Hydration for Athletes: Electrolyte Replenishment, Combating Cramps, & Sweat Testing ft. Andy Blow

Hydration for Athletes: Electrolyte Replenishment, Combating Cramps, & Sweat Testing ft. Andy Blow

Authored by Zhill Olonan • 
October 4, 2018

Hydration. It's more than just drinking "enough" water.

Like everything that goes into the human system, hydration has nuance. There's room to optimize according to your own biology, needs, and goals.

Andy Blow, a triathlete and sports scientist, suffered from serious cramps throughout his athletic career. There are many reasons why people cramp, and a key mechanism is through dehydration and poor electrolyte replenishment. All athletes sweat, yet there's a huge variance in sweat and sodium losses, which can lead to sub-optimal performance and a terrible feeling we've all experienced: Cramps. To combat this, Andy founded Precision Hydration to help endurance athletes and a number of teams in the NFL, NBA, and MLB meet their personalized hydration and electrolyte needs.

In this discussion, you'll discover:

  • The misconceptions of hydration and electrolytes, and how there is a huge variance in how much sodium each individual loses when sweating
  • How and why endurance athletes tend to lean more into the quantified-self philosophy than other types of athletes
  • The physiology behind cramping

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Putting your finger on exactly why [cramping happens] is very, very difficult. It's been suggested it's to do with the ratio of fluid and sodium inside and outside of the muscle cells, the pressure that it creates, because you get extracellular and intercellular fluid shift. There's obviously sodium is involved in muscle contraction and in nerve impulses. Those could be some causes there.Andy Blow - Episode 84


Geoff: Andy, awesome to finally connect and have you on the program.

Andy: Yeah. Great to be here, Geoff. Thanks for inviting me.

Geoff: So you have an English accent. Are you calling in from London, UK?

Andy: No, far from London. I'm about two hours southwest of London on the south coast.

Geoff: Okay. Okay. Great. So here it's quite muggy this time. I don't know what it's like typically in summer of England, but I hear it's a little bit muggier than usual?

Andy: Yeah, and we had about two inches of rain yesterday. So business as usual out there.

Geoff: So water, hydration, that's your wheelhouse. I'd love to hear a little bit about the technology and history of Precision Hydration. So from a laymen and a customer, as we all sweat, we all have different electrolyte demands and requirements as we sweat different levels of electrolytes. It seems like you guys had the first technology to really apply that insight into a sports application use case. I'm actually curious, my colleagues mention that this might have come from a clinical application or a therapeutic application. I'm curious to hear the story of the technology providing Precision Hydration and also your personal story of how this became an interest for you.

Andy: Yeah. Sure. Yeah, your colleagues are dead right. We haven't invented any novel technology here. We're using technology that already existed, largely. We've written some software and things, but the technology was originally used, and still is actually used in a lot of parts of the world, to test and diagnose cystic fibrosis, which is a genetic condition, which one of the characteristics that doctors can spot is increased loss of sodium chloride in sweat.

So the sweat test was originally developed for that purpose. We were the first people to really take it in a large way and use it with athletes. Athletes have done sweat tests for many years and there's been a lot of research done in that area, so people have typically collected sweat using different methodologies and analyzed it in the lab, but we took this at rest sweat testing technology and started using it with athletes probably about 10 years ago now. That's where the technology comes from.

The story of why we started doing it was quite a personal one for me. I was racing. I run triathlons, often in the heat in places like Hawaii, and found that whilst my performances in the cool were pretty good, my performances in the heat were terrible. A lot of the symptoms that I showed here consistent with hydration issues, electrolyte loss, hyponatremia, which is where you over hydrate and under-replace salt.

Ended up in a medical tent a couple of times. So it was a personal journey which led me down this line of figuring out that actually, I was someone with very high sweat and sodium losses. I needed a test to help me diagnose that. Then once I found it out, I was able to go on and compete in the heat without any problems.

Geoff: Very cool. That's an interesting lens. So this really came from an application or an insight from you personally. So when you were an elite, Iron Man triathlete, how did you come across the technology? What was the insight? How'd you connect cystic fibrosis to elite triathlons?

Andy: Yeah, I started off basically where most people start off these days, with Google. Just looking around and typing in the word sweat test and salt test and things. There was a few things came up and I read some interesting forums and some articles, but it was pretty clear to me there was nothing in a wide scale being targeted to athletes to help with this. 

So I did come across, repeatedly came across the cystic fibrosis testing world, which is completely separate online and in the real world to groups of people that work with athletes. I ran the idea across a friend of mine who's a medic, he's a heart surgeon. I said, "Look, would this test actually test what I want to look for?" And he was like, "Well, yeah, basically that would." And he kindly arranged for me to have a test, actually.

He said to me, 'cause he'd known about some of the problems I had with racing, "I bet that your score on this will be really, really high. Almost off the charts. 'Cause I've seen the state of you after these races." He'd even noticed there's white salt deposits on my kit and on my face after a race. And he said, "This will be high." And sure enough, I came out and it was super high. It's actually not the highest we've tested. We've tested quite a few people higher than me now, but for awhile, I had the record in our sweat test games. 

Geoff: That's interesting. So what is the typical range? What are the units that you measure?

Andy: We measure it in millimole per liter and a really, really low score, scores that we report in the literature go down into the low single digits for millimole. We typically have not seen many people below 12, 15 millimole. And realistically, a low, and for our population, seems to be around 20s. 18 to 22, something like that at the high end. In non-CF groups, we see up to around about 100, maybe just over 100 millimole. That can be ... Then with cystic fibrosis, we can see up to 130, 135 millimole. And then there's kind of a bell curve between.

Geoff: Yeah. So this is not a trivial difference. We're talking about real ... it's like a 5x multiple difference in terms of salt usage, salt [crosstalk 00:07:30].

Andy: Yeah, I would say it's even 10 times would be what we'd tend to, 10 to 100 very roughly. 

Geoff: Yeah. I'm seeing the range. Yeah.

From a layman's perspective, it's like, "Oh, everyone sweats and everyone's sweat's salty. Maybe there's 10% variance, 50% variance," but we're really talking about 500%, 1000% variance. This is a real difference that you're seeing and detecting.

Andy: Absolutely. Yeah. I think when you then, what confuses people and what confused us at first is you then have to multiply that up by someone's sweat rates as well, because obviously some people ... I know now, in retrospect, that not only do I have an unusually high sweat sodium concentration, around 85 to 90 millimole, but I have quite a high sweat rate as well. And then you multiply that up over the number of hours it takes to do an Iron Man and it's very easy to see why I would run into the problems. I was losing 15, 20, 25 grams of sodium in that race, which is 10 times more than we're recommended to eat in a day. Other people, if you look at the other extreme, we meet people with a very low sodium concentration, very low sweat rate. They could be losing just a couple of grams in the same time period. So it's when you really see some big differences when you multiply it by sweat rates and different durations of activity.

Geoff: Right. And how do you measure sweat rate? Is that something you also do as well?

Andy: Yeah, so what we do if we're time constrained with an athlete is we'll often just get them to estimate their sweat rate. Not numerically, but we're just getting to classify whether they think they're low, moderate, high, or very high sweater. With a lot of athletes who train and compete a lot, they know their bodies quite well and they can give you a reasonable explanation, then we would put that into our algorithm, determine what kind of drinks they might need. For the more professional athletes or the more advanced, we would often either teach them how to do this or do it with them and measure their sweat rates during training sessions or competitions by weighing them before and afterwards. So you'd basically take the change in body weight, correct for any fluid that they've drunk, and you get an estimation of their sweat rate.

Geoff: Okay. So you can get pretty particular in terms of doing body weight adjustment in terms of how much fluid loss. Okay. That's pretty interesting. So you're essentially building a formula for sweat physiology, the amount of concentration times the flow rate equals overall loss during the activity. Interesting. Perhaps, for a devil's advocate here, what if you just said, just take a bunch of salt. Let's not be overly precise. Are we affecting people that have low salt consumption overly negatively? What are the levers that you're playing around here? Obviously not enough salt, you're crushing yourself 10, 15 years ago, too much salt. What's the danger on the other end of the spectrum?

Andy: I think it's a really interesting question. It's one we get asked all the time. Acutely, say during a competition, I think that the risk of taking a little bit more salt rather than a little bit less, I would always advise athletes to take a little bit more. That doesn't mean to say you should just take loads. We always want to give a reasonably targeted amount. But the reality with an athlete in competition is if they're sweating a lot, they're sweating out a lot of fluid and salt. They'll also urinate out any extra, either immediately or after the competition, depending on the length of it. So a little bit more is not so much of a problem.

Athletes who take a lot too much, we had a case of a cyclist who took too much, or we heard of this during one of the grand tours, and I think it was the tour of Italy or it may have been the world tour. One of the tour cycling events. He was given very strong salt supplements by the team, 'cause it was hot. They all were. And he actually gained weight over a number of days because he was absorbing and retaining so much fluid. It wasn't until they took him off the salt supplements, he was able to start peeing it out and he normalized his weight again.

In a short time span, or chronically, you can retain extra fluid if you take on too much salt. But for most people, that wouldn't be such an issue. We always say this is like hitting a bond or not hitting a bullseye on a target. We just need to get it about right for the athletes. More sweat, more salt, try taking extra. See how you feel, see how your body reacts. And then if you're not sweating a lot or if your activities are a short duration or you're just not a big sweater, it might be that you don't need electrolytes supplementation. You might be fine with stocking up a bit before you go and then replacing it again afterwards. It is highly individual.

Geoff: Yeah. That makes sense. I actually just came back from a sports science summit and there's a couple key hot areas and traumatic brain injury concussion is one popular area of discussion right now, but of course personalization, how do you periodize and cycle per individual athlete. Me, as an athlete, is going to respond very differently to a stressor than someone like yourself. So how do we curate and help the athlete adapt? It makes a lot of sense.

Andy: You're 100% right. That's the way everything's going. And the nuance of that often gets lost in a lot of the older debates. When you talk to people about hydration, the debate's very polarized.

Do we drink to thirst or do we drink to a plan? Do we just drink water or do we need a sports drink? None of these question have yes or no answers to them or they all require a look at the individual circumstance, because we work with athletes who absolutely benefit from a very aggressive strategy of salt and fluid supplementation during activities they're doing, because of what they're doing and because of the nature of their physiology.

I'm talking about guys basically or girls that are doing long duration, very high intensity endurance exercise, in the heat, sweating a ton, tour de France riders back to back days, Iron Man athletes that are out there all day, football players doing two a day practice and pre-season, that kind of thing. These people benefit from aggressive fluid and salt loading because they're losing so much.

Right down the far end, you've got people who are going out and doing local 5K heart run, they're jogging a few times a week, they might do some yoga and stuff. These people don't need to be smashing a sports drink every day. And these completely, the debate will never come up with a right answer for everyone. It's got to be case by case.

Geoff: Arguably, you could make the strong thesis that it's bad for people out there smashing Gatorade. When Gatorade was first invented in the 60s, it was an electrolyte drink and now it's more of a sugar bomb, which is a devolution of what the purpose of that product was supposed to be. So if you're just slamming essentially soft drink full of sugar twice a day when you're doing a 5K, you're basically on the track of giving yourself diabetes.

Andy: Yeah, agreed. I think that's part of the problem people have with the sports drink industry. It's got a bad name these days because it's seen as having been co opted by the soft drinks, the soda industry, because the big players, Gatorade is owned by PepsiCo, and Coca Cola has Powerade and it's just bought a big share, I believe, in Body Armor, which is another new up and coming sports drink. So I think quite rightly people are starting to kick back against these things a bit, just because we're selling this as this is branded on all in the US, all of the major sports leagues all around the fields, everything we see people drinking is Gatorade bottles, and they've done that thing where they're associated with athletes, make it look healthy, it's a healthier alternative. In reality, it's not really, but ...

Geoff: I don't even know if any team actually uses Gatorade. Thinking about it, I think they have it out there, 'cause it's required by contract, but the athletes themselves, we kind of overly generalize, because I think half the time the sports nutritionists are trying to take athletes off of Skittles and candy bars and the other half are pretty delved into their nutrition. But I would say that more and more people realize that's not what they need for optimal nutrition.

Andy: Definitely. We've been in and around a lot of US sports teams because we do our sweat testing, we actually supply a lot of hydration drinks and products to major sports teams in the US. I've seen a reasonable amount of Gatorade drunk, but I see a lot of other products being used these days. I see, I definitely can't name names, 'cause it would get someone into trouble, but I've seen one NFL team donating a lot of its Gatorade into a local high school for their football team that doesn't have any major funding, because they just can't get through the amount they get given. People are becoming more sophisticated. A lot of people in sports and around sport realize that just because the guys are drinking a Gatorade bottle doesn't mean it's got Gatorade in it. But we've got a long way to go to break the mass public perception of that, I think.

Geoff: Right. I don't want to go overly extreme here. There's a role of carbohydrate, role for sugar for exercise. So it's not like you don't eat sugar, you just go full keto. That's incorrect. You want sugar for anaerobic movements. So I'm curious, with Precision Hydration, is that another variable that you offer your customers where you have electrolytes and you vary the electrolytes based on your sweat test results? Are you looking for other personalized variables for your line, or is it mostly just focused on electrolytes?

Andy: At the moment, we're focused predominantly on electrolytes. We definitely understand that our products don't contain a lot of energy. A lot of them contain zero energy, zero calories, and then we have one line of products that contains a very small amount of carbs. So around about 2.5%, 3% carbohydrates solution. When you compare that to say, a Gatorade at 6% or 7% or a soda at 9% or 10%, it's quite low in sugar, and the idea with that one is that it just gives, sometimes in certain situations where athletes need that little bit of sugar in solution with electrolytes to help speed transit of fluid across the gut, so it helps with that. 

With regards to personalization, we definitely do a lot of one to one consultancy and work with athletes, either just on email, people who get introduced through our website or when we go into teams and work with them to figure out the nutrition strategies that go alongside that. Because for endurance sports in particular, figuring out that relationship of what do I need to drink and eat to perform at my best in different scenarios is critical. 

Definitely, we're seeing people moving away, I think, some of the time from liquid calories, to more solid calories and gels and things if they're doing long endurance events in the heat, because they realize that the very sugary drinks can give them gut issues. Obviously nowadays, there's a lot more interesting endurance athletes being more fat adapted and ketogenic or using ketone supplements or whatever to improve their metabolisms from that point of view. 

So again, it's so hard to generalize, but it's a case by case basis.

I know that one of my colleagues, Shawn O'Mahony, who I raced a swim-run race with earlier this year, he actually used the HVMN Ketone for the first time racing when we did this race and was amazed at how much less carbohydrate he consumed during the race.

We were out there for a very tense event for about 5.5 hours. You consume very few additional calories, just water and salts. It was pretty awesome.

Geoff: That's cool to hear.

Andy: Yeah.

Geoff: Yeah, that makes sense. Obviously HVMN Ketone is not going to reduce salt load or salt usage or salt expenditure, but it's definitely gonna preserve your glucose or glycogen reserve, so it makes sense to stack something like Precision Hydration with HVMN Ketone. That's a cool story. Then I guess in terms of types of athletes, it sounds like it's very similar with our experience dealing with athletes that cyclists, ultra performance, endurance athletes tend to seem to be the earliest adopters for these technologies. I have a sense of why I think that's the case, but I'm curious to perhaps hear your insight. Why does it tend to be triathletes, cyclists, and then move towards something like basketball or American football?

Andy: Yeah, it's a really good question. I don't know. I think coaches has something to do with it in the sports. Especially with sports like triathlon where people who have done that sport have always been seen as early adopters. It was a very strange sport when it started in the 80s and even when I started it in the 90s, we were little groups of people meeting on a Sunday morning, running around in speedos and little tiny vests. It was all a bit strange, with aero bars on the bike. I think that culture is embedded and that we would, within reason, try anything new and innovative to go a bit faster. Because when I started triathlon, there were very few books, even. Dave Scott had written a book on how to train, but the rest of the time, you were asking other people who did the sport and you were making it up as you went along. So there's a lot of room for individual innovation.

I think also, because of the lack of that club or team sports environment where you would go into a system and be coached on how to do it, you would freestyle it. So part if it's that. I think part of it also is that people who do these sports probably are more affluent, have a little bit more money to play with, they're not afraid to throw a bit of money at trialing things. And anything to go faster. These triathletes will spend $10000 on a bike happily. And $1000 on a wetsuit and stuff. So they're not afraid to spend a few dollars to innovate as well. So I think that's got a lot to do with it.

Team sports, on the other hand, a lot of people who have worked in team sports for 20, 30, 40 years who are still in the system who are doing things the way they used to do, teams just seem like a bit slower to pivot because they're making the decision whereas an individual athlete is making decisions to try something out that their performance is gonna live and die by. If you're in charge of, I don't know, the New England Patriots, if you ever implement something new and radical, you'd better be damn sure it's gonna work. 

Geoff: Yeah.

Andy: Otherwise, your job's on the line. There's a little bit of that.

Geoff: Yeah. And again, those 60, 80 guys, and half of them are still eating candy bars, and you're like, "OH, what's the biggest problem that I've got to solve in my busy schedule?" I would say the last part, and I think those two points are important for it, very individualized and experimental, and I agree with you, the triathlete community, just looking at some of the market segments, is one of the more affluent demographics for sport. People are buying $10000 bikes. You're going to South Africa to compete in a world championship. You can't just go to your local basketball court and shoot some free throws.

I would say the last part of that that was interesting is the amount of quantified self and measurement in triathlon and cycling. People have these power meters to track their wattage, obsessed with Strava, which is measuring exactly their time and altitude and their distance. And obviously, if you're measuring to that level, any single intervention's gonna be helpful to actually see material difference. If you're not measuring it, how do you know if it works? And if you actually just are in that culture where you just constantly measure all these variables and any single tweak, you should be able to pick up.

Andy: Yeah, I think you're 100% right. We've all got one of these watches and it's always on. Nowadays, it's amazing. I was talking to someone the other day. I used to love my training. I was an early adopter of this kind of stuff. But even in the past, I would tend to use it fairly selectively, so key workouts. But now, because these days it connects straight to the phone, it uploads everything automatically, it's so easy to log absolutely everything you do. That can be a great thing. It can also be a dangerous thing to the addictive type personalities you get in sports or endurance sports, I think. But it's certainly, yeah, you can measure it all and see what's happening with your performance.

Geoff: Yeah. I actually ask this question to most guests who have some sort of experience here related to this. What is your thought on the quantified self? And to give you a couple sense of the poles, you have certain athletes who are all about it, let me measure everything, let me be a scientist, let me be about, let me tweak every single variable and obsess over the data. Then you have people on the other side of the spectrum that I would say are more just animal instinct, animal smell. I just want to understand the intuition around my body so well that don't give me all the stuff that's just a distraction. Let me just be on my bike, let me just be on the road running and feeling it. What is your sense ... Obviously I think there's value to both sides. I think you really converge. But have you played with that philosophy battle in your own head?

Andy: I would say, having been fortunate to be around a lot of elite athletes over the years, either training, competing with them, or now working with them as an external consultant, the majority of the really top athletes that I've worked with tend to be more intuitive and more led by their bodies.

That doesn't mean that they all shun technology, but I think that they trust their body first and use data to back up or add to what their instincts and things are telling them. I think athletes that are led 100% by the data or get too wrapped up in that can lose something in that process, potentially.

Especially when it comes down to racing. I think it depends what you're doing to a degree. If you're a track cyclist who's riding solo or a road time trialist where it's all about aero position, being a data geek probably helps with that a lot. If you are more like a road racer or a runner who's in a mass participation, a marathon, like you see at the front of the marathons these days, it's largely all East Africans. None of them are wearing watches. They're going out there and they're racing each other and it's man on man and you've got to live by your instincts there.

As a sports fan and as a fan of elite athletes in general, that's what I love to see is I love to see them without the technology, like people racing. I think though, what's fascinating is then being able to record that stuff. So maybe getting some of these guys to wear watches and collect data an then being able to retrospectively analyze it or I would love to work with some athletes like that and help them. Maybe you could uncover some things from measuring it and looking at it afterwards. I know a lot of people are into that.

Geoff: Yeah. I think there's a sensible conversion of those two methods. I think when you're actually competing, you're not trying to look at your heart rate variability. Just win the damn race. Why are you looking at data? But when you're in training, when you're reviewing, it's nice to have that data so you can actually tweak and play around. So I think there is, of course, value to both side of things.

Curious to hear about your thoughts on ... I don't know if you've read Alex Hutchinson's new book. Have you heard of her? We actually spoke to Alex last week. So our conversation is percolating in my mind. I think one of the biggest takeaways from that book was the story around Tim Noakes and Samuele Marcora and their approach towards support science with the brain being the dominate organ, or at least a very important contributor to physical performance. Psycho biological and theory, the central governor theory where the body's almost a sub input into the brain, but the brain ultimately decides whether you're putting out more or putting out less.

Some of the interesting results in terms of experience showed that for a sugar drink, if you drink a carbohydrate drink, but you pump that carbohydrate drink out immediately, through a stomach pump, that athlete still performs better than placebo, if someone's just drinking water. I'm curious to get your sense of that kind of psycho biological effect on an input and if there's any applications towards electrolytes. I don't think that's been studied, but curious to get your thoughts. Is that salt load helpful physiologically to control the ion shuttling in your cells? I imagine that's an important part of it, but mostly, I'm wondering is there a psychological effect? You'd have some salt in your mouth, your brain's like, "Oh, we got some electrolytes."

Andy: I think it could well be. The closest that I think people have come to actually studying that formally is looking at the effect of pickle juice cramping. For instance, a lot of people, cramping is a whole debate in itself. Some people think cramping has got nothing to do with electrolytes, some people think it is the answer. Again, the reality exists, I think, in the gray area in between where sometimes cramps are people who are predisposed to cramps with large electrolyte deficits. For many years, pickle juice with a very high sodium content has been used to alleviate cramps in football players and other people. 

Now, when they've measured it, you put pickle juice in someone's mouth, and it can alleviate a cramp. But it happens so fast that you have to rule out the fact that it's been absorbed and got down into the body at a cellular level.

What it's done is they think it's maybe affected some receptors in the mouth, which then go on to create a cascade of events in the central nervous system, which then allow the muscles to relax. So there are some products on the market that are claiming to be able to take advantage of that, which is a really interesting theory.

I also think, on a purely, if you like, the purely perceivable psychological level, though, definitely that carbohydrate mouth rinsing has been proven to be effective. I certainly think that if you've got athletes, especially if they've had a past history of problems with sodium depletion of hyponatremia or cramping, you put a salty tasting drink in their mouth, that's gonna make them feel good. Anything that makes you feel good can give you that little bit more gas, basically. There becomes a point when if you're becoming so dehydrated, sodium depleted, blood volume's dropping so much that your performance is gonna fall off, you're gonna need to drink something and absorb it for it to have a cast iron physiological effect. Like you said, that book, Alex's book, was so good at pointing out how blurred that line is between what is a psychological effect and what is a physiological effect and the fact that the two are effectively intertwined and it's really, really interesting.

Geoff: Yeah. My quippy take away from that book is that the best way to train is to trick your brain or train your brain, but the best way to train your brain is to actually just do the damn exercise. So it ends up being just exercise a lot. Any thoughts on that?

Andy: Yeah, I agree, largely. I think there's elements, by understanding it. There's things you can take away. I definitely took a lot away from it. Something I'd already figured out over the years anyway, but if I've got hard training to do, I have to do it first thing in the morning. I have two very young kids and a pretty busy job now. By the end of the day, I'm spent, even if I've not lifted a finger with training. So I've been swimming hard lately for a swim run race. If I've got 4K swim set to do, that has to be at 6 in the morning, 'cause I have to get out of bed and have a coffee and go and then I can give it 100%. But mentally, it's challenging. If I try to do that at 7 PM, I would just not get the performance.

Geoff: Your brain is exhausted.

Andy: So it was great to have that reinforced, because I've fallen into that habit many years ago of training first thing in the morning, but to understand that actually it's a real thing and you're not just being a bit of a wimp is quite good.

Geoff: Or it's like if you actually do a 7 o'clock race or practice after all that work through the day, it's more of a harder adaptive training session. It's like an extra bonus training session. I'm actually curious to dive into the physiology of cramping. We've all cramped. I think you're a professional athlete, you're just someone that did physical education as a 15 year old boy or girl, we've all cramped. What is the best explanation of what's going on there? You get a tightness in our side, doesn't feel that good, then you walk it off. What's going on there?

Andy: Yeah, it's a really good question and no one understands cramping fully. When you get cramps in large muscle groups during exercise, the typical ones would be someone's pulling a cramp in their hamstring or their calf when they're sprinting or running at the end of a football game or something like that. That's a, it's like a tectonic muscle contraction where the muscle just goes into spasm and just keeps over contracting. And in the instant, the only way to really relieve it is to stretch it very gently. Then what you find is that causes the cramp to relax because you reverse the pressure on it, which control the muscle firing, they send signals out for it to relax the muscles.

No one has ever come up with a great theory that completely encompasses why muscles would cramp. Part of it, I think, is that it's a way of the body slowing you down when you're pushing the limits, be that very explosively and very fast, or whether it's endurance exercise when you're becoming depleted in terms of fluids and electrolytes and carbohydrates and fuel.

If you start to cramp, you have to slow. So wherever your body is saying no, enough is enough, we've got to slow down here. We're running, we've got to walk, 'cause we've got to ease this cramp out.

We, in a joking way, talk about different flavors of cramp because we see it with triathletes. A lot of triathletes will get cramp in the swimming pool if they do a bike or run session. Then they jump in the swimming pool and try and do some kicking, they kick and they're pushing off the wall, they get a cramp in their feet. And it's very hard to pin a cramp like that on electrolytes depletion because quite often, the preceding exercise hasn't been long enough, they're not all that dehydrated. It seems to be something neuromuscular. You're taking the foot from the position where it's very loaded to a position where it's unloaded, but you're asking it to do an opposing action and neuromuscularly, it doesn't like it. It goes into spasm. And it seems those kind of cramps within reason tend to get better with practice and they get better with fitness and with training.

Other cramps, the cramps I used to get when I was doing an Iron Man, which starts off usually in my quads on the run and I'd feel my quads nipping away and I could tell that a cramp was coming down, it might start nipping in the calves as well and hamstrings and before you know, it could be full blown cramps in both legs. And they were definitely, as far as I'm concerned, were electrolytes and fluid depletion related. Because as soon as I was able to get salt and fluid back in and walk it off, a few minutes later, I could be back running again.

We see numerous cases of that with people who have been doing endurance exercise for a long time, increasing problems with cramps, especially in longer and hotter events. We put them on a regime of more aggressive sodium in relation to the fluid they're taking in. So I would say seven or eight times out of 10, it solves the problem. Putting your finger on exactly why it does that is very, very difficult. It's been suggested it's to do with the ratio of fluid and sodium inside and outside of the muscle cells, the pressure that it creates, because you get extra cellular and intercellular fluid shift. There's obviously sodium is involved in muscle contraction and in nerve impulses. So it could be causes there. It's a tricky one to study. And I think that's part of the issue is that setting up a study where you actually research cramping in a sports science lab is almost impossible to reliably create cramping and it's also quite unethical. 

Going back to the Alex Hutchinson thing about the mind and body connection, I would also argue that cramps tend to happen with athletes very often when they're pushing themselves extremely hard. Which tends to happen in competition. Now, some athletes can push themselves very hard in controlled conditions in the lab, but very few will push themselves as hard as they can compared to when they're going to capture a ball that they've got to catch to score a touchdown or climb a mountain. So it's a tricky one. We're a long way from resolving all of that tone.

Geoff: Yeah. No, it makes sense. It sounds very similar, actually, to the emerging research around traumatic injury and concussion where there's not great mile markers for that, and of course the ethical side. Every single concussion is different and you're not gonna just drop bricks and 50 pounds of force on someone's head and just measure it, can we rescue the damage. I can see similar challenges with cramping. Everyone cramps a little bit differently. How do you correct for that variation of the ideology of where that cramp comes from and the severity of the cramp? Those are a lot of variables to correct for.

Andy: Yeah. I think what a lot of people do is potentially if cramps are related to sodium and fluid imbalance, people sometimes make it worse because dehydration has been labeled as a cause for cramp. So what people will do is drink more water. Then they end up further diluting the sodium that was in the body further, which could make it worse rather than better. When you look at a lot of the literature outside of sport around people getting hyponatremia in hospitals through various reasons, when you look at kidney dialysis patients who have the amount of sodium in the system dialed up and dialed down, all of these people exhibit quite a lot of cramping, and that's listed as a symptom, when their sodium levels drop too low. In a completely different scenario, we get people cramping when we mess about with their sodium and fluid levels, but it's just in a different domain and I don't think many people have looked at that research and then crossed it over with sports to see if there's any correlation.

Geoff: No, that's a good segue to something that I wanted to ask you about or at least discuss with you around Professor Tim Noakes idea about being water logged. Traditionally, I think if you look at the arc of sports science, hydration was one of the key buzz words probably, I don't know, maybe 20 years ago where everyone's under hydrated, make sure you drink a lot of water, a lot of water, a lot of water. Noakes is saying, "Hey, everyone is just full of water. It's worsening their performance." Do you drink to thirst? Do you just drink a lot of water all the time. Let's dive into that. Help us unpack this here. What are your thoughts there?

Andy: It's a massive topic. Again, another one that we get challenged on all the time, because I think what Noakes has done with that book, Waterlogged, and with all his research is definitely highlight a huge issue, which is over drinking.

So there are a lot of athletes that consider dehydration to be the root cause of all athletic ills and just drink and drink and drink and drink. It's almost like you can't drink too much, so just keep topped up. You've got to be peeing. When you pee, it's gotta be clear. You've gotta pee loads all the time. If you're not, you're not properly hydrated.

I grew up through that era in the 90s. If you weren't carrying a water bottle around with you as a sports science student, you were doing it all wrong. You needed just to be drinking the whole time. In that dimension, and all the cases of hyponatremia, which is really what got Tim Noakes interested in this, which is where people dilute their blood sodium levels down to critical levels, that has been shown the principal problem with people getting hyponatremia is over drinking. So you just drink beyond the dictates of thirst, fill themselves up, and have problems. 

To a large extent, I don't have a problem. I think what Noakes has done there, 90% of what he's saying is really good. And athletes should listen to it. It's a counterpoint to 30 years of Gatorade marketing saying we need to drink more. It's the natural reaction to that after an amount of time. Where I think there is a problem with it though is it's Tim Noakes' take home message on water is just drink water to thirst. That's it.

Geoff: Yeah.

Andy: For a lot of people, a lot of the time, that's good advice. When you get, though, into endurance athletes doing very long training sessions or races, when you get into football players doing two practices a day in the summer heat, anyone who trains in hot environments, sweat and sodium losses can be very high. And there's a lot of evidence, some of it's anecdotal, but some of it's good published research as well, to show that by adding sodium and fluids together to rehydrate and maintain blood volume and blood sodium levels, you get a better performance effect and a better health effect than you do from just drinking water alone.

I think that's where, again, that nuance is lost in that debate. We've gone from sports drinks are all you need to drink ... Well, we started off at before Gatorade and everything, no one was allowed to drink during exercise. So we went from don't drink anything at all to drink as much Gatorade as you can to Tim Noakes, just drink a bit of water when you're thirsty. 

Geoff: Right.

Andy: These are all soundbites and they're not telling the complete picture. When we've published some research earlier this year, when we looked at two very interesting cases, people who got hyponatremia, one was a cystic fibrosis patient and remember, they have this very high salt loss in their sweat. And this guy was young adult, working in Haiti as an aid worker, drinking lots of water and some Gatorade, trying to stay hydrated, and ended up in the ER with hyponatremia because he diluted his body sodium level so low. 

We found another case, which is very, very similar in terms of looking at the numbers in the hospital report from a lady who's doing an Iron Man triathlon in the US, who'd also drunk some sports drinks and some water, but had got hyponatremia. When we tested her, we did a sweat test with her, she had very, very high salt losses in her sweat as well. A bit like I do. I've suffered mild case of hyponatremia in the past. We were able to get this piece published in the BMJ, not directly as an attack on Tim Noakes by any stretch, but as a counter point to the suggestion that it's only over drinking that can cause hyponatremia. Because when you are losing salt water in a high rate, the higher the rate of salt loss, the less fluid you need to drink to cause relative dilution in the body. It's relatively simple, straightforward concept. 

Geoff: Right.

Andy: But until recently, it's not been very widely accepted. So we're trying to change that opinion a little bit and saying, "Look, as much as the principal problem with hyponatremia is over drinking, and Tim Noakes has got that dead right, we have to draw the line though and say it's not the only reason." People with very high sweat salt losses, and a really interesting group to study with this is hyponatremia. So is cystic fibrosis patients. Because in hot weather, when they exercise, CF patients, it's accepted they have a far higher risk if hyponatremia. So if we then just go down that continual a little bit and go, "Well, what about the guys who haven't got CF, but are losing 100 millimole of sodium per liter? Surely their risk is higher.

Geoff: Yep.

Andy: So it's just, we all exist on this continuum somewhere and I think that's a very interesting concept and one that we're working with a CF doctor called Dr. Doug Louis, and a researcher called Dr. Tamara Hugh Butler, who was actually one of Tim Noakes' students in Cape Town, and she's been working on this with us. And yeah, like I said, we've got this paper published and hopefully it's the first of a few in that vein that we're trying to get out there.

Geoff: Very cool. Getting the randomized control trial, at least the peer reviewed published papers is quite an endeavor. Congrats on that. I want to dive into a little bit on the research side, but I want to just comment on the notion that it just seems that within the mainstream of sports science that people like simple answers and as an engineer by background, or a computer scientist by background, I think perhaps engineers are more comfortable with just spectrums or continuous distributions as opposed to just a polar on or off binary switch. But I think through the good work of folks like yourself and just the broader movement int the space, I think people are starting to be able to handle more variables.

But I think just from someone that might have come from just a different background into the space of human performance, it just seems like, "Okay, the human physiology has a lot of variables and I think ..." It's obviously easier if you're an athlete to think about one or two variables, like water and salt, and those are the only two variables you need to think about. But obviously as talking about with the specific case of just electrolytes, there's the factor that you're losing and then total fluid loss.

Just all these variables. Maybe it just takes time for people to just realize that the human system, like any other system, is a system that encapsulates much more than just one or two variables to think about.

Andy: I think you're 100% correct with that, and it's a problem that we have all the time because we'll get challenged by people who will ask, "Well, I thought you needed to drink just water. You're telling me I need this." Or the classic ones in sport recently that I can remember are, and you'll be very familiar with this one with what you guys do, is carbohydrates. You are either pro carbohydrate and think you should eat it three times a day and three meals all the time, or you're anti carbohydrate.

Geoff: Right. You're a keto fanatic.

Andy: Yeah, you just live on bacon and almonds. And we saw it not too long ago as well with running with shoes. Barefoot shoes, ultra cushioned shoes, or stability shoes. Like you said, they always seem to be polarized and people want the answer. They want a soundbite. They don't want to necessarily ... We're all guilty of it. I think we all can be until it gets point outside of your main domain of interest and expertise, it's very easy to go looking for what's the quickest, best, easiest solution for this. Someone walks into a running store, and they want the best running shoes and everyone's going, "No soul, just a flat soul or with a big cushioned soul." It's like, well, you need to sit that person and start a whole long conversation about what kind of running they're doing and what their background is and what kind of foot shape they've got. 

Ironically, where you end up with a lot of these things is with all of the intelligence you can put into it, going out and trying it is a big part of figuring out what works for you. Because we can think about some of the ... We always say this to people who have a sweat test. We measure their salt loss, we look at their sweat rate if we can, we look at the type of activity they're doing, the duration, the intensity, the environment, then we have an algorithm which then gives them a recommendation on what kind of volume and what kind of strength of hydration products to use. But it has to say, in very big letters, you need to go out and try this and test and adjust and work with this to dial it in, to make it 100% yours. Because that's how you actually get the best result. Being comfortable with the fact that there is not a right answer or a wrong answer, there's just degrees of being a little bit more wrong or more right and somewhere in the middle exists your right answer. It's very important.

Geoff: Yeah. I understand from a sports physiologist perspective, okay, you've got to have some best practices to recommend to people because people want simple answers. I understand that. You just cannot tell everyone all the nuances all the time. Otherwise, information overload. So I understand that desire to have a simple framework or a discussion, but let's not take that to mean the complete picture. Obviously, with each individual, there's nuances and let's not obfuscate the details for the sake of expediency of explanation.

Andy: Yeah, that's it in a nutshell because sometimes you have to dumb things down to get people to get started, to help them over the line to try something new, to try something to push them in the right direction. But then you can't just exist without being the be all and end all of your advice or your offering, because then you do miss out on other good stuff figuring out the details.

Geoff: Right. Andy, it sounds like you actually have some research going on. What's in the research pipeline? What are the collaborators and what are you guys most interested in and then how can we expect to see your work and the broader Precision Hydration work continue to evolve?

Andy: Yeah. We are.

We're trying to be more and more active in research. I think for two reasons. The first one is because we have a genuine curiosity to find out new and novel things or to add to the existing knowledge base out there about hydration and push it all forward. The second reason is that we're a small, but growing company and in order to be taken seriously in what we do, quite rightly, you have to be publishing some science, putting some data out there.

So what we're looking at at the moment is we're actually, hopefully, gonna be co funding a PhD program for a candidate starting next year in 2019 to do all sorts. But where we want to end up is we want to look at performance trials that evaluate the effectiveness of different levels of personalized electrolyte replacement on endurance exercise in the heat, because I think that's where this all started and that's where I was having problems and where I think there's a lot to be learned because we have all these great war stories and anecdotes in the field of how people have successes on different strategies. We want to put some of those to the test, which is going to mean some very long, hot laboratory sessions, I think, with people doing some pretty nasty performance trials and seeing how they get on.

On the way to that though, there's a lot of other stuff we want to do. We started recently with just looking at some reliability and accuracy trials, looking at the equipment that we use for sweat testing and comparing that to what we'd call the traditional methods of sweat testing, so putting patches on the body, getting athletes to run around. We test people with a sweat sample that is taken from the forearm. That is not gonna be totally representative of sweat from every other site on the body. We believe from some of the work that we've done that it's quite representative. It's a good place to start with. Certainly if we want to put people in a bucket and say you're a low, medium, high or very high salt sweater, then we can do that from that site. But what would be really interesting is to actually take some full sweat results from some people, compare them with the forearm sweat and maybe see if we can be a little bit more accurate with what we're doing.

So we're literally talking to some people at Loffery University in the UK at the moment who may be able to conduct that type of study with us. Then I think between that and the performance trial, there's different things to look at with just general sodium supplementation versus placebo in some lab trials and in some competitions. There's a great piece of work done by some researchers in Spain years ago where they blinded a bunch of subjects doing a half Iron Man triathlon in the heat, gave them all some capsules, which either had salt in or just had a placebo in there. And they got a very strong, positive result with the athletes taking the salt capsules because those athletes, they're allowed to drink as much as they want to going back to Noakes' drink to thirst. They chose to drink more, probably because they were thirsty or because they were ingesting salt, which kept their blood volume higher, which led to them being on average quite a few minutes faster over a half Iron Man. So I think we'd like to look at those kind of studies in the field and see if we can replicate some of those results because obviously that's of great interest to us.

Geoff: Yeah, that'd be a good proof is in the pudding type of result that you can show an NFL team or other customers. Curious, are you guys also looking to bring some of the new research back into therapeutics, the clinical side of things as well, or are you guys solely focused on the sports performance?

Andy: We are pretty focused on sports performance. On area where it crosses over quite a lot is with the work of Doctor Doug Louis I mentioned a few minutes ago. We published a paper with him already and Doug is an interesting character because he's a CF doctor is his main day job. So he's working with a lot of CF patients. But he's also an Iron Man triathlete himself. He's very into sport. He's also a world champion sweater as well. He can sweat more than any other man we've ever met, I think. So he's a great colleague for us.

And he's got a strong interest in looking at the hydration strategies in his CF patients because a lot of them are, even if they're not doing sport, they might just be building a house or working out in the summer heat or digging a garden. Like this guy working as an aid worker in Haiti or whatever and we're working with Doug to try and use what we learn from heavy sweating sports people to say, "Okay, can we advise CF patients a bit better," because Doug's believe is that their current evidenced based guidelines for fluid and salt replacement aren't very good because CF, unfortunately people suffering with CF until relatively recently didn't live very long. Now they're living into their 20s, 30s, 40s, so they're living a much fuller and more normal life, and hopefully with more exercise involved. So there's an emerging subgroup there where I'd like to think some of what we've learned can go in there and vice versa. That could be quite ...

Geoff: Yeah, that makes sense. So this is a fascinating conversation. I think it's one of these topics where I think just growing up in somewhat sport focused life, I think almost all of us learn something in physical education classes around sport that hydration's something that's so baked into all of us and I think it's helpful to just unpack some of the confusion and some of the points around hydration. So where do people find out more about your work? There's the sweat testing. I know you have different centers or areas to do that. Where do people find you online? What's the download in terms of all the way to access and learn and keep up with your work?

Andy: Definitely the best place to start is precisionhydration.com, which is our website. It's a largely consumer facing website where people can do a free online sweat test, which uses an algorithm that we've developed based off of the results of a lot of our proper sweaters. So basically, you answer some questions and it says to you, "Right, we can't say for sure, Geoff, but it sounds like you're gonna be a guy who needs this type of drink for this type of activity." Then you can go give it a try and we have a lot of people that do that. So that's a really good place to start. We've also got a tab on the website, which is the hydration advice tab, which is actually becoming more of a blog. It does have a lot of hydration advice in there. It has a lot of general performance articles as well, just areas of interest. 

We're on all the usual social media, like Facebook, Precision Hydration. Twitter is @thesweatexperts. We try to tweet all sorts of useful stuff on there. And Instagram is Precision Hydration as well. Through any of those, they can DM us. We're a pretty friendly bunch. We try and get back to everyone, so we're not just sitting here ignoring the messages. If people want to reach out and email us, they can always email hello@precisionhydration.com as well. We'll always get back to you.

Geoff: Awesome. Thanks so much for the time, Andy.

Andy: No worries. Thanks for having me on.

Geoff: We've got to hang out in person next time, either when you're in San Francisco or when I'm in the UK. I'll drop you a line.

Andy: There is always an open invite in our offices.

Geoff: All right. Andy, this was great. Thanks so much.

Andy: Thanks. Bye bye.

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