Caffeine and Performance with Nanci Guest, PhD, RD, CSCS | Koopcast Episode 71

trail and ultra runners what is going on what's happening welcome to another episode of the KoopCast as always i'm your humble host coach Jason Koop and this episode of the podcast is with the incredible and the incredibly unique dr nancy guest dr guest is a registered dietitian she's a personal trainer as well as a strength and conditioning coach to elite athletes and everyday athletes alike she has served as canada's head dietitian for the vancouver 2010 olympics as well as the 2015 pan american games she has also prepared athletes for the last four olympics in london sochi rio and pyeongchang dr guest has an illustrious research career which accumulated with the 2019 dr michael c archer award for research excellence and i cannot understate how amazing that is to actually receive congratulations nancy that wasn't that long ago that she actually received that this podcast is all about one of nancy's areas of expertise which is caffeine and performance for athletes in particular in an ultra marathon situation ultra runners are in this really unique proposition where we can use caffeine for aq performances for workouts we can use caffeine to

stay awake and alert during the wee hours of the morning for those overnight ultras and we can also use caffeine to stave off fatigue for those long runs or for ultra marathons and those are all very unique propositions which nancy and i talk about throughout the course of this podcast i had a lot of fun with this nancy is an awesome follow on twitter the links to that will be in the show notes go give her a follow on twitter you will not be disappointed but for right now i'm going to step out of the way here's my podcast with nancy guest all about caffeine and performance i actually forgot about this how did you get it how did you get so kind of like wrapped up in caffeine in the first place because this is like one of your many things that we were talking about before we started recording like caffeine just seems to be one of those things how did you get involved in in the first place yeah so where that came about um working with athletes obviously and just uh active people uh caffeine is is well known uh to to sort of give you a a little boost and most of us of course do enjoy our morning cup of coffee and and most of us have those pleasurable effects uh but where i became more serious in looking at the research was because i found with my own athletes i worked with not everybody was getting a performance enhancement from caffeine so there seemed to be

some inter-individual variability just in my practice and of course there have been a number of studies written on caffeine and i had read several of them uh but there it wasn't consistent that every study showed a benefit and what became more apparent after i started my PhD was as i looked more closely we rarely see individual raw data being presented and we just see the overall effects that the cat the outcome on average there was no effect of caffeine or there was an effect and because my lab uh looks at uh the research is in nutrigenomics so nutrient gene interactions this is where i sort of thought perhaps the same thing is going on as we see in the caffeine research with regard to heart disease that depending on your genetics uh you may have a risk of high blood pressure or heart attack uh and if you have a a certain uh variant uh you may have there may be a protective effect uh so so this sort of brought me to the the the potential realization that this may be happening in the sport sciences as well where we're seeing different responses to caffeine through differences uh genetically in the metabolism of caffeine and uh so that's where i embarked

on this journey to see if caffeine in fact was uh the response was modified based on your genotype in certain genes that we look at that have been known to affect uh caffeine metabolism and response and we're going to go over that uh genetic difference in just a second um i've almost felt that over the years you and i've been practicing for a similar amount of time that caffeine and altitude have kind of followed the same trajectory where and i've talked about this on this podcast before the listeners will remember a little bit of this dialogue where it wasn't that long ago maybe seven or 12 years ago where the de facto thing to do was to go and do an altitude camp we thought everybody responded positive positively to it all the elite athletes were doing it you know live high train low there were altitude symposiums and conferences and things like that and then as the practice kind of got more and more nuanced we started to notice that not everybody responded and we're taking a little bit more of a cautious look at it now the reasons for that difference and that that individual difference in response is not solely related to genetics on the altitude side of things but caffeine has kind of followed a similar pattern where yeah i mean you remember in the especially in the like the late 90s with all the cyclists and things like that i mean they were downright abusive towards towards caffeine and caffeine use and we're starting to filter out a little bit more use of it have you

like seen the same thing with cat with caffeine to where now we're trying to like almost like tailor it down a little bit more but is is it really at a genetic level to where that tailoring is most appropriate well you know what i like to say about uh life in general is there are only two things that are impacting uh your behavior or your health uh genetics and the environment or the interaction of your genetics and the environment uh so basically almost everything could be traced back to our genetics uh so we have not identified all the genes that affect uh altitude training or caffeine or creatine or uh our response to various phytonutrients uh there's a lot out there that is yet to be discovered but i do believe that we have enough data showing differences when it comes to feeling jittery or anxious or more energetic or uh having more difficulty sleeping so sleep disturbances are on a spectrum uh between individuals among individuals and then we have the severity of withdrawal effects and there have been associations to genes but i think really uh when it comes down to an individual there's going to be some interaction with their past

experience uh coming from perhaps the the habits of their parents uh their mother during pregnancy all the way to how they train how experienced they are what their habitual use of caffeine is uh their and what their choice of the form of caffeine so there are several factors and you're right what we are trying to do is sort of pin it down to give the best personalized and individualized recommendation and i think we do have to guide our recommendations based on several layers of personalization and so it's not just about genetics uh you know that's one layer that i provide guidance to my athletes uh but there are many other things to consider just like with general diets um you know there there are many factors that go into what is the best diet for you uh so when i think it the same goes for supplements and we can get into sort of all those reasons and and how i assess an individual of whether they should use caffeine at all even if it is providing a benefit we still may advise again on a one-to-one level i have some athletes that i try to um discourage them from too much caffeine use because i can see the uh severe uh response they have to sleep disturbance and then

certain individuals that may be at risk of taking sleep aids whether over the counter or prescription so that's sort of an area that needs to be addressed we can talk about uh but i do think people need to be on their individualized caffeine uh program and i i say that similar to my my colleague amy bender which some of her research will come up uh where she talks about athletes being on an individualized sleep program and i think we need to take all those factors and decide how are we going to approach caffeine with this athlete you know it's so funny you mentioned that because i know a lot of athletes out there that are going to use caffeine particularly in an evening evening workout in order to get the ergogenic effect within the workout itself but they don't realize the effect that it has on sleep afterwards and it's almost like one up one down or one up two down maybe maybe they get a little bit of boost on the workout and they can reap some benefits from that workout but then if their sleep and their recovery is impacted it's almost it almost comes out as a wash before we get too far into the weeds into the individualization and we we people like you and i we love to do that right yeah people want to know what are just the general guidelines if they're looking to use caffeine in what i'm going to call a traditional ergogenic way right they're going to use it right before a workout or a hard workout in order to or race in order to enhance that and there

are lots lots of studies partially because it's easy to get college kids to it's easy to recruit college kids for two things alcohol and caffeine so we have a lot we have really robust research on how that on how this actually works so let's start with that framework if somebody's going to use caffeine in that traditional ergogenic sense for a workout or a race what should that look like in terms of dose and timing well it's an interesting question because we have the practical experience and then we have the research the published research and sometimes that doesn't always align uh so i sort of wear two hats i have the researcher hat and then i have the sport dietitian hat and uh so uh first of all i i have a uh very uh thorough assessment with each athlete i'm going to be working with so it depends on the sport uh so for example if uh if a training session or a race or a competition if we're looking at 90 minutes or under i think uh probably the most consistent and beneficial approach we see in practice and in the research is to supplement anywhere from 30 to 60 minutes ahead of time and that is going to be with your traditional three to six milligrams of caffeine per kilogram of body mass now where uh this can can

differ we sort of have a a bit of latitude with our approach is some individuals are getting that benefit on a dose as low as two milligrams per kilogram of body mass and i in my research wanted to i try and identify that that dose where we could see that benefit so i use we can get into that the two and four milligrams uh but in my experience and as far as a lot of the published research i don't believe we need to go up to that six milligrams per kilogram so i i would have an individual start out with the the three to four milligrams and again 30 to 60 minutes before they begin uh that training session or that competition if it's around 90 minutes uh and i think that's the the best approach for that time frame now if we're looking for uh an endurance sport that or a training session that's lasting longer so looking at two to three to four hours all the way up to uh ironmans triathlons uh ultra uh endurance events then our strategy shifts and we wouldn't want to start out with such a high dose but we would look to start out with a smaller dose and then have those intervals of the smaller doses uh throughout especially as the athlete starts to fatigue and i think uh we do see a consistent benefit physically

and cognitively when we give caffeine at a point where fatigue is starting to set in so i think caffeine may have its strongest benefits when you're starting to get tired and your your listeners will be uh glad to know that the most consistent benefits we do see with caffeine are in the endurance arena so the shorter the span of that uh exercise test or that sport um i think the research gets mixed but the longer you're training or competing or racing uh there seems to be an increase in the the chance that you're going to benefit from caffeine we'll have to consider other factors uh but the good news is i would say most endurance athletes will benefit significantly and i i don't mean that necessarily statistically but have a a huge benefit anywhere from one two three four percent and that's that's a big jump this conversation is going exactly like i had uh for thought that it would where it's just giving us more and more of an excuse to take in more caffeinated products from an ultra marathon perspective though i can almost see three different scenarios not to dive down too many rabbit holes but you're giving them to me so i'm going to take them yeah the first of which is just what you mentioned it's a

workout i'm going to go and i'm going to do a hard workout it's less than 90 minutes and i'm going to take some dose of caffeine 30 to 60 minutes before the session itself and before we get too far into all these different scenarios just to level set uh things for people you mentioned this range of i'm going to give the bigger range two to four milligrams of caffeine per kilogram of body weight practically speaking what does that look like well that and that's actually a good question twofold uh that looks like uh so for example for an 80 kilogram male um and i'm accustomed to this just from my research where uh we did give the two and four milligram dose that's generally one and a half cups of coffee or three cups of coffee so the two milligram was the one and a half the four milligram for that body weight now uh the caveats there is that having a coffee uh let's say you go to your if we don't want to name names but one of the most popular uh retail coffee outlets uh globally uh one day you can go and get your tall brewed coffee that may be 150 milligrams the next day at the same location that same tall maybe 250 milligrams so we have that variability which uh in my opinion it means that i if i want to be more

precise with dosing i do advise tablets or capsules and of course the more elite athlete we have or in the research uh under research circumstances we need to be exact with those doses uh but i do think that that's where we run into uh some issues with differences in outcomes is we don't know exactly how much that individual took uh so so 70 milligrams for example is a typical espresso shot okay so so uh you know having two espressos that's 140 milligrams now that's not quite going to reach your two milligrams per kilogram for a heavier male but certainly that reaches it for a 150 pound athlete okay that puts it in the ballpark i just wanted every ultra runners we're a pretty extreme lot right and if i'm glad that you mentioned this six milligram per kilogram type of threshold because in absence of that we're gonna go overboard and yeah in everything like any other endurance athlete okay so back to my point we've got these three scenarios right we've got the workout scenario where you're kind of like taking it in advance right we have the what i'm gonna call the long run scenario and i agree with you that i think that bang for your buck that's where caffeine is really going to shine through where you where you're going out there for two three four five hours and there's some level of fatigue that's going to be imposed that's where you can get some big hits from caffeine usage and then

we've got this third scenario that we might have to speculate on a little bit because it's really unique to ultra running and most of the research is going to be derived from military on this and that is from a cognitive and a sleep deprivation point of view a lot of these ultras are going 20 hours 30 hours 40 hours into one over one night and maybe over multiple nights and ultra runners are going to want to they don't care about the traditional ergogenic effect in the early part of a race they care about hey i need to be able to stay awake and make good decisions later so let's talk about the the kind of like the latter two as fatigue starts to kind of creep in to an endurance session you mentioned that caffeine can be kind of like layered in in small doses as that starts to happen what what does that look like because there's a number of sports nutrition products that athletes can choose from that usually range between 12 and a half to up to 200 milligrams of caffeine per kind of uh serving size right unit yeah unit yeah so what does that look like from a practical perspective if we're looking at using caffeine on like a long run or a long type of event well my first uh response is always it's individual uh you know the context matters and um it depends on the person uh but i would say uh you certainly don't

want to start out with that big hit from the get-go and uh hopefully we can get an athlete started uh with no caffeine just being well rested well fueled and start uh implementing those those small uh doses as as as you need more fuel so perhaps when you need that gel or you need that you know in the in the second or third hour i take a hit of caffeine there uh once you're perhaps at that eight hour mark you need a higher dose and maybe you actually do a 50 milligram tablet or half a tablet um so something interesting is to consider your circadian rhythm so there's sort of other confounders that are involved in this uh approach or knowing what the outcome may might may be and uh so what we've seen in some of the sleep deprivation research is that the their circadian rhythm is very influential and uh not only on your ability to stay awake but also your performance and so one study showed that even at uh the 30 hour mark when it was daylight there it was easier for subjects to stay up um than it was when at the 24 hour mark when it was dark so they were more sleep deprived but because their body was used to being awake at that daytime even after missing a whole 24 hours of sleep they could better handle it so

i think in the evening so when it's dark these athletes are probably going to need to pump in the caffeine at perhaps 50 milligrams or more per hour and i think we do see uh at the end of some of these events uh that uh over a 24 hour period some athletes are at the at the 100 to 200 milligrams some are up to close to close to a thousand milligrams that they've consumed in that time period so i think uh knowing when you're starting to drop off and trying to get it just before you you know sort of get into that uh beyond the point of no return um but i i would say uh to consider uh the if the daylight also what time um you would be eating and so we're more likely to be awake at meal times and so to sort of foresee uh when those are occurring during the event but when your body is actually going to be winding down and sleeping in regular life uh in this 24 hour period that's when you're going to need those hits probably at the greatest frequency um and that that moderate dose though 30 to 50 to maybe 70 and uh i i would say through uh tablets uh you know broken up or um again if you're needing the fuel as well through that form through sports nutrition products yeah so we're kind of we're

kind we're kind of getting into the typical ultra marathon situation especially 100 mile ultra marathon situation and there's this there's this phenomenon that's not just in ultra running but we tend to we tend to think it is and it's called the witching hour and so typical rays start out at 5 6 a.m sometime around 2 or 3 or 4 a.m and there's actually really good research to to draw upon with this is the highest rate of dropout for any ultra endurance type of event it's right before that 24 hour period of when they've actually been going it also happens to coincide when everybody's the drowsiest and and the sleepiest yeah and knowing this most ultra runners will want to try to counteract that with with something sometimes they'll use a pacer to keep them awake sometimes they'll use music and caffeine is one of those substances that they will actually use but i think there's a lot of confusion to how to actually implement that in real time when what i'm hearing you saying is to roll it in at a slightly lower slightly lower and smaller doses perhaps in the hours before that time frame yeah or more frequently so every 60 to 90 minutes uh taking that it also depends on on energy expenditure so um i think if you are or uh intensity so if you're going through if this is a flat race or

if it's um if you're the fatigue is setting in and you have some elevation to conquer uh i think perhaps you need to you know to to hit your system with a a bit of a higher dose depending on body weight again so we we do see that typical 100 milligrams used as flat cola for example we have the research behind that now that's a different hit for someone who weighs 120 pounds versus 180 pounds uh so so i think um if we look at the one milligram per per kilogram of body weight per 60 to 90 minutes that's super important yeah so i think that's sort of uh you know we get into that that ballpark now i would not be doing that for a 24 hour period but uh if if you're saying that that's that witching hour is uh about uh 2 to 4 a.m you said yeah somewhere around there yeah yeah so and then there's also going to be uh another uh sort of uh that afternoon sleepiness as we see the adenosine rise and so that's really what we're trying to counteract in the body is uh the adenosine which is that sleepy calming hormone that gets released uh in higher amounts throughout the day and it peaks at bedtime right so that's uh

what caffeine does is it blocks those adenosine receptors so you can't have that calming effects occur and you can't have sort of that that sleep induction uh you are blocking it and uh causing a stimulating effect in most people not not all individuals will in fact have that effect um but so i would um look at the smaller doses in anticipation of that 2 to 4 a.m so perhaps at 10 p.m right start that hourly or every 90 minutes and try to um have a wider span uh through the daylight and that's easily achievable with most normal and reasonable caffeine-laced nutrition products gels or blocks or things like that if i've always felt that if athletes just switch from the non-caffeinated version of the fort of the sports nutrition products they're using to the caffeinated version of the sports nutrition products that they're using at about midnight or something like that they're going to get themselves in that correct dosage by the time that they actually need it yeah i i would agree i still do feel nervous about the caffeine concentration and how uh well that that is controlled uh in the product in the product uh so we don't have i mean of course we have the evidence for uh well we do have with pre-workouts

and different formulations now if you're looking at something like a gel uh i would feel more confident that the milligrams that's on the label is in the product uh but unless we're batch testing these products and i'm i'm sure probably something like consumer lab has done done this uh but i think that's important and so what i would err on is to break up tablets so i know for sure what's in it and just stick with your caffeine free products um so that that is my approach uh just to be a little bit more in control yeah uh so but i i do think that you probably have a very good chance of uh being uh it being you can be confident that the the dose that's on the label is probably uh true to to what you're receiving if with an error maybe plus or minus 10 percent um but if it's i mean i guess this is coming from a perspective of someone working with uh professional athletes or olympians and with regard to our national athletes for example we don't even risk it being made at a pharmacy with an encapsulator we use our own encapsulator to make sure there's no contamination and the dose is exact through the powder uh for the need of the body mass of that specific athlete so the more precision the better and especially when you're looking at a substance that uh you you want those performance

enhancements but also where getting too much or too little can either uh you know be not allowing you to achieve achieve that uh ergogenic effect or too much may cause anxiety or other adverse effects uh so perhaps if you're in a race where you can sleep for two to four hours or um or with athletes that are in the playoffs and we want them to be able to sleep uh we do want to err on that lower dose so again you know it does depend on that sport but if we're sort of sticking with that um that 24-hour time period uh i still would i would make that known to the runners right that listen if if you really want if you feel you're sensitive in in on both sides of it that you will be too tired if you don't get enough and you may get a little bit anxious uh if you get too much so if you find that you're an individual that needs to be very precise i would uh get you know get the caffeine powder and make your own capsules um or uh certainly some of the tablets i i find are reliable like the no dose or wake up that type of thing and some athletes they just don't like the taste of the caffeinated version of their sports nutrition products we're we're gonna we're gonna dive down the individual rabbit

hole because i know that's your an area of passion for you especially on the genetic side but i've got a pretty hilarious story about this that i think will dovetail into it pretty nicely and it has to do with the maximum dosage um i was i was pacing somebody um at the end of a hundred mile race several years ago and the way the situation was is there was only two people ahead of us on the course at the time and i'm running alongside with my runner and i find a one of those blister packets of it's either no dose or viver and i can't remember right now i should be able to remember because one's white and one's yellow anyway i find a blister packet of of one of those and there were six unopened individual 200 milligram caffeine tablets okay and i i just knew and i'm gonna keep this anonymous because this person would appreciate that i knew who had it ahead of me because they were a very habitual caffeine user but the only thing that i could think of is it was the intent of that runner to take all of those all 1200 milligrams because they would not spare one extra ounce there's no reason for them to have six and not just two right i knew i knew that the intent was to take all six and i remember looking at it and processing this whole story in my head at the time knowing who it was and knowing this person is is is is going to was going to take all six and going i'm really glad that i found all of these

and not an arrhythmic runner another couple miles down the trail because he or she had taken all of these so your point of there's a maximum dose that we want to avoid i think is really well taken because you can't you can absolutely have a lot of negative effects for exceeding and there's no positive effects for exceeding the six milligrams per per kilogram ratio yeah yeah no that that's um very interesting maybe you saved saved a life i didn't do anything i just found it yeah yeah well no you well you picked it up you didn't run after them and give it back right no i kept them i showed them afterwards i was like you're gonna take all these weren't you and this person was like yeah i was i'm like i'm glad yeah and so i gave them the lecture so how did they do in the race uh i well i can't tell because it would give it away oh okay well perhaps they didn't need it yeah yeah they definitely they did they did well let's put it that way okay okay they definitely did not hamper them that they dropped this yeah okay well there you go there you go that was an important lesson for them oh my gosh anyway you probably didn't listen to me at the end of the day um okay we've we've dabbled around the surface of this kind of final component that i want to talk about but i really i really want to relay this to all the listeners as well we're starting to appreciate more and more that there are these individual uh variances in people's tolerance and the way that they are affected by caffeine and you mentioned that there's there's could it's either

going to be environment or genetics or the confluence of these two a lot of hype gets put on the genetic piece of it i've had a genetic test i know that i'm a slow metabolizer so i shouldn't be drinking caffeine in the afternoon which i still like to do but but a lot of people are going to be familiar with just getting an over-the-counter direct-to-consumer genetic test that can that can determine this before we dive into that like paint the whole landscape in as briefly as you can of this individual variability in terms of how caffeine affects people sure uh well there's the genetic component of course but i'll i'll just list uh a few other areas to consider that is the training status uh so the research is mixed but that may play a role whether you're a trained athlete or not as well trained um if you're caffeine naive meaning you don't use caffeine regularly you may have a greater response but on the flip side being a frequent user doesn't necessarily impair that enhancement so i think the research is really leaning toward the size the side that uh habitual users can get just as much of an effect uh so i don't think we have to worry and i certainly would not advise that someone take uh and i get this question all the time should i take a week or two or a month off caffeine in order for uh during

my uh competitive phase or you know in season to get the most benefit well you may lose out on some important training uh adaptations in that two three four week period so certainly if caffeine is something that's benefiting you in in training and in competition you really don't want to give up those weeks of not having as as a high of a quality of training session um you we also need to consider and this is related to genetics some individuals have a greater withdrawal effect than others so we see uh through through research that have been associated to to certain genes as well we haven't done uh necessarily interventions on this but we do know with questionnaires that some uh can skip three days of using caffeine and they're fine they can oh i'll have a coffee this morning i won't have a coffee for the next three mornings doesn't really affect me too much others can have severe migraines severe severe fatigue uh so when we look at research where they've only abstained from caffeine for 24 hours that's where we we may not uh see that true performance enhancement and maybe falsely we think there was a benefit only because it's bringing them out of that withdrawal so if i'm feeling awful and tired because i'm having this withdrawal effect and you give me some caffeine i might perform better but it wasn't really better uh you know due to the caffeine it just brought me out of withdrawal so that's

something to consider that's something that used to be de facto practice and you remember this where we used to take people off of caffeine before their critical event or whatever and we ended up screwing them up more than more than actually helping them that's why i that's why i do not advocate for that for that uh to to for athletes to abstain for from caffeine for the one to two weeks before an event because it typically has more negative effects or it can have more negative effects than positive effects at the end of the day i'm really glad that you mentioned that yeah no for sure we don't we don't want to uh sort of get someone um yeah sort of off their their program uh mentally and physically and uh especially when we're dealing with something that is a psychoactive substance and uh we we want to keep the mind the mind clear and focused and so i don't advise changing up much of anything in your in your few weeks before your event uh including diet i mean if you taper down your training uh your your glycogen is obviously going to be uh at a higher level if you're not expending as much but otherwise you sort of don't want to rock the boat um so now when it comes to genetics uh so when i began uh my research uh i guess we're looking at eight years ago now when i started my PhD the the first study that did look at genetic uh differences was uh uh christopher womack um and he did find that when looking at one gene uh the

cip1a2 gene which is part of the the p450 uh uh enzyme uh sort of uh pathway within your liver that detoxes uh various substances including caffeine so this identifies an individual as a fast metabolor metabolizer of caffeine they break it down quickly or a uh slow metabolizer and then we do see a third genotype which is what we label as an ultra slow metabolizer now most studies combine those slow metabolizers so they're not seeing perhaps a true effect of the ultra slow individuals which is what my study did i did find that there was a difference in performance between the uh fast metabolizers or a a genotype the heterozygotes really had not much of an effect some had a small improvement some had a a small impairment but then it was that third group uh unfortunately only eight participants so i only had eight athletes with that genotype which is typical of the frequency we see in the population is around 10 percent uh but i had uh over a hundred athletes yet only eight of the athletes were of that ultra slow metabolizing genotype so that really is not uh allowing us to uh conclude much it it needed to be replicated but unfortunately the studies that have come after uh have uh some of them have shown that the fast

metabolizers are i think in all but one study do appear to perform the same or better so it's always been those fast metabolizers that are likely getting more of an ergogenic benefit now when those groups are combined uh and we don't see that there's an impairment to me uh it's those uh smaller studies where maybe there's only one uh ultra slow metabolizer one or two and so we don't have enough of a sample size to to replicate what i found uh so i think what we do need is a study where we have uh 50 perhaps in each genotype we need a larger sample size in that ultra slow metabolizing group now we have uh there was a recent study showing with a a caffeine uh mouth rinse that uh out of 10 subjects that they recruited nine of them were actually in this ultra slow genotype which is interesting and one was a heterozygote and so just a regular slow not ultra slow and this is a group out of brazil and uh so i've asked the authors of course are you sure you found nine metabolizers be or ultra slow because that's not the usual but they're they're certainly did it could be the the ethnic background uh in that population but they did not have uh a benefit from this caffeine mouth rinse uh so so so i would i would say that we're we definitely can't conclude for sure we know there are differences

uh but certainly what i advise to athletes is that if you are a fast metabolizer and you want to perform better in your sport i would advise that you do try caffeine now if you are a slow metabolizer either the moderately slow or ultra slow i would monitor your performance and i would try uh some workouts or some races i mean of course try try it in training uh without caffeine and see how you do and i do have a couple of anecdotes of course and i did have one runner that had uh had been a runner 10k runner for over probably 12 15 years and had always used caffeine his genotype was that ultra slow metabolizer and i said you know what just try some runs without caffeine see how it goes he was convinced that that's you know he was not going to perform better so he ended up doing 10 runs without caffeine because each time he was surprised uh that he was actually performing the same then two out of those 10 actually were a personal best for him and so he couldn't believe it because he didn't have that and this brings us to another point he didn't have that sort of mental uh jacked up beast mode which i see also in some of my unpublished unpublished research that just because you're feeling mentally jacked up uh it doesn't mean that that you're going to perform better so there can be a

mismatch there because in my rct uh some athletes that said they they felt jittery but they also felt more energetic uh that they actually performed better on the placebo trial and in the cycling time trial than on the the caffeinated trials so what that tells us is that even though you're feeling stimulated you're feeling more energetic it that does not necessarily translate into better physical performance right but perhaps if you need to be awake but not physically acting so if it's purely a cognitive setting uh you know maybe the our recommendations will differ um so that's one aspect of uh so the simp weight 1a2 gene we also have the adora gene and that um so i i have a paper that will be published shortly uh looking at at this gene and um i am not seeing um a benefit with with this gene as far as endurance performance and we've sort of we've we've seen mixed uh results in the literature in in some other studies including one out of out of our lab with with strength and uh power uh that there there may be um an effect with the sip 1a2 gene but not necessarily with that with the adora gene but what this adora gene is showing as that is performance related is the risk of experiencing feelings of anxiety so we have the

the three genotypes so this adora gene uh stands for uh adenosine so it's a it's uh the adenosine receptor gene so the gene that's encoding the activity of that adenosine receptor and remember that's what caffeine blocks to give you that stimulating effect so we do see that some individuals the tt genotype for those that are uh interested in the exact genetics uh that they have a higher risk of feelings of anxiety and this you can maybe override and still have a performance benefit but for many athletes this anxiety may hamper their performance and certainly when we uh have sports where you need to be focused uh concentrating like going for 24 hours or like shooting in the biathlon yeah yeah things like that so the jittery or anxious and then we have those that are associated with uh greater sleep disturbances and so that's actually a study i would my colleague amy bender and i would like to do is to see what uh athletes and of course important for the military who is well equipped to handle sleep deprivation and get the rescue from caffeine and who is actually uh possibly dangerous without sleep and the caffeine is not rescuing that stable cognitive uh you know headspace to make the right decisions and and then that is going to translate to athletes i and i and she always argues because she's a sleep

scientist sleep is the ergogenic aid getting their sleep is important and you know i was on the caffeine side but i'm not really i mean i'm interested in the truth and the best for our athletes um but i just want to add one quick thing about sleep is that many athletes or individuals will have caffeine later in the day and say i have no problem falling asleep you know uh and that's fine but when we look at studies where we do the ec uh the the ecgs or the eccs is the eggs um just looking at the uh uh activity in the brain um that yeah it must be ecg uh but there's a few of them i know it's not emg no that's the muscle uh but looking into the brain that they are actually not uh reaching that restorative sleep so the death of sleep to the same degree and that's really important for glycogen resynthesis muscle repair immunity uh so we have many factors that are uh or many areas that are impaired with with not having this restorative sleep so even if you felt like you didn't wake up caffeine is still negatively impacting your sleep and uh so so that's an important factor too of taking it too close to bedtime yeah once again this is going back to the original or back to some of the initial part of the conversation is i feel that caffeine in the traditional ergogenic sense where you're using it before a workout can be a one up one down

or maybe one up two down or the workout's a little bit better but the sleep is worse and sometimes the sleep being worse either counteracts the effect of the of caffeine or is even counteracts it to a greater extent yeah um your adaptations uh you know not not over time you're not getting uh stronger perhaps you're not uh uh building uh more mitochondria right uh you know you're not getting that mitochondrial biogenesis which is what we actually use caffeine for in fasted training and we try and rescue those uh training sessions using caffeine without the fuel substrate in order to increase the mitochondrial biogenesis and that's that approach of glycogen depleted training and perhaps the caffeine is not allowing you to have those adaptations because the research is mixed and that could be one aspect that has not been controlled for so many rabbit holes okay you mentioned the fast metabolizers the slow metabolizers and the older slow metabolizers for the cyp12a gene yeah roughly what percentage of the population is going to fall into those categories yeah great question 50 are fast metabolizers 40 are slow but the slow heterozygotes about 10 are the ultra slow so i would say with the heterozygotes we still see some that are improving now this could be the result of

another gene i did uh we published a paper on the htr uh 2a gene which is uh serotonin uh receptor activity so that was uh showing that if you're a fast metabolizer having the cc genotype of this additional gene uh sort of sort of reinforce the fact that you're likely to benefit uh so i think that you why i say monitor is that there's not only one gene involved we have multiple genes that could be working together interacting counteracting each other so with those heterozygotes i would say that still many of them will still improve performance and so i don't think it's just 50 percent of people out there that will have an improvement um and if if we look at sort of my raw numbers of individuals at that four milligram dose 58 did better on the caffeine trial uh 10 had really no change and about 33 worsened so um i i would say as a generalization uh what i see in the endurance in my experience and in the the literature probably about uh you know you probably have about a 75 chance of having a benefit of caffeine as an endurance athlete uh you know considering your your your if you didn't know your genotype so there could be that 25 that's not getting much of a benefit or possibly an impairment but but um yeah but so so if we look at being a fast metabolizer or

20 of the heterozygotes we have 50 plus 20 of your 70 percent so so the genes aren't automatically going to screw you if you're a slow metabolizer or an ultra slow metabolizer i think i think the listeners can take away two things from this one if you have had a genetic test we're going to talk about in a second and you know that you're a slow metabolizer or an ultra slow metabolizer you still you still could have some positive ergogenic effect from caffeine and you're going to have to trial it because it's a multi-factorial type of drug the second thing and i have to mention this with our audience is if you are in the slow or in the ultra slow category or you think you're in the slow metabolizing or the ultra slow metabolizing category that doesn't give you permission to take more more is not the answer here right nancy yeah yeah absolutely if there's something that i would suggest playing around with it would be taking it sooner so perhaps take it 90 minutes before you start your run or your race and uh that those are studies that need to be done i think uh we don't have enough research on the timing so how much beforehand uh how much during i think we really need to to sink our research teeth into that and see what are the differences with taking a uh a small dose a uh 90 minutes before and then another top up dose maybe just before uh in the middle of training as we discussed

so i i think what happens in research is because the methods are done one way we give six milligrams per kilogram of body mass 60 minutes before the start of this exercise testing and almost every research group tends to do that uh so in my study we had different timing because the exercise tests i did four four strength power anaerobic the wind gate and the endurance cycling time trial so uh some of them started at 30 minutes 40 minutes the cycling time trial started around 60 minutes uh but we also had um so not only the timing uh beforehand um but that we need to consider but the amounts at each of those intervals have have not been um i i don't think research consistently or or enough i'm almost feeling like this is following the carbohydrate path right where first we add in layers of okay we know this is the general range of carbohydrate for an endurance athlete this is the range of carbohydrate intake we need to target for any endurance athlete here's what we need to do for an endurance activity that's higher intensity here's what we need to do for lower intensity here's what we need to do for this type of person for that type of person i almost feel like caffeine's kind of following that same maybe like five or seven years behind that same kind of pathway where every few years we start to get a little bit more tailored and tailored recommendations yeah yeah i agree and and we do know with the

multiple transporters that was uh quite a uh you know sort of some of those landmark papers just recognizing and that is also genetics because we have the genes that are encoding those glute uh two receptors and you may have a a max capacity of how much glucose you can absorb and having that if you have a low cap a low ceiling there you would be an individual who may benefit by having more fructose or galactose or uh so so so that's also where where genes can play a role there so i think um i guess the exciting part of research and not so much for athletes that want to know now exactly what to do is there's no shortage of things to examine and investigate and we're learning more with time and uh but but i think one thing that's consistent in our learning journey is that there are many factors uh multiple layers of that individualization uh multiple layers of that individualization and uh we there are there are often questions that are not being asked of athletes that i think uh is important and just as a a quick example i see a lot of team sports uh use caffeine in a way where somebody comes with the bottle and each rugby player or basketball player gets their tablets and

there's there's not only the fact that it might not sit well with some athletes but also the fact that there's a little bit of this uh club this peer pressure and you know somebody says no i'm not going to take any um you know i see i see that also with my org ordering plant-based meals or vegan meals if you're not eating you know the the chicken or the uh the chicken wings or the ordering the steak as part of a male team uh you know it's risky it's risky of being ostracized and i i think we need to sit down with our athletes and say what you know what are your barriers how are you feeling how are you sleeping and i think that's that's going to be our path to success that's the path to gold is to to consider um perceived and real barriers and and that heart to heart i i can't emphasize enough of sitting down with an individual and you know looking them at the eye and saying let's make you the best you and how are we going to do this together as a team nancy i've had the exact same experience in consulting with some of the league sports teams where you walk in and they have the exact same prescription laid out for the entire team you're using the recommendation of of caffeine but we've had it in other particularly nutrition for whatever reason uh elements and i've always looked at the coach or the trainer whoever's prescribing that and going okay would you tell everybody here to bench press 250 pounds yeah would you tell them

all to squat 300 pounds every single person on the whole team no of course you wouldn't do that so why are you doing that with this one recommendation and and finally for whatever reason that kind of like makes the makes makes the connection so needless to say with that one of the things that you harped on is it's not just genetics and these direct to consumer genetic tests are really prevalent right now um you can you can get them you can get them everywhere you get them sent to your house you spit in it or you provide a small little droplet of blood you send it back and you get this whole portfolio of things depending upon the the test that you're actually getting one of them and it inevitably is going to be this most of them are just dividing it into fast metabolizer slow metabolizer at least as far as i've seen has that been your experience as well on the caffeine side yes yeah they're not making the the third category the third category but yeah i want to get your general thought on that and you've already gone through the fact that that's just one part of the equation but how useful can things like that be to tailor something like caffeine dose for for an individual if they're out there and they don't really kind of know they can't get a sense of you know how they feel on different dosages and things like that is that a reasonable option to try to to try to like narrow down these broad recommendations to an individual uh by doing a genetic test yeah you mean yeah um i think uh one way that that definitely is helpful

is it is increasing awareness so an athlete that is going to go uh out there and buy a test and read the results and and uh sort of take note of how they're feeling and what the test says uh i i think that that uh in itself is a good thing just like we say when individuals journal food uh they they are having greater awareness of what they're eating or anyone who starts a diet whether it's uh the appropriate diet for them at least they have greater greater awareness of what they're ingesting now i i would say that we have to be careful of some of the direct to consumer tests out there because some of the interpretations are not correct uh such as caffeine sensitivity and the markers they're using for that we don't really um have a uh we don't have a test for caffeine sensitivity in that term there isn't sort of a scientific definition for that so we want to make sure they using the gene that is associated with anxiety or is it a sleep disturbance and we actually don't know uh it's not consistent what genotype it increases the risk of sleep disturbances even though we have one uh the adora gene which does look at look at that uh but we see that one study is sort of different from the other three so i don't i think we need more research in that area um so i the direct to consumer tests uh

me disclaimer i do work for a genetic testing company i'm on the scientific advisory board of nutrigenomics based in toronto so that's with an x the company name that um we we we really are about the science and that's all the lab does this this testing company is is partnered with the university of toronto but what i do see is in some of these direct to consumer is that they're interpreting even science that we've published they're interpreting it incorrectly so giving the wrong advice so i believe that going through a health care practitioner and that's what we do with this company but there's other companies out there i would have that accountability uh that is resulting from you having to answer to the dietitian nutritionist whoever is uh collecting your saliva sample uh doing the test and going through the results with you because i think uh it's easily to miss it's easy to misunderstand yeah uh the the results so i'm 100 with you nancy here's my experience on that just from the listener's perspective and i i don't mind mentioning this at all so we we had a product on helix's marketplace um so helix works for the listeners that aren't familiar with all these direct to consumer tests helix kind of works like the app store where people can come in and kind of plug and play their their different genetic things that they're pulling out of one sequence so helix the

company will send somebody a test they'll get sequenced and they'll do anything from like here's the type of wine that you're supposed to like to you know we had a health and fitness product on there and things like that and i actually wrote the guidelines for what we call endurance dna which is kind of specifically tailored for endurance athletes we worked with the scientific advisory board on you know on helix aside hey you can write this you can't write this and things like that i had to water it down me this is me writing it i had to water it down so much i didn't like what i was presenting in either case a because it was too watered down and then b because i didn't feel like it you know provided any sort of value to the consumers so at the end of the day what i decided is we would rather pair it with a consultation with a coach who can actually look through it all in context with the in context with the training in order to really provide some valuable insights so as not to kind of like bastardize the research that's been done and create a really slick product now the caveat to that is is boring right i mean it's a boring product because you can't say oh well you've got the blue gene so you need to freaking lift weights or whatever it is everybody wants that like super simple answer yeah and i i take issue with some of those recommendations because uh there are too many variables and i don't i think it's really a disservice to the athlete and what i say in giving lectures is uh your coach knows best how you should train uh compared to the current direct-to-consumer genetic test

uh currently available in the marketplace so trust your coach trust your own intuition and don't start lifting heavier or doing more cardio because of a test i i think you can that can be some layer of information but you don't want it to be the end-all be-all it's it's you want to take information from a variety of sources so perhaps your genetics your blood work your diet your coach your yourself yeah you know that you know especially with runners you can feel a lot if you tune in dial in to your own intuition i i think is underrated yeah so the way that i've always the way that i've always presented it is it can shade the prescription not should shade the prescription it can shade the prescription because i've had once again personal experience this is another rabbit hole we're going to be on on my hair for four hours nancy oh i've had the i've had the experience where i've had an athlete really good athlete really successful athlete have a genetic test get the results back and had i known those results and followed what i was supposed to do based off of the test i would have done something completely different yet i still did something different and athlete was really really really not just one but several athletes really successful so i always throw out those like little shades of caution when these things kind of come back because like you said from the onset it's genetics and environment

environment that impact you and your genes aren't necessarily 100 of your destiny yeah and also that we have um so many genes uh i mean we there are millions of variations i mean you and i can differ in hundreds of thousands of areas yet we're both human beings and it's it's amazing that one letter that shows if you're a faster slow metabolizer of caffeine also one letter can determine if your hair is brown or blonde or if your eyes are blue or brown so i don't think we should uh dismiss uh some of these single uh nucleotide polymorphisms or snips when it's just one one variant of one gene uh but for most outcomes if you look at vo2 max or strength or uh the ability to put on muscle mass all of these involve thousands of genes so looking at one is not going to give us a complete answer and if you think of looking at a genetic test and say hey you know what that may influence my outcome or my training by one percent but i can't forget that there's another 99 that i should be addressing at the same time or perhaps uh more importantly because i have better control over it um so i i think if if you could uh you know understand 50 of your genes and you think of all of them put together maybe can impact your

performance or you know predict some somewhat of your your future ability by five percent sure use that guidance but it's also like supplements you know you you want to work with your your foundation don't work with the supplement that might give you point five percent improvement you know unless you're deficient some of these supplements or micronutrients are not going to make or break you it's are you hydrated are you getting enough carbohydrates you know start with those things that aren't as sexy but that that's how we build an athlete is is going from the foundation up you know and then we add the sprinkles on the ends too many rabbit holes i know we'll bring you back on again it was awesome it took us a long time just to get this first one off the ground maybe like three years from now we'll have another one when we can travel i'll come up to toronto and we'll do it well you know what i would love to talk about is uh plant-based nutrition so that is my my new passion and i would love to help runners uh learn more about how they can eat more plant-based or uh vegans uh be vegan on disclaimer i am vegan but i'm also a messenger of the research and i'm i'm doing a bit of research in this area now and i i think it's really important um especially for those that are feeling uh concerns for the treatment of animals the environment and many that feel uh that uh for their mental health they want to make this switch

and how can we do that and still have them perform optimally um because it's you know it's not just about your physical health and and you know the macronutrients but it's overall your philosophy for life and what really plays a big role in that is is how you are eating and interacting with with the planet and with others and so so i think this is an area of extreme growth in the next several years and and i'm really excited to be uh part of um helping with that direction of those that that want to still be able to perform their best and we have some exciting research coming out all right well there you go open invitation you get to come back on and talk about that that was my very first podcast by the way i don't know if you knew that we had uh vegans versus the omnivores or something like that it was right around the game changers and i was totally taking advantage of all the hype you know how that goes yeah the game changers that's something yeah dismantling that but i there's two sides to that story totally absolutely totally i mean i i am shocked of the amount of people that came out of the the woodwork to slam that movie and it's like relax no one is gonna take away your steak you know it was just the whoa that was uh i i mean never in history i don't think if we had so many athletes come to their coaches sports nutritionists and say oh my gosh you know should i go vegan or what am i missing and and that that really caused some some major waves some tsunamis i would say it was an interesting

catalyst i i totally get you because it had the right come it had the right combination of timing really slick production an intriguing storyline as and it polarized kind of both sides of the argument and i think in an equal and opposing fashion and it elevated the stature of the movie because of that well all of which was intentional i mean a hollywood people behind it they know how to push people's buttons but yeah we'll bring you back on nancy absolutely 100 we'll talk about it um really quick tell people where they can find you and particularly your twitter handle because you were an awesome twitter follow oh thanks jason you're really okay yeah so my twitter is uh is uh nancy with an i guest uh rd PhD i believe is what it is so so nancy guest rd PhD and nancy with an i um yeah there i want to do more on instagram it's a matter of time uh so i'm i'm not uh too active uh i i will uh more so on instagram and i want to try and add more science to to instagram but certainly on on twitter and i do uh interact with a lot of people the one thing i do like about twitter is that you can have discussions and you can have multiple conversations and i think that's really important to have some of this important scientific discourse and to have disagreements and opinions and talk about a study

and you just can't have those same kind of discussions on instagram and the same number of people uh participating so and i do answer questions if someone responds to one of my tweets i do my best to answer everybody so that's also a way of capturing me uh um you know and asking questions go follow nancy on twitter you won't be disappointed she does engage thank you yeah you do engage very well nancy you do it in a respectful and intriguing way one that's entertaining as well i always appreciate it i i lurk way more than i comment just because it's fun but anyway go give nancy a follow anything else you want to plug nancy before we go uh no i you know i just um well one you know i hope the olympics is a success um my heart really goes out to athletes that i have been training for tokyo and and what's happened uh but everyone you know be safe out there and and things are going to get better and um yeah we're just i i think if you look at the roaring 20s after the spanish flu of course and in um 1918 i think we're really in for a lot of activity out there a lot of events and i think we have a lot to be excited about and certainly that's going to happen in the sport community so people just hang in there and uh and a lot will be happening so so take this time to listen to your podcast because otherwise you're going to be out in the world you know doing stuff perfect yeah okay thanks jason we'll

talk again thanks nancy appreciate it okay take care bye bye all right folks there you have it there you go nancy we will absolutely take you back up on the offer to come back on the podcast and talk all about plant-based nutrition i know it's something that you're really passionate about listeners go follow nancy on twitter it is worth your time it is really fun and i guarantee you you will learn something along the way thank you nancy for coming on on the podcast today i appreciate it the listeners appreciate it as well i appreciate the heck out of each and every one of the listeners thank you guys you are what really makes this podcast that's it for now people as always we will see you out on the trails