In Episode 70 of The Athletes Compass, hosts Paul Warloski, Dr. Paul Laursen, and Marjaana Rakai bust major endurance training myths with science-backed insights. From the ineffectiveness of sodium supplementation during exercise to the power of maintaining blood glucose over muscle glycogen, this episode is packed with paradigm-shifting ideas. They also explore fasted training, metabolic flexibility, and why fat is the endurance athlete’s forever fuel. Listeners get a masterclass in power profiling, testing methodologies, and how to optimize training for individual physiology. It’s endurance science with a practical edge.
Key Takeaways
- Sodium During Exercise Is Overrated: No scientific evidence supports sodium supplementation during exercise to prevent cramps, dehydration, or improve performance.
- Power Profile Testing > Ramp Tests: The Athletica power profile provides broader insight into an athlete’s anaerobic and aerobic capacities.
- Short Intervals for Twitchy Athletes: Short VO2 max intervals are more effective for sprinter-type athletes than long intervals.
- Critical Power Curve Guides Training Zones: Accurate power profiling helps set effective training zones for peak performance.
- Blood Glucose Trumps Muscle Glycogen: New research shows maintaining blood glucose may be more critical for endurance than glycogen stores.
- Fasted Training Builds Fat Adaptation: With consistency, athletes can train the body to become metabolically flexible and use fat efficiently.
- Insulin Regulates Fat Usage: Lower insulin levels from low-carb diets promote fat burning and intramuscular fat storage.
- Fat Is a Superior Long-Term Fuel: At 9 kcal/g, fat provides longer-lasting energy than carbohydrates.
- Paul Warloski - Endurance, Strength Training, Yoga
- Marjaana Rakai - Tired Mom Runs - Where fitness meets motherhood.
Transcript
So here's another huge myth, and that's that you need to take in sodium during exercise.
again, credit to the author that's really led the charge in this one on that is Martin Hoffman, Dr. Martin Hoffman,
there is zero evidence that ingesting sodium during exercise, like sodium pills, electrolyte tabs, it does really anything with the exception of making you feel thirsty so you might drink a bit more.
Paul Warloski (:Hello and welcome to the Athletes Compass podcast where we navigate training, fitness and health for everyday athletes. Today's episode is all about listener questions in mind too. And we've got some really good ones from power testing strategies to sodium intake trends, muscle glycogen studies and fasted training. We're diving into the science and practical applications behind these key endurance topics. So let's start off with power testing.
Paul and Marjaana, one of my athletes has done the power profile test that is based on the Athletica test a couple of times. He puts out a lot of power in the short tests, but has been unable to complete the four and 10 minute tests. I'm guessing that he has a high anaerobic capacity and perhaps he's starting with too much power in the long tests. What do you think could be some factors that might cause this?
Paul Laursen (:Yeah, so let's just be clear. So if anyone wants a little bit more context, and they want to try this test, this is on Velocity. So you can come to Velocity and do this test. Or it's been pre-recorded there. This is also, if you do any of the cycling training programs, you will have a cycling power profile. And if this isn't there on your profile, you could create a cycling
train to maintain or cycling event that you want to target and you will get this test. And you can just always save that to your library. So what Paul is kind of alluding to is with the Power Profile is you're really trying to kind of draw what your capacities are on your charts for your cycling power profile or power outputs. That is, what can you do for your sprints, real short?
Marjaana Rakai (:cycle power per pump, power outputs. That is, what can you do from your sprints, real
short, what can you do sort of in the mid-range, and what can you do in terms of your aerobic endurance capacity.
Paul Laursen (:What can you do sort of in the mid-range and what can you do in terms of your more your aerobic endurance capacities?
Now Paul was telling us here that you know, he's got an athlete that's really almost kind of we'd say twitchy You know sort of sprint Good sprint ability goes all in on those sprints gets really solid scores But dies pretty solid in the four minutes, which is around your vo2 max
targets your VO2 max and the 10 minutes, which is more threshold or FTP critical power kind of markers. yeah, ultimately Paul, if the four and the 10 minutes aren't good, then we're showing deficiencies in that domain at the end of the day. there's two reasons. So one, as we mentioned with the,
Paul Warloski (:Yeah.
Paul Laursen (:this athlete is clearly a, they've got good sprint abilities, but they need to work on their endurance abilities. And if they do more endurance work, things like VO2 max work, things like zone two work, we will see improvements in those, both the four minutes and the 10 minute efforts. Yeah, because training works. I think we know that.
Marjaana Rakai (:If he's a twitchy athlete, would you do VO2 max long or short intervals?
Paul Laursen (:definitely short. So the short intervals are going to improve, which is totally actually what you wouldn't think, right? You'd think, why wouldn't you train what you're not good at? And sure, could go and do that, right? Like, so for example, if you're bad at four minutes, why wouldn't you do repeated four-minute VO2 max efforts? Right? You'd think that, but that's actually
Paul Warloski (:Okay.
Paul Laursen (:not the fastest road to Rome. And we know that because we know the short interval is kind of superior for the twitchy athlete. And that's because when we take these more repeated, quicker recoveries, we learned about this before, the myoglobin resaturates. The myoglobin is like the hemoglobin of your muscles and it quickly resaturates. In other words, quickly slurps up more oxygen and it keeps the overall lactate profile.
that whole session lower. When lactate is lower, that's less demand on the central nervous system, specifically the sympathetic nervous system. So you don't get as stressed in the whole thing. it's just, we've discovered for more twitchy kind of athletes, it's a better road to Rome. They tolerate these better. This has specifically been shown in the team sports area where
And again, I credit my colleague Martin Besheit, who's really sort of been the pioneer in this. And he uses this across team sports to optimize the tolerance ultimately of this type of work a lot better and gets a lot improved results. So I would guess that this is a twitchy athlete, MJ, and I would guess that this athlete would respond better in terms of their VO2 max work to the 30-30 sort of type of session.
like you lead on velocity. Compared with if this was a diesel type of athlete that could just munch up those long intervals for breakfast, we would then give them the long interval, but not for Paul's athlete that he's describing to me.
Paul Warloski (:Why do we use the power profile test on Athletica and not a ramp test, which is that gradual increase in power over time to build to a maximum effort? What are the pros and cons of the testing?
Paul Laursen (:Yeah, so in the RAMP case, you're really only going to get your threshold and your VO2 max in that. With the power profile, we're actually getting more of these, the anaerobic, we would call them anaerobic, or peak capacity kind of, you're describing that in the individual. You just don't see that in the VO2 max type.
Marjaana Rakai (:Yeah. So in the RAM case, you just really won't. You're really only going to get your threshold and your view to that.
Paul Laursen (:type work because you can't get very, very high because you're fatigued ultimately before it's time to push really hard towards the end. yeah, just, it's a better, it's kind of, you're doing reverse in this way, right? In the VIA2Max work, you're going from sort of easy to a hard. In this one, you're going from hard to easy. You will never see the peak capacities if you just do a VIA2Max test.
because they're always, they're blunted in the aerobic work. You're already fatigued.
Marjaana Rakai (:And with the VO2 max test, you mean the ramp test, right? Yeah. So increasing.
Paul Laursen (:That's right, yeah, yeah, the ramp test. So going from easy,
so yeah, so what is a ramp test? A ramp test would you'd start at maybe 50 watts or 100 watts, do that for like three minutes, three to five minutes, then go up another 30 watts and go up, you know, or, and there's lots of different sort of ways to do that. But yeah, you just, you're going easy to hard.
Marjaana Rakai (:Mm-hmm.
But in
your lab, you would do lactate tests and have a metabolic cart. So you would get a lot more data points as you ramp up the intensity. But a lot of these platforms have ramp tests that are just based on power, right? So you only get one data point in increasing
Paul Laursen (:huh.
Marjaana Rakai (:effort levels, right?
Paul Laursen (:Yes, yes.
Yeah, I wasn't aware. I wasn't even actually aware of that. Like it doesn't, doesn't make too much sense just to do a, ramp test without measuring gas and lactate. So, but those exists though, do they?
Marjaana Rakai (:Yeah.
Paul Warloski (:Hmm.
Marjaana Rakai (:So, Swift have one, TrainerRoad, all of them have like this ramp test and they try to estimate FTP or a threshold using the ramp test. And I think it's based on 75 % of the last stage. Last minute. look at your...
Paul Laursen (:Hmm.
Paul Warloski (:The last minute, yes. Yep, over the last chunk.
Marjaana Rakai (:If you look at your athlete who you suspect he's got high anaerobic capacity, using the ramp test then would probably overestimate his 20 minute power or sustainable power, right?
Paul Laursen (:That's a good question. I think it would depend on the ramp, right? So I'm sensing that this individual, don't sound like they're too... Yeah, like if it's a fast ramp, like if you're ramping up, 30 watts every one minute, then it's probably going to overestimate it. Conversely, if the ramp test is doing a slow ramp test,
Marjaana Rakai (:Mm-hmm.
Mm-hmm.
Paul Laursen (:and we're doing like 50 watts every five minutes, it would probably underestimate it because it would be, the individual wouldn't have the capacity to go very high. Well, actually it would probably be more accurate. It would be, because it'd be pretty, the individual would get a low score which the individual should get. So, yeah.
Marjaana Rakai (:Mm-hmm.
Long time.
Mm-hmm.
And if you...
Paul Warloski (:Yeah, I definitely noticed in several
other of my athletes who are sprinter types that the short ramp would tend to do exactly what Marjaana just said is it overestimated their FTP.
Paul Laursen (:Yeah. So what we, and just to be clear, what we do in Athletica is we do a, on, we do invisible monitoring based on all of your data. And we use models to estimate your critical power and your ability across sprint efforts, VO2 max efforts, two to five minutes, and long duration work, critical power out to like from two minutes to 60 minutes.
Marjaana Rakai (:Yeah, I've seen that too.
Paul Laursen (:and using a critical and power model and then an omnipower model thereafter as well. So, yeah, we do modeling across all your work, invisible as well. And then this critical power test that we let off with is sort of almost like the litmus test. like, okay, let's sort of, and it's especially useful when you first enter into Athletica to sort of see where these sorts of things are sitting.
I will say, I'll give the limitation of the critical power test that we just spoke about is that just to Paul's point, it's like some of these previous efforts do sabotage subsequent efforts, right? They take a toll, they take a taxing on your abilities in those ones. A true critical power test...
is when you just go and do one all out effort in any of the different domains across. And say you would do like three, for example, you might do like one for, you know, 30 seconds or a minute, right? And that would just be all out. Then you might do another one like just for three minutes. And then you might do another one just for 20 minutes. And these are on completely separate days every time I'm talking about this, right? Fully rested so that all of your effort is just into that one. That's truly your ability across that.
that duration for whatever power you can produce. That is the perfect kind of critical power. This is sort of a quick and dirty, you know, quick and dirty measure of what that power curve is kind of looking at. Why is this important? Why are we even caring about this and bothering? Well, it's all gonna go back to your zones, right? Your zones are prescribed based on what the critical power curve and critical speed curve
Marjaana Rakai (:The results are prescribed based on...
Paul Laursen (:if you are the runner looks like. So that's why it's important. That's why it's important to test. And that's why it's important to get these efforts every once in a while.
Marjaana Rakai (:I would argue that the critical power test, like how we do it is more real world than, you know, do it proper physiological testing, like every few days when you're completely rested. Because when do we ever train fully rested? Never.
Paul Laursen (:Hmm.
Marjaana Rakai (:Right. And then in a race situation too, like if you're, if you're doing, you know, cycling, you will be doing some hard sprints after, you know, how many hours of riding. So.
Paul Laursen (:Yeah, well, and I should also, you we didn't even really start with the origin of the Critical Power Test that we use. Well, this was done by my PhD student genius, Mark Quad, with supervisors, Dr. David Martin and Dr. Jim Martin. So credit to all of those guys. And this has been used within the team Oracle GreenEdge, Garmin Slipstream, and many, many others. So this is sort of where that test or,
originated and it's used in the best of the best. So yeah, it's probably good enough for us to use also.
Marjaana Rakai (:I'd say so.
Paul Warloski (:Marjaana do you want to take the second question? Yes.
Marjaana Rakai (:From Jack.
With the recent look at the high carb trend, would it be possible to have a zoomed in look at the other race day considerations of sodium slash electrolytes? There is also a push for high sodium intake over a hundred, no, over a thousand milligrams per hour without consideration for the trace electrolytes. And I'm wondering if the science backs this up.
versus the generally conservative traditional approach of slow sodium to guard against gut issues and a focus on wide range of electrolytes.
Also, look at other electrolyte trends, isotonic hydrogel compounds, sugar replacement inclusions to stimulate similar responses to carb intake in the brain. Over to you, Prof.
Paul Warloski (:Yeah.
Paul Laursen (:boy, it's just a myth-busting couple episodes here lately, isn't it? So here's another huge myth, and that's that you need to take in sodium during exercise. again, credit to the author that's really led the charge in this one on that is Martin Hoffman, Dr. Martin Hoffman, and he's published many, many a work on this.
I've been fortunate to be a co-author on a number of these, so learn from the experts. But there is zero evidence that ingesting sodium during exercise, like sodium pills, electrolyte tabs, it does really anything with the exception of making you feel thirsty so you might drink a bit more. But it basically like, you know, it makes you more hypertonic. It makes you more, you know, it adds kind of like
to the concentration of sodium that's really just only in your stomach. And yeah, there's nothing there that really suggests that it benefits performance. It's never been shown to improve performance. It's never been shown to prevent muscle cramping. It's never been shown to prevent dehydration. It's never been shown to prevent hyponatremia.
never been shown to lower levels of nausea. And one of the key studies was one that Professor Hoffman did at the Badwater Ultramarathon race, where he looked ultimately at across individuals that were supplementing versus not, sort of not supplementing. And there was no difference in the groups that were supplementing.
with very high levels of sodium intake, on average 13 grams. That's like just massive amounts. The body, the body, and you know, so we should all, we should go back to some physiology. Why wouldn't this be the case, right? Surely, you know, I'm looking at all of these athletes and they've got, they're caked in sodium. They're totally losing all of that salt. My goodness.
Surely they've got to replace it, right? Okay. Well, I agree. That's what it looks like. They are losing a lot of sodium. The cool thing about that whole process is that with physiology, everything's always doing something for a reason. So we kind of have to go back and learn about the story of the eccrine sweat gland. So the eccrine means it's like an organ in our body, the sweat gland, and its job is to
again, regulate homeostasis. And what's happening ultimately is that the body is sensing there's too much sodium in the bloodstream and we need to get rid of some sodium. So the reason why you're caked in salt and your clothes in these hot races and such is that the body doesn't want to feel thirsty like that. It's trying to kind of regulate things. So it pushes out
Paul Warloski (:you
Paul Laursen (:Basically, if you've got bunch of sodium all over your clothes, the only conclusion you can come to at that point is that you've got more sodium than you actually need in your bloodstream and your body's doing something about that. It's trying to regulate that.
Paul Warloski (:Hmm.
Marjaana Rakai (:So the marketing message has been if you see white stains on your clothing after a workout, that means that you're a heavy sweater and you're losing too much sodium in your sweat and therefore you need to
replace that sodium while you exercise. that I think that's what he's Jackie's referring to. but you're saying yes. Yeah. That's the marketing. So
Paul Laursen (:Yeah, that's marketing though, right? Like that's just, all that is is marketing. And marketing
always wins, right? But that's the astute listener, the astute viewer, they get to kind of make their own sorts of decisions and they should know the science and we'll include Dr. Hoffman's work that he's done at these ultra races and others. find out these things for yourself that you're absolutely...
Marjaana Rakai (:listener, the student viewer, get to kind of make their own sorts of decisions. you know, they should know the science.
Paul Laursen (:That's not the way physiology works.
Marjaana Rakai (:So let's talk about a person who does take these sodium electrolytes high concentration. What happens then is they also couple it with a lot of fluid intake in fear that they're losing not only lots of salt, but fluids. God forbid that we lose more than 2 % because that it will
of our body weight because that will then affect our performance. But when you're taking in, when your body is working hard to get rid of that salt and then you just pour in more, you get thirsty, right? Like you start feeling like thirst when you're taking in more sodium. That's how I felt. Like I used to
Paul Laursen (:Yeah wait.
Marjaana Rakai (:I need over a thousand, like:Paul Laursen (:Correct. And that's what the science shows as well. That's what the studies show too. So if you take these electrolyte tabs, just like Marjaana did and experienced, you'll always feel thirsty and you'll always want to keep kind of drinking. So you can actually run yourself into more trouble on these ultras than if you were to not do that practice.
You know, again, remember if you're always thirsty and you're always drinking, you're potentially running into the problem where you dilute your bloodstream with too much water. Too much water in the bloodstream actually creates hyponatremia. So hyponatremia, low sodium level. And what happens there is that it actually causes your brain to swell. All right. And then if your brain swells, it's called hyponatremic encephalopathy.
Marjaana Rakai (:There is
Paul Laursen (:And it can lead to, if you've ever felt dizzy in any of these ultra races, and I
have when I did things incorrectly in the day, yeah, you wind up, you can, know, many, I wouldn't say many, but occasionally you can, especially in small individuals, often women, they've died, unfortunately, in these races. So it is, yeah, and you don't die from dehydration.
It's, but you can die from, you know, hyponatremic encephalopathy. yeah, long, long the start of it, it, long the start of it is, is, it's unnecessary, likely more creating harm versus benefit with the exception maybe of the placebo effect. If you believe that the salt tablets are helping you perform, the belief effect will potentially go.
But towards like from a physiological standpoint, making you feel comfortable during the race, they're not going to do that. So you should work towards taking this out of your practice in terms of that. That's what the science says.
Marjaana Rakai (:that work towards taking this out of your practice.
Paul Warloski (:So our third question is really, kind of my question and it's a nice segue from what you just mentioned about the 10 grams in the blood glucose, because we, you did your episode on training science with Philip Prinze. We talked about his study in detail a couple of weeks ago. You also in the episode with
mentioned the studies back in the 60s and 70s with the Swedish and Norway the Bergstrom and other studies about muscle glycogen in the 60s and 70s. So I happen to be reading a textbook and listening to this episode and thinking about what you've been saying about maintaining blood glucose. What happened then to the muscle glycogen? Should we not be worrying about muscle glycogen? it?
they saw it drop with exercise and assumed that that meant exercise depleted muscle glycogen. Is that accurate?
Paul Laursen (:Yeah, yeah. So let's just go in review a little bit more back to the print study for the listener. So what they did, this is like, you know, this is an exceptional study and the amount of work, you know, I think I really believe you need to be a little bit more of a researcher and actually understand how much work is involved. Like this study would have taken years, honestly. it was planned for four years of students speaking to Philip, like it was, and then to execute it even.
Paul Warloski (:Yes.
Wow.
Paul Laursen (:Each time they did this study with 10 subjects, repeated measures, they adapted six weeks across both diets. So this is done with a nutritionist. And a nutritionist is standing by feeding these individuals, ensuring they're sticking to a high carb or standard or a low carb diet, ketogenic, less than 50 grams.
of carbs in a day. they're adapted to both diets. And then now, so the first thing that they found in the study was that the time course of adaptation and achieving metabolic flexibility can take between four and six weeks. So that's the first really important point of the study. Now they're looking at the acute phase. So they get both sort of situations, same athletes in both cases and when they're
They're high carb and the other one they're low carb. And then they do a 70 % VO2 max exercise test to exhaustion. So to put this into perspective for the Athletica users, this will be around your zone 3B pace. So go at zone 3B, between zone 3A and zone 3B to exhaustion. So that's sitting around your 70.3 kind of pace.
Right? How long can you ride at that power? That's what they asked. So they started doing that and that was sort of the first little bit. And that you would expect classically, they go for about between 90 minutes and two hours. Right? And classically, that is usually, now they're at the end and they're like exhausted. can't go anymore. They can't hold an RPM of 60. So they end.
and 60 RPMs and then the person that's conducting the test says, no, done, you're exhausting. then so RPE is like, it's like six out of 10, six or seven out of 10 between hard and very hard, right? But it's like, they can't actually execute the 60 RPM, right? Imagine you're on velocity with Marjaana, you can't pull that pedal over anymore. So, doom, done. Now that you have probably...
depleted a lot, if not all of your glycogen. Well, not all because we know that never happens because you're always protecting it. But a good chunk of that muscle glycogen that Bergstrom initially kind of was investigating is gone. Let's say the individual is likely, we don't have muscle biopsies so we don't know, but they're likely down to like 25 % of their muscle glycogen level. Now we're gonna ride them again.
exhaustion, but this time they're going to get either placebo, kind of sweet drink, or they're actually going to get sugar, and they're going to get sugar, you know, glucose at three, was 10 grams total, but it was like 3.3 grams every 20 minutes. And what, and they, you know, they had to do so much piloting to find out this minimal level that would just kind of maintain
Paul Warloski (:you
Paul Laursen (:maintain your glycemia, maintain your blood glucose level. And that's what they did. So both conditions ride it to exhaustion. And yeah, and what they found was a 20 % improvement. Didn't matter if you were the carb adapted individual and you should have in theory had lots of carbohydrate in your muscle or low carb. Again, when in theory you shouldn't have any carb in your muscle.
And yeah, when all it took was the maintenance of the blood glucose level so that your brain was happy and you went 20 % longer in your time to exhaustion pinning everything on Don't become hypoglycemic. That's all you need to do So I'm not sure if I answer as I answered the question Paul, but it's like basically this where things are really going with this is there's
understanding now that there's two carbohydrate pools in the human body. Our large carbohydrate pool, which is the muscle glycogen level, Bergstrom, and the small carbohydrate pool, which is your liver alongside your blood glucose. All that's important is that you maintain your small carbohydrate pool to a sufficient level. That's what the science is suggesting.
Of this is like one study, new hypothesis, but this study is incredible and it really points a strong finger on the importance of the small carbohydrate pool, not the large carbohydrate pool. Basically that with respect to muscle glycogen, your fat level, the ability of your muscle to...
to use fat as a fuel is probably the more important thing.
Paul Warloski (:Okay, so the muscle glycogen was also depleted, but what matters is maintaining your blood glucose.
Marjaana Rakai (:Mic drop.
Paul Laursen (:Yeah, because if it was muscle glycogen that was the issue, and the muscle glycogen should have been so low, then we should have seen a higher level of performance in the high carb athletes with higher muscle glycogen levels. And we should have seen, again, with something as small as 10 grams of carbohydrate supplementation.
It shouldn't have mattered. It's so small. It shouldn't have been any different than the placebo, but that wasn't the case. It improved performance by 20%. That's a lot. So it was very profound, the supplementation, where it shouldn't have been.
Marjaana Rakai (:It's so small. It shouldn't have been any different than the placebo. But that wasn't the case. It improved performance by 20%.
Paul Warloski (:Well that leads us into our fourth question. Marjaana do you want to take Wombat's question?
Marjaana Rakai (:How does low carbohydrate intake fit in the fasted training? Does fasted training help with fat adaptation? What's the purpose of fasted training and does consuming fat help burn fat?
Paul Laursen (:Yep. Awesome question, Wombat. So yeah, I think low carbohydrate intake prepares you for fasted training. I think fasted training can be very difficult in the beginning, probably back to, like you said, Paul, this prepares us, the background that we just talked about prepares us well for this question. Because if you're...
Marjaana Rakai (:Thank
Paul Laursen (:if you are not metabolically flexible, then you're gonna struggle with fasted training. If you are metabolically flexible, you shouldn't have a problem with this. And metabolically flexible comes back to this whole idea with the power of your small carbohydrate sink, right? The liver and the blood glucose. And so,
yeah, you're in the fasted sort of condition. Sorry, if in the, let's, let's say in the metabolically flexible in the high fat metabolism situation, you basically, you know, you have fat taking on the power of the metabolism, the energy, it's producing the energy, substantially, and it's not drawing on the, the carbohydrate levels.
Marjaana Rakai (:reducing the energy substantially. And it's not drawing on the carbohydrate levels
Paul Laursen (:specifically in the small glucose compartment, right, that I just mentioned, liver and
Marjaana Rakai (:specifically in the small glucose department. Right? But it's delivering.
Paul Laursen (:blood glucose. It's not drawing on that. So it's, yeah, it's kind of part and parcel of it. yeah, so it definitely fasted training 100 % helps with fat adaptation. And I'll hand over to Marjaana maybe to provide her experience on
how improving your fat metabolism helped with your fat adaptation and fasted training maybe helped with your fat adaptation.
Marjaana Rakai (:Yeah, let's see if I can tell a good story. When we first started working together, I was such a mess. Like I couldn't do half an hour of fasted training. was just like starving and just like my blood sugar level just dropped. So I had to go out and have a banana with me just in case. And that...
time kind of just extended slowly that I was able to like, I wasn't able to do more than 30 minutes. It was crazy. I was just like, nope, hitting the wall. But then that, that, duration increased as I kept, you know, practicing it and getting my metabolic,
Paul Warloski (:you
Paul Laursen (:Yeah. So
let's go back to the large carbohydrate pool and the small carbohydrate pool again, right? So in the case when you just started and you're doing that 30 minutes with the banana for reserve, when that exercise, that moving, it would draw so strongly on your small carbohydrate pool because you didn't really have much of a buffer, right? So it pulls on that sink.
so quickly and it makes you want to go for that banana. yeah, and this is why just like with any of stuff we're talking about with the last lecture or the last chat on strength training, it's principle of progression. You've got to progress the stimulus as well. So continue. How did you progress it?
Marjaana Rakai (:Yeah.
Well, over time, then I also cleaned my diet. So I went keto for a little bit and that was
you know, like these athletes, they converted to a low carb diet and that really boosted the fat adaptation. And then I could be, I was able to do three hour rides fasted, four hour rides fasted.
Paul Warloski (:you
Marjaana Rakai (:So yeah, that's...
Paul Warloski (:Well, what's the purpose of a fasted, of fasted training? Why do we want to do it in the first place?
Paul Laursen (:What's happening in the fasted condition? And I'll just mention, this is not, well, if you're listening to this and this sounds new to you, this was used by the Tour de France racers and their coaches in the 50s. So this has been around for a long, long time, right? Like they've known the benefit of this. And this is really, laying down your base. So remember the base training forms the foundation.
of all your performances. This is why you do math tests, right? You want to do, the easy training should be easy and that allows the hard training to be hard. So...
Yeah, you do this to build your base. There's an ultimately fasted training which draws on, it has to draw on fat metabolism, right? Because carbohydrate isn't really around. So it just speeds the development of your mitochondria, the mitochondria, the powerhouses, organelles of the cells that munch all of the fat. And yeah, when...
Marjaana Rakai (:Yeah, you do this to build your base. There's an ultimately fasted training which draws on
Paul Laursen (:you know, when, when carbohydrate isn't around, they force it to draw on fat. They also force the liver to produce more ketones and, and there's a bunch of other benefits as well too, in terms of like the autophagy and whatnot, which is basically cell cleaning that happens. So there's, there's so many different benefits of this, this fasted training and it's a great practice to have in your
in your training diet every once in a while. And of course I know some will argue that it's very dangerous and that we're going to develop REDs, is reduced energy, what is it? Something energy deficiency syndrome.
Paul Warloski (:Thanks.
Marjaana Rakai (:Reduced energy availability in sports, is that? Yeah. Okay. So let's pack up a little bit. Where does the fat come from? Because we have like stored fat, we have intramuscular fat, and then we have free fatty acids.
Paul Laursen (:Yeah, I don't know.
Marjaana Rakai (:So say that we do, yeah, so let's say that we do a faster training. Where does the energy come from? Like what fat stores are we utilizing?
Paul Laursen (:subcutaneous.
Yeah, such a good question. I'm so glad you asked it because it really kind of goes back to your adaptation thing and also really the question about, you know, how does low carbohydrate intake fit in with the fasted training? We forgot to mention the key hormone that's regulating all of that and that's insulin. So with your replacing more fat, good fats for, you know, sugar and carbohydrate in your diet.
Marjaana Rakai (:Mm-hmm.
Paul Laursen (:your insulin response isn't as high. Now insulin is the key regulatory hormone that's going to tell your body to store, store energy as fat or pull energy out, pull the fat out of your adipose cells and get burned by the mitochondria. But also one of the key adaptations that happens and Marjaana was alluding to this as well. Where does that fat come from?
You actually wind up storing more fat in your muscle cells, which is pretty cool. It's called intramuscular triglyceride. You want to store fat in your muscle cells. That's such a cool adaptation. And the reason why you might kind of expect, right, is if that fat is sitting right beside the mitochondria where it's going to be able to be burnt, like it's, you know...
It's ready to put fuel on the fire, right? Put log on the fire, right? Everything we're doing here, we're converting chemical energy to mechanical energy. That's the whole
we're such intelligent species, ultimately, to be able to do this. But one of the key adaptations when you do any training, it doesn't just have to be fasted training or...
Marjaana Rakai (:intelligent species ultimately to be able to do this. But one of the key adaptations when you do any training, you don't just have to do that fasted training
or fat adaptation training. The whole process of training itself is to cause for intramuscular triglycerides to be that pool in the muscles, essentially to be increased.
Paul Laursen (:fat adaptation training, but the whole process of training itself is to cause for intramuscular triglycerides to be that pool in the muscles is actually to be increased. So
that is such a great question.
Marjaana Rakai (:And why is
fat so important like energy wise? Why is fat superior to carbohydrates?
Paul Laursen (:Is it? Yeah.
Yeah, the energy yield, like nine kilocalories per gram of fat burned in terms of ATP produced versus for glucose. Glucose is like, it's a quick fix. It's a quick energy, but it's not forever. fat is your forever fuel. And you just burn it all day long.
Marjaana Rakai (:Aww.
Forever friend.
Paul Laursen (:It
Paul Warloski (:Yeah
Marjaana Rakai (:Right. Right.
Paul Laursen (:Yeah, like it gets it gets such a bad name, right? Gets such a bad rap. But it's like
it's not it's yeah, it's your friend.
Paul Warloski (:right. Well, thank you for the questions everybody and keep them coming in our forum and in the social media as we've been getting a lot of good ones. And thanks for exploring the path to peak performance with us today on the Athletes Compass podcast. When you subscribe, you'll ensure that you're always tuned in for our next journey into endurance mindset and performance. And when you share this episode with a friend, teammate or coach,
you'll be helping them discover new ways to level up their training and their lives. Take a moment now, subscribe, share, and let's keep navigating this endurance adventure together. For more information or to schedule a consultation with Paul, Marjaana or me, check the links in the show notes. For Marjaana Rakai and Dr. Paul Laursen I'm Paul Warloski and this has been the Athletes Compass Podcast. Thank you so much for listening.