Dr. Trent Stellingwerff: A Blueprint for Fueling the Marathon

Mark: Hi Trent. Welcome to the podcast and thanks so much for joining us today.

Trent: Yeah it’s great to be here. Thanks for the invite.

Mark: It’s great. No problem. I know that there are a lot of runners out there who are going to get a ton of useful information from our chat today and I myself am also excited. So why don’t we start with you giving us a bit of background on who you are, where you grew up, where you studied, and what you’re up to today.

Trent: Sure, no problem. I grew up near London, Ontario in a small town and was fortunate enough to be a decently fast high school runner and earned a scholarship to Cornell University, which is in Ithaca, New York. While at Cornell, I majored in nutrition and minored in exercise science while being on the varsity cross country and track and field team. I was mainly a middle distance runner – the 800 and 1500 – but also ran some cross country for them. After that time, I kind of got into the research bug and coaching bug and made my way back to Canada to the University of Guelph, where I did my PhD from 2000 to 2005 and at the same time worked quite closely with the head coach there, Dave Scott Thomas and his group, the Guelph Gryphon Varsity cross country and track and field program, which since the early 2000’s has probably been the dominant University running distance program in Canada and won many, many C-I cross country titles and even a few indoor track and field titles. I did my coaching education and degrees – kind of school national coaching program – with Dave Scott Thomas as my master coach and helped coach middle distance athletes while I was there. Then my wife and I met during that time – my current wife and my only wife – and she’s an elite middle distance runner who has made four or five world championship teams and was an Olympic semifinalist in London in 2012…

Mark: That’s amazing.

Trent: …In the Women’s 1500. We then moved to Europe and I worked as a research and development lead for Power Bar in Switzerland for six years and now we live in Victoria. I’m the lead of research here at the institute of Olympic training here – the Canadian Sport Institute Pacific. In a short, roundabout way, we’ve lived all over the place in many different countries and had lots of different work and cultural experiences.

Mark: That’s great. As I mentioned before we started recording here, I’m from Victoria as well, so I definitely know that there is a big running scene out there and a lot of the national teams training out there so that’s great. If you don’t mind me asking, which athletes do you work with primarily now? Are you working in particular with athletics or with other sports?

Trent: Yes, with my job at the Canadian Sport Institute, I’m the direct report for all of the nutritionists, all of the physiologists and all of the strength and conditioning coaches. But I specifically work closely with athletics, so track and fields and work quite closely with rowing and triathlon. But I help supervise staff that work across all sorts of sports from BMX to cycling to swimming to snowboard to women’s soccer. So we service a lot of different types of sports but I’m primarily focused on rowing and track and field.

Mark: Cool. Well that’s actually where I wanted to focus our chat with today was actually on fueling and in particular fueling for a marathon. So why don’t we start there. From what I have read and heard mostly, fueling doesn’t seem to get the attention that it deserves. Why do you think that’s the case?

Trent: I think it’s one part of the puzzle and it probably doesn’t get the attention it deserves because I could design some of the best fueling programs on the planet, but if they haven’t picked their parents right – so they don’t have the right genetics – and if they haven’t put in the right type of training, they fueling is only going to get them so far. But it is an important aspect. it depends on the race, the type of situation, how long it is, the type of athlete, but getting your hydration and your carbohydrate intake protocol down and sorted and optimized can bring anyone from, say, 2% performance benefit all the way up to 10 or 15% depending on the situation. 2% doesn’t sound like a lot but for an elite marathoner who runs two hours and 15 minutes, 2% improvement performance is two and a half minutes and that brings you from a 2:15 marathon, which wouldn’t qualify you, say, for a world championship, into a situation where you’re two and half minutes quicker and you do qualify for a world championship. For elites, 2% improved performance is massive. It’s one of those things as well that compared to altitude training or maybe other supplements or the training itself is an add-on that maybe is an afterthought and a lot of athletes who just race the half marathon or under, you can probably get away with it and not need a really dialed-in fueling program or protocol but as soon as the race distance gets over about 30 kilometers it becomes a requirement that you have to start to address and master. Some people realize the requirement quicker than others, that’s for sure.

Mark: Absolutely. As I mentioned, again, before we started recording, I had my own set of marathon fueling disaster going into my first marathon in Dublin in 2008. I was very naive and took a training program off of Runners World and just thought that I could do it getting by on my athletic ability and then, as I mentioned, at my second marathon a few years later, I paid a lot more attention to fueling largely due to the podcast I listened to with you and Coach Jay Johnson. As you mentioned – actually, you did the math quickly, that I improved my performance close to 20%, which I attribute a lot to fueling, myself. Obviously I trained a little bit differently and smarter, but I just felt better those last 10 kilometers just because I had some fuel in the tank.

Trent: For sure that’s the thing with the marathon that all of the popular press right now claims that we are born to run, but I would strongly suggest that we aren’t born to run marathons fast. Any one of us can get up and slowly walk or jog and get through a marathon tomorrow.

It’s 42 kilometers apart. As fast as possible. The human body actually wasn’t that well designed to do that so we have limited glycogen fuel stores and when you run hard, they can be used up in 75 to 90 minutes. Even the world class athletes are right on the edge of using up and going through all of their storage of glycogen and they need a good fueling protocol as well to optimize performance.

Mark: Yes, absolutely. So why don’t we talk a bit about why the marathoners need to fuel and the uniqueness of the marathon race itself for requirements to fuel. Let’s talk a little bit about types of fuel and in that, I know that there are gels and sport drinks and even natural foods or real foods which people use as well. Let’s talk about what the best types of fuel are and the science that goes into developing these more synthetic types of fuel.

Trent: Sure. No problem at all. I think that there has been an explosion of research in this area over the last 10 years and prior to that it was the early nineties when a researcher down at Texas named Ed Coyle first started to do some studies examining just the intake of glucose during endurance as a way to mitigate fatigue and maintain blood sugar and allow extra fuel to be delivered to the muscles during exercise. In that seminal landmark study, basically what they did was they did a ride to exhaustion and on water the athletes lasted three hours and on carbohydrate they lasted four to four and half hours. That started to open the idea that taking in carbohydrate during exercise was the way to go and a lot of studies followed after that with just using glucose. Primarily that makes sense, initially, because glucose is the carbohydrate currency that the muscle uses primarily. Everything is converted in the body back to glucose. You can take protein during long duration exercise and the liver can throw a bunch of processes called gluconeogenesis and produce glucose as well. But then about 10 years ago, a researcher and professor, Asker Jeukendrup, based out of the UK, on some ideas on looking at different types of fuels, did a seminal paper where they looked at glucose and fructose blends and found out that basically you could use, absorb and deliver about 20 to 30 or even 40% more carbohydrate than glucose alone and that primarily has to do with the fact that the intestine is the rate limiting site for absorption and in the intestine there are transporters for glucose and there are transporters for fructose. They are separate transporters, so having a carbohydrate source or a type of carbohydrates that’s multi-transportable that contains both glucose and fructose blends in approximately a two to one ratio or even a one to one ratio does result in more uptake of carbohydrate across the GI tract and more delivery to the muscle. If you type in Jeukendrup – and it’s Dutch, so it’s Jeukendrup – and carbohydrate and performance, you’ll see probably 25 to 30 published research papers consistently showing this outcome. It’s analogous to the idea that if there are a whole bunch of people on a subway platform waiting for the train to come up. If you take just glucose, it’s like having just one door on the subway train so the people need to queue up and wait to get on the subway train. The subway train represents your blood – the absorption across the intestine into the bloodstream – while if you’re then able to utilize a second transporter for fructose, you’re able to absorb 20 to 40% more carbohydrate during exercise and there’s a lot of indirect measures as well that suggest that since you’re absorbing more, less of it is going down to the lower intestine or lower colon, and less of it is later going to minimize issues with gastrointestinal discomfort or gut rot or some of these other things that happen. Out of that research, almost every major sports nutrition company products are made out of glucose and fructose. Certainly Gatorade is, Power Bar is… Goo is… and most of them utilize a mix of glucose and fructose-type blends. But not all of them do so you should still read the label of what you’re consuming and hopefully you see maltodextrin, which is glucose as well, and fructose is the two ingredients listed as number one, two. Or you might see sucrose and fructose. Those would be the key things to look for.

Mark: You said that’s also the case with sports drinks as well? You mentioned Gatorade and I’m assuming others use the same sort of formula?

Trent: Yes, so in short, I’m actually on a whole bunch of these papers where at my time at Power Bar we did a whole series of studies looking at glucose and fructose blends in sports drinks versus gels versus the actual power bar and we also looked at it in both cyclists – because almost every study ever published just uses cyclists because it’s easier to control versus runners. Long story short, regardless of the form, as long as you’re taking in the same amount – and that is actually harder to do with bars because of the chewing aspect – but as long as you’re able to take in the same amount, all of the different forms are utilized just as efficiently and are oxidized and utilized by the body just the same. Obviously, under high intensity exercise situations, taking in fuel or carbohydrate in gel and liquid form is a lot easier than in bar form but conversely, during long training runs or if there are triathletes listening to this and you’re on a long ride for three, four or five hours, then yes, taking in some carbohydrate as real food or as a bar or as a banana is also something I would strongly encourage because it allows for a bit of a fullness feeling as well.

Mark: Now, how does the hydration aspect fit in? Also I want to ask too – I know that the gels or the carbohydrate is a bit more highly concentrated than you would get, say, from drinking Gatorade so I know that most of them recommend that you consume some water with them primarily, I guess, so that your stomach can handle them a bit better. How does hydration fit into the equation as well, especially for a marathoner, when you’re trying to get all of these carbs in but knowing also that you have to get some fluids in as well?

Trent: Absolutely. We have to remember that there are two sides to this equation and that there is fuel or carbohydrate needs and there are also going to be fluid or hydration needs. Those are two separate and unique things that need to be addressed in a good fueling and hydration protocol or program. For example, hydration needs are completely weather dependent. So on a really cold race day your fluid needs are going to be a lot lower than if you’re racing a marathon in Hawaii. That makes sense. The fluid requirements are very weather-dependent. The fuel requirements, or the carbohydrate requirements, are much more or almost completely weather-independent. If it’s a cold rainy day in Vancouver in a marathon, you’re still going 42 kilometers and you still have carbohydrate requirements. Early on in my consulting career with Elite Marathoner, we had a situation where this marathoner I was working with was in a two hour and 45 minute shape and she ended up running about 258, dying over the last 12 kilometers on a cool, rainy day in Vancouver. It was because she said that she wasn’t thirsty so she just didn’t drink anything. I said, “You’re right. Your hydration requirements and needs were low, but you still had fuel and carbohydrate needs” so it was a good learning for all of us, especially for me to stress practicing in goal and target weather and even on cool days you still need to take in carbohydrate and some fluid. So that means that the ratio of carbohydrates to fluids will change depending on the type of weather that you’re going to race in. Most sports drinks are an 8% carbohydrate solution which means 80 grams of carbohydrates per liter – that’s 8%. Something like a Coca-Cola is a 12% carbohydrate solution or 120 grams of carbs per liter. A gel, straight up is nearly 40 or 50% carbohydrate solution, so we generally recommend, or at least I do, that with a gel, you’re also taking in water at the same time. I’ve had athletes, depending on the race and the heat and the temperature, their fluid needs and carbohydrate needs be anywhere from a 5% or 6% carbohydrate solution all of the way up to nearly a 20% carbohydrate solution. Once you get over about 15% of a carbohydrate solution, though, there is an increased risk for some stomach upset and some gastrointestinal issues because the carbohydrate ends up pretty concentrated in the stomach. You’re constantly playing with those things and practicing that.

Mark: You mentioned in your podcast with Jay Johnson ‘The rule of 15’ as a guideline. Can you explain what that means?

Trent: No problem at all. So ideally, you’re practicing multiple times – eight, nine, 10 times before your target race. Something like getting about 15 grams of carbohydrate every 15 minutes and 150 milliliters of fluid. So 15, 15, and 150. If you’re in that type of ballpark, you’re going to do absolutely fine. So 15 grams of carbs every 15 minutes is around 60 grams an hour. It’s about 600 milliliters of fluid an hour and if you can get into that ballpark, most runners will do completely fine. With some of our athletes, we’ll try and push them even more. If they handle that on a really hard training run that’s at their goal marathon pace in goal marathon projected weather, we might push them and tell them next time to try a little more or even a little more but at least getting that 15 grams every 15 minutes is ideal. Most gels, just to put this into perspective, are around 26 to 30 grams so it’s a half to three quarters of a gel every 15 minutes or so and that is a really good, easy type of rule to use in practice first before race day.

Mark: That’s great and that sort of brings me to my next question which is practicing fueling. For someone who is new to fueling or who has experimented a little with fueling, what tips do you have for a marathon runner looking to practice their fueling for an upcoming race and where do they start?

Trent: There’s definitely a few things that you can think about doing. The biggest thing is trying to mimic the demands of what you’re going to face on race day. I’ve seen the mistake made before that people practice fueling just on their long runs and I ask how long their long run is and they tell me that it’s 30K and I went 30 seconds per kilometer slower than goal race pace. I’ll say that of course they didn’t have GI problems in that type of effort because you haven’t mimicked the pace or the intensity of what you’re going to have on race day. I think that that’s really important is, when you have some key execution workouts, hopefully with your coach or a program or whatever you’re utilizing, where there are some long, hard days maybe once a week or once every two weeks that really mimic the demands of the race and those are the days to also practice your fueling because those are the days that it’s more stress on your body and your GI tract. Hopefully you can also practice your fueling in the target projected weather conditions because heat and humidity also can add increased stress to your gut so if you train all winter and you have a really hot race day, not only will it slow you down but it might increase the chance for stomach and GI upset as well. So that’s number one. Number two is that in those key sessions and workouts try to mimic what you will get in the race as well. So if there are aid tables, go on the website and find out what type of sports nutrition provider is at the race – is it Power Bar? Is it Gatorade? Is it Goo? – and get those products and practice with them and see if they agree with you. If they don’t agree with you, you’re going to have to carry your fuel with you on a fuel belt or something like that. Find out where the aid tables are. Are they every five kilometers? Are they every seven point five kilometers? Are they every three miles? Try to find the profile of the course. Mimic that in your training. Find ways to mimic the frequency of aid tables at the marathon in your training. So if it’s every five kilometers, for some people – for the elites – that’s every 15 minutes. For the non-elites, it might be every 30 minutes. If it’s every 30 minutes, then between the aid stations, to try and satisfy that rule of 15, you might need a fuel belt. So every 15 minutes you might take a little bit of fluid and carbs from your fuel belt and then at the 30 and 60 minute mark, theoretically, you might pass the five kilometers and 10 kilometers and be able to use the fuel that’s provided by the race organizer on the course. So really think it out and really try to mimic it in practice. I’d also suggest trying it out on a few of these key workouts at least six or seven times so that you feel really comfortable with what you’re going to do on race day. You might even write down what you consumed, how you felt, how it went, so that you have a record of it and next time around you can write it down so that you develop a little bit of a profile for yourself. Lastly, one kilogram of body weight or one kilogram of fluid equals one liter. So it’s really easy to track your sweat rate by measuring your body weight pre and post-run in kilograms and subtracting out how much you drank. So if you have water bottles with millimeters on the side of them, you can have a good sense of what you consumed. So if you’re 70 kilos at the start and you dropped all the way down to 65 kilos and you drank two liters, you’ve actually lost a net of seven liters of fluid over a three or four hour run and you can figure out how much you sweat per hour and then give yourself a sense of that as well. Most runners, if they’re feeling really well, will only lose somewhere between two to sometimes 8% – for the elites – of their body weight. If on a run you’re not losing 2%, you’re probably over-drinking. 2% of your body weight as a percent loss from pre and post weights. If you’re losing north of 6% or 7% or even 8% and you feel that you could consume some more fluids, try and do it. It’s probably better that you lose only a 2% to 5% range. There is evidence of some elites being able to lose more than that and dehydrate and still perform pretty well but ideally you’re able to consume enough fluids to not be that dehydrated. As I said, it is normal to lose at least 2% of your body weight. I think that sometimes newcomers to the sport are so aware of dehydration that they overdrink and they actually gain weight and that can actually be bad for your health as well.

Mark: And dangerous as well. Is that true?

Trent: That’s correct. It’s called hypernatremia, which is when you overdrink, and ‘hypo- means a dilution and ‘natremia’ is the science term for salt. So you actually flush out all of your electrolytes and sodium and there actually have been deaths from this. I don’t want to scare you. For every ninety-nine dehydrations there is one over hydration. But yes, you should lose a little bit of weight and get a sense of what your sweat rate is and how much you lose on different types of weather conditions and practice that. Over time you collect a little bit of information. You basically do a little study on yourself and you learn a lot about yourself and you’ll come into the race feeling much more confident and ready to go with a fueling plan that works for you.

Mark: I can definitely attest to that. I think I read somewhere – perhaps it was in another podcast with you – that some of the best or the top marathoners in the world are actually the most dehydrated at the finish due to the fact that they’re going so hard that they’re amongst the most dehydrated finishers in the race. Is that true?

Trent: There was a very neat study that came out in 2012 and it was titled ‘Drinking behaviors of elite male runners during marathon’ and first of all, sweating is the way that the human body dissipates heat, so one mechanism by which you adapt to dissipating heat is an increased sweat rate. When it gets hot in the spring, your body actually adapts by increasing blood volume for some people up to 10% due to heat acclimation. That takes anywhere from 10 to 15 days in the heat but you can start to get effects in as little as five days. Secondly, you actually increase your ability to sweat. What that does is it dissipates heat, but sweating also comes at an expense of dehydration and dehydration primarily due to decreasing blood volume, which is what causes your heart rate to go up higher in the heat because your heart tries to compensate by pumping quicker. Long story short, the elite of the very elite are so adapted and so good at dissipating heat – and that’s part of the mechanism of why they’re so elite – that a lot of them lose significant weight. So Haile Gebrselassie, the 26 time world record holder, in this paper had a 6% body weight loss during the race and it took him just over two hours but he had an over three liter per hour sweat rate, which is insanely high. The next highest person I’ve ever measured – and he wrote about this in his blog, so I’ll talk about it – is Rob Watts, one of the elite Canadian Marathoners. He was at 2.6 liters per hour at the Moscow World Champs in the heat last summer. It was 26 or 27 degrees Celsius there and he did a good job in the heat and paced himself well and I think he was in fiftieth place at the 5 kilometers and ended up 20th place overall. I truly do believe that with all the monitoring we’ve done on him, part of it was because he can sweat nearly two and a half liters of fluid an hour. So that’s what partly what makes these guys so world class is their ability to sweat so well.

Mark: Wow, that’s amazing. Going back to some of the practicing tips you made, what about practicing fueling while you’re running? Do you recommend for people that run over a certain time that they actually slow down and prioritize their fueling over running through the station and perhaps not getting enough fuel at the aid station?

Trent: Hopefully, again, if you’re able to practice and satisfy that rule of 15 and able to mimic that in your training and measure things out – it takes a little bit of math but it’s simple math – and at the end of the workout you can count how many gels you had per hour – two gels per hour equals 60 grams – and can count that you had 600 milliliters of water, which is great because that is what you are targeting for, then if you are able to satisfy that by running through the aid station and not spilling a lot of fluid out of the cups and you practice that then that’s great. That’s no problem. For some people, they have to slow down and walk to be able to do that. With the elites, they all have marked bottles and it’s a lot easier for the elite to do that because they just grab their bottle off of a table, it’s usually a squeeze bottle with a top on it with a nipple and they can just…

Mark: Suck it back.

Trent: …Suck it back and they can run with it. Sometimes they grab it and they’re sucking on it right away and I think, “Just take your time!”. Run with the water bottle for a kilometer if you have to and just take your time. For the masses, that’s not so much the case so another thing I can say is that when you get those little cardboard cups, right away squeeze it almost in half so that you kind of close the cup and a lot less spills out and because you’ve squeezed it, you’ve actually made a pouring device that is actually kind of like a pitcher. It’s a lot easier to get a lot more fluid and a lot more carbohydrate that way out of those little paper cups.

Mark: That’s so true.

Trent: The other thing is that you might offset that by having small fuel belts with the ability to take on fluid and carbs that way as well.

Mark: That’s so true. I’ve used those cups and the top is useless but I have tried squeezing at the top and it’s a lot easier. And you’re able to take your time more because before, when you keep it open, I found that if you don’t gulp it down right away it just starts spilling the more strides you take.

Trent: I totally agree. Again, that’s something you can practice. If there’s a key 5K loop in your neighborhood and it goes by your house and your friend or your partner or whatever is willing to come outside every 15 minutes or leave a little table out there, you can practice it or maybe you have friends that are doing the marathon and one of you that week can set everything up so you practice your fueling for that week. But grabbing stuff off of a table and handling the paper cups is something that’s really easy to practice.

Mark: Yeah for sure. Let’s switch gears a little bit. I want to ask you about training on an empty stomach or going out for your long run first thing in the morning when you’ve taken in no fuel and you’ve essentially been fasting since you’ve eaten last the night before. I know that there’s some thoughts that this helps you better utilize your fat stores that you have. Is there any truth behind this and is that a technique that you use with your athletes?

Trent: There’s been a few research studies in the last five or six years that have examined the idea of during training – not racing – training on low carbohydrate availability. One way to do that is to have dinner the night before, obviously just go to sleep like normal, get up the next morning and just have some water and a cup of coffee and head out the door for a run and you’ve actually depleted some of your liver glycogen and you don’t have as much fuel stores on board and indeed, studies do show that you do force your body to use more fat as a fuel to run and adapt your body to allow for more fat oxidation and fat metabolism. So with our elites, we’ll purposely do that in some of their training program maybe once or twice a week. It is very hard on the body. It is hard to recover from. It doesn’t always feel as pleasant. You mentioned how you felt in your first marathon when you didn’t fuel versus your second marathon when you did. It’s not for the faint of heart but it might give you a little more bang for the training buck, especially if you’re really busy and you don’t have as much time to train or if you’re trying to find other ways to break through a training plateau than this is something to think about or consider but again I’m not talking about the Atkins diet here or low carbohydrate diet, I’m just talking about periodically training with low carbohydrate availability.

Mark: I tried that definitely in my last marathon last year for two or three 20k plus runs and you can get through those runs but as you say you’re not going to be running the pace that you’re accustomed to when you’re fueling but I find that they do help and I find that it helps a lot with your confidence too, just knowing the fact that you can run that distance having not taken in any fuel.

Trent: That’s spot on. Nothing every mimics the last 10 or 12 kilometers of a real marathon – let’s be honest – but it at least gives you a teaser of what the last 10 or 12 kilometers are going to feel like and exposes your body to that really depleted feeling. But you don’t need to run 30 kilometers to get there.

Mark: Which is always a good thing.

Trent: Yes. So, again, the elites are a whole other breed. For them to do a 30 or a 40 kilometer long run is no problem because it’s two hours so they bounce out of it with no problem but for the non-elites, when you’re doing a long run that is three or four hours in duration or more and it’s really going to kick the snot out of you for a few days. Here’s a way to make training harder without having to run more, so to speak. In some ways it’s like altitude training. You go to altitude and you take something away and that something is oxygen or in this situation, you train periodically and you take something away and that thing is being well-fueled, having breakfast and having your sports drink all of the way through and it just makes training a little bit harder but it forces the body to adapt a bit more and again, this is something that I would only do 16 to maybe six weeks out from the marathon. In that last six to eight weeks you really want to transfer and switch over to practicing fueling primarily and carbohydrate and everything we’ve talked about previously.

Mark: Now, in respect to your time, I have one last area I want to chat to you about and that’s if there are any interesting breakthroughs from a science or research perspective that you think are being working on or that will change the way marathoners are fueling? Is there anything that is happening right now that really sparks your interest?

Trent: I think that overall I don’t foresee any huge revolutionizing breakthroughs in that front. Instead what I see is a lot more emphasis and value being placed on sports nutrition and sports nutrition research. For example, six years ago, there were no studies on glucose and fructose blends or there were no studies on beetroot juice. There were less studies on how caffeine can improve performance or a host of other small things that might or might not work. The evidence needs to come out on some of them but I think what we are seeing here is that you can’t have physiology without food and nutrition and substrate so there’s a really tight link between physiological adaptation and how nutrition supports each of those rate limiting steps that produce energy in the human body. I wrote a piece with Asker Jeukendrup. A few years back there was an academic letter to the editor about when we were going to see the first sub two hour marathon and the whole paper just talked about physiology and how the body needs “a VO2 max of this and need a running economy of that” and it spurred a whole host of something like 50 plus letters to the editor of people asking about socioeconomic status and the desire that, say, African athletes have to get out of poverty. That’s going to drive someone to sub two hours. We wrote a paper on sports nutrition and all of the evidence there and someone else wrote a paper on – there’s no evidence for this – but the fact that a lot of the African nations are malnourished and you end up with a lot of the world-class male marathoners are 5â??3â? and 120 pounds. That is amazing for the marathoner because they don’t have to carry extra body weight around the running course. Why is that? Well part of it might be that they were malnourished as kids. That’s interesting. It’s a hypothesis. It’s going to be this whole myriad of things that really drive performance to the next step and if you look at the massive explosion in marathon times in the last five years – I mean, the world record a few years ago was 2:06 and now we’re down to 2:03 – it’s the fact that as a Kenyan or an Ethiopian you can make a 150,000 dollar payday in one race to win Boston or New York plus all of the appearance fees, plus all of the shoe contracts that come with it. That money is what is driving literally 300 or 400 Kenyans to run through 300 kilometers a week consistently as a route out of poverty for them. It’s inspirational. I don’t think Canadian or American or Westernized muscle is any different than Kenyan or Ethiopian muscle, it’s just that they have 300 or 400 people who are willing to do 300 kilometers a week. We’re close to 300. We only have maybe five or six guys willing to run north for 200 kilometers a week so I think that’s where you’re going to see your big jumps in performance in the coming years.

Mark: That’s very interesting. Very quickly, what about caffeine? Not to take too much time, but I know a lot of the gels utilize caffeine and I think the Cliff blocks that I certainly use have caffeine. It’s hard to say but I would think it helps and from what I understand it sort of helps to lathe that muscle soreness that you can get late in the race. Can you talk with that quickly?

Trent: Yes, you bet. No problem. Caffeine, in the last few years, the mechanism is primarily due to interaction within the central nervous system and caffeine is also in a lot of pain medications so what it does is it helps you focus and distract you and blocks some of the pain that’s associated with very hard effort such as long racing. The evidence is quite strong. There’s meta-analysis to show that caffeine does improve racing and endurance performance. It’s not on the banned substance list by WADA. Athletes certainly utilize and strategize and use caffeine whether it’s a strategic cup of coffee or a caffeine pill or caffeine in gels certainly to help focus later in the race and minimize discomfort. You’re still in pain but you’re able to run a little bit faster at the same level of pain. The recommendation there is to take approximately two to three milligrams of caffeine per kilogram body weight 30 to 60 minutes before the race. So for most people that is 150 to 200 milligrams of caffeine and then you might have 25 or 50 milligrams an hour after that throughout the race. Most cups of coffee – large cups of coffee, say an Americano at Starbucks – will provide 100 to 150 milligrams of caffeine and that’s the ballpark for most people of what they’re looking for.

Mark: How long does it take for that caffeine to get into the bloodstream?

Trent: It depends what’s in the gut. If you have an empty stomach it will be 30 to 45 minutes it peaks. It already starts to come into the bloodstream within 10 to 15 minutes. If you’ve eaten something it can be maybe 60 minutes to peak because there is a little food in the gut that delays the emptying of the caffeine but the first rate of appearance of the caffeine can be as quick as 10 to 15 minutes but then the peak is 45 to 60 minutes later. That’s why I said to take it 30 to 60 minutes before the start of the race.

Mark: With regards to caffeine, if you are looking to run a three hour and 30 minute marathon, does it make sense then to take in some caffeine about two and a half hours into your race so that caffeine is dripping into your blood throughout that last hour of the race?

Trent: With most people I work with, they’ll take some 30 to 60 minutes before. That 250 to 200 milligram range and part way through they might include a couple of 50 milligram gels back to back at around the half marathon mark just to give them another 100 milligram boost which then suffices for the rest of the marathon. You’re certainly not going to sleep well after that but it’s also a one off race so who cares?

Mark: Exactly. You’ve trained that much so sleep is not your priority there. Well listen Trent, with respect to your time, why don’t we end things there. I just want to thank you very much for joining us today and having a chat. Can you let us know where people can follow what you’re up to or if they want to connect or see what you’re up to online?

Trent: For sure. The best spot to follow me is on twitter @TStellingwerff and I’m usually sending out stuff all of the time be it new studies or comments on this study or that study and that’s probably the best spot.

Mark: Perfect. Listen Trent, thanks very much and we wish you all the best.

Trent: Great, thank you very much!