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Jamie Pugh of EXO Analytics on Carbohydrate Utilization
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This week, Michael welcomes Jamie Pugh, co-founder of EXO Analytics and senior lecturer at Liverpool John Moores University. Jamie’s research focuses on carbohydrate metabolism and the role of gut function during endurance exercise. The conversation explores the novel means that EXO Analytics brings lab-grade carbohydrate oxidation testing to athletes, the physiological insights behind carb intake, and the practical implications for fueling strategies in training and racing.
Key Takeaways
- What EXO Analytics Measures: EXO tests how much of the carbohydrate an athlete consumes during exercise is actually used by the muscles, using stable-isotope tracers and indirect calorimetry.
- Why It Matters: Understanding exogenous carbohydrate oxidation helps athletes personalize fueling to avoid both under-fueling and gastrointestinal distress.
- Individual Variation Is Wide: Even among trained athletes, optimal carbohydrate use ranges from about 60 to 120 grams per hour, with little correlation to performance level.
- Gut Training & Adaptation: While athletes can improve tolerance to carbohydrate intake, current evidence doesn’t confirm that “gut training” increases absorption efficiency—though it likely improves comfort and logistics.
- Beyond the Lab: EXO’s home-testing kit combines breath sampling and portable metabolic measurement, offering a simplified way for athletes to assess real-world fueling capacity.
To learn more, visit exoanalytics.co.uk or follow Jamie on Instagram at @jamiepughperformance.
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Transcript
Understanding the Ileal Brake
00:00:00
Speaker
if calories of carbohydrates make it to certain parts of the small intestines that typically shuts down things further up so we have things like the ileal break if if you detect calories there it a sense ah essentially sends ah feedback a signal to the brain to say slow down everything that's emptying from the stomach and so if anybody's experienced that sort of symptom where you go ah just cannot take another drink or gel on this might be why
00:00:34
Speaker
Hi everyone, I'm Andrew.
Podcast Introduction with Jamie Pugh
00:00:36
Speaker
And I'm Michael. And you're listening to the Endurance Innovation Podcast.
00:00:55
Speaker
everyone, and welcome back to Endurance Innovation. And as I sit here recording this at the end of September, I got to apologize to all you listeners for having anything in your feeds for the last, i don't know how many months, three months.
00:01:08
Speaker
um But we've got a couple of shows coming up that I'm super excited about. And the first one, i am very happy to announce that I've got Jamie Pugh, who is the co-founder of So,
00:01:25
Speaker
um but super interesting to me because exoanalytics is all about carbs and carb combustion ah which if you've listened to the show in the last ah last few months even though there haven't been that many episodes It's a topic that I really enjoy talking about. So, Jamie, thank you so much for taking the time today to join us and talk about what you folks are
Jamie Pugh's Research Journey
00:01:48
Speaker
working on. No, amazing. Thank you so much for having me on. And thank you for for rearranging after the the issues that I brought up for the first time we tried to record this. So really appreciate you trying to reschedule this and us and let's getting this done.
00:02:01
Speaker
For sure. Yeah, we want to make sure we get to we get great quality audio. um Jamie, ah can you give our listeners a brief introduction? Kind of what's your background? What's your interest in the kind of stuff that you folks are are doing? So my other job, I suppose, I'm a senior lecturer and researcher, and that's how I came to to do research in in this area. So exogenous carbohydrate oxidation.
00:02:24
Speaker
So looking at if you consume carbohydrates during exercise, how much of it do you actually use? um So that began in one of my early PhD studies that I did at Liverpool John Moores University. and I was really, really lucky in that one of the staff members was one of the godfathers in this this area, in this methodology, Anton Wagamakers, one of the first people to to use this as a ah method in exercise metabolism studies.
00:02:51
Speaker
um And he essentially taught me through how to do this technique, some of the considerations around the theory and the methodology. um And then it was after I did that study that I sort of spoke to a few professional athletes. So I've also done some consultancy for Team New Balance Manchester, who's a professional athletics group, some of the Team GB, England Athletics.
00:03:16
Speaker
Once I spoke to some of those organizations and they understood this was a thing you can do, like you can get somebody on a treadmill or on a bike, give them carbs, and then measure how much of that they use.
00:03:29
Speaker
They were all blown away um and they were fascinated.
Carbohydrates in Endurance Sports
00:03:33
Speaker
Fast forward this 10 years since and we've decided to try and bring this from the from the lab, from university laboratories out to recreational athletes, semi-professional athletes, and make it something that anybody can do essentially.
00:03:48
Speaker
Awesome. And that's why I reached out to you folks, because I can't remember who i I know Chris Beckman's posted about working with you folks. And we'd, we'd been talking to Chris for a little while. um But there was somebody else even before that, when you first popped up on Instagram, and I was like Oh, whoa, these are folks I definitely need to have a conversation with, because this is and very much in the, ah in the zeitgeist, at least for me, and very much a ah topic of interest. But let's um Before we talk about the technique and exactly what you folks do, um let's do just a very high overview of why carbs are relevant to endurance sports. And I know most listeners, this is probably going to be very much a refresher, but Jamie, just super high level. Why do we care about carbohydrate intake when we are doing endurance sports? Yeah, definitely. And I don't want to too deep because then like this is always so divisive, isn't it, as well? I think i think for sure it always swings back and forth. I think it's probably coming back towards the most people recognize the importance of carbs ah during endurance exercise. But some of the benefits, some of the mechanisms are are really well described.
00:04:52
Speaker
So from the fact that we need to maintain ah blood glucose levels, this is something we've known since the 1920s. So one of the very first studies was done in Boston Marathon.
00:05:03
Speaker
And m they looked at the condition of some of the runners when they finished. They measured their blood glucose and found that there were so many people whose blood glucose was dangerously low. And so they brought a load of those runners back next year, gave them carbohydrates, and saw actually they all ran quicker, they all looked better, and their blood glucose was more stable.
00:05:23
Speaker
And that sort of kicked off this area. We know that muscle glycogen levels seem to correlate and be associated with your ability to sustain power output or velocity when you're running.
00:05:36
Speaker
And we know there's even central nervous system effects. You don't even have to consume the carbohydrates. like Loads of mouth rinse studies have shown that just by putting carbohydrates in your mouth, they're detected by some of the sensors there.
00:05:48
Speaker
This sends a signal to the brain that can improve performance. So there are lots of these mechanisms, which it seems to improve performance. It also seems to be the preferential energy source for the muscles.
00:06:01
Speaker
If you give the muscles carbohydrates, they will use it primarily and use it almost to the same extent in which you put it in at the same time to, like, obviously there's a ceiling. Um,
00:06:12
Speaker
One of the reasons for this could be that it it seems to be more efficient. So for a given amount of power output, for a given amount of energy turnover, you use less oxygen when you metabolize carbohydrates than when you do fat.
00:06:26
Speaker
And I always say this to athletes. It doesn't matter if you're an elite athlete or a semi-pressional athlete. If you've got a VO2 max of X, 60, 60, you know that if you're going to burn 100% fat, you might be working up at 80% of your max.
00:06:42
Speaker
If you're burning 100% carbohydrate, that's going to be a few percent lower. And that few percent is normally the difference between being over the red line or not. like And for sure, when we're exercising submaximally, taking it nice and easy, there's maybe more scope and more nuance. But sure elite athletes, even us everyday athletes, there are going to be times where we want to push and hold ah as high a sustainable power output as we can.
00:07:08
Speaker
That's always going to be better if we're able to metabolize carbohydrates. Yeah, the the engine has to burn a little bit harder to burn the fat in order to produce the same amount of useful power produced. Yeah.
00:07:20
Speaker
And I think that was kind of what sold me. i remember, i him remember who it was that I was talking to, but um back in my early coaching days, so that, that, That's the real value of carbohydrates ah for for exogenous intake is that you have um you're you're going to use less oxygen for the same amount of substrate burn. Yeah. yeah And these are just the mechanisms that we know about. There may be others that we haven't fully understood yet. um the The study by... um I forget the research group, but it looked at 120 grams an hour in ultra marathon runners and showed that the recovery was better the following day.
00:07:57
Speaker
So even this, if you're trying to put together back to back to back, heavy training days, heavy training weeks, maybe even there are these ah other components that we're not familiar fully measuring fully understanding that seem to lead to more sustained consistent training over the course of a season you will end up a better athlete as well so there are all these other more nuanced bits that aren't just okay in the one-off training session um that are probably leading to some of the improvements that we're seeing in marathon running uh long duration cycling events triathlon events that all of these events seem to be getting improvements at the moment
00:08:32
Speaker
Yeah, for sure. I think I saw Asuka Jokindrup talk about I don't know if it was his study or not, but it was just in a review that that he mentioned that I'd seen that that information. And I think also don't have to preach to anyone here about how important recovery is to sustain training, right? That's recovery is how we all get stronger. That is obviously, you know, that that's a truism, I would say.
00:08:54
Speaker
ah So if you can do something to improve recovery, then of course you should do it. So um I've got more questions about carb utilization because ah there was a conversation I recently recorded that I want to reference.
00:09:06
Speaker
But I want to put a pin in that for now.
Measuring Carbohydrate Utilization Methods
00:09:08
Speaker
And that's ah ah shift a little bit towards ah the the methods for quantifying this ah exogenous carb utilization um or even like endogenous carb utilization, to be honest.
00:09:21
Speaker
um And let's start with ah kind of the the methods that I think most of our listeners will be familiar with. And that's the, you know, the metabolic cart gas exchange model. And the reason I want to start here, Jamie, is just so, you know, we can start a conversation from something that folks are familiar with, and then we can launch into ah the the method that you and your team has developed.
00:09:43
Speaker
Yeah, definitely. and I think this is really important actually, because one of the things that we've, we've learned and realized early on is that there's, there can be a little bit of confusion about what we're doing in there. Oh, you can already go to a lab and measure your carb use, and which is like for sure. It's true. Um, so you can go get hooked up to one of the metabolic carts.
00:10:01
Speaker
They measure the intake and the, the output of oxygen, carbon dioxide, measure the difference. Okay. Now you have your oxygen consumption.
00:10:12
Speaker
your carbohydrate production and then through the the ratio of the two you can then to estimate begin to estimate what's going on at the muscle um and then convert that so how does that work if we spend like a couple more minutes on it if i know i'm kind of i didn't i didn't ask you to prep for this but if you if you happen to know it what's the what's the math like how does the the ratio of expired o2 versus co2 tell you what the ratio of uh substrate utilization is This is a test of Ian when I sometimes lecture to the first year undergrad and exercise metabolism, which I've not done in a long time.
00:10:47
Speaker
the the basic The basic thing to to think about is that we know that when you go from carbohydrate or fat and you metabolize it with oxygen, then the that gets converted to carbon dioxide and water.
00:11:00
Speaker
And then so it's to do with the amount of oxygen that's burnt that has ah an energy equivalent depending on how much is burnt from carbohydrate or fat. Like what we've already alluded to, there is a difference.
00:11:13
Speaker
And this so it's it's looking it's looking at those factors um and then you can convert that into an absolute amount. um So it's, yeah, hopefully that's,
00:11:25
Speaker
sort of understandable yeah and then at the same time you're measuring some kind of mechanical power up like you're you're measuring power on the bike or you're some kind of like pace while running right so so that you can do do tie that together or does that is that not relevant no no no so you don't need that that can be independent so this is the same way that if you were to do like a resting metabolic rate you would just lie down and you'd have the metabolic mask and it's doing the same thing but obviously the numbers would be much lower because your ventilation is lower your oxygen consumption your carbon dioxide production is so much lower um Um, so it's, it's independent of the exercise you're doing. There are relationships like cycling is often a little bit easier, a little bit cleaner because it, it does correlate very, very well to power output.
00:12:08
Speaker
And you just see these small differences in efficiency. Um, but in the most part, yeah, you could get a pretty good guess on somebody's oxygen consumption just by the power output they're putting on the bike.
00:12:19
Speaker
But to get a true measurement, you would need to then hook them up to the metabolic cart. Fair enough. So I guess based if you know how much how many calories per unit of oxygen, whatever we whatever we're measuring here, and you're you're comparing the inspired to expired oxygen, and and that's how you that's how you do that math? Exactly. Yeah, yeah exactly that. Okay.
00:12:37
Speaker
The engineering brain in me needs to understand how, even if we're not talking exact numbers, how the thing works for me to really trust it. You know what mean? Yeah, yeah. And that's important for the stuff that we do as well with the exogenous carbohydrates because that's almost one of the components that you need. So we still need that bit. You still to use the metabolic carb, look at the oxygen carbon dioxide.
00:12:58
Speaker
Yeah. The other side then is how do we determine how much of your total carbohydrate use is coming from the drink or the gel that you take on during exercise?
00:13:09
Speaker
And the the way that we do that is by the use of of what we call a tracer. So of effectively, that we're tracking something from the drink all the way through metabolism. um And then we can literally follow it through.
00:13:22
Speaker
The one that we use And this is what... Sir, interrupt. I mean, this is ah this is the this is the kind of the special sauce of what you guys do. But before we get there, I got one lot one little yeah like interjection question.
00:13:32
Speaker
um Why do we care how much of what we ingest... how much of that gets that gets utilized. So before we get to talking about ah how we quantify it, why do we care? Yeah, this is this is really interesting. I think this might be something evolves as well because at the moment, I think the the two most important use cases at the moment, and especially for, again, middle of the pack riders, maybe might be susceptible to both of these.
00:13:56
Speaker
One is that we know that people have never really maybe taken on carbohydrates before. They have some of this fear of, Am I going to get gastrointestinal symptoms?
Gastrointestinal Symptoms in Athletes
00:14:05
Speaker
Am I going to be able to tolerate it?
00:14:07
Speaker
And so this might give them the confidence to go, known you can use 80 grams an hour comfortably. So this is an amount that if you take on, most of it will get to the muscles, most of it will be used, and you won't have a lot of residual carbohydrates remaining the gastrointestinal tract that could lead to bloating or symptoms. Yeah.
00:14:26
Speaker
interesting I think the other, the other end is, is, is okay. I've heard, or I've seen that you now have pro cyclists taking on 160, 200 grams an hour. I'm just going to do what they do.
00:14:38
Speaker
And then something like this, a test or understanding how much your body can use can just make sure that you're not increasing your chances of GI symptoms by overconsumption. So if you did the test again and again, your number is 80 grams.
00:14:52
Speaker
it gets to point that if you're taking 200, so much of that isn't going to the muscle to be used. yeah I'll only caveat it by saying at the moment, it isn't fully understood where does that excess go.
00:15:05
Speaker
um Does it have any use whatsoever? So again, maybe taking on little bit more that might help with recovery afterwards. We don't know at the moment. I think that for performance, the interest is very much in optimizing the intake for muscle use during exercise.
00:15:21
Speaker
But it's not to say that in... some years time when more research comes out, we might get a better understanding of of how you could then tweak it again for for different reasons. Yeah, that makes so much sense ah in in my view of the world. kind of i've I've been on both ends where you know everyone's bonked who's ever done a ride or a run.
00:15:43
Speaker
But there was this I was playing around with really high intake of carbs and I i stuffed up my math. as i'm saying yeah I like math, but sometimes you know we all make mistakes. Yeah.
00:15:54
Speaker
I think I ended up with something like 200 grams in a bottle that i I drank over the course of like the first hour of a long ride I was doing on my trainer. And I would not care to repeat that. it It was not it was not nice. I was I was aiming for 100 and I ended up with two.
00:16:12
Speaker
Yeah, it was I was off for a little while. I was not good. So definitely from that perspective, not ideal. This is something that's, but so maybe, sorry, I got jumped to the exo stuff too early when you asked about my background. No, you're good, you're good. So my PhD was effectively looking at the causes of gastrointestinal symptoms in endurance athletes.
00:16:30
Speaker
So literally looking from one end to the other in terms of the gastrointestinal tract. And so one of a lot of the things I got to do read about the physiology and the the biology of the
Tracer Method for Carb Metabolism
00:16:41
Speaker
gastrointestinal tract.
00:16:42
Speaker
And there are so many almost like safety nets for the gut to stop you from over-consuming. And I think as athletes, we've probably experienced lamoster these that he said like So if if calories, if carbohydrates make it to certain parts of the small intestines,
00:16:58
Speaker
That typically shuts down things further up. So we have things like the ileal break. if If you detect calories there, it a sense ah essentially sends a signal to the brain to say, slow down everything that's emptying from the stomach.
00:17:14
Speaker
And so if anybody's experienced that sort of symptom where you go, i just cannot take another drink or gel on, this might be why. Because you have that signal in your brain saying, don't send anything more down. There's already more here than we can deal with.
00:17:28
Speaker
Interesting. That's super cool. And as a coach of as as a coach for coming up on 12 years of recreational athletes, especially folks doing like long stuff like Ironman, ultra running, I've seen race reports with that so often. With that description, it's like, I know the race plan says I need to drink X and eat Y, but I just can't. Like it just it isn't going in. So this is the first time, I'm pretty sure it's the first time, that I've heard of a potential mechanism mechanistic explanation for what's going on.
00:17:58
Speaker
Yeah. And there's other things as well. You have the further along the gastroinestine gastrointestinal tract you go, the more dense the bacteria. And so if you have sugars that get to more and more bacteria, this is just food for them. And they're going to start fermenting on it.
00:18:15
Speaker
That gives off gas. That draws water into the small intestine. That's what gives you maybe that feeling of bloat again. in the most extreme cases, it's going to lead to like... Yeah, we all know what.
00:18:27
Speaker
Yeah, the porta potty stops that are the best case in that context. Yeah, exactly. Yeah. Oh, that's super interesting. um Okay, so ah I think you've made an amazing case for why we should care about how much we actually, of the stuff that we ingest, we actually can ah use at least for for the muscles.
00:18:48
Speaker
So let's get into it. let's and Tell us about what the how the technique of doing that quantification works. This is something that's been done for for decades as well. okay So oh some of the ah ah earliest exercise metabolism studies to use as a technique were in the early 1980s. So this isn't anything that's new.
00:19:09
Speaker
um And I think the the cheaper that it's become, the the more mass spec machines we have and things like this has just made it a little bit more accessible. And you see today more studies that do this.
00:19:21
Speaker
And it's what's made us ah it's what's helped us be able to bring it um out of something that can be done commercially. But all that we do is we take a a tracer. So that's just a fancy way of saying that we have ah a heavy carbon.
00:19:36
Speaker
So nearly 99% of the um carbon in the the atmosphere is carbon-12. So it's 12 protons, neutrons. around 1% has an extra neutron. So it's ever so slightly heavier. that And that weight mass difference can be detected on a mass spectrometer.
00:19:56
Speaker
Oh, cool. Okay. So what it means, because it's such a small component, if we give you more of it, and then we measure it in your body somehow, we can say, okay, that's pretty much come from that drink that we've given you.
00:20:10
Speaker
We have a drink. Heavy carbon in the drink. Yeah. Yeah, exactly. So you have a drink that's got lots of heavy carbon in it. if that drink is a carbohydrate drink, essentially the carbon atoms are going to be in the glucose or fructose molecules. You're going drink it. going to empty from the stomach.
00:20:28
Speaker
It's going to be absorbed into the ah from the intestines, go to the liver, then go to the muscle. Then when you metabolize it, again, like we've already that goes from carbohydrate plus oxygen to carbon dioxide and water.
00:20:41
Speaker
So now if you can picture in your head, those carbon atoms have gone from the glucose, to the carbon dioxide. And then that carbon dioxide is what you breathe out.
00:20:53
Speaker
So if we can capture your breath, like physically capture your breath, we can then put that on a mass spectrometer and measure, okay, how much of these carbon atoms are carbon 12? How much of them are carbon 13? Hmm.
00:21:06
Speaker
That's one part of it. And again, we just tie that in with the indirect calorimetry. And that's what gives us the the absolute value using all of those same techniques that we spoke about earlier, all those same assumptions for how much, what's the energy or the calorie equivalent for some of the ah carbon dioxide production.
00:21:24
Speaker
So just to be clear, and I know we you've you've told me about this when we had our intro chat, but you're still using indirect calorimetry, which I know we're sort of using a a few different
At-home Testing for Athletes
00:21:35
Speaker
terms. This is the metabolic cart slash gas exchange sort of analysis of ah that we're we we all know and love, correct?
00:21:43
Speaker
Yeah. The athletes that get in the lab often just say it's the Bain mask. That's what they, that's what they know as. It's the one where I have to put the mask on. that Yeah. Yeah. That's, that's the one. And yeah, that's it because you couldn't, because it's, you need both of them to be able to fully understand what's the grams per hour.
00:21:59
Speaker
and So, cause if you had just had the enrichment, you and I could have the same enrichment in our breath. We could have the same total carbon 13, but if one of us, is 10 kilos heavier exercising they they use more oxygen ah produce more carbon dioxide that would give us two different numbers even though it's the same identical enrichment so you need both of those to enable to to fully quantify it Okay.
00:22:27
Speaker
There's two kind of two paths that I want to follow here. and We're going to go down both of them, but um let's do the first path. Let's do ah how does it physically work? If I am a, if I'm a recreational athlete or semi-pro pro athlete who purchases a kit from you, let's assume I can't actually make it into your lab.
00:22:46
Speaker
um What is, what am I expecting to see and get and how does the process work? Yeah, hopefully much more simpler than what I'm trying to describe here, because all you've got to do is, all you've to do is there's some dietary restrictions the day before, because I said carbon-13 is naturally abundant.
00:23:04
Speaker
um So some of the foods that you consume could have a higher amount of carbon-13. So we give you some dietary restrictions, things like sports products, corn-derived foods. Oh, okay.
00:23:14
Speaker
Then when you come to do the test, you take a you blow through a straw into a glass tube and that captures your breath. So that's your baseline. So we can see to begin with before you had the drink, how much carbon 13 was already in your body.
00:23:30
Speaker
You then do your exercise test, so running, cycling, for 90 minutes. Okay. And you collect the breath sample at the end as well. And then between, you just consume the drink that's supplied. Well, we supply the carbohydrate powder. You make that up as a drink.
00:23:47
Speaker
You consume that every 15 minutes. And then so what you're doing is you're putting the carbon-13 into your system. You're going to be metabolizing it. Then by taking that final breath sample,
00:23:58
Speaker
we have that difference in enrichment. And then the indirect calorimetry bit is just the last 10 minutes. So in the home test that we have, we supply a metabolic mask in there. We give you all instructions how to use it.
00:24:10
Speaker
And you just put that on for the final 10 minutes. Very cool. And whose product is that? Because it reminded me, we talked about it when we did the intro. So we've been looking at a couple of ah few different ones at the moment. and We've been trialing the Calibre device, ah the US-based. um We're trialing a few different ones. We also have some partner labs in the UK at the moment um where ah UK-based athletes can go if they're they're unsure, if they want somebody else to just put them through it.
00:24:39
Speaker
and They can. In the home test at the minute, we have the Calibre devices. i don't know if you've used them, I've talked to the folks a couple of times. i I want to get them on the show because I think they have a really interesting idea.
00:24:50
Speaker
um So I am aware of it, but I've never used their their product. I have some questions about it too. yeah yeah Yeah. From our experience, it can be temperamental, definitely. it has to be calibrated and used in the in the right way, which is why we try to give real specific instructions. We also...
00:25:07
Speaker
ask people to to do a resting sample the day before so that they can become accustomed to it. They can go through the instructions. Some of our testing that we've done, we've compared it to two different metabolic carts at the same time.
00:25:21
Speaker
In our tests, I'm saying this isn't published data. This isn't a huge clinical trial. Sure, sure. yeah But it sat perfectly between the two of them in terms of VO2 and VCO2.
00:25:34
Speaker
So we were that's what gave us the confidence to initially to trial it. And one of the things that we're going to do in this first 12 months or so is to see how do users find it? What numbers do we get back? For cycling, like I said, it's really nice because you have some...
00:25:48
Speaker
good guard guardrails. Cause you know, that for given power output, there is an expected oxygen consumption, give or take the, you know, the small differences in efficiency. and so um, so that's going to be one of the things that we're doing, but we're pretty confident from the early tests that we've done that we get some really good numbers.
00:26:05
Speaker
so Amazing. Yeah. And I i think this is little bit of a sidebar, but I've definitely seen lab results from using, you know, even like university research grade, ah metabolic carts and everything in between that just don't make any sense. I've sent athletes to labs that I no longer longer send athletes to where the results came back and like this doesn't this isn't this is not possible that this is the correct result based on your performance, right? Because performance doesn't lie. Like you're able to run at this pace for this time.
00:26:34
Speaker
We've seen that. That is fact. And these ah the numbers I'm getting from your from your metabolic cart results just make that impossible. So one of these two things cannot be true, in which case, since we've seen the performance, it has to be the med cart results. So yeah, i'm i'm you know I guess you would want to be super careful with with that part of your analysis.
00:26:55
Speaker
Yeah, and this is the good thing is that because we are exercise physiologists, like as by background, we're all um because we've all worked with athletes in applied settings, like these numbers are second nature to us. So it's been, do you know what, as they somebody loves this stuff, it's been quite fun putting together some of the guardrails, some of the internal calibration and quality checks.
00:27:18
Speaker
We're actually hoping to collect enough data that eventually we could... I might say maybe replace like the metabolic cards essentially like for recreational athletes if we could collect some metadata around ah from them around the test date.
00:27:34
Speaker
but So we we are trying that at the moment in the background and just seeing how close we could get maybe more out of our own curiosity ah to begin with but it's a, it's something that'd be fun to do, but yeah, especially in terms of, okay, is that a typical number? Is that a number we would expect? They say, if you've got somebody cycling at, I don't know, the most extreme thing, out like 150 Watts and it comes out four liters a minute when they only weigh 60 kilos, you can look at it go yeah, this is clearly ridiculous. Like there's something gone wrong, but I'm exact. I'm the same as you. I've seen maybe not quite that stupid, but like stupid results from athletes when they go to to labs. Yeah.
00:28:13
Speaker
Okay, getting back to kind of the the logistics of of what you what you folks do. um So you if let's say you're not visiting a lab, um you get an at-home kit, you've got the currently the and the caliber device and the the powder, and then you do the test.
00:28:29
Speaker
um And then after the 90-minute exercise test is done, what happens next? So you collect that ah final breath sample, you put the breath samples into a prepaid postal envelope, send that, that's analyzed by mass spectrometry.
00:28:47
Speaker
We use that with the data from the indirect calorimetry, so the caliber mask, and then we put together a report that we send over, and that typically takes one to two weeks.
00:28:58
Speaker
so cool So within that report, you'll see your own exogenous carbohydrate oxidation rate, And then our recommendations um for different durations of exercise with a little bit of explanation and a little bit of caveats to say that what we want to try and do with the test is show athletes what your absolute ceiling for this is. So in the pretest instructions, we give you advice like make sure you're well hydrated, make sure you have enough carbohydrate the day before so that you're not depleted.
00:29:29
Speaker
Do it in a,
Can Gut Training Improve Carb Utilization?
00:29:30
Speaker
you can do it in different environment temperatures, but make note of it because it can change. And then we have some explanations towards the end of the report to say, okay, this number could be affected if, and then we list out some of those things. If you're dehydrated, if you're depleted, when you begin exercise, if you do this in a warm environment, if you do this at altitude, and it can give somebody the understanding that we're not saying this is the number you have to hit every time.
00:29:57
Speaker
Like I said, this is your close to your ceiling. You can now use it to to tailor your needs from different situations. You could test it again. um would it's There's no evidence at the moment to say that you couldn't change that number for the better, but there's also not data to show that gut training would improve it.
00:30:18
Speaker
That's interesting. That's where I was going to go next is like, we keep hearing about gut training. It's the question we get asked every time. Can I make it better? first Yeah. And that's the first few tests that we did. Everyone, no matter how big that number, the question was, oh, can I get it? Can I make it higher?
00:30:32
Speaker
and What do I do to make that number bigger? um And I think it's, I think a lot of people will probably be of the same opinion in this space that, you we will eventually see data to show that you can improve this number.
00:30:46
Speaker
It would just be a case of understanding what are the most important factors to do it. Because let's be clear now, we when we talk about when we talk about gut training, we're training mostly the tolerance of the GI system to increase the the the you know the the throughput of carbohydrate, right? Yeah, that's it. I think I always think of it as it's a logistics training.
00:31:06
Speaker
um So you're practicing how much do I put in a bottle? When do I take it on How much, how they said, what's the concentration in my bottle? And then like that you said, okay, what can I tolerate? How much per hour do I take before I get that sick feeling, bloating feeling before it's too much, which is, and that's all really, really useful. Yeah. um But we don't know if that does translate to,
00:31:30
Speaker
can I now take on more from a physiological perspective? So does my stomach empty quicker? Do I absorb more from my ah intestines quicker?
00:31:42
Speaker
It probably, you probably can. And I said, you look at the professionally eating world, you can see that the the gut is adaptable. yeah You can increase the size of your stomach. You can move things through the stomach a little bit quicker.
00:31:56
Speaker
And there are studies that have shown that, so even within a a short period, if you change your diet and you eat more carbohydrates, you you can absorb more and use more during exercise. um my The thing I was thinking with this bit is the small intestine turns over around about every three days.
00:32:17
Speaker
So you have a full cell turnover approximately every three days. So I'm yet to be convinced that once a week going out on your Sunday long ride, smashing the carbs on just that ride is going to have any impact on your ability to absorb carbohydrates when you then come to to race day.
00:32:36
Speaker
That's a super interesting perspective because, yeah, you don't you don't think about the fact that, yes, the those epithelial cells, they don't last forever. No, no, and that's and you think they're exactly what are absorbing the the glucose, the fructose from the gut.
00:32:48
Speaker
So for athletes that I coach, I always try and get this point to them that, again, one of the most important times to gut train is in the last few days for your race. And i even wonder, is this something that you see, ah in the pro peloton? So if you're now looking at the the tour, if you look at the Giro, maybe these athletes can take on more and more because they are literally training their guts as they go. They do it every single day yeah and they're taking it on during exercise.
00:33:17
Speaker
Um, just my, little work in theory at the minute. Yeah. Could that, uh, improve the efficacy of carb loading? If, if that's, uh, if that's, I mean, carb loading, obviously you're trying to top up muscle glycogen, but maybe there's, there's a little bit more to it.
00:33:32
Speaker
Yeah, possibly. And this is where the the other side of it that we said earlier about we don't really know where the excess goes during exercise.
Personalized Carb Intake for Athletes
00:33:42
Speaker
v um Because, yeah, not that people are smashing 200 grams an hour in their carb load, but we know that we can take on over the course of a day a lot of carbohydrate. Lots of it will go to the muscle and to the liver and be stored.
00:33:56
Speaker
um So there are all these little these finer these finer points to to think about. Okay. I want to spend a little bit more time on um like the practical takeaways. And I really appreciate the fact that you're, you know, you're being honest with what you don't know. And it's, it's, ah it's refreshing because sometimes you, you know, I've spoken to a few founders of novel technologies and,
00:34:20
Speaker
There's a lot of, yeah, this is going to revolutionize the space kind of talk. um So I appreciate you you know you saying when you don't know something, that's always really nice to hear. ah But yeah, that's just an aside. um Practical applications for your technology, maybe like with a case study or two or in your own coaching practice, um how how have you used it or how have your athletes or folks you've worked with used the findings from EXO?
00:34:49
Speaker
Some of the, I think this is always going to be the way isn't it? With initial uptake for a product and service like this, we're going to have the very keen people. Yes. So lots of our early adopters are taking the recommendations at almost like full face value.
00:35:03
Speaker
Okay. This is exactly what I'm going to do in the race. um And then we've had some really successful um outcomes from it. We've had people who've gone from taking on 120 in to around 80 grams. in a marathon to around eighty grams because that's essentially where the the test told us that their maximal is.
00:35:20
Speaker
um Because this is an amateur athlete, that means, again, logistically, they have to carry fewer gels on the race. um They actually save money because now in their training and in their race, I'm not having to buy my however much, i don't know, save brands. But you know like we all know how much expensive gels can get now. Yeah, they're nuts.
00:35:40
Speaker
And then... I think carbohydrates over the last few years have become so dominating, it can almost overtake the performance itself.
00:35:51
Speaker
um How do you mean? In the sense that the most important thing is always going to be how fit you are. Mm-hmm. Like, and the person that went to the race- you can't eat your way out of not being fit enough to do something, that's for sure. Yeah. And I think like fueling during exercise is just to be able to maintain your maximal optimal physiology during the race. kind of So it shouldn't be this like big, scary thing, this like something that we all think about a crazy amount. It should just be, yeah.
00:36:19
Speaker
I go out at this pace, this power output, and I take on the optimal amount of fuel just to sustain me. um So I think what the test does is just simplify things completely. Rather than overthink it it, can just give you and ah number, an understanding, and you can, and I think what I try and tell a lot of athletes to do is just now this should just sit in the back of your mind.
00:36:40
Speaker
It should just be... secondary to the performance itself. Um, you can just go through every 20 minutes, every 15 minutes, you just take your drink, take your gel. There's no worry.
00:36:50
Speaker
Is this going to be the one that sends me to the portal? Am I going to bonk? Um, because you know that this is your optimal intake. Yeah, I love that answer because there's a lack of certainty around just how much to take. And, and you know, recently the the pendulum has swung. OK, let's see how much we can stuff in our faces and not poop our pants over. um And yeah, having a ah little bit more certainty and and sort of personalized precision around that incredible.
00:37:16
Speaker
is very useful, especially with all the other stuff you got to optimize. Like I was, you know, total, total aside, but I was out doing aero testing yesterday because again, I have this Ironman coming up and I kind of want to know what, what position on the bike going to give me the best, you know, return on my Watts. um So there's a lot to consider there. And then there's a lot to consider around other equipment and everything else. So if there, if you can put to bed this question of, well, just exactly how much carbohydrate I need,
00:37:42
Speaker
That is, i would say, especially to folks who are motivated by performance, that's very useful. Yeah, there is a range. This is one of the things that, like said, I'm a scientist researcher um by background.
00:37:55
Speaker
And so the the thing that really caught my attention and and made me feel, well this is something that would be useful for athletes, is just the range that you do see. So it isn't a case of, if everybody just took... 90 grams an hour, this is going to be it.
00:38:08
Speaker
Even we did a ah test event a couple of weeks ago down in London with 11 runners, a range of abilities.
Carb Utilization in Cycling and Running
00:38:19
Speaker
um Some of them going for, think like 220, 225 marathons, some going for four hour marathons. We also had a couple of- So a proper range then, yeah. Big range. We had some international ultramarathon runners,
00:38:33
Speaker
um Yeah, a range of backgrounds, specialisms. um When we then looked at the numbers, we only had the numbers back ah this week, actually.
00:38:44
Speaker
The range of recommended intakes was between 60 grams an hour and 120 grams an hour. and was it correlated to performance, to speed? No, that was the most interesting thing. If you look at individuals, you could go, okay, yeah, that makes sense because of this.
00:39:00
Speaker
But for example, one of our highest recommendations was what was from our second to slowest runner. Was it correlated to size or muscle mass? Yeah, so that's on the other side where you look at it and you go, okay, but actually, yeah, that was...
00:39:14
Speaker
not a big one, but one of our taller, slightly heavier athletes. um but not as But I'm not talking like a six and a half foot giant or anything like that. i'm not This was just somebody who was slightly bigger than the other athletes. And then you go to the other side and we had um some smaller but quicker athletes and they were on the lower end of the recommendation.
00:39:35
Speaker
So they're running decent pace, but the the recommendation was was a little bit lower from what they were using. This is fascinating. What about between sports? I know you mentioned cycling and running. It sounds like those are the two sports you folks are focusing on. Is there a difference between, have you done the same athlete across both sports and compared the results?
00:39:53
Speaker
um so you probably won't mind me saying because you've already mentioned, but we did, we measured with Chris, but what we did with, with Chris Beckmans is we, when he did the run test, we tried to sort of simulate the conditions he might have as an Ironman athlete. So when he did the run test, he had already done two and a half hours on the bike before he came in. Okay.
00:40:14
Speaker
And then the run number was lower than the bike number. Interesting. Which is contextual, right? Like, I mean, it's not maybe, you know, it's not an absolute comparison, but it is a more, perhaps a more useful comparison for my cohort.
00:40:28
Speaker
And it's always the same. Like every researcher must say this when they come on a podcast, but it just shows that where like, we often have these really interesting questions because nobody's ever really done that where they've looked at running versus cycling.
Role of Carbs in Professional Cycling
00:40:39
Speaker
It can be a hard comparison because the, The energetics are going to be different. The muscle um recruitment is going to be different. So even if the same athlete, like actually, okay, now how much of this is quad versus car versus wherever, know. It's so interesting. Like the the fatigue mechanisms for the the long course run are fascinating.
00:41:03
Speaker
Yeah. Something I'm thinking about a lot right now. It's like, okay, well, what's, what, just personally, cause I've, I've, I'm racing in a bit. Like, what am I, yeah what's it going to set, what's going to set me up for the least amount of fade on that run?
00:41:14
Speaker
Yeah. And well even even the differences between, so we were we've been trying to think about the difference between so cycle on the bike leg of ah an Ironman triathlon versus the like ah a tour stage or something like that. Because actually they're pretty different because the power output profiles can be a lot more steady in the Ironman.
00:41:35
Speaker
They're often a little bit nicer to you. They give you slightly flatter routes. They're often like smaller loops. Whereas if you think of a ah tour stage, like you could be sat at the back of the peloton, you could be going downhill for 10, 20 minutes or so where you're effectively not doing that much. you probably just spinning your legs out.
00:41:54
Speaker
Yeah, we've tested a couple. but We've tested a couple of different pro cycling teams this year. One of them, we did it. um This is really cool. Actually, we set up a lab at about 1800 meters up on the the top, like the side of the mountain in Andorra.
00:42:10
Speaker
yeah Okay. The team went round a 90 minute loop. So they did some sprints, some steady state work on the flat. They did a moderate intensity climb. And that's where we had a couple of turbo trainers. They jumped on the turbo trainer, got into a steady state on there for 10 minutes. And we collected the breath samples and the indirect calorimetry on the metabolic car.
00:42:31
Speaker
And then they went back off on the downhill, on the descent, and then the whole thing again. it ended up being a four and a half hour ride. we we saw some of the highest ever numbers for exogenous oxidation. We had numbers above 160 grams an hour.
00:42:49
Speaker
ah whoa. Part of our potential theory for that is it could it be that, and you alluded to this earlier, could it be that you're in some ways replenishing maybe muscle glycogen, maybe liver glycogen on the on the descent? Yeah.
00:43:04
Speaker
um because they're they're still peddling, but the the output is probably so low. ah So low, yeah. But if they're still consuming, and if they're consuming at such a high rate, again, don't know if that is the case. That is literally just our theory from a small number of tests that we've done, but probably such a specific use case for for that.
Exogenous Carbs vs. Muscle Glycogen
00:43:25
Speaker
And then maybe something for people to think about when they do see these numbers of This ride is taking on 160, 180 grams an hour. um The demands of the sport are so important when it comes to think about what you need, what you should take on, what you should use.
00:43:42
Speaker
For sure. And especially with these guys that were where it's a tour, right? It's a multi-stage event where recovery is absolutely king. It's, you know, we we we spoke about it a little bit earlier how it's it's massively important that they can repeat those efforts, especially for the, you you know, the GC fellas and the girls. yeah it's it's it's a very It's a very context specific, I think, application.
00:44:08
Speaker
Yeah, definitely. And because it's like even just practically, if you're the time you warm up, you do the the stage, you cool down, you might have do some media stuff. Your practical opportunity for feeding is so diminished. right You almost have to think about the calories that you take on during the ride itself.
00:44:26
Speaker
Yeah, it's like a spread out meal. Yeah, that's that's a really good point too. You just yeah you you need you need sleep. you Yeah, it's ah it doesn't leave you that much time. um Well, so, Jamie, you kind of, well, I teased out earlier that we're going to talk more about carbs, and I think now is a good time. You talked about liver glycogen, muscle glycogen.
00:44:43
Speaker
So I'm going to throw this question at you. It has nothing to do with XO, but since I've got you on the show and I'm curious, um the received wisdom for me has been that one of the reasons that we you know want to maximize or optimize, let's say optimize the better word.
00:45:01
Speaker
the the intake of exogenous carbohydrate during exercise is that it spares
Carbs and Endurance Performance
00:45:06
Speaker
muscle glycogen. but um And you and I have talked about this a little bit already in a conversation I've recently had with Marianess Peterson. no and nu peterson um He suggested, and you I think maybe I want to hear your thoughts on this, is that the that's not the that's not what's happening, that it's not it's not really ah sparing muscle glycogen, all this exogenous carbohydrate that we take on. So what's going on?
00:45:31
Speaker
No, no. and So I mentioned one of the the people that got me into this area is Anton Wagamakers. He was one of the first to show this in a study, actually, that if you take on huge amount of carbohydrates, what it seems to do is suppress liver glycogen use, but you see no change in muscle glycogen.
00:45:51
Speaker
So, and there've been lots of different techniques in that have shown this. So the trace of methodology that we've really spoken about, that's been used to, in order to quantify how much of this comes from the drink that you're given, how much of this comes from the liver, how much of this comes from the muscle.
00:46:06
Speaker
And then we also know that you can take muscle biopsies. And so muscle biopsies have shown the same. If you give people keep like, ah carbohydrate drinks during exercise trials in the lab. You take muscle biopsies.
00:46:18
Speaker
If they had the drink or didn't, it didn't seem to affect the final muscle glycogen content. So this is something that is pretty well established. um And ah the way I then try to explain it to athletes is that we've already mentioned that carbohydrates are the most um efficient fuel source during exercise.
00:46:36
Speaker
So by continuing to take on carbohydrates during exercise, First of all, yes, you're going to spare liver glycogen, and that's another reservoir. That's another tank, if you like, for carbohydrates.
00:46:47
Speaker
sure So they're going to still be used. They're still going be released, go to the muscle and be be used. And then it just means that you can keep your carbohydrate like your total carbohydrate oxidation as high as possible for as long as possible.
00:47:02
Speaker
So we've done some studies again in the labs in the Pujamores where we've we've introduced this idea of like a crossover effect. So once more of your energy comes from fat than it does from carbohydrate,
00:47:14
Speaker
It does seem to have an impact on exercise performance or fatigability, durability, perception of effort, whatever measure that we want to take. It does seem to be a consistent.
00:47:28
Speaker
And so by consuming carbohydrates- Impact which way? So when you switch to more fat, it impacts performance which way? Negatively. they said people, you feel more tired, the RP drops.
00:47:39
Speaker
We've seen it in the study trials where participants don't last that much longer afterwards. um And again, I don't want into the, could you keto adapt? Could you fat adapt? Could you improve? Like maybe there is this. Yeah.
00:47:53
Speaker
I think one of the the things that separates elite athletes, like truly athletes, is that they have massive capacity for energy turnover from all sources.
00:48:07
Speaker
And it makes sense. If you're if you're putting out 500 watts, if you're running 21K an hour, even if you're very efficient, that still needs a lot of energy to be turned over.
00:48:19
Speaker
yeah So you need to be able to use carbohydrates that you consume. You need to be able to store carbohydrates as glycogen and use that. And then to be honest, you probably do also need to be able to use a lot of fat.
00:48:31
Speaker
for sure And so when you measure the best athletes, they have high capacity for from all of these sources. And then I think as you get lower down, one of the limits for, for again, us mere mortals is probably we don't have that capacity across the range.
00:48:45
Speaker
Something will be limited. We know that elite athletes can store more glycogen than recreational athletes. We know they have higher fat oxidation than recreational athletes. So think they are just better at all of these ways in which they can turn over energy.
00:49:02
Speaker
Super cool. I love the fact that this is also, you know, I think I said this earlier that we're, that you folks are coupling this thing that helps, that will help athletes across the spectrum of abilities, but also that you're, you know, you're learning from it, that you're, you're trying to put together, you know, maybe new models or new, new recommendations for, ah for performance. That's, that's pretty neat.
00:49:25
Speaker
Yeah. It's, and I think that like, it comes back from, this is our interest. Like we've all worked in sport, um All of us have worked with elite athletes, recreational athletes, and you just see the the benefit that it can have and you see that it is something that is important to them at all levels. um It doesn't matter because we've had, we're an Olympic champion in the labs at Liverpool John Moores that tested using this technique.
00:49:49
Speaker
They're just as interested as when we have study participants or we've had our first customers through EXO. They just want help and understanding some of this stuff.
Future of EXO's Testing and Research
00:49:59
Speaker
Yeah, yeah, that's super cool. because yeah And I know we've said this a bunch of times already, but like it up until this point, it's just been it's been very, very subjective, right? Like, oh, i if i if I take 60 grams versus 90 grams, how do I feel at the end of a five-hour bike ride? that's That's been my metric. That's been my metric with my athletes, too. It's like, what's your RPE?
00:50:18
Speaker
you know what how How much is your RPE climbing towards the end of a workout? um versus how many, you know, let's say we keep work rates steady versus how much carbohydrate you took on. so that's been that's been the the yardstick so far. So it's kind of fun to see that there's something on the horizon that is a little bit more quantitative than that.
00:50:38
Speaker
Yeah, definitely. Because i I don't know if you have the same experience, but AthleteShire Coach, Like said, that's the best we've got sometimes, but you know that it it's flawed in some ways because you can attest a good or a bad run to completely the wrong thing.
00:50:52
Speaker
probably like you could You could have had a bad night's sleep, but you sort of forget it and then go, do know what? This other thing made me have a terrible run today or a terrible ride today. yeah Because it's it's so hard to compute all of the inputs that we have.
00:51:04
Speaker
I think that's where... lab testing or tests like this can be useful because it can just separate all of that and you just get an exact measure on something. I love it. I think this is a, a great place to, to start to wrap it up, Jamie. Thank you very much for, ah for your time as always. And ah for our listeners who are interested, um where can they learn more? Where can they follow ah you or XO?
00:51:27
Speaker
Yeah, so XO, they're on all of the socials. So on LinkedIn, on Instagram, you'll find us there. and I'm on Instagram as jamiepughperformance.
00:51:38
Speaker
And then the the website is xoanalytics.co.uk. Very cool. And um I noticed I was just on the website before we started chatting. I see that the kits for order are available just in the UK for now. ah Are there plans to expand the geographical range for availability?
00:51:55
Speaker
There are definitely. And yeah, North America, we've had quite a lot of inquiries. So it's something that we're actively looking at at the moment. We're also looking at potentially coming and hosting some some testing days as well.
00:52:08
Speaker
So if we if there's enough interest, um we've already started exploring that as well that we might come over because it's probably something that we can do sooner than set up the the home tests. Cool. Well, listen, i know that I know a few practitioners with labs in the Toronto area i in Canada. So if you're yeah if you're interested, um we can we can chase some trees and see if we can if we can get you enough interest to make it worth your while to do that.
00:52:32
Speaker
Awesome. I love traveling. So even if we didn't make money, I mean, i just always always happy to have an excuse to just travel around. Toronto's a pretty cool place. I mean, I know I was complaining about the traffic and trying to get out of the city on my bike. That's a little bit of a drag, but otherwise it's, yeah, it's pretty cool.
00:52:48
Speaker
ah You should definitely come for a visit. Awesome. No, I'd love to. Again, thank you so much for the time. And listeners, as always, thank you for tuning in. Again, apologies for being so long off the off your feeds. But like i said, I got a couple more in the in the tank here. So I hope you tune back in. And if you like what you hear, give us a rating and a review wherever you listen to podcasts.
00:53:10
Speaker
Thanks, everyone.