re right. I mean, you’re definitely going to be getting calories. So you’re definitely getting sugar across how much sodium I cannot remember off the top my head, but I do think it’s less than glucose itself.

Rob Pickels  1:00:22

Yeah, fair? Well, I obviously don’t know, which is why I asked you so don’t don’t feel bad.

Trevor Connor  1:00:28

Well, then let’s shift gears. As I said, this history is so robust. Now, we can’t cover everything. But I do think there’s one last important trend to cover that you really saw in the 2000 10s, which is the movement from this isoh tonic beverage to more hypotonic beverages, I think a drink mixes like Scratch Osmo even put in their name, what they’re all about precision hydration, that they are now moving to they’re not reducing the concentration of electrolytes, but they’re reducing the sugar content down to three 4% From that, that six 7% you saw before, and I’m going to throw this to you. But before I do, I am going to mention one review that it was a fantastic review. I really enjoyed reading this. The lead author was Dr. David roelens. And the title is the hydrating effects of hypertonic, isotonic and hypotonic sports drinks and waters. So you mentioned these waters where there’s no carbohydrates, just electrolytes on central hydration during continuous exercise, the systematic meta analysis and perspective and what they did. So again, this is a meta analysis, not a single study, but pulling together multiple studies, I think they had 26, in this 128 studies, isotonic beverages in terms of just rehydrating in the body performed the worst. And what performed the best was the hypotonic sports drinks, they do a good explanation of the physiology basically saying sugar, slow down gastric emptying sugar, slow down absorption, where electrolytes actually help that so you bring down the sugar content, bring up the electrolyte content, and you’re going to absorb the fluids better. So throw it to you, Dr. Kenefick. I’m very interested in your thoughts on this. Yeah,

Dr. Robert Kenefick  1:02:22

no, that’s exactly right. And this is why you’re seeing, you know, like Gatorade went from six to four. And you know, even for less so interferes with gastric emptying. But then if you actually can go to lower concentrations, you can decrease that as a factor that slows down the uptake or the actual appearance of fluid and fuel in your vasculature. So again, leveraging science, making adjustments to the beverage, and then now what you’re seeing to even more so is this idea of do I really even need glucose at all, you know, because sugar in and of itself. Now, you know, the sugar wars, and the increase in issues with obesity increases with issues with insulin sensitivity, especially with children, you’re seeing, at least what I’ve seen in the industry is decreasing the amount of glucose or sugars in beverages, because they’re, for lack of a better term being called Sugar Bombs. And so you see increase in education of the consumers parents are saying, I don’t know if I want to give my kids this sugar bomb. So a lot of companies now are moving, you’re talking about that review paper and a great review paper talking about performance. But you were talking about the actual market itself. Most of these beverages are not consumed by athletes, they’re consumed by the general public. Yes. And you’ve seen that education of people are saying I don’t think I need all the sugar and they don’t, they really don’t. So there is a big move to try to move towards this lower glucose, lower sugar type of beverage or no sugar whatsoever.

Trevor Connor  1:03:53

I do think that’s a really important point we’ve talked about before, and I’ve been trying to avoid in this episode bringing a bias used to as simple sugars. But it’s really important for people to understand I’ll just use myself as an example at two weeks. I’m going down to do a five hour race on the equator, it’s going to be brutally hot, it’s going to be incredibly humid. And trust me, I’m bringing sports drinks down because I won’t finish that five hours without those sugars without those electrolytes. You would never catch me sitting on a couch drinking Gatorade or any of these sports drinks. They are candy. We aren’t the only ones that feel there’s been an overemphasis on the so called Sugar Bombs. Let’s hear from Dr. William Adams who feels that water is still best,

Dr William Adams  1:04:34

you know, outside outside the heat illness round and the thermal realm. My other area of interest and passion is in the hydration science realm of things. And I’ve done a number of studies that have looked at various hydration products on fluid retention and iteration status and performance and whatnot. And, you know, I’ve enjoyed you know those experiences isn’t everything. But you know, I think from a hydration perspective, you know, we there’s a ton of a ton of products on the market, as far as, you know, beverages to have, and companies, you know, making some claims about, you know, about hydration. And, you know, I think that there’s a number of things to think about, when it comes to hydration, you know, one related to, you know, what’s what’s, what’s the need, or why why that beverage, right, where, if we’re looking at just day to day hydration, you know, water is going to be our most effective way to to hydrate most of our body, you know, greater than 50% of our body is made up of water. And if we go without water for a prolonged period of time, we have some pretty bad outcomes for occurring. So, you know, replacing those any water losses with with just plain water is very good. Also, that helps reduce other comorbidities that come along with other beverages that have other content to them, whether it be you know, certain sports drinks that have, you know, they do have some electrolytes, but they have a lot of glucose, bottle Sugar, sugar sweetened beverages, so, you know, any type of soda, or pop, depending on where the listeners are tuning in from, you know, those do have some other comorbidities associated with, you know, cavities within the teeth. And with habitual consumption of those beverages is just added energy, which creates a positive energy balance within the body that could lead to risks of being overweight or obese. So there’s, you know, some other downfalls to that, you know, with habitual consumption. So, I always recommend, you know, plain water is great, but you know, there’s other beverages that are effective in replacing body water in certain medical conditions. So think of like, someone who may have diarrhea, for example, they may have an illness of viral illness that has diarrhea as a, as a symptom. You know, having them replaced fluids with an oral rehydration solution, and the who has a has a, that’s kind of an algorithm, if you will, or a formula for what an oral rehydration solution should contain as far as the amount of sodium and chloride and potassium, etc. And that’s based on evidence that has been shown to promote the absorption of that fluid into the body to restore some of those electrolyte losses and everything. So it really just depends on what the use is, and you know, the context and the environment. I think one of the questions people always ask me is, you know, what, about, you know, what about sports drinks? And, you know, if it’s hot outside, should I drink? You know, should I drink a sports drink instead of water? And I think the answer is usually is, it always depends, it depends on, you know, the temperature depends on the type of activity, it depends on the duration of activity, it depends on the intensity of the activity, where I always recommend the hey, you know, if you’re doing if you’re doing continuous endurance exercise, that’s over, you know, 75 minutes in duration, and a pretty high intensity, and it’s hot outside. Yeah, supplementing you know, water with a sports drink, or, you know, adding a sports drink to your hydration strategy or plan along with water, could be helpful to offset some of those, you know, losses, will those water losses, as well as to help provide some energy back to the body for to be able to maintain that intensity. Whereas if exercise is under that, you know, 75 minute timeframe, you know, water is going to be your best choice. It’s going to be it’s going to be effective, it’s going to be healthy. So yeah, that’s, that’s kind of my take on that. But I mean, it’s really cool to see all these different types of beverages and how companies are modifying certain constituents to address certain things physiologically, with how well that that fluid is absorbed in the body.

Trevor Connor  1:09:18

I think one last important thing to point out about these hypotonic beverages, which touches on what you were just talking about is you might hear this and go well, I’ll just buy Gatorade powder, because it’s cheap. And I’ll just dilute it more, I’ll add more water to it. That’s not the same thing. These hypotonic drinks, they reduce the carbohydrates, but they keep the electrolytes high and in some cases, they actually increase the electrolytes where if you just buy the Gatorade powder and dilute it more, you’re diluting down the electrolytes so much you’re almost not getting the benefits from them. So it is actually a different formulation.

Dr. Robert Kenefick  1:09:54

Yeah, I agree. And And remember, you know now the electrolyte and in the sports beverages, you know Already in Gatorade, about a third of what you would see in your plasma. So you know, 14 16 million equivalents or so, you know. So there’s not a lot of electrolyte replacement in those beverages themselves. And in fact, if you were to look at retention beverage hydration index is a measurement of how how well you hang on to a fluid. But are they driven by electrolyte, they don’t hang on any much better than water does, because the electrolyte is not really that high anymore. So in and of themselves, they’re almost hypertonic as they are now. But you’re right, what you are seeing now, and what I’m seeing a lot of this, I think, for differentiation purposes, electrolyte is getting a lot of play. Now, a lot of beverages are coming out, putting high electrolyte concentrations in their beverages, and using that in their marketing, not even telling you why it’s important, just telling you about the habit. And I don’t know what that means the consumer and understand why I’m taking you know, even more electrolytes, in some cases, that could be appropriate. In some cases, maybe not people who are salt sensitive or have high blood pressure, or blood pressure issues definitely shouldn’t be concerned about taking these types of beverages in. I think everything has its place. But right now, I think some of that has really been driven by marketing and differentiation.

Trevor Connor  1:11:15

Coach and professional athlete, Jen Sharp has been a big fan of hypotonic drink mixes for her racing. Let’s hear what she has to say.

Jen Sharp  1:11:24

The biggest shift for me has been the like hyperhydration, right before a really hot and humid race, I as a bigger writer, just my engine gets really hot really fast. So I have to make sure that I’m staying on top of hydration. And I’ve used Stacey Sims products. And then also I have a limb stuff that scratch labs and either one of them have worked well, especially with my digestive system. But constantly thinking about hydration. And then also imparting that on to athletes to there are, of course, salty sweaters and not very sweaty people. Like I don’t actually really sweat that much, which is crazy. And then I’ll look over my husband who’s who when we’re doing indoors with together and he’s like buckets of water streaming. Yeah, so hydration needs are different for every person. And it’s important to figure those out.

Chris Case  1:12:16

You know, it won’t apply to everybody. What is that when you when you are faced with a very hot race day or something? What’s your What’s that routine beforehand, the pre hydration routine?

Jen Sharp  1:12:27

Yeah, so probably, I would say an hour before Well, of course sipping on water or electrolytes beforehand, depending on how hot it is and what type of environment you’re in prior to the race, if you have access to a hotel or wherever that race might be, and you have air conditioning, like stay in it as hard as you can. And then at once you get to the race venue and you’ve picked up your number or whatever. Maybe about an hour before you start to even get on the trainer is when I would take a water bottle full of ice and put the hydration, you know, whatever that might be the hoop hyperhydration and then water and then be sipping on that. Or pretty much drink it as quickly as you can within 20 minutes or so then also having electrolytes with me during the warmup. And chances are usually those throws raises like I’m thinking specifically of Chris, you won’t be able to drink much when you’re when you’re right racing. Like it’s just depending on the course. I mean, there are times and whenever you can think of it, you know, drink, and it would take a big swig noun. But yeah, it’s hard when you’re racing. But then also, after you’re racing, it’s important to continue the hydration. So if you, if you didn’t get that hyper hydration in beforehand, you need to make sure you get something in after otherwise you will be dehydrated. And your performance will be affected the next day and or the next week or I mean, the domino effect

Trevor Connor  1:13:53

will seem to match it because I’ve heard this criticism, somebody who’s talked about hypotonic drink mixes in the past people have said, well, if you take a gel with it, then you’re getting all those sugars, you get the sugar bomb, so so it kind of defeats the purpose. And the answer to that is the hypotonic drink mixes, they’re just trying to focus on rehydrating you. And if that’s what’s really important, that’s all you should be taking. But if you’re in a race, and you’re early in the race, and it’s going easy, and you need to get those calories in or you have a point in the race where it kind of calms down. And you’re more focused on the calories than the rehydration side then you get that through the stuff that’s in your pocket, whether it’s food or gels or goos. But the other points like if you’re going really hard, you should really just be focusing on the rehydration side. Yeah,

Dr. Robert Kenefick  1:14:40

I mean, a lot of it really depends on the activity. You know, I can remember doing cross country rides on a bicycle and you know the intensities because you’re on for hours and testing is not very high. You can almost have a Thanksgiving meal as you’re riding along. But, you know, if you’re doing like a time trial, that is absolutely not the case. So a lot of its delivery system too and what you can Do give them a circumstance that you’re doing. You know, running marathons, difficulty eat food. So fluid is easier. goos a little bit easier depends a lot on the situation in the individual. So people cannot eat at all when they exercise. I’m one of those people. So we that’s not going to happen or even before exercise. Some people can eat, I’m always envious. I’m watching people eat like a stack of pancakes, and then like going hitting the gym and tearing it up. And I’m impressed by that. I don’t know how they do it. So I think there’s a, you know, again, you just get back to the individual aspects of an individual, and then all the things that need to be taken into consideration with the event they’re doing. So like a five hour bike ride, you’re probably going to be taking a lot of stuff with you as you go, right? Oh, a

Rob Pickels  1:15:41

whole lot. It’s something that I’m having a little bit of a difficult time squaring and so I’m hoping that you guys can explain this to maybe bring clarity to the topic is, when we were initially discussing the tonicity of drinks, we discussed how sodium was one of the biggest drivers of tonicity. But kind of as we’re at this segment now, and we’re talking about isover. As hypo versus hyper, or we haven’t really talked about hypertonic, we’ve switched the tonicity driver, and now we’re beginning to discuss the percent carbohydrate, the percent carbohydrate versus the sodium levels, and tonicity. How is all of that playing together,

Dr. Robert Kenefick  1:16:19

they all play a role. So glucose, when you put in sugars into a beverage, it has an osmotic effect. So you have to think anything you’re putting into a fluid, the molecules have exert pressure that has osmotic force. And so it plays a role it contributes a lot depends on the concentration to you talking about what’s the major driver, I could have such a low concentration of sodium, and it’s not a big driver and a really high concentration of glucose or sugars, where they would be the major driver of osmotic pressure, or vice versa. So a lot depends on what you’re putting in how much you’re putting in. And then ultimately, it figure out how much of a driver it is.

Rob Pickels  1:16:59

Yeah. So ultimately, it seems like to me tonicity is a really difficult way to define different drinks, right? Because you could have two drinks with exactly the same osmolality and achieve that in two very different ways or through different combinations, say of electrolyte and carbohydrate. And that alone might affect things like gastric emptying, the ability to transport, you know, through from the lumen of the gut into the bloodstream as well.

Dr. Robert Kenefick  1:17:25

Yes, you’re right. That is That is correct.

Rob Pickels  1:17:29

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Trevor Connor  1:18:13

Well, guys, we’re actually a little over our time here. So I think we’re gonna finish out with one question and let’s just spend a couple of minutes on it. But interested in your opinion on this. What do you think now that we’ve covered the whole history? What do you think is the future of sports drinks?

Dr. Robert Kenefick  1:18:31

There’s a lot of direction in sports drinks, I think what you see now is a lot of differentiation going on exports, waters are now pretty big. So what you’re seeing is no sugars at all. And then a small amount of electrolytes. So that’s a burgeoning market that have been sports waters out for a while now. And you’re seeing more companies get into that. So that’s, that’s one of the areas, again, the tonicity aspect, you’re seeing a lot of more companies changing the amount of electrolyte and so we didn’t, I just said we didn’t really touch about hypertonic solutions, but there are a number of higher electrolyte averages, even getting close to what we would call an oral rehydration solution, you know, something akin to a Pedialyte. So that’s another aspect. And then the last area I could talk about is the work that we’ve been doing probably for the last four and a half, five years now is leveraging amino acids, we’re trying to use those as carriers. So we’ve been publishing a lot in this area of how you can leverage special certain amino acids that carry a lot of sodium and you don’t have to have any glucose at all, and then be able to leverage the actual carrier and transport electrolyte and fluid in, in some cases even better than glucose. So that’s, that’s a future that we think, you know, as a hydration expert in the area, my colleague, Sam Shavon. And I started doing this work again about four and a half years ago. And so this is, at least for us in our burgeoning area of science that We’re publishing. And it’s interesting, I think there are a few other things out there. But the combination of certain things, certain combinations of other substrates that I’ve been reviewing a number of papers on, that are coming out. So I think you’re going to start to see that how well that science gets borne out, you know, come full circle, some of these things that are being added, people can’t tolerate, you know, theoretically would have, you can see why it could have a benefit to performance, but they can’t drink it, or they can’t tolerate it in their stomach. So I think we’re gonna, you know, we’re always looking at the next thing. And so that’s probably what you’re going to start to see more of, what other substrates can we put in here? What other types of, for lack of a better term ergogenic aid in research, can we put into a beverage that’ll that will help performance? And I think you’re always going to be seeing that, but you know, people are getting more clever. There’s a lot more good work going on right now. Where labs are looking at some interesting things to leverage either getting through the stomach faster, getting absorbed faster, or preserving performance

Trevor Connor  1:21:03

to your point and talk about coming full circle in 2024. Gatorade is releasing Gatorade, unflavored water,

Dr. Robert Kenefick  1:21:12

yeah, they’ve been doing a lot of things with light. They’re their sports, water just came out two weeks ago. They’re launching their rapid brands. It’s out now I haven’t seen it yet. You want to look at it. So they’re leveraging they’re going back to some of their older science and leveraging that for some of their products as well. So yeah, they’re they’re beginning differentiating they have to and you look at companies we just talked about, you know, the markets, the bigger companies right now liquid IV is become a very big company. And what they’re doing they’re definitely higher electrolyte company. So in Pedialyte is another one, I’ve been trying to go from, like a kids brands, really for vomiting, diarrhea, and now be used for more things and try to open up the market for themselves more increase their market share, you know, so you’re looking at averages that are talking about not even in this country and other countries to give a beverage in Mexico, you know, that gets touted as an hour or rehydration solution. It’s not really it’s more of a sports drink. But one of their big claims to fame is addressing hangover. So that’s another thing you’re seeing these companies start to push out. So I think it’s interesting is there’s, there’s a lot of players in the beverage industry and a lot of players worldwide, at least in the US we don’t think about and a lot of different things that are being done, especially for the marketing and things that you would be surprised the big thing I’ve seen of late is this hangover thing, and what some companies are saying, to just try to increase that market share. So I think you know, just because the competition is getting bigger, you’re seeing companies like Gatorade having to start to come out with more products. You know, they’re it’s all a competition, and they only had Gatorade, right? It’s because around my age, probably a little younger, like when I grew up, it was first it was just the lemon lime, right. And then you had the lemon lime, orange. And then now you see like this rainbow of colors. And if you go to other countries, there’s other flavors that you don’t have here, because they’re more popular in other countries. So and then they’ve gone now they’re like, all over changing concentrations of glucose or glucose, fructose, their electrolytes going to sports waters going to this rapid so yeah, I mean, you’re seeing a lot of pressure in the marketplace that companies are starting to differentiate in different ways.

Trevor Connor  1:23:23

Well, guys, it’s been a really fun conversation. I think we just touched on the history of sports drinks, but it was fun kind of going down that path and seeing how we got to where we’re at. So you’ve been on the show before. This is where we finish out with our one minutes. So it’s the most salient or important point you think our listeners need to take from this episode. And Dr. Kaktovik? If you’re ready, we’ll let you go first.

Dr. Robert Kenefick  1:23:51

Thanks. You know, we touched on a number of times in our discussion, and I’ve written about it before, in my own work, I think that at least somebody’s at least a serious athlete, or semi serious, so wants to perform, you need to understand a few things about yourself, what works for you, you know, if it’s hydration, you need to have an idea of what your sweat rate is, you need to plan have some kind of game plan individuals who are just starting out, you know, there’s a lot of trial and error, but you need to be cognizant of what your own individual needs are, what you can and can’t tolerate as far as you know, food and fuel, etc. And to experiment with these things in your training. And one of my mentors, Dr. Zhang, Finn would always say, you know, your body is your laboratory. I say that oftentimes now, you do need to try these things. You do need to work on these things. The day of the event is not the time to try something new. That typically leads to disaster. And so again, you know, the human human variability is huge, and it isn’t one size fits all. What works for one athlete or an individual doesn’t necessarily work for another one. And so it takes time to figure out what works for you. And so I think people should understand that and began to think about that for their own training is for their own performance.

Rob Pickels  1:25:04

Yeah, that was such a good answer that I’m going to kind of restate it, I think, and maybe some slightly different words, but probably add nothing new. The major theme throughout this conversation has been that as our learning has changed, so have the products. In the beginning, we had no learning, we had no knowledge. And we had no products, people were told not to take anything. But over time, as research has come out, we’ve realized that different aspects of hydration products can have different improvements within our own performance. And what’s really important to me right now is that people understand, in my opinion, and Dr. Kenefick, working for intrinsic bioscience, maybe you do have the perfect product out there. For me, it’s not even about the product, right? It’s about the individual and what that individual needs. And there are hundreds, if not 1000s of products in the marketplace, you can find the product or make the product yourself that is perfect for your needs. As an individual. We’ve thrown out some names throughout this episode. They’re probably amazing for the right person and terrible for the wrong person. Trevor, you and I don’t agree on accelerate, I can’t drink it. You were addicted to it.

Trevor Connor  1:26:13

I haven’t had a 10 years, but I love it. Well, this,

Rob Pickels  1:26:16

this is a throwback, I’m telling you to go out and buy some or somebody send Trevor a bag of accelerate. How about that. But ultimately, I think that if individuals begin understanding themselves in there, if you can’t do it, or you don’t think that you can do it, there are a lot of resources online, or this is where a coach can really help you. But determine what it is that you need and your body and your performance and find the product that matches and gives those things to you. I’m a very sweaty person, Dr. Kenneth fix that he’s a sweaty person, but I think I roll up to the start line 2% dehydrated, just just from warming up, you know. And so my needs are very different, you know, Trevor, probably from you and yours, and the same for all the listeners. So for me, it’s not about the perfect product, it’s about the perfect product for you.

Trevor Connor  1:27:02

So I think you too touched on the most important point. So I get to go a slightly different direction with my take home, which is kind of the fun I had going through the history of sports hydration, and what it made me realize, which is it when I was in school, and first getting into exercise physiology, there was just the research. You read the research, it was all current. It was all great. You are getting caught up on what’s the current science, I’ve realized that I’ve now been around long enough. And this is what really made me hit home. That a lot of this research I was reading back in school is really outdated

Rob Pickels  1:27:46

current anymore, that

Trevor Connor  1:27:48

it’s making me more and more not just say, here’s a study. But look, what’s the date on this study? What is the context of the study? And why is that important to our listeners, is important, because you’re gonna hear people all the time say, well, there’s research on this. There’s research on that. When was that research? What was the context of that research? Because we can pull up some of that GSSI research from the 90s from the early 2000s. That was good research at the time. It’s outdated now.

Dr. Robert Kenefick  1:28:22

Yeah, if you look over my right shoulder, I have a number of books here on this on this desk. They’re the blue volumes, there are all GSSI books that they came out from their research. And as a student, and as a young professional, I prided myself on getting all of these books and reading them. And you’re right. And when I look at them, I’ve looked at them less frequently now. But you know, look at some of these studies. And they go, oh, yeah, we’ve gone way past that. Now. I still like to have the books though. So yeah, you’re right. I mean, it’s it has changed a lot. And it’s it’s going to continue to change. I mean, the area of hydration now in other areas, looking into hydration health, just in general.

Trevor Connor  1:28:58

Well, Dr. Cataphracts always a pleasure to have you on the show. That was a really fun conversation.

Dr. Robert Kenefick  1:29:03

Yeah, thank you. I will say it’s fun. I mean, you can spend so much time in any one of these areas.

Rob Pickels  1:29:08

That was another episode of Fast Talk. Subscribe to Fast Talk wherever you prefer to find your favorite podcast. Be sure to leave us a rating and a review. The thoughts and opinions expressed on Fast Talk are those of the individual. As always, we love your feedback. Tweeted us @fasttalklabs or join the conversation at Learn from our experts at or help keep us independent by supporting us on Patreon for Dr. Robert Kenefick, Dr. Timothy Noakes, Dr. Paddock and Dr. Churchill, Dr. Adams, Jen Sharp, Lindsey Gulledge, and Trevor Connor. I’m Rob Pickels. Thanks for listening!