Can short bursts of hard cardio outperform hours of Zone 2 for the average person? Exercise physiologist Dr. Martin Gibala explains how HIIT can improve VO2 max and metabolic flexibility, why elite athletes' 80/20 split may not fit a time-strapped schedule, and how to judge vigorous effort without chasing a perfect heart-rate zone.
Dr. Martin Gibala is a Professor of Kinesiology at McMaster University and one of the world's leading researchers on high-intensity interval training.
Can short bursts of hard cardio outperform hours of Zone 2 for the average person? Exercise physiologist Dr. Martin Gibala explains how HIIT can improve VO2 max and metabolic flexibility, why elite athletes' 80/20 split may not fit a time-strapped schedule, and how to judge vigorous effort without chasing a perfect heart-rate zone.
Expect to learn how to scale HIIT for beginners, what RPE and the talk test reveal about vigorous effort, when short sprints differ from VO2 max intervals, why elite athletes’ 80/20 approach may not fit your schedule, how Zone 2 definitions can mislead, and what metabolic flexibility and mitochondrial capacity really mean—and much more.
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Episode Timestamps:
[00:00:00] Dr. Mike T Nelson: Hello
[00:02:14] Dr. Martin Gibala: How are you?
[00:02:16] Dr. Mike T Nelson: I'm good. How are you doing?
[00:02:17] Dr. Martin Gibala: All right.
[00:02:18] Dr. Mike T Nelson: Good. Well, thank you so much for taking time here. I really appreciate it.
[00:02:22] Dr. Martin Gibala: Yeah. Thanks for your interest in, uh, our work.
[00:02:25] Dr. Mike T Nelson: Yeah, for sure. I've been following your guys' stuff for quite some time, so this'll be fun.
[00:02:31] Dr. Martin Gibala: Amazing.
[00:02:32] Dr. Mike T Nelson: Awesome. Any questions before we get started?
[00:02:35] Dr. Martin Gibala: No, I, I think just from the email thread, I have a sense of what you might wanna talk about. Can you just remind me who your audience is? I'm sure it's diverse, but who are we mainly talking to?
[00:02:46] Dr. Mike T Nelson: Yeah. It's primarily, I'd say, intermediate to some advanced fitness enthusiasts. About 30 to 40% are actually coaches or trainers themselves.
[00:02:58] Dr. Mike T Nelson: Um, so it's kinda split. So you can get as geeky as you want into mechanisms and studies and all that kind of stuff. That's, that's totally fine. They... Everybody seems to like that.
[00:03:08] Dr. Martin Gibala: Okay. Great.
[00:03:11] Dr. Mike T Nelson: Awesome. Well, I'll do a short pause, and then, uh, off we go.
[00:03:15] Dr. Martin Gibala: Sounds good.
[00:03:18] Dr. Mike T Nelson: Awesome, man. Welcome to the podcast. How are you today?
[00:03:20] Dr. Martin Gibala: I'm great. Thanks for having me.
[00:03:22] Dr. Mike T Nelson: Yeah. Thank you so much for being here. My first question was, you have published a ton of research on high-intensity interval training, which we'll dig into a lot. But I think the thing that most surprised me when I read your research, especially early on, was that you did it not necessarily in high-level athletes, but some of the people were, you know, general population, and some of them possibly you could argue were a little bit detrained.
[00:03:48] Dr. Mike T Nelson: I think there's kind of a myth that, you know, if you're not pretty well-trained already, like you shouldn't be doing any high-intensity interval training. What are your thoughts on that?
[00:03:58] Dr. Martin Gibala: Yeah, absolutely. Um, you know, I'm-- we definitely have an interest in high-level performance, but to your point, the vast majority of work has not been in high-level athletes, and a lot of the work, especially the more recent work, has been in individuals with overweight and obesity, people with type 2 diabetes, certainly people at risk for many different chronic, uh, conditions.
[00:04:18] Dr. Martin Gibala: And so, uh, high-intensity interval training, it just needs to be scaled to starting fitness level. Uh, and you know, there's literally hundreds and hundreds of studies now that have applied relatively vigorous interval training to a wide range of individuals, including, as you say, some of those that are, are quite deconditioned.
[00:04:38] Dr. Mike T Nelson: So how would someone start that? Like, 'cause then the, the other question is, one, obviously it has to be tailored to kind of where they're at. 'Cause I do agree that you can definitely... If you don't have a big aerobic base or high VO2 max, it's pretty easy to kind of torch people with too much intensity.
[00:04:55] Dr. Mike T Nelson: And then the second part was, if I remember right, one of the, I think one of the things you said in the follow-up study is you continued training one of the groups after the study had finished because they actually, air quote, "enjoyed" that kind of training, which I can't remember if it was, like, a 30-second Wingate or what it was, but it was some pretty relatively hideous intensity you were using.
[00:05:18] Dr. Martin Gibala: Yeah. And so I, you know, maybe even to, to, to start a little bit, you know, what is interval training? It's just alternating bouts of higher intensity exercise with recovery periods. Uh, I, I think for a lot of people, you, you know, just getting over that hump and, and appreciating that interval training can mean lots of different things, right?
[00:05:37] Dr. Martin Gibala: So we're not necessarily getting people who are very condi- deconditioned, getting them on the bike and, you know, having pedal their hearts out or, or do a, a Wingate- Mm-hmm ... test or something like that. So we just wanna get into that, that, that vigorous, uh, range. And, you know, ideally, we'd like to start low, go slow, just like the general advice is always given.
[00:05:58] Dr. Martin Gibala: But definitely people can start with intervals and then, and then build from there. So, you know, people don't need to be afraid from interva- f- afraid of interval training. It doesn't mean it's only as hard as you can go, gut-busting type exercise. Uh, and so to your point about starting out, um, you know, many of these people are starting out with m- moderate interval training, but also we're ramping them very quickly.
[00:06:19] Dr. Martin Gibala: You know, if, if you're interested in the potential time efficiency of intervals, this needs to be done with vigorous effort. And, you know, here I'm, I'm, you know, reminded of the fact that the public health guidelines for all of us, uh, certainly adults and including older adults, is generally 150 minutes of moderate to vigorous exercise.
[00:06:40] Dr. Martin Gibala: And, and vigorous exercise, uh, is, is just that. So when you think about it, interval training just being an intermittent version of vigorous exercise that's already widely advocated for the vast majority of, of adults, it's perhaps not as scary or not as surprising that this type of training, uh, regime can be widely applied.
[00:07:04] Dr. Mike T Nelson: Cool. And then all of you check your volume on that side, 'cause for some reason it seems pretty quiet. I don't know why, but I have it- Ready? ... turned up here, but
[00:07:17] Dr. Martin Gibala: Yeah, my apologies. I can try and, uh-
[00:07:19] Dr. Mike T Nelson: No, that's all right ...
[00:07:20] Dr. Martin Gibala: okay, try and get that, uh, get that up a bit. Or I, I, I, you know, I am speaking into a mic. I could just try and get rid of that if you think it might be, uh- Yeah, try
[00:07:28] Dr. Mike T Nelson: it without and see if that makes a difference.
[00:07:30] Dr. Martin Gibala: Okay. Sure.
[00:07:34] Dr. Mike T Nelson: It's Zoom, so who knows what happens in the background.
[00:07:52] Dr. Martin Gibala: Ah,
[00:07:52] Dr. Mike T Nelson: sick
[00:07:57] Dr. Martin Gibala: Okay, how's that?
[00:07:58] Dr. Mike T Nelson: Oh, that sounds a lot better, actually. Thank you for doing that. Oh, okay. I appreciate whatever it was you did.
[00:08:02] Dr. Martin Gibala: So, so much for the mic, right? But, uh-
[00:08:04] Dr. Mike T Nelson: Yeah, yeah.
[00:08:05] Dr. Martin Gibala: I don't know if you wanna start again off the top, or if you can, uh, or your audio team can, uh, can fix that
[00:08:10] Dr. Mike T Nelson: a little bit. Yeah, we'll get, we'll get it fixed up.
[00:08:11] Dr. Martin Gibala: Okay.
[00:08:12] Dr. Mike T Nelson: Um, great. So if someone is listening to this, and how would you define high-intensity interval training? There's tons of different, obviously, different methods and different definitions, but in your mind when you're talking about high-intensity interval training, how do you define that?
[00:08:31] Dr. Martin Gibala: Yeah. We're talking, um, anything above moderate intensity.
[00:08:35] Dr. Martin Gibala: And so what I mean with, by that is it, it generally aligns with vigorous intensity. And why we like that, to use that term vigorous, is it, it's already really well-defined in a public health context, in an exercise prescription context. You know, if you look at guidelines from the American College of Sports Medicine, uh, for example.
[00:08:53] Dr. Martin Gibala: And, you know, for those who might be interested, I'd, I'd really refer your listeners to a, a recent consensus statement that I was privileged to be part of that the ACSM put out, talking about exercise intensity terminology and how we define it both in a resistance exercise context and an aerobic exercise context.
[00:09:13] Dr. Martin Gibala: But in an aerobic exercise context, to be clear, we're talking a 7, uh, or 8 out of 10 on a 10-point scale. You know, that's when you're into to vigorous effort, moderate being, uh, about a 5 or 6 on that 10-point scale. On a traditional 6 to 20 RPE scale, we're typically talking 14 to 17 is vigorous intensity effort.
[00:09:36] Dr. Martin Gibala: Uh, VO2 max, you're around 65% or so of VO2 max. Percentage of maximal heart rate, you're around 77% or so of maximal heart rate. Um, you know, we can use RPE also, just perception of, of it, of being a hard effort. Or if you're interested in metabolic thresholds, things like ventilatory thresholds, lactate thresholds, we're talking about, uh, above the second, uh, metabolic threshold.
[00:10:03] Dr. Martin Gibala: So the point being is there's no single definition of what counts as interval exercise or high-intensity interval ex- exercise. You know, a lot of people will use... And we previously in our early days used, you know, a rough approximation of about 80% of maximal heart rate. But certainly we've learned that when you do these brief vigorous efforts, and, you know, now looking at the exercise snacks, um, literature, these physiological measures including heart rate, they tend to lag behind RPE.
[00:10:31] Dr. Martin Gibala: So certainly within 45, uh, seconds or so, if someone's doing vigorous air squats or something like that, um, perceptually and effort-based, they're already in the vigorous range if you ask them, but their heart rate will lag a little bit behind that. So all that to say, there's no single indicator of high-intensity interval training, but I would really advocate that individuals- Contextualize it in terms of vigorous exercise, vigorous effort appropriate to their context.
[00:11:04] Dr. Martin Gibala: Whether it's, you know, a public health setting, whether it's an exercise prescription context, uh, whether it's high-level training for athletes and you're anchoring some of these physiological metrics to metabolic thresholds, you know, all, all of those, uh, are suitable. Um, but it's really important to contextualize it to the individual a- and the context in which you're working.
[00:11:25] Dr. Martin Gibala: You know, you can make it as complicated as you need to, uh, but you really don't have to either. And coming back to subjective effort, that's a, that's a pretty good one.
[00:11:33] Dr. Mike T Nelson: Yeah. I, I feel like there's this over complication of it at some level, especially for general population, that people are so worried about, "Oh, now I gotta poke my finger with lactate," or, "Oh, I don't have an output," or, "Oh, I gotta do this certain percentage of heart rate," and then, "Oh, 220 minus my age isn't very accurate," and then, "No, wait, he said second lactate thing."
[00:11:53] Dr. Mike T Nelson: They go, "What was I doing again?" I'm like, just if you do something that's moderately hard, you're probably gonna be okay, right? Which is much better than the nothing or the just the low-intensity stuff you had been doing before. I think that gets lost a lot of times in the context.
[00:12:09] Dr. Martin Gibala: No, absolutely. You know, there's nothing wrong with the old talk test, right?
[00:12:12] Dr. Martin Gibala: Yeah. If you can continue a conversation, even if it's a little bit strained, probably you're still in that moderate effort range. If you're getting to the point where, you know, you can spit out a few words or, or talk in some brief halting sentences, you're probably into that, uh, vigorous, uh, range. You know, that's, that's not a bad indicator as, uh, as well.
[00:12:30] Dr. Mike T Nelson: For someone who's new, and then we'll get into a little bit more advanced stuff, like how would you have them start? Are you a bigger fan of keeping the intensity a little bit high and try to hit more of a frequency? Or do you kinda like to do it more on start with, you know, one day that's kinda more your higher intensity day, or do you have any preference from how they could kinda set up a week?
[00:12:54] Dr. Martin Gibala: Well, you know, uh, I don't wanna be that careful scientist that's always hedging and saying it depends or something like that. Yeah, yeah. You know, and I, I'm, I'm, I'm primarily, primarily a researcher, but I'm very interested in knowledge translation, science communication. But, you know, I'm not necessarily in the trenches as, as a, as a personal trainer.
[00:13:10] Dr. Martin Gibala: But, you know, my observations would be the biggest thing is ideally pick someone that people like and enjoy, 'cause they're more likely to stick with it. So there's, there's no single best type of interval training. You know, m- many people get interested in this area because they're interested in the time-efficient, uh, side of things.
[00:13:29] Dr. Martin Gibala: And, you know, for example, they, they definitely wanna be less than 20 minutes for their interval workout. You know, we've gone down as, uh, many, many, uh, protocols lasting, uh, 10 minutes or, or, or less, right? So we started- Total time ... with, for example, a, a 10 by one. So that's 10 one-minute efforts with one minute of recovery.
[00:13:47] Dr. Martin Gibala: Little bit of warmup and cool down, you're done in 25 minutes. And then over time, that progressed to a five by one. Five one-minute efforts with one minute of recovery. Because we found that much of the improvement in, in markers like cardio respiratory fitness, VO2 max, were, were almost as good. So I, I, I think when you're working with a client or an individual, you know, you, you first wanna say like h- how, rather than just prescribing something to them, "How much time a week do you have to give me," right?
[00:14:17] Dr. Martin Gibala: Mm-hmm. And are, are we trying to work in our resistance exercises within, within that? Uh, are, are there types of intervals that you enjoy? And, you know, if they don't know when they're first starting out, try them with different ones. You know, lo- long, you know, quote, unquote longer intervals lasting four or five minutes or so.
[00:14:34] Dr. Martin Gibala: Shorter intervals that might be more, uh, you know, more frequent 30-second repeats. So I, I, I think it's important to work with the individual, figure out what they like and enjoy, and then, and then maybe build, uh, build from there.
[00:14:46] Dr. Mike T Nelson: Do you think there's a, a huge difference between the kind of VO2 max intervals, the four to five-minute, versus doing more repeats of the, I hate to use the word anaerobic, but kind of the 30 to 60-second high output stuff?
[00:15:03] Dr. Mike T Nelson: Like, if you look at the literature from what I've seen is depending on the person, depending upon what they're trying to do, like, you could kind of make an argument for either one or perhaps both at some point, too.
[00:15:14] Dr. Martin Gibala: Yeah, so I guess two observations. O- one is generally speaking, for most people, there's no single best type of interval training, and you can certainly improve your VO2 max cardiorespiratory fitness with lots of different, uh, intervals.
[00:15:28] Dr. Martin Gibala: You know, just like you can, uh, improve VO2 max with continuous exercise, you just typically have to do a lot, lot more of it. Now, if you're looking for what's the single best protocol, it's probably these longer repeats, so these three to five-minute intervals, so that's closer to the VO2 max type training that you'll read about.
[00:15:49] Dr. Martin Gibala: You know, three to five-minute hard efforts at the highest sustainable intensity repeated multiple times, you know, six, seven, eight, 10 times if you want to have the highest likelihood of optimizing VO2 max for a given individual. But we also know that responses to exercise are highly variable, and so I, I, I think for most people they probably wanna vary it up.
[00:16:15] Dr. Martin Gibala: You know, I always use the investing analogy. You can hit a home run by betting on a single stock, but, you know, for most of us, we're, we're better off spreading the risk and using different, um, approaches. Uh, and, and I think that's generally the best approach for, for most people in terms of optimizing exercise responses w- within themselves, uh, again, mindful of things like personal preference, time available, that sort of thing.
[00:16:42] Dr. Mike T Nelson: Any preference in terms of modality? I believe a lot of your research has been either treadmill or you've done a lot of work on the, the bike in terms of the lab.
[00:16:51] Dr. Martin Gibala: Yeah, we have. So, you know, the vast majority of the studies were on the bike. It's easy for us to quantify things like work and power. Um, but I, I, I, I don't...
[00:17:00] Dr. Martin Gibala: You know, from a cardiovascular training standpoint, I don't think it matters, right? There's that old saying, your heart doesn't know what your muscles are doing, and I think that's broadly true. So, you know, for a given intensity of effort, uh, you can stimulate the cardiovascular system with cycling intervals, ellipticals, swimming, ballroom dancing, right?
[00:17:18] Dr. Martin Gibala: It, it probably doesn't matter. You know, if you're looking in a more sports-specific context, uh, then I think it does. You know, the specificity of training, uh, still, uh, still holds. But otherwise from a cardiovascular conditioning, I don't think it matters that much.
[00:17:35] Dr. Mike T Nelson: And you had mentioned, like, the 150 minutes guidelines.
[00:17:38] Dr. Mike T Nelson: Is that for vigorous exercise? And if your intensity is pretty high, do you think you could probably shorten that total amount of time if people are really looking for kinda the biggest bang for their buck in terms of time investment?
[00:17:55] Dr. Martin Gibala: Yeah. I, I, I do, right? And so it, it, you know, it depends on whose guidelines you're looking at, you know- Mm-hmm
[00:18:00] Dr. Martin Gibala: the US, uh, guidelines, the Canadian guidelines. But, you know, even if we take the, the WHO, the World Health Organization, obviously the, the, you know, the world leading authority on this, the WHO does make a distinction. So you'll, you'll see 150 minutes of weekly moderate-intensity physical activity or 75 minutes of weekly vigorous physical activity, you know, or some combination of, of both.
[00:18:25] Dr. Martin Gibala: I think that reflects the fact generally, um, that an equivalent amount of vigorous exercise... So you know, s- so 75 minutes compared to 150 minutes of moderate, that typically will result in the same amount of energy expenditure, right? Which historically is this is where a lot of the guidelines are based on, trying to get to 1,000 met minutes and, and- Mm-hmm
[00:18:46] Dr. Martin Gibala: things like that. But, uh, you know, the more recent research would suggest, uh, when you do vigorous compared to moderate, uh, the bang for your buck in terms of cardiorespiratory conditioning is more than a 2:1 ratio. Mm. So it might be three, four, 5:1. So all that suggests that the more vigorous effort may require less time.
[00:19:08] Dr. Martin Gibala: And so the guidelines aren't there yet. You know, we don't have 150 minutes of moderate, 75 vigorous, you know, 35 minutes of, of really intense interval training a week. Uh, but I think you could make a case, uh, f- for that. Uh, and, and you know, to my mind, there's exponentially greater benefit with more vigorous training compared to lower intensity, uh, exercise.
[00:19:35] Dr. Mike T Nelson: Yeah, and to that end, you wrote a really cool paper I liked that was the Zone 2 training, kind of the much ado about, uh, nothing with our friend Christie, who's been on the podcast here. And I'm always curious, like, how did that paper come about, especially when people are doing kind of their choice of kinda narrative review type papers?
[00:19:54] Dr. Martin Gibala: Yeah. Shout out to Christie, who was the lead author on that, and, you know, uh, her supervisor at Queen's University, Dr. Brendan Gerd, was, uh, the corresponding author. I was, uh, grateful to have the opportunity to, to contribute to that work. But I think it really stemmed from conversations around this, this narrative that was increasingly seeming to be taking root of, uh, you know, uh, spending most of your time doing Zone 2 training was optimal, uh, to develop, you know, your health, your mitochondrial capacity, your fat burning, uh, capacity.
[00:20:29] Dr. Martin Gibala: You know, and, um, the, uh, uh, you know, I know you talked about some of this during your interview, but- Mm-hmm ... you know, that's largely rooted in the training of high-level athletes, right? And if you're training- Yeah ... 25 hours a week, uh, 80% at low, low moderate intensity, um, 20% at high intensity, that's still five, six, seven hours a week of, of vigorous intensity effort, which is a lot, right?
[00:20:53] Dr. Martin Gibala: And we know that's very much a tried and true formula to optimize performance in high-level endurance athletes. The, the, the issue that we had was this blatant suggestion, you know, many influential podcasters were talking about this, that 80/20 was the optimal ratio for, for everyone, and I think some of those individuals have, you know, they've backed off on that suggestion.
[00:21:16] Dr. Martin Gibala: But that's really where the impetus for the review came from, was, okay, let's explore this. You know, let's look at the science behind, uh, this, and there's, you know, we really couldn't find any. Uh, you know, if anything, there's suggestions that high-intensity exercise for a given dose or amount is gonna result in, uh, greater improvements in mitochondrial capacity, greater improvements in, uh, in fat max.
[00:21:41] Dr. Martin Gibala: And, you know, for people advancing those positions, I, I would just say, "Show me the data," right? Show me the evidence that suggests that 80% Zone 2 is, uh, is optimal for everyone, uh, including if you're doing two and a half or maybe three, four, five hours a week. Last point on that, you know, we know the biggest barrier for most people is a perceived lack of time, and so y- you know, the current guidelines are two and a half hours a week of physical activity.
[00:22:08] Dr. Martin Gibala: If we're saying, "Okay, wait a minute, you gotta... You know, at a minimum you gotta start with three to four hours of- ... of Zone 2," you know, I, I, I think we're just raising the barrier to entry when so many people are finding it challenging even to get in that 150 minutes a week.
[00:22:24] Dr. Mike T Nelson: Yeah. And I know I had, in the past I had, you know, clients do...
[00:22:28] Dr. Mike T Nelson: And they were probably, I'd say intermediate to, you know, may- maybe advanced, not really advanced in the aerobic domain. A fair amount of zone two, and we still did like one interval training session per week for the most part. And, and some people, they got better, and some people They didn't. And then when I started looking at the literature, I made the error of looking only at the high-level athletes, and then I kind of fell in the same trap I think a lot of other people do of, you know, hearing well-named, you know, people in fitness and you just...
[00:22:58] Dr. Mike T Nelson: I made the assumption, "Well, they must have looked at the data. There, there must be other data I haven't looked at." I just looked at the high-level athletes. I saw the 80/20 split and things of that nature. And then the more I started looking into it, I was like, "Oh, hey, wait a minute." And then it's even, as you know, more confusing for people trying to figure it out on their own that a lot of times we don't use a simple five-zone model for a lot of the literature.
[00:23:21] Dr. Mike T Nelson: A lot of it is a three-zone model of, you know, kinda easy, kind of, you know, moderate, and then like you're talking about, kind of the, the vigorous stuff. So that makes it even more confusing because you will find stuff that says zone 2 resulted in more mitochondrial adaptations. But you pull the paper and you actually read the physical paper, well, that was a three-zone model and their intensity was actually higher than the classic zone 2 in the five-zone model.
[00:23:49] Dr. Martin Gibala: Bingo. Right, and I, I think that's where a lot of the confusion started. Classically in exercise physiology, there's a three-domain model, right? Mm-hmm. The moderate, heavy, severe, and that's sort of become conflated now and it's like, okay, we're not really talking about that middle second domain here. We're talking about if we break up the first domain into two zones, and the higher part of that zone just below lactate threshold, the first lactate threshold is, is zone 2.
[00:24:17] Dr. Martin Gibala: But to the point, you know, people throw around this term zone 2, have some sense that it's low/low moderate intensity exercise. Um, but, you know, th- there was a recent, uh, paper that looked at this. All of the, the defrent- different definitions of zone 2. You know, the most common ones would be just below the first lactate threshold, you know, equates with, with submax.
[00:24:43] Dr. Martin Gibala: It's around a lactate value of, of two, uh, millimole. And then they looked at those values in individuals and, you know, no surprise, there's tremendous variability. Um, those common metrics don't align, so someone's zone 2, their lactate threshold, doesn't necessarily equate to their fat max. Mm-hmm. And for a lot of individuals, their zone 2 when you measure it in terms of a heart rate, which is I think the easiest for most people, they're below moderate intensity physical activity, which per the guidelines, it doesn't even count then in terms of a health-boosting type exercise.
[00:25:25] Dr. Martin Gibala: It, you know, it's, it's still light activity, which is great. Uh, you know, whereas other people- Their zone 2, they're up around 85% or so of VO2 max, which is very vigorous exercise. So it just speaks to the point, you know, we've, we've suggested. Just, I don't think this is gonna happen, but throw out this term zone 2.
[00:25:44] Dr. Martin Gibala: Because it's so confusing for individuals, and, and just get back to the guidelines. Moderate is this, vigorous is this, because they're so well-defined in terms of heart rate, RPE, which I think are the most common metrics, uh, for individuals. You know, last point, lots of us are interested in wearables, but, you know, if you look at an Oura Ring and what it tells you the zone 2 heart rate range is, it's not the same as your Garmin, right?
[00:26:11] Dr. Martin Gibala: So it, it just speaks to the, the, the point that we're, we're raising here, I think.
[00:26:16] Dr. Mike T Nelson: Yeah. And if you look at the output of those high-level athletes, like, you know, Tour de France cyclists, and, like, the, um, the elite of the elite, their zone 2 outputs, even when they do lactate testing, they stay below 2.0. One, their whole lactate mechanics are completely different than the average person.
[00:26:32] Dr. Mike T Nelson: Like, that's a whole separate thing. And then two, just the flat-out wattage that they can put out and still be in probably a legitimate zone 2, is probably above most people's maxes.
[00:26:45] Dr. Martin Gibala: No. It's
[00:26:45] Dr. Mike T Nelson: just, like, almost in another universe somewhere else.
[00:26:48] Dr. Martin Gibala: You know, a- a- absolutely, right? You know, the, the, uh, the... put a fine point on that.
[00:26:52] Dr. Martin Gibala: The average adult VO2 max is 35 mils per kilogram- Mm ... per minute. If you wanna run about a 2:15 marathon pace, which is, you know, it's pretty good. It's, uh- Mm-hmm ... it's still not quite world-class, but it's, it's getting up there, 2:15. Yeah. You have to maintain a VO2 of 65 mils per kilogram- Ooh ... per minute for over two hours, right?
[00:27:14] Dr. Martin Gibala: So, you know- That's average ... that's right. That's not peak. Yeah. And you know, that's not your peak. That's just what- Yeah ... you're holding. Yep. And, and, you know, most of us can't even get there for 30 seconds. So it's, uh, it's absolutely incredible, the power outputs, the high VO2s, that these individuals, uh, can sustain.
[00:27:29] Dr. Martin Gibala: But, you know, v- very different from, uh, from most of us and, and, and mere mortals who are, you know, m- uh, maybe training two and a half, five hours a week at most, even though they might still be seriously interested in performance. But it's, uh, uh, you know... I, I, I would advocate a higher percentage of time at a higher intensity to optimize their mitochondria, their fat burning, their VO2 peak, their performance, if they're looking to run a, a 5K or a 10K.
[00:27:56] Dr. Mike T Nelson: Yeah. When you compound, like, just the amount of errors, like if you're- And I have a Garmin, I've got an Oura, I've, I've tested all the things. I got a frigging, you know, um, metabolic cart, and what you realize is, like, the, the light on the back running through the wrist has gotten a lot better, but if... It'll miss a lot of peak heart rates.
[00:28:16] Dr. Mike T Nelson: So if you're just going off of the peak from your Apple Watch, and now you're using 220 minus your age, and now you think your zone... Like, you just have all these errors that sort of compound. And I've noticed just working with clients, I'll ask them, and I'm like, you know, "Well, how did your..." You know, a client a couple weeks ago, "How did your zone two feel?"
[00:28:33] Dr. Mike T Nelson: He's like, "I don't know. It just feels pretty hard." He dropped it, added a little bit more intensity stuff. He feels way better. All of his metrics are better. And then you have other people who are like, they're like, "I don't know. I don't even feel like I'm doing anything." And they're probably even below a, in a real zone two.
[00:28:48] Dr. Mike T Nelson: And it's good movement, and it's things like that, but when you're making, like you said, the time investment in it, like, I think most people want a payoff, you know, for that. And I've seen things even as far as, well, you need a, a base of zone two for two to three hours to even build your VO2 max. Which, if I was a new person and I invested three hours in legit, legit zone two training, and after eight weeks and didn't see my VO2 max go up at all, I'm gonna be pretty pissed off about it.
[00:29:20] Dr. Martin Gibala: Yeah. I... Clearly, that would not be the best, uh, time investment in terms- No. ... of bang, bang for your buck. And, you know, you raise a good point about, um, maximal heart rate. You know, huge inter-individual vil- uh, variability if you're gonna just estimate it, right? Based on 220 minus your age or some of the other formulas that are out there.
[00:29:37] Dr. Martin Gibala: So I think ideally, if you're serious about this stuff, you wanna try and measure maximal heart rate, uh, on your own, which, you know, really just involves doing a vigorous effort for two or three minutes. You know, the old run around the track at the local high school- 400 meters. ... two times as hard as you can.
[00:29:53] Dr. Martin Gibala: And, uh, you know, you're gonna get pretty close to your own individual, uh, maximal heart rate. But that's, that's really key, right? Um, and then ideally you might know your waking or your resting heart rate, then you know heart rate reserve, right? And you can start to play around with, uh, with some of those formulas and, and dial it in a little bit better, I think.
[00:30:11] Dr. Mike T Nelson: Do you think there's anything to this concept, it's been around forever, which again, my bias is I think it's sort of derived more from athletes, that you have to paradoxically build your air quote "aerobic base" first before doing any higher intensity stuff? I'll leave it kind of vague as I know it's extremely vague, but...
[00:30:30] Dr. Martin Gibala: No, I, I, I appreciate the point. I, I, I think for most individuals I, I don't necessarily, you know, subscribe to that. And, and the reason I say that is, you know, w- we just see such tremendous and rapid improvement, um, in individuals who are deconditioned when they start out with a more vigorous intermittent approach to their physical activity.
[00:30:53] Dr. Martin Gibala: They can make very, very rapid gains. We can see rapid improvements in their peak aerobic capacity. Um, you know, we've done biopsies in individuals with type 2 diabetes who've performed, you know, two weeks of vigorous interval training, and see marked improvements in their mitochondrial content, uh, in their capacity for glucose transport.
[00:31:15] Dr. Martin Gibala: So, uh, you know, I, I appreciate where those suggestions are coming from. Uh, to your point, I think it's largely rooted in the training of athletes. But I think for most individuals, you know, you don't, you know, the- this whole base of the pyramid thing, I, I, I don't think it necessarily applies, and you can clearly, uh, enhance your aerobic capacity, which to my mind, uh, is this aerobic base, uh, fairly rapidly with, uh, with intervals.
[00:31:40] Dr. Mike T Nelson: Yeah. I, I've been trying to figure out, that's one of my new things, is like where, where did this come from? Like, how did this, you know, sort of start? And as far as I can tell, which I haven't been able to trace it back, uh, too far, is that there is some truth that the paradox of the more trained you are, the more training stress and the more volume or miles-
[00:32:47] Dr. Martin Gibala: You're back?
[00:32:47] Dr. Mike T Nelson: We're back. Sorry about that. I'll rephrase the question. That's okay. I know. It's really annoying. Yeah, no problem at all. Um, I mean, as far as I can find with aerobic base, it, it just seems like just a weird paradox where, yes, the more trained you are, the higher VO2 max or whatever parameter we're looking at, like you, you can handle more training stress.
[00:33:06] Dr. Mike T Nelson: But it seems like as far as I could figure out, this got then translated into you must magically have this aerobic base then from a practical standpoint of back to low intensity work to kinda build these things where, you know, you've highlighted in your review too that at least higher intensity stuff, there, there seemed to be a threshold upon which you can expect an adaptation, and zone two appears to be kinda below that threshold in terms of intensity
[00:33:37] Dr. Martin Gibala: Yeah, no, agree, right?
[00:33:38] Dr. Martin Gibala: I, I, I think the bottom line is the way that high-level endurance train for performance is not necessarily a blueprint for how regular people who might be training 1/10th the amount- Yes ... should train for their, for their health and fitness, right? I, I, I think that's the, that's, that's the bottom line. And again, um, you know, I, I, I'm not at the coal face here.
[00:33:59] Dr. Martin Gibala: I don't work with high-level elite athletes, and I, I, I readily admit and accept that this tried and true formula of 80/20, uh, is, is very well-established for, uh, for, for performance. Now, you know, I also know there's some high-level athletes who can, uh, train at a very high level and compete at a high level, um, on, on much less volume, right?
[00:34:23] Dr. Martin Gibala: Mm-hmm. And you can look at classic examples in the literature, David Costill's classic swimming studies- Yep ... where they looked at collegiate swimmers. You know, one group, they cut their volume by half, and yet at the end of the season, there were no differences in the average time or performances between the two groups, even though the one group of swimmers was, was doing 50%, you know, more, more training.
[00:34:44] Dr. Martin Gibala: You know, Roger Bannister, when he made his assault on the- Yeah ... four-minute mile, was very busy medical student, right? And he used to run intervals- During his lunch period ... around a cinder track on his- Yeah ... on his lunch, right? So, you know, you, you, you could see those examples. But a- again, I, I, I think that's the bottom line.
[00:35:01] Dr. Martin Gibala: The, the way that high-level athletes train, uh, for performance, uh, is not a blueprint for the way that, uh, regular folks, uh, should train for their health and fitness, especially if they're only doing 1/10th, uh, or so of the volume.
[00:35:16] Dr. Mike T Nelson: Yeah, and my read on the literature from that too is that I would agree we've got pretty good data showing the 80/20 approach works.
[00:35:24] Dr. Mike T Nelson: However, we don't have as good of data stating why it works. And I have this little theory that if you've ever worked with high-level cyclists, like, to try to get them to do nothing and ride less is almost impossible. So I wonder how much of that is, "Okay, you're still gonna ride. We're, we're still gonna be, air quote, 'training you,' 'cause we can't seem to cut back on your volume, but we're gonna have you do a lot of zone two stuff, so we're really not taxing recovery in as much."
[00:35:54] Dr. Mike T Nelson: And I, I do agree that if you're gonna go hard at that level, like, yes, we need to look at output, and we need to, to do all of those things. So I would love to see a study, which will probably never happen, of just, okay, take that a standard approach, and then instead of zone two, tell them to go walk around a track for a while or you know, do something else- Yeah
[00:36:12] Dr. Mike T Nelson: that's very low, low intensity, and see how much is that sort of low-end volume kind of buying us, even at that level.
[00:36:21] Dr. Martin Gibala: Yeah, no, no, agreed, and there was a recent paper that talked about this, right? Like, why, why 80/20 for high-level athletes ranging from, you know, it's absolutely critical for lots of physiological or psychological, uh, responses that allow them to be high-level athletes, uh, right down to it's not providing any, any benefit at all, and it's all about the, the vigorous, uh, 20%.
[00:36:43] Dr. Martin Gibala: You can you can have a fairly- Mm-hmm ... robust debate about that, of course, and that paper- Sure ... stirred up a lot of, uh, a lot of interest and, and commentary, but the point's well taken, right? And I, I think most, uh, I think if you talk to athletes, high-level coaches, a lot of them are gonna say, "Yeah, you know, if it, it's, it's just time on the road," right, or, "It's time in the saddle that, that, that, that's crucial to allow me to, uh, you know, perform, uh, in the Tour," or something like that, right?
[00:37:09] Dr. Martin Gibala: And it's, uh, you know, there may be lots of things that we're not measuring, connective tissue adaptations. Again, just the mental fortitude- Mm-hmm ... uh, to, to, to, you know, to, uh, to engage in, in, in these activities. Uh, but again, point is, the, you know, those performance-based metrics are, are not necessarily, um, relevant or applicable, uh, to, uh, to regular folks.
[00:37:33] Dr. Martin Gibala: You know, uh, on, on m- our own podcast, we just had Alex Hutchinson on this week talking about- Oh,
[00:37:37] Dr. Mike T Nelson: nice. I wanna listen
[00:37:38] Dr. Martin Gibala: to that one. Yeah. He's great. Uh, you know, if you had five hours a week to train, uh, what do you do, right? Mm-hmm. So you're a serious recreational athlete. You know, you wanna perform or race as high as you can, but you're a regular person.
[00:37:51] Dr. Martin Gibala: You have job, family commitments, uh, you know, and you might have five hours a week to train. How do you break up that, that time? And, uh, so we had a really interesting conversation with, with Alex, uh, about that.
[00:38:03] Dr. Mike T Nelson: Yeah, the one highlight I saw, which I made a note, I have to check into this more, was he was talking about the, was it Norwegian two-a-day threshold training?
[00:38:12] Dr. Mike T Nelson: Yeah. And it sounds like it was- Just kinda hang out at what lactate threshold, but do it twice a day. I think he was saying two days a week. Is that correct?
[00:38:21] Dr. Martin Gibala: Yeah, that's basically it, right? So it's, it's, um, double threshold training. Yeah. Uh, you know, that's really, uh, taken a lot of the training world by, by storm again.
[00:38:31] Dr. Martin Gibala: And, and you know, it, it's, it's interesting because for... You know, I think things come in and out of fashion, right? Mm-hmm. And that's the bottom line. For a long time it was, you know, polarized training, right? Yeah. Make your hard days hard, your easy days easy, and don't spend too much time in the mushy middle.
[00:38:47] Dr. Martin Gibala: Yeah. And now this is sort of- Charlie
[00:38:48] Dr. Mike T Nelson: Francis.
[00:38:48] Dr. Martin Gibala: Yeah Yeah. It's a seeming return a little bit to the mushy middle. But the idea is, you know, you're, you're getting close to, uh, you, but you're not redlining, right? And, and so you're pushing that, um, tempo, uh, type, uh, type, type training. But you know, Alex made a- another great point.
[00:39:05] Dr. Martin Gibala: You know, Mike Joyner always raises this, uh, point, right? You know, there was, uh, an Olympic final where sort of one through four, all four athletes trained in dramatically different ways. Mm-hmm. You know, one was only a long slow distance person, one was almost exclusively an interval trainer, and yet here they were, you know, a second or so apart, uh, in an Olympic final, right?
[00:39:26] Dr. Martin Gibala: So it, it just makes the point that, um, you know, there's, there's lots of different ways that an athlete could train to be successful, and I, I don't think we know the, you know, the, uh, the, the optimal way. And of, of course, it's very different depending on an individual, uh, their own physiology, what they like and enjoy, things like that.
[00:39:45] Dr. Mike T Nelson: With the, the two-a-day, the threshold stuff, do you think there's anything to... It kinda reminds me of the old, um, almost like for lifting, like the Russian block periodization, where we're really trying to just hammer on the set of adaptations, you know, per day and try to, and this is with high-level athletes, try to concentrate the stress within either one training session or two training sessions versus kinda splitting it out ov- over the week.
[00:40:10] Dr. Mike T Nelson: Or do you think it's as simple as getting high enough quality work in that time between those two sessions just allows you enough rest period where that second session is of a high enough quality to get the specific adaptation you're trying to attain on that day?
[00:40:28] Dr. Martin Gibala: Yeah, to my mind it's, it's more the, the latter, right?
[00:40:31] Dr. Martin Gibala: Mm-hmm. And, and, and you know, like, you know, w- we, we know, um, we can make things extremely stressful on athletes. Oh, yeah. And, you know, literally break them down. But it doesn't mean they're going to improve, right? Yep. And there's some classic studies out there where they did, you know, the same sort of very intensive training over two weeks versus six weeks.
[00:40:49] Dr. Martin Gibala: Uh, and in the two groups, all the physiological adaptations were the same, but only in the group that did the hard intervals over a six-week period did you see improvements in performance, right? And it speaks to the point you're making, you know, adequate recovery while still keeping the training, uh, stimulus, uh, s- sufficient, right?
[00:41:09] Dr. Martin Gibala: I, I think, you know, this is the, the art of coaching, right? When you take an athlete, uh, for that individual, how do you manipulate the stresses to keep it novel, to keep it interesting, uh, to, so that they, they, they, they, they keep improving.
[00:41:24] Dr. Mike T Nelson: Yeah. And how much would I think of these trends are just the belief of the athlete, right?
[00:41:30] Dr. Mike T Nelson: If they see all these people doing this, you know, two-a-day threshold training and they're seeing them all of a sudden do better, like subconsciously that, that's a very powerful placebo almost. Like, oh my gosh, like this, this is a thing, and look at all these examples of this person, this athlete, and this.
[00:41:47] Dr. Mike T Nelson: Well, well, I have to do this, so I, I, I'm already have an expectation effect that I should be also getting these results too.
[00:41:55] Dr. Martin Gibala: Yeah, absolutely, right? If you look at classic altitude training studies, you see that as well- Yeah. ... right? Where these individuals are already very high level collegiate runners, but you know, you bring them together for a training camp first, um, and almost all of them improve before you apply, uh, the altitude intervention.
[00:42:12] Dr. Martin Gibala: So there, there is something to that, um, for sure.
[00:42:16] Dr. Mike T Nelson: Uh, a little bit different topic, but what do you think about, at least in high-level athletes, the use of what appears to be... I kind of kind of call it, like, the carb wars of, like, who can now seemingly take in the highest amount of carbohydrates during, you know, say, like, a standardized one-hour period?
[00:42:33] Dr. Mike T Nelson: And it, it, it seems like every time I turn around, I hear some, you know, claim, which a lot of times is hard to verify, of just higher escalating amounts of carbohydrates and supposedly, like, increased performance to go with it.
[00:42:49] Dr. Martin Gibala: Yeah. So, you know, if you don't mind, another shout-out for our own podcast and, uh- Yeah, please do
[00:42:53] Dr. Martin Gibala: you know, the episode before- I was gonna ask you about the podcast ... the episode before Alex, we had Professor Louise Burke, right, who- Oh, I love Louise Burke ... without question is- Yeah ... the top sports nutritionist in the world, uh, talking about, uh... Of course, uh, we, we covered keto a little bit, but, uh- Mm-hmm
[00:43:07] Dr. Martin Gibala: carbohydrate versus fat, uh, loading for, uh, for performance. Um, so I, I'd refer your listeners to that if they might be interested in a detailed or a deep dive in, in some of these topics. But to your point, I, I think what we've learned over the last decade or so is that clearly, uh, there's multiple carbohydrate transporters in the gut.
[00:43:26] Dr. Martin Gibala: Uh, people can train, uh, the gut. Uh, seemingly athletes can tolerate, uh, higher... You know, at, at first it was, uh, 60 grams a minute, you know... or 60 grams an hour. Yep. Uh, you know, then went, went at 90 grams, now we're up to 110, 120 grams or so, uh, if you use these multiple transportable carbohydrates, uh, and, and you've trained the gut, and the athlete is someone who can tolerate those, those very high levels.
[00:43:52] Dr. Martin Gibala: So, you know, I, I think that's not the blanket formula for everyone, but if you are that type of athlete, clearly, uh, you can likely tolerate a higher amount of carbohydrate, uh, taking that on board. And as long as it escapes, uh, the gut, gets in the bloodstream, gets to the muscles, uh, seemingly can take advantage of that as well because, you know, as you know, maintaining a, a high level of carbohydrate oxidation is absolutely critical, uh, for the vast majority of high-level endurance athletes.
[00:44:23] Dr. Mike T Nelson: Yeah, and I don't think we have a tracer study yet in high levels of carbohydrates, do we? 'Cause I'm, I'm always curious in terms of just the mechanisms of is it getting all the way through? Is it just stabilizing blood glucose? Is it actually getting to the muscle? Is it being burned? Is it, you know, like you've seen with the mouth rinse studies, is there some sort of feed forward neurologic mechanism where your brain thinks, "Oh, we got tons of carbohydrates coming in, so we're fine"?
[00:44:49] Dr. Mike T Nelson: And yeah, the, the mechanisms of that always just are, I find super fascinating.
[00:44:54] Dr. Martin Gibala: Yeah, and, uh, and, you know, I'm not, I'm not following... Y- you know, there's only so much literature you can stay on top of, right? Yeah, yeah. So I'm, I'm not following the latest in this area absolutely closely, but, you know, we know from, uh, when the, you know, I'm thinking of the work of Asker Eukene droop and the- Mm-hmm
[00:45:11] Dr. Martin Gibala: their very elegant tracer studies, uh, you know, showing, um, you know, w- uh, that athletes were able to tolerate higher amounts, and importantly, they could oxidize, uh, this, uh, the, these higher amounts. And I, I, I sp- suspect the data's out there or coming, uh, in, in terms of these even higher amounts above 100 or so.
[00:45:30] Dr. Mike T Nelson: What do you think for the high performance, and what do you think is coming next in the, the future if you were to bet in the next couple of years? Like, what do you, would you kinda guesstimate as the sort of new emerging trends?
[00:45:42] Dr. Martin Gibala: Yeah, you know, I, I, I think a lot of these recovery stra- or, or purported recovery strategies are, are of interest, uh, right?
[00:45:50] Dr. Martin Gibala: And, you know, a, a lot of these are being... You know, oftentimes these are used or implemented, uh, and the science maybe lags behind or isn't as supported of it, and, you know, maybe some of this is placebo effects for athletes or they think it's gonna help them. Um, you know, I, I, I, I think, uh, some of the nutritional stuff is, uh, is, i- you know, maybe there's gonna be some newer nutritional strategies, uh, you know, uh, c- coming out, right, on, on the lines of the beetroot juice, and, um, and, and, and, uh, and, and, and, and things like that.
[00:46:22] Dr. Martin Gibala: You know, w- we were interested for a while in, um, exogenous ketone supplementation, right? Yeah. I, I, you know, I think most people accept that, uh, ketogenic diet, um, you know, can have a place, uh, for health and, uh, uh, w- weight loss and, and, and strategies like that. But clearly a ketogenic diet is, um, you know, is, is not ergogenic, uh, for high-level endurance, uh, athletes.
[00:46:48] Dr. Martin Gibala: I, I think that, um, you know, the, the data from Louise Burke, even on, uh, individuals like race walkers, um, uh, it, it, it, it's made that very clear, right? And your, your exercise economy is, is impaired, uh, when you, uh, uh, fat adapt. Um, but, you know, uh, ketone supplements, of course, the idea was that you could take advantage of this alternate fuel, uh, while not going through the severe period of, of carbohydrate or, or energy, um, restriction.
[00:47:20] Dr. Martin Gibala: Uh, our work, including in very high-level cyclists, showed that the ketone supplements were, were not ergogenic, and in fact, it appeared that they also, uh, impaired exercise economy. But now there's a lot of interest in, uh, ketone supplements during, uh, recovery, uh, maybe manipulating it with an altitude stress.
[00:47:42] Dr. Martin Gibala: So I, I, I, you know, s- s- another example would be, um, interval training when you apply a hypoxic stimulus on top of that. So, you know, I, I think, a- again, at the elite level, once you, uh, almost- ... optimize performance, there's only so much more you can do, right? But I think there's continued interest in these novel nutritional, uh, strategies manipulated with perhaps a novel exercise stress that, that might, uh, lead to some, you know, further, uh, further responsiveness.
[00:48:16] Dr. Mike T Nelson: Yeah. I mean, if I were to guess on that literature, I would say that like some of the Brandon Egan stuff where you're doing, uh, some type of high physical stress or hypoxia combined with some cognitive task. I think there... If I were to guess, I, I think there's something there just, again, this is anecdotal and worked with a handful of athletes and, you know, some marquee and others have published.
[00:48:40] Dr. Mike T Nelson: I, I think at a high enough dose, which you probably need an ester to get to that amount, I, I think there's, there's something interesting there.
[00:48:48] Dr. Martin Gibala: Yeah, absolutely right, and I think we've also learned that maybe there's a Goldilocks dose range, right? Sure. Like, at first it was, uh, get it as high as you can.
[00:48:56] Dr. Martin Gibala: Then it was like, okay, wait a minute. Maybe that- ... that is not beneficial. You know, maybe we wanna be in this two to three millimolar, uh, range, but, uh, yeah, some of that work is, I think, quite fascinating and is gonna continue to, uh, to evolve in the coming years.
[00:49:11] Dr. Mike T Nelson: Yeah. And then most of, and, you know, unless you're doing a tracer study or something like that, you're, you're really only looking at blood gluco- or blood ketone levels, and the argument I've had for years is that if your ketone levels are super high, does that mean it's not being distributed to the brain and the muscle?
[00:49:28] Dr. Mike T Nelson: Like, y- like, your sink is kind of backing up. And again, it's hard to, to figure out exactly where all the components are going for a certain dose, and then you've got different types and, you know, 1,3-butanediol, which gets converted to a diol and a partial ketone, and then you've got the direct BHB, and so it gets kind of messy pretty fast.
[00:49:49] Dr. Martin Gibala: Yeah. You know, I, uh, sometimes I've asked a question on my fourth year integrative physiology course, you know, is a, is a high blood lactate a good or bad thing, right? Mm. It forces the students to think about, okay, well, wait a minute. It probably means it's getting out of the muscle, so it's not changing the pH in the muscle.
[00:50:04] Dr. Martin Gibala: If I can tolerate a very high blood lactate and still perform, maybe that's okay. So it, it sort of speaks to the point you're making.
[00:50:11] Dr. Mike T Nelson: Yeah. Do you think lactate would be useful as a supplement?
[00:50:15] Dr. Martin Gibala: Um, not, not really. You know, and I, I think the data right now would say, uh, uh, no, right? It was interesting. I was on a, uh, a, a thesis defense earlier this week, and, uh, it's some of the work coming out of, uh, Wilfrid Laurier and, uh, Tom Hazel's lab.
[00:50:32] Dr. Martin Gibala: They're- Hmm ... looking at, uh, interval exercise lactate, but more appetite control. And, you know, there's- Hmm ... some evidence that, uh, lactate may suppress some appetite markers. And so I, I put it to the student, I said, "Boy, you know, would, would chronically s- uh, supplementing with, with lactate," right, or f- you know, rather than an insulin pump, you had a lactate pump.
[00:50:50] Dr. Martin Gibala: Yep. Could that be a beneficial strategy? Just, you know, I thought maybe a good, a good thinking question. But no, to your point, I, I, I, um, I, I, I don't think so. Um, you know, I, I, I, I, I think, uh, athletes who are, you know, producing high blood lactates in, in- endogenously, um, that's... And being able to sustain a high rate of lactate/pyruvate oxidation, that's a different thing from, from, from infusing it or supplementing with lactate.
[00:51:22] Dr. Martin Gibala: So my, my short answer is n- no.
[00:51:25] Dr. Mike T Nelson: Yeah. Yeah, I've been fascinated by that for a long time. My, my hypothesis is I, I think so, and I'd say maybe, but again, the early data, again, it's very limited, just isn't super supportive. But if you just think back and go, "Okay, if you could get it to where it needs to go," we know it's a super high efficient fuel.
[00:51:46] Dr. Mike T Nelson: It's just- All the other monkey motion that comes with it, and the hydrogen ions, and all this other pesky stuff that just shows up at the same time endogenously when you're producing lactate.
[00:51:58] Dr. Martin Gibala: Yeah, no, exactly, right? And, and, and pH regulation, ionic balance, it's such- Yep ... a challenging area, and so many things can influence that, right?
[00:52:06] Dr. Martin Gibala: So, um, yeah, it... You know, I always sort of go back to literature. What do we know from the limited evidence that's available? And to your point, it's not super supportive right now or suggestive of a ergogenic effect.
[00:52:18] Dr. Mike T Nelson: Awesome. As we get closer to wrapping up, just a couple more questions. Um, how, how trainable do you think fat max is, and how important do you think it is in the, the bigger sort of metabolic health picture?
[00:52:30] Dr. Martin Gibala: It's clearly trainable. I do think it's, uh, an important metric or something that people should maybe worry about. Um, you know, it's, it's arguably the best measure of metabolic flexibility, which- Mm-hmm ... uh, I think, you know, is generally defined as the ability to, uh, switch or be flexible in terms of your fuel choice, particularly between carbohydrate and, uh, and lipid.
[00:52:51] Dr. Martin Gibala: Um, you know, I, I think fat max is largely related to your muscle oxidative capacity and your, your mitochondrial content. But, you know, if, if people, uh, could have, uh, a, a sense of their, their VO2 max, right, the aerobic ceiling, as well as fat max, which is a, a really good measure of metabolic flexibility that doesn't require any invasive testing, uh, and I think those two markers could be, uh, extremely, uh, beneficial.
[00:53:17] Dr. Martin Gibala: You know, it's, it's funny, one of my mentors was, uh, Bank Stenzhorn from, from Copenhagen. Hmm. And I was, uh- Oh, wow ... having a, I was having a... I, I did a postdoc, uh, with Bank after I finished my PhD, which was amazing. And, you know, I was just... I was having a similar conversation. Someone asked me about, you know, what is metabolic fitness?
[00:53:34] Dr. Martin Gibala: And I said, "Well, it's not really defined in the scientific literature, but probably it's, you know, uh, equates somewhat with metabolic flexibility." And then of course I, I, I said, "Has anyone ever used this term?" And of course Bank had used it 25 years ago in a paper that's only available in Danish, but I thought- Oh
[00:53:50] Dr. Martin Gibala: of course, only Bank Stenzhorn was thinking about this 25 years ago. And, you know, now, uh, we're, we're, we're... I- it's become more of interest. But, you know, Bank was always well ahead of the curve in terms of thinking about these things.
[00:54:03] Dr. Mike T Nelson: Yeah. That's probably why David Kelly gets credit, because he probably was the first one in the sort of the US language, and that paper probably just didn't get translated.
[00:54:13] Dr. Martin Gibala: No. And, and obviously Dr. Kelly's advanced this, uh, this work- Yeah ... uh, tremendously. But, uh, yeah, no, to, to your point, I, I, I, I think fat max as an indicator of metabolic flexibility is, uh, is a useful, um, health-related, uh, m- measure.
[00:54:28] Dr. Mike T Nelson: And if you were to train it, how would you conceptually go about training it?
[00:54:32] Dr. Mike T Nelson: If it's low, what would you look at or what would you kind of consider doing?
[00:54:36] Dr. Martin Gibala: Yeah. Well, I, you know, I, I, I think there's two ways, right? You can raise the ceiling and keep the percentage the same, uh, or you could keep the ceiling the same and raise the percentage. You know, either of those is gonna increase absolute fat max, and ideally you'd wanna do both, right?
[00:54:51] Dr. Martin Gibala: So coming back to the start of our conversation, I, I, I would look for training interventions that have been shown to elicit improvements in both, right? So ideally you wanna do training that's gonna raise the ceiling, your VO2 max, and you wanna rai- uh, do training that's gonna raise mitochondrial content, mitochondrial capacity, oxidative capacity, because that, that's gonna allow you to oxidize both fuels at, at a higher rate.
[00:55:18] Dr. Martin Gibala: So, uh, you know, and in, in, in some ways it comes back to the start of our, our conversation, and I think an efficient way to do that is interval training. Um, but you know, it doesn't mean it's, it's, uh, it's the only way
[00:55:31] Dr. Mike T Nelson: Yeah. That's what I find also so fascinating, like the more I've looked at physiology of how...
[00:55:37] Dr. Mike T Nelson: 'Cause even when I started looking at metabolic flexibility, which was a topic of my PhD defense years ago, I just thought like, oh, the- 'cause we were always taught they're two separate silos. You got all your carb metabolism here and you've got your fat metabolism over here. And what we learn is that they're just so interconnected to each other.
[00:55:53] Dr. Mike T Nelson: And like you said, ironically, using more carbohydrates to do higher output stuff to raise your VO2 max long-term actually allows you the greater capacity to use fat as a fuel, which at first blush- Yep ... seems kinda contradictory, but they're not.
[00:56:10] Dr. Martin Gibala: Yeah. Abso- I mean, they all converge on the same point, right, which is acetyl-CoA- Mm-hmm
[00:56:13] Dr. Martin Gibala: which is the entry into- Yep ... oxidative metabolism. So from that standpoint, it's, uh, maybe not that surprising. But you're right, all of the extraneous transport capacities in that are, uh, are, are, are quite distinct, right? And, uh, fat versus, uh, carbohydrate transporters.
[00:56:29] Dr. Mike T Nelson: Awesome. Well, tell us about your podcast.
[00:56:31] Dr. Mike T Nelson: I know you're on there with our friend, uh, Dr. Stu Phillips, and you guys have had a lot of, like, super interesting guests so far.
[00:56:36] Dr. Martin Gibala: Yeah, no, I appreciate the opportunity to plug it. This has, uh, been a, a, a while in the making. Um, so it's called Exercise Science. Our tagline is Hard Facts, No Hype, and that's what we try to stick to.
[00:56:48] Dr. Martin Gibala: Uh, we take topics that are of broad interest to exercise, uh, physiology, roughly half on the strength side, which is more Professor Phillips', uh, strength, as you know, and, uh, and half on the aerobic side, and, uh, which is, which is more my, uh, forte. And to this point, uh, half the episodes have been either me interviewing Stu about a topic or vice versa, and the other half we try to bring on, uh, interesting guests who are either leaders in their field or, or have really thought about topics a lot and can shed light for our audience.
[00:57:18] Dr. Martin Gibala: Uh, it's produced by our friends, uh, Ghost Bureau out of Toronto. Hmm. Um, the, uh, lead partner there is, uh, Chris Shogan and, uh, Chantel Gerton. But Chris co-authored, uh, my book, uh, so that was, uh, when we first- Oh, okay ... uh, partnered. And so Chris has been in our ear saying, "You guys really should do a podcast."
[00:57:35] Dr. Martin Gibala: And as you would well know, you know, I respect the fact that you've done hundreds of episodes. Um, you know, w- we're happy to leave the production side to Chris. Oh, for sure. And, and Stu and I just worry about the science for the most part. But, uh, we're actually meeting next week to plan out, uh, season two.
[00:57:53] Dr. Martin Gibala: And so, you know, if there's any listeners who would, uh, like to float in some topics they'd like to hear or any feedback on the show, it's, uh, it's still early days for us, so we'd appreciate all of that.
[00:58:03] Dr. Mike T Nelson: Yeah. And I loved your little outtakes there where Stu said you were number one with your little backgrounds and stuff.
[00:58:09] Dr. Martin Gibala: Yeah, we were worried about that, but, you know, we, we wanna show that we're real people a little bit, and, uh, we make a ton of mistakes doing this. And, uh, Chris cleans it all up, so it's, uh, it's been a lot of fun to do so far. Stu and I have been friends and colleagues for a long time, you know, well over 25 years at McMaster, and so, uh, we've, we've had some, you know, some good feedback and, uh, probably the point being it doesn't just look like, you know, two guys recording it in their basement.
[00:58:32] Dr. Martin Gibala: So that's, uh- ... that's been some of the, the best praise that we've received, uh, so far, but it's been fun to do.
[00:58:38] Dr. Mike T Nelson: Yeah. And it's kind of a nice split between, you know, actual from exercise physiologists, like actual legit material and, you know, kind of about half strength stuff and half endurance stuff.
[00:58:49] Dr. Mike T Nelson: Because I think to me, like that's the next big thing in health and fitness is we'll hopefully stop arguing about, oh, is it strength or is it muscle size or is it aerobic stuff? It's, it's probably both. Like, you probably need both. Like, if you're really far off on one end, like you're gonna have some longevity issues.
[00:59:09] Dr. Mike T Nelson: It's not a either this or that, it's a both thing.
[00:59:12] Dr. Martin Gibala: No, 100%. You know, and, and both, both Stu and I, we're, we're interested in, you know, science translation, knowledge, uh, translation, science communication, you know, much like you're, you're doing here and I know highly committed to. So it's been, uh, it's been really nice to have the podcast as an outlet.
[00:59:28] Dr. Martin Gibala: Um, you know, and we're also trying to be aware of, as my, uh, friend, uh, Gary LeBlanc from Everme says, "You know, we gotta be aware of what's happening in the zeitgeist," right? Yeah. It doesn't mean there's a lot of evidence for it, but if people are talking about it, you know, we better be talking about it as well to say, "Yeah, there is evidence behind this," or, or, "No, there's not," right?
[00:59:47] Dr. Martin Gibala: So we're really trying to be mindful of, of, of what people are, are, are talking with right now and talking about rather and, and might like, um, to, to assess more robustly the, the evidence base for, for it or against.
[01:00:01] Dr. Mike T Nelson: Yeah. And I'll make sure to send all my peptide questions to Stu. I'm totally kidding.
[01:00:06] Dr. Martin Gibala: Yeah.
[01:00:06] Dr. Martin Gibala: Yeah. We, we got a little bit of feedback on the peptide episode. But, you know, to the point there, trying to have, have great guests- Yeah ... right? And, and Lee Backs was, uh, uh, tremendous, right? And works in this space, so, uh, very well dialed in and, and I think that was a very authoritative take on, on where things stand in terms of the peptide landscape.
[01:00:25] Dr. Mike T Nelson: Yeah, which I think is good because I think people want to know what does the actual data say? And then, hey, if you wanna do something crazy or whatever like that, that's up to you. But it- I just hope that people do things out of an educated stance, and I think a lot of stuff now is just not educated.
[01:00:44] Dr. Mike T Nelson: It's just the hype. It's the next trend. It's the next thing, and it's almost like everyone's doing it, so I feel like I need to do it. And yeah, so it's nice to see actual, like, legitimate science and saying, you know, "Hey, here's what we know. Here's what we don't know," and just, you know, kinda go from there.
[01:00:58] Dr. Mike T Nelson: Each person can decide on their own.
[01:01:00] Dr. Martin Gibala: 100%.
[01:01:01] Dr. Mike T Nelson: Awesome. Well, thank you so much for all your time today. We really appreciate it, and we'll make sure to link to the podcast and everything else. Thank you so much.
[01:01:09] Dr. Martin Gibala: Yeah, amazing. Thanks for having me on. I really appreciate the conversation.
[01:01:12] Dr. Mike T Nelson: Yeah. Thank you