The Tim Ferriss Show Transcripts: Dr. Martin Gibala (#217)

Please enjoy this transcript of my interview with Martin Gibala, Ph.D., professor and chair of the kinesiology department at McMaster University in Hamilton, Ontario. Transcripts may contain a few typos—with some episodes lasting 2+ hours, it’s difficult to catch some minor errors. Enjoy!

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#217: The One-Minute Workout Designed by Scientists -- Dr. Martin Gibala


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Tim Ferriss: Hello boys and girls, this is Tim Ferriss and welcome to another episode of the Tim Ferriss Show, where it is my job to deconstruct world class performers of all different types across every possible discipline to tease out the details that you can use and apply to your own life. This episode, we have a scientist who is also incredibly good at teaching. Dr. Martin Gibala, or Martin Gibala, Ph.D., is a professor and chair of the Kinesiology Department at McMaster University in Hamilton, Ontario.

His research on the physiological and health benefits of hi-intensity interval training, or HIIT, has attracted incredible scientific attention and worldwide media coverage. If you recognize the name, there are many reasons you might because he’s published more than 100 peer-reviewed articles. He has been featured by the New York Times, Wall Street Journal. He also appeared seven years ago in the Four Hour Body, because I followed his research and found it fascinating.

He is frequently invited to speak at international scientific meetings and has received multiple awards for teaching excellence; the reasons for which I think will become incredibly clear as you listen to this episode. He is the coauthor of the brand-new book, The One Minute Workout, and that may sound ridiculous but by the end of this episode, you will not think it’s ridiculous; you will think it is entirely scientifically support. We dig into some exact protocols that you can test yourself to take this for a test drive.

So, please enjoy my conversation with Marty Gibala. We do get into the weeds so if you’re having trouble grasping something, bear with us for 30 seconds and we’ll come out the other side and end up somewhere else that is perhaps more easily digested. It is a fun conversation; I had a blast and it is extremely applicable and practical so please enjoy.

Marty, welcome to the show.

Martin Gibala: Thanks, Tim.

Tim Ferriss: We were chatting very briefly via Skype video just a few moments ago and it was really nice to pair a face with the name because A) I’ve wondered who is this guy, because I’ve read your name so many times and written your name in The Four Hour Body, among other places; what you look like, and then B) how does he pronounce his last name? We have addressed both of those this morning and I’m very happy about that. Where are you sitting, just to place some context for people?

Martin Gibala: I’m at my desk in my office at McMaster University in Hamilton, Canada and again, we were chatting offline. There’s been a water main break out front so in Fahrenheit it’s about 50 degrees in my office today, which is pretty chilly.

Tim Ferriss: Well, you know, cold exposure is all the rage these days, although I suppose if you’re in Canada, it gets old pretty quickly.

Martin Gibala: Absolutely.

Tim Ferriss: Which department are you part of?

Martin Gibala: I’m in the Department of Kinesiology in a faculty of science.

Tim Ferriss: Could you just explain for people who may not know, what falls under the purview of physiology, or what is physiology?

Martin Gibala: Physiology is basically how the body works, so how the systems act in an integrative manner. One of the fascinating things about exercise is it stresses the body in unique and different ways so it makes it really, for me, an interesting topic to study.

I teach a fourth-year course called “The Integrated Physiology of Human Performance,” and in that course we talk about how the body’s systems come together to meet the demand of exercise. So, the cardiovascular system, the muscle system and for me, that’s what make it a really interesting topic.

Tim Ferriss: In that class, since you brought it up, what do students find most exciting or fascinating as part of that curriculum and what do they find most counterintuitive or difficult?

Martin Gibala: One of the main things they like is what regulates the performance of elite athletes, or simply put, what makes elite athletes great. So, a lot of students who come into kinesiology, not all of them but a lot have a background in exercise. They’re interested in sport.

So, what I try to do in that course is, if you will, trick them a little bit or cajole them into learning a bit more about how the body is regulated. So, we talk a little biochemistry, we talk a little physiology so that they have a really good understanding of how the body works. We often present that using elite athletes as an example because it’s a prism that can often ground them.

Another thing I’ll try to do in that class is all of the students have to perform a V02 max test on each other, and they have to feel what it is like to do a V02 max test. So, when we talk about an athlete pushing out 1000 watts, for example, or 1,500 watts or holding 400 watts as a pace on a bike, they know what it’s like to come close to that for a couple of seconds and I think it really helps to put it in context a little bit. Bot bottom line is they have an appreciation for elite athletes and then we talk about the underlying physiology.

Tim Ferriss: I have a few questions related to that. The first is a definition question, just for people listening because I think it will come up a few times. Can you define V02 max, and then can you tell people if it is malleable and if so, how malleable or improvable it is?

Martin Gibala: V02 max, or maximal oxygen uptake, also known as maximal aerobic capacity is the highest rate at which the body can take up and use oxygen. That’s typically during heavy exercise. So, how we would test is have an individual do progressively higher workloads; that could be on a bike, that could be on a treadmill and at some point your body is going to reach its maximum capacity to use oxygen. That’s important if you’re an athlete, but it’s equally important for health. So, when people talk about cardio fitness, what you’re really talking about is your V02 max.

It reflects the underlying ability of the cardiovascular system, the respiratory system so your heart, your lungs, your blood vessels to deliver oxygen to working muscles, and the ability of the muscles to use that oxygen to produce energy; so literally to burn fats and carbohydrates to produce fuel. If you’re going to be an elite endurance athlete, a high V02 max is necessary but not sufficient for success, because obviously there are lots of other factors involved. But the underlying physiology is the same so it’s also a really important parameter for your health.

Tim Ferriss: Is it a fixed metric the way people might think of height, or is it something that can be meaningfully improved?

Martin Gibala: No, it’s definitely something that can be meaningfully improved. We talk about this in my class. If you want to be an elite endurance athlete, we hear the phrase “pick your parents properly,” and that’s true.

Because in some ways, it’s a bit like a mortgage. There’s a fixed element and there’s a variable element. So, the fixed element is determined by things like the genetic capacity for your heart size, for example. But there’s definitely a highly variable element, and we know that because it can respond to training as well as de-training. A typical or average person if they do traditional endurance training for a couple of months, they might be able to boost their V02 max by 20 percent.

But it’s a highly individual value or parameter as well, and we know some people, their value doesn’t change very much even though they do highly structured training, whereas other people, they can change it by up to 100 percent. People may be familiar with the term “hard gainers.” There are some hard gainers when it comes to V02 max as well, but fortunately it’s a relatively small percentage. And to answer your question, it’s highly malleable in most individuals.

Tim Ferriss: I was chatting with Peter Diamandis not too long ago, a friend of mine; he’s the chairman of the X Prize and involved in many different companies. He is very good friends with Ray Kurzweil. They cofounded Singularity University together, which I think it is still hosted at the NASA Aims Center in Moffett Field, California. I remember he mentioned to me at one point at least two things, but two that really jumped out of the data that correlated to longevity, or maximal lifespan or flossing and high V02 max.

He said, “I’ll be the first person to admit that I think flossing might be correlation and not causation.” It could be that people who are anal retentive enough and disciplined enough to floss on a daily basis are also disciplined enough to do other things on a daily basis to contribute.

On the V02 max point, if you had to speculate– or maybe you don’t have to speculate – do you think that that is causative or correlative with the high V02 max and extended lifespan?

Martin Gibala: I think it’s causative for sure, and there’s a lot of data out there that would support that. Obviously, it’s tough to do a proper randomized clinical trial to look at something like that.

Tim Ferriss: To death with humans, yes; hard to get the IRB approval for that.

Martin Gibala: We know that if you look at, for example, mortality or risk of dying from all causes, there’s a concept called a MET, or a metabolic equivalent which I’m sure you’re familiar with, and some of your listeners may be familiar with that. It’s essentially a unit of measurement for V02 max. Individuals who have a 1 MET higher value; that translates into about a 13 percent lower risk of dying from all causes. Obviously, that’s correlational data but it’s based on fairly strong epidemiological evidence.

You might also be familiar, just a couple of weeks ago there was a paper in JAMA which was calling for V02 max or fitness, cardio-respiratory fitness to be a vital sign. So, it’s something that we should measure in the doctor’s office, just like we measure weight, and height, and things like blood sugar. The problem of course is that it takes some time to properly measure V02 max accurately, and obviously that’s not feasible in a lot of physicians’ offices. But there are now some very good online calculators that can give individuals a sense of what their value is.

Tim Ferriss: How do they approximate that online? I’m very curious. I’ve never taken one of these myself. I have had the great joy of having the garden hose stuck in my mouth and my nose clipped while I run on a treadmill; I have done that before. But I can see why a lot of doctors’ offices would not be super keen to have that as part of their 11 minutes with their patients. How do they try to infer V02 max from online inputs?

Martin Gibala: I’ve just seen this recently and actually put my own data in to see how accurate I thought it was. It was reasonable. It asks things like your age, your sex, things like that, your types of activities you habitually do, and it does ask for a measure of resting heart rate. So, based, I assume, on some parameters that relate to your habitual fitness level and also your resting heart rate; those are probably two of the main drivers.

Obviously, I don’t know everything that goes into the algorithm but that’s typically what it’s’ based on. I think probably these online calculators, the greatest benefit even if there’s an absolute error in the number, you would hope that it’s a fairly reproducible number.

So, if you do some training and your resting heart rate is lower; presumably the value it would predict for your V02 max would be higher. That’s what it’s based on. But as you say, having a V02 max test measured directly is the gold standard, but there are also some reasonable ways to estimate it based on running speed over a set distance, or a heart rate response to sub maximal exercise. So, I think it’s fairly easy and maybe we can leave folks with some tips on the online aspect of this interview with ways that they can get a sense of their fitness on their own.

Tim Ferriss: For sure. You said something I want to underscore for folks because it’s so important. Many of these tools, one could argue even most of these tools, are not 100 percent accurate in the absolute sense. But as long as they are consistently inaccurate, you can trend properly, right?

Which is also why it’s so important if people are trying to gauge body fat, which is notoriously error prone for a host of different reasons, that they’re using the same tool and if they’re using a practitioner or some type of clinician, that they’re using the same practitioner or clinician so at the very least they’re comparing apples to apples so they can trend properly and look at how an intervention like the training we’ll be talking about affects the numbers that they’re putting in.

Martin Gibala: Agreed; that’s an excellent point. If you’re looking at something like bioelectrical impedance, for example, to measure body fat percentage, there are some concerns around the absolute validity of that test. But when you use the same test repeatedly over time, it gives you a good sense, as you say, to know whether you’re trending positive or trending negative and that’s the important thing.

Tim Ferriss: When did you do your first studies or begin researching sprints or interval training, and what catalyzed that?

Martin Gibala: It would be around 2003, 2004 and believe it or not, it stemmed in large part from that course that we mentioned at the outset of the interview.

I’ve taught this course, “Integrative Physiology of Human Performance,” for quite awhile now. I think this is the 16th or 17th version of it. And it does go back to that idea of students who are interested in the training programs of elite athletes. They were often surprised by the fact that elite endurance athletes through the course of history surprisingly used interval training, either because they were quite time-limited, or because they really wanted to push their overall training volumes.

Or often, it related to the notion of time efficiency. One of the classic examples would be Roger Bannister when he was training for the assault on the four-minute mile; he was a very busy medical student who had about a half an hour at lunch to train. He would repeat short intervals around the track at a very high tempo.

So, that led to my initial interest in the topic, and then that led to some very simple early designs around some studies around how low can you go. So, a theme through my research has been time efficiency of exercise, and definitely this idea of how low can you go both in terms of boosting performance if you’re an athlete, but increasingly in terms of boosting health if you’re an average individual or someone with metabolic syndrome, or type 2 diabetes, for example.

Tim Ferriss: You’ve had a number of influences, and I’d love to just place these on a timeline as well because it’s such a fascinating set of research that you have and how it has evolved over time. Could you talk a little bit about Richard Metcalf and Tabata?

Martin Gibala: Yes, of course and a point I would make is that we don’t know what we don’t know. So, when I first got into this field, obviously we were very interested in the topic.

But over time, I’ve definitely developed an appreciation both for the scientific history of interval training, which goes back to at least the late 1950s and probably before that, and the athletic history which certainly dates to the turn of the century. We were influenced, of course, by some of the work that Tabata had done. He has a classic paper from the mid-1990s that led to Tabata style training. And there of course we’re not working in a vacuum; we’ve been influenced by other researchers as well.

You mentioned Richard Metcalf and there are some other researchers working with him in the UK who have had this similar type of question, and that’s this idea of how low can you go. So, Richard and some others had done a scientific study where they were looking at just two bursts of interval training lasting only 15 to 20 seconds, and showing that if subjects did that a couple of times a week for six weeks, they could boost their V02 max.

So, that was influential in terms of our research, and it led the design of what we call the “one minute protocol” or the one minute workout, which of course is a teaser headline; it’s not really a minute start to finish when you build in recovery and a short warm up and cool down. But it’s all variations on this theme that short, hard bursts of exercise can be extremely effective and extremely time efficient in order to boost performance and boost health.

Tim Ferriss: We’re going to talk plenty about that but I want to come back to Tabata for a second and ask you a question, or a few questions that were sent to me by a friend of mine who’s an MD, very accomplished athlete, and a huge fan of interval training. Maybe before we actually get to his first question, could you define for people what the Tabata protocol is?

Martin Gibala: The classic Tabata protocol is eight repeats of a cycle that involves 20 seconds of effort and 10 seconds of rest.

So, you repeat that eight times, and so start to finish the workout is four minutes in duration. The original classic study that was described was done on a bicycle, so bicycle exercise at an intensity of around 170 percent of V02 max. People might say if V02 max is max, how can you go at 170 percent of that? But it goes to the workload setting that you would have on the bike. So, you might have a workload, for example, of 300 watts and that’s sufficient to elicit your V02 max.

But you could work at above that value, or 170 percent of that value for very short periods of time. That’s the classic Tabata protocol, and as I say, it was described on a bike. Although over time, it’s probably more well-known to most of your listeners for more callisthenic-type style of training: Burpees, mountain climbers, air squats, things like that although the original protocol was described for a bicycle.

Tim Ferriss: Thank you. The first question from this friend of mine is is Tabata especially magical, or have the data been over interpreted? Keep in mind this is someone who is part of the choir, so to speak, not necessarily for Tabata but it’s been so widely discussed and so widely, I would imagine, maybe misinterpreted. But is the Tabata protocol particularly magical or have the data been over interpreted in any way?

Martin Gibala: I don’t think it’s particularly magical. I think Tabata is an example, and obviously a well known example, of the concept we were talking about. And that’s this idea that short, hard bursts of exercise can be extremely effective. So, the original Tabata protocol, the main outcome measure, was maximal aerobic capacity or V02 max. Tabata showed that short, hard intervals on the bike as we’ve described could be effective for boosting V02 max.

They didn’t perform muscle biopsies, for example. There weren’t a lot of underlying physiological measurements performed. That’s one of the additions to the scientific literature of our work, as well as other researchers that they’ve looked more mechanistically at what’s happening. So, for example, we’ve been very interested in short, hard bursts of exercise improving muscle health and boosting things like mitochondrial content in your muscles. There has been some overstatement in the fact that Tabata is viewed with almost these magical properties.

When it comes to Tabata style training that I think most people think of, and that’s body weight style intervals, there is surprisingly less scientific evidence that speaks directly to that. There are really only a handful of studies that have looked at Tabata style body weights and the effect on strength and maximal aerobic capacity. That being said, those studies have shown that it’s a very efficient way to train.

So, I think of it as a very good middle ground. The benefit in aerobic capacity that you’ll see might not be as great as if you do large amounts of other traditional endurance style training, and obviously the improvements you have in strength and hypertrophy are not going to be like heavy resistance exercise. But again from a time efficiency aspect, body weight style intervals provide a lot of bang for your buck.

Tim Ferriss: I think also perhaps what contributes to the smaller data set when it relates to the body weight training is that it would strike me as harder to measure, in some respects. If you’re using wattage, you can go from 100 percent to 170 percent with a lot more precision if you want to manage that and really look at how the inputs affect the outputs, or how different degrees of, say, super maximal effort affects the outcomes.

But it would strike me as a lot more difficult when you’re doing callisthenic type exercise in a research setting, at least.

Martin Gibala: You make a really good point. People ask us all the time why is most of our research done on a bike, and how does it translate to other types of activity. The main reason, as you say, we can quantify things like work and power very accurately so that enhances the scientific rigor of the study in terms of our ability to control the stimulus. And then we’re obviously often looking at very specific physiological markers that require us to perform invasive measurements.

Whereas if you’re just doing a set of Burpees, for example, it’s a little bit more challenging to precisely control the stimulus so that sometimes can go to the impact of the study, if you will. And there I’m talking the scientific impact because I have to worry about things like where I publish my papers, and journal impact factors, and things like that. But ironically, a lot of the public doesn’t care about an impact factor; they just wan to know if I do this type of training, will that benefit me.

So, there’s sometimes an inherent tension there between the scientific impact of a work, and really the translatability of a work and answering questions that people actually want to know about.

Tim Ferriss: Let’s talk about the scientific a little bit more because I think it’s easy for people who have had no experience in academia or research to talk about people in their Ivory towers doing all this theoretical this, that and the other that doesn’t translate without recognizing the importance of a properly executed scientific method if you want your data to be persuasive and defensible, which you really need first and foremost before you can prescribe some type of variant to be applied in the real world with some degree of confidence. But that’s not the question I’m going to ask, or related to the question.

What I wanted to ask is in your own research as it relates to interval training, what was the first study that surprised you in some way? Because you’re forming hypotheses beforehand, you have a lot of experience with physiology and exposure to interval training. Was there a particular study that sticks out for you as surprising even to you?

Martin Gibala: Yes. Our first study, actually, was one of our most impactful. I was influenced by a number of scientific papers, of course, but one of the most interesting to me was this group in Europe had taken two groups of subjects. They applied the same training stimulus to both groups. And the training stimulus involved 14 consecutive days of hard workouts. One group did them every day consecutively for two weeks, and one group did them every couple of days over a period of six weeks.

So, the training stimulus is the same, and really only all that was different was that obviously one group was getting recovery days. At the end of the study period, the physiological adaptations between the groups were virtually identical; so measuring specific changes in their muscles, or how much an enzyme level went up. But the performance was only better in the group that got recovery days. I’m sure your audience is listening going: duh, that sort of makes sense.

But it hammered home for me this idea that recovery was important. So, our first question was what if we had people only do two weeks of interval training, or the period of measurement is only over two weeks, but we give them those recovery days. That led to our initial study where we had people do six sessions of interval training over 14 days.

What we measured in that study, the two major outcomes, was endurance performance so basically time to fatigue on an exercise bike; how long can you ride a bike until you’re exhausted. The amazing thing was that subjects’ endurance capacity increased by 100 percent on average. Basically you could double endurance capacity with six sessions of interval exercise, and we’re talking this short, hard, sprint-type exercise. So, the type of intervals that people were doing only required them to do two to three minutes of very heavy exercise every couple of days.

We backed that up with some physiological markers. We took biopsies from the subjects’ legs, and we measured an important enzyme that relates to how well the body uses oxygen to burn fuels to produce energy. We saw that that enzyme increased by about 35 percent, if I recall.

Tim Ferriss: What was that enzyme?

Martin Gibala: It’s an enzyme called citrate synthase. It’s arguably the most commonly measured enzyme in exercise physiology. It’s a marker of the Krebs cycle or the TCA cycle. It correlates quite well with the overall amount of mitochondria that a subject has in their legs. Again, people have a pretty good sense of cardio health and what that means; the ability of your heart to pump blood and deliver oxygen. Citrate synthase or mitochondrial content is a pretty good marker of muscle health; how well your body can utilize the oxygen that gets delivered to produce energy.

It’s also important for things like predicting your risk for diabetes. If you have a higher citrate synthase content in your muscles, your risk for developing type 2 diabetes tends to be lower. But the short answer is when people did the six sessions of intervals over two weeks, they doubled their endurance capacity and they markedly increased the amount of this enzyme in their muscle. That’s where I really sat back and went: wow, maybe we’re onto something here.

As a cautious scientist, the first thing you do is you tell your grad students: make all those measurements again; show me that the data are reproducible. Because when we first published that study, I don’t want to say there was opposition but there was skepticism, to be sure. And certainly we were happy as more research studies were conducted, both in our own lab and around the world, verifying some of these initial findings.

Tim Ferriss: Quick question on methodology because I’ve always been very curious about this. I’ve been a test subject in a number of different experiments that were not designed by the amateur professional dilettante, which I know is a contradiction in terms – Tim Ferriss – but actual, legitimate scientists at places like Stanford. I was part of a body cooling experiment, or the intervention was body cooling using a vacuum and a glove, of all things, looking at heat exhaustion and marching in saunas. It was a disaster in terms of just subjective experiences; it was pretty miserable.

I’ve been a participant in a number of different labs, and I’d love to know in your lab what is the right way to identify when someone on a bike has ridden to exhaustion. How do you define that? Because of course if you have rats, it’s a lot easier. This is not something I’ve personally done but I know they’ll do swim tests, and to exhaustion means the rat basically doesn’t necessarily drown because it probably doesn’t die – or it might – but they put them in a bucket and let them swim until they can’t swim anymore.

Not as easy to get approvals to do that with, say, college students or other human subjects. So, how do you define and determine when someone has ridden to exhaustion?

Martin Gibala: We would measure or define fatigue as a point at which subjects are unable to maintain the power output.

So, if we’re going to have you ride at 200 watts, you could ride at 200 watts for a certain period of time and then literally you get to the point where you’re unable to turn the pedals. So, what typically happens is you’ll see cadence fall. So, if someone’s maintaining 90 revolutions per minute, obviously the force per revolution or the load per revolution will seem a little bit lighter than if they’re only riding at 50 RPM. So, we use bikes that are electrically braked cycle ergometers so that we know, regardless of how fast a subject is turning the pedals, the workload is the same at 200 watts.

So, as people approach fatigue or exhaustion, they literally can’t turn the pedals. For us, it’s usually defined as their RPM is falling below 40, because that’s where the manufacture will guarantee the workload setting on the bike. What you find is they tend to hit exhaustion pretty quickly, so it’s not very hard to figure out when they have to literally stop.

Sometimes we’ll use time to exhaustion tests but as a colleague, Mark Hargraves will say, “There are no Olympic events in time to exhaustion.”

Tim Ferriss: That would be a riveting spectator sport, though.

Martin Gibala: Exactly. So, most athletic events are you need to cover a set distance as fast as possible. That’s why certainly more recently but often in our studies we’ll use time trials as well, where subjects will have to complete a set amount of work. We’ll say think of this as a ten kilometer bicycle race and as they go through, they’re able to see elapsed distance or work done so they can work towards a goal, and again it more closely simulates normal athletic competition.

Tim Ferriss: You mentioned citrate synthase, which I remember having a biopsy done in South Africa at Tim Noke’s facility, who has some really interesting thoughts on central governors and so on.

But I remember coming into look at the results, and I’m effectively below the Homer Simpson sedentary line in my citrate synthase in I think it was the vastus lateralis or maybe it was medialis they took it from in the quadriceps, which is obviously something I should address. Could you please describe what mitochondria are and why they’re important, and how citrate synthase relates to mitochondria, if at all?

Martin Gibala: Mitochondria are often termed the powerhouse of the cell. They are these specialized organelles, or a component of a cell where fuel is converted into energy using oxygen. So, obviously the internal processes there are quite complex, but essentially mitochondria suck in fuels like glucose and fats and use oxygen to combust, to burn those fuels in order to produce cellular energy in the form of ATP.

People may have taken a biology course or read a textbook, and you’ll often see mitochondria as these bean-shaped organelles in a two-dimensional image on the page. Certainly what we know now is they’re much more complex networks that run throughout, in this case, the muscle cells. So, they’re very impressive structures. When you have mitochondrial biogenesis or an increase in mitochondria, it’s a bit like an expansion of this intracellular network. So, if you imagine a garden hose, it would be a bit like the garden hose growing more tentacles and this network expanding throughout the muscle cell.

Mitochondria contain many different enzymes that are involved in this process, called oxidative phosphorylation, which is just another name for that process of producing cellular energy. A common enzyme that’s relatively convenient to measure because if you’re going to try and assess mitochondria, you need some different markers and some of these markers are better than others. But citrate synthase is a specific enzyme located inside the mitochondrial compartment or network, and that enzyme is involved in oxidative phosphorylation.

So, the measurement of the content of that enzyme provides a pretty good index or a marker of the overall mitochondrial network capacity.

Tim Ferriss: Got it. So, when you are tracking mitochondrial improvement, per se, through high intensity interval training, is citrate synthase the primary marker that you’re tracking? Or are there other markers or, for that matter, graphic representations of density of mitochondria or something else that you’re looking at closely?

Martin Gibala: We almost always measure citrate synthase because again, it’s a fairly robust and commonly accepted marker of mitochondrial content. Ideally, though, we’ll include other measurements as well, either performed in my laboratory or through collaborations with some other scientists, both at McMaster and elsewhere. So, typically, we’ll measure a suite of enzymes, so not just citrate synthase; we’ll measure a couple of other ones as well. Sometimes we’ll measure what’s known as mitochondrial respiration.

This is just another way to demonstrate how much oxygen the mitochondria are using. You can see, for example, an increase in mitochondrial respiration rate after training. And sometimes we’ll measure molecular compounds that are signals that mitochondrial biogenesis is taking place or in the process of taking place.

Some of our studies, for example, are acute exercise studies. We’ll have someone do a single bout of exercise, and then we’ll take biopsies in recovery and we’ll say okay, the mitochondrial synthesis pathways, are these activated? And we’ll measure certain proteins that are representatives of that. Other times, we’ll do training studies and that’s where we would commonly measure citrate synthase and some of these other markers to show that these enzymes had, in fact, either the maximal activity or the content had increased owing to the training protocol.

Tim Ferriss: So, to jump to protocol or go out to the 30,000 foot view a little bit, I remember doing some reading in prep for this conversation, and finding I guess an assertion – I haven’t looked at the data behind it – that even interval walking in many respects could be considered more effective than steady state walking for catalyzing health improvements.

Why is that? Why does this type of oscillation in effort have profound effects, and why does it apply to something at a low level of output like walking all the way up to sprinting? What does interval training do to the training?

Martin Gibala: It’s a great question. We can get into some of the details and it’s certainly something that keeps me interested as a scientist; trying to figure out the mechanisms at play here. Your question also raises another point that I think is important to note. And that is that interval training is almost infinitely variable. People have this idea in their head of what interval training looks like, but for some individuals interval training is just if your only exercise is walking around the block, picking up the pace for a couple of light posts and then backing off.

That’s gentle interval training; you’re just interval walking, as you alluded to. I would often give that example for more deconditioned individuals; that’s what interval training looks like for them. But there is certainly scientific evidence to suggest that that type of training, just veering up the pace a little bit, is going to be more beneficial than continuous steady state walking.

Just to cite one, quick example there’s a study out of Denmark that was looking at individuals with type 2 diabetes. They divided them into one of two groups; one that did steady state walking that elicited about 66 percent of their maximal heart rate, and the other group did interval walking that the overall average intensity was the same; 66 percent.

But they would just pick up the pace a little bit; maybe go to 70 percent, and then maybe back off a little bit. After several months of training, what they found was that the interval walkers, even though the total amount of exercise done was the same, their fitness was improved o a greater extent.

They had lost more body fat, their body composition was superior, and their average blood sugar had decreased by a greater amount even though the total amount of exercise that was done was the same. That goes to the question of why.

Tim Ferriss: The lowered fasting glucose being reflective of the greater ability to utilize glucose by mitochondria or muscle in general?

Martin Gibala: Yes, also a greater ability to store it, as well. So, a question is always if you lower your blood glucose, where does that glucose go? Part of it is probably an enhanced ability to store the glucose inside skeletal muscle, for example, as stored glycogen. We know that exercise training almost of any sort increases the muscles’ ability to take up glucose so glucose transport capacity increases.

That also is a function of exercise intensity. So, when we have done some of our interval training studies in people with type 2 diabetes, we see that there can be marked increases in glucose transport capacity and the amount of glucose transporters that these subjects have in their muscles, following a period of training.

Tim Ferriss: You’ve done many different I’m sure personally variations of interval training. You’ve designed studies and imposed said regimens on many different subjects. I’m going to give you a profile and this is out of pure self interest. Let’s just say you had a former competitive athlete with more than a few injuries but nothing hugely debilitating, maybe a sprained ACL in the past, some issues with planter faciitis, etc.

So, not generally going to be looking for any type of sprinting on, say, flat ground where my risk of tearing a hamstring at the end range or something like that, which has happened before; who is willing to put in some time, but not too much, if that makes sense. I’m not looking for the absolute, bare minimum that would elicit a change; I’m looking for the minimal effective dose that I might experiment with which would produce hopefully a profound change of some type, or improvement over my baseline which is pretty shitty, to be quite frank.

I’m not an endurance athlete by any stretch of the imagination and my V02 max is quite poor. What might a protocol look like for me to start with?

Martin Gibala: I’d probably probe that individual or ask you, for example, for a little bit more.

Tim Ferriss: Yeah, you can ask me.

Martin Gibala: What are the goals, here? Are the goals boosting cardio-respiratory fitness for health? is it more from a performance element? What is the goal of the exercise training program? Is it general maintenance of health and fitness in a very busy life and trying to fit that in as best you can?

Tim Ferriss: For me, it would be in a generalized sense improving endurance and V02 max not for any particular sporting event, but for general application. I went to a high altitude in Colorado last year for five or six days and it was, I would say, ten to 12 hours of very high intensity hiking per day, often at a very steep incline. So, for A) generalized cardio-respiratory and muscular endurance, and these are not in order of priority.

And then B) for ostensible life extension purposes; that’s it. I’ve always been more of a power athlete or strength athlete than an endurance athlete. It would be – fun may not be the right word, but it would be worthwhile I think for me to establish a baseline and then attempt to improve the markers that matter and watch that over time.

Martin Gibala: I would say then if you could give me three 25-minute blocks of time a week, so let’s say we’re going to design this to be a 25-minute session of training that you do three times a week. We’ll have a very short warm up and a very short cool down. So, let’s assume we have 20 minutes to work with where we’re actually putting out some effort.

Tim Ferriss: Not to interrupt – I apologize – but I’d love to hear what you would recommend for warm up and cool down, also.

Martin Gibala: The warm up and cool downs would be quite short. Let’s describe the protocol. What I’d have you do is come in and do two minutes on the bike at a low workload setting to warm up. I’m saying the bike because you alluded to maybe some joint or connective tissue issues there with the hamstring. Many people have aging knees; I put myself in that category so all of my interval training, or almost all of it, is on a bike. But the warm up would be brief and it would be perhaps 75 watts; so a low workload setting.

Then we’d get right into the hard work. From the outset, let me say we would always recommend that someone see their physician before they begin or change an exercise routine. So, let’s get that out of the way. In our studies, even individuals with type 2 diabetes, metabolic syndrome, we typically keep the warm ups and the cool downs quite short because otherwise, it detracts from the time efficiency.

So, in almost all of our studies, the standard warm up is two minutes and the standard cool down is three minutes. That’s typically just very light cycling; unloaded cycling or maybe at a very low workload setting, as I said around 50 watts or so.

Tim Ferriss: I’m going to ask a nitty gritty question, and I apologize. What type of bikes do you use for these studies, in terms of make and model?

Martin Gibala: We use a variety of bikes. At home in my basement I have a 95 C Lifecyle that I use. Inside of our research laboratory we have a couple of different bikes. We have Lode Excalibur Sport, which are one of the Cadillac versions on the market.

Tim Ferriss: What was the first word in that name?

Martin Gibala: Lode, L-O-D-E. It’s a company out of Germany. They would be a gold standard ergometer that a lot of exercise physiology labs would have.

We’ve also used Racermate bikes in the lab and we’ve also recently purchased a couple of Kettler bikes, which are certainly cheaper than Lodes but they’re electrically braked ergometers so they’re quite accurate in terms of holding the power output that’s set. So, we use a couple of different bikes but those would be the ones.

Tim Ferriss: Gotcha. Sorry to interrupt. So, we’ve gone through the two-minute warm up with potentially 75 watts.

Martin Gibala: Right. Then I would have you do a series of hard intervals that last between three and five minutes. So, let’s say if you have 20 minutes, to start, to pick one we’ll do three five-minute efforts with a little bit of recovery in between. So, I’d have to check my math but that would basically be 15 minutes of hard riding within that 20-minute period.

I would structure initially the intervals to last between three and five minutes. We would adjust the workload setting appropriately so let’s say you’re doing three-minute repeats; you don’t want to go much more at the end of those three minutes. But if I give you a period of recovery, you’re able to repeat the three minutes a couple of times. Or if it was a five-minute interval, it would be the same thing. We would set the workload so the intervals are challenging, and you’re almost ready to give up where you’re getting towards the end of the three- or five-minute interval.

But then we give you a little bit of a break, and you do it again. And why I say the three- to five-minute intervals, if you look at the literature, and there have been a number of review articles and meta analyses that have been conducted, and just through practical experience with coaches and athletes, many would recommend that that repeated intervals of three to five minutes in duration is going to provide the most effective stimulus for boosting V02 max.

That’s where I’d start but we would vary it up, as well. Another common protocol is what we call the ten by one. So, one minute of hard exercise with one minute of recovery, and you repeat that ten times. So, there’s no magical or best formula but I’d probably start with those three to five minutes because based on the literature, that would be my best guess for boosting your V02 max.

Tim Ferriss: During the interval – and of course you would calibrate this as you’re working with the subject – but how would you determine the wattage setting to start with?

Martin Gibala: Again, if it was you, ideally how we’d do this in the lab for example, if we had the opportunity to do it in advance, we would have you come into the lab and perform a V02 max test. Typically in our lab we use Ramp V02 Max Test so we have a very standard protocol of if we increase the workload setting one watt every two seconds.

Basically what it feels like is you’re climbing up a hill that gets steeper and steeper and steeper. It starts out pretty easy, and then the workload catches up on you over time. Why we like the ramp test is again, at some point you’re going to hit exhaustion or fatigue, and I can say: Tim, your peak power output was 388 watts, or 452 watts. Then we would begin by taking percentages of that peak power output…

Tim Ferriss: Got it; that peak power output becomes your 100 percent.

Martin Gibala: Exactly. We know from experience that there’s always a little bit of trial and error. But if you’re a relatively fit individual, you might be able to do repeats at 90 or 95 percent of that peak power output and hold that for a couple of minutes. Whereas other individuals, especially those who are very deconditioned, if I put them at 60 percent of peak power output, they would struggle to last for one minute.

So, that’s where knowing a little bit about the typical training background of the individual comes into play, but there’s always a little bit of trial and error there. The other way we could do it if we didn’t have access to that V02 max test in advance, is say okay, we want you on these ten by one intervals ideally to get to 85 or 90 percent of your maximal heart rate during every interval. Then we could adjust the workload setting in a corresponding manner. So, we can either do it very objectively based on wattage, or we can do it more subjectively based on heart rate responses or even ratings of perceived exertion.

Tim Ferriss: Got it, that makes sense. The ten by one, that is ten pairs of one minute hard, one minute easy, effectively? So, you have ten sets, per se, of single minute hard so it’s a total of 20 minutes?

Martin Gibala: Correct. Again, we’ve used that protocol extensively in our research. We didn’t design it. As I learn more about the scientific literature, this was a very common protocol used in Germany in the mid-‘80s on individuals in cardiac rehabilitation settings. So, that’s a protocol that I think has wide applicability. We’ve used it on individuals with type 2 diabetes. My colleagues and others have applied it to individuals with cardiovascular disease in a cardiac rehabilitation setting.

And we’ve used it on very fit, young men and again, that’s where we scale the percentage of PPO. But in all of those individuals, it’s been effective to boost their health outcomes and boost their maximal aerobic capacity as well.

Tim Ferriss: PPO, not to be confused with HMO and PPO in healthcare in the U.S.; that’s the peak power output?

Martin Gibala: Correct.

Tim Ferriss: Okay. How do you determine just for the sake of illustration, the three- to five-minute intervals times three versus the ten by one? Which subject to apply one of these protocols to?

Martin Gibala: Probably the deconditioned individuals we would start with shorter, more frequent repeats. One of the reasons I think the three to five minutes is so effective for boosting V02 max is it’s challenging to maintain a relatively high workload for a period of time of three to five minutes or so; that’s very challenging. The way that even the energy systems in the body are utilized to produce energy to sustain that is different. So, I think the more deconditioned the individual, the more effective protocols and the more tolerable programs for those individuals involve more frequent repeats that last a shorter period of time.

And then of course the progression is either increasing the workload and keeping the protocol the same, or if you play this out what you basically do is increase the work interval, decrease the recovery interval until at some point, that individual might be able to sustain 20 minutes of continuous exercise at that pace.

Tim Ferriss: I suppose it depends, as with many things, on your goals. In the case of the goals that I laid to before we chatted about the protocol, for the three- to five-minute intervals, is it pure rest in between those intervals or is it easier cycling and why?

Martin Gibala: Good question. Ideally we want the recovery to be active.

Tim Ferriss: Why is that?

Martin Gibala: One of the reasons is especially when you do very hard exercise and then you completely stop; the risk of things like fainting is increased. That’s because you can have a fall in blood pressure when you stop after doing very hard exercise. One of the reasons for that is: you have all this basil dilation of opening of the vessels, especially in the legs, and you have a pooling of blood in the lower extremities.

One of the reasons people can faint after doing a very vigorous bout of exercise when they stop, is that they have this pooling in the lower extremities. They don’t have the venous return or pushing the blood back to the heart, and of course the blood flow to the brain then transiently decreases and so you faint. So, one is a very practical reason, and that is we want to minimize the risk of fainting, especially in some of these older or deconditioned individuals. And of course the risk of fainting is higher, the more intense the previous exercise. That’s a very practical consideration.

Also, you want to just keep the blood flowing a little bit; flush out some of these metabolites you’ve produced during the previous hard bouts so that’s a consideration, as well.

All things being equal, active recovery at a very low workload setting is preferred. But let’s face it; sometimes these intervals are very, very demanding and people would rather just stop and wait. If you’ve ever done a Wingate fest, you don’t want to do much exercise in the subsequent few periods of recovery. You just want to stop and maybe sit on the ground. This is where there’s that tradeoff between the preceding intensity and what the recovery might look like.

Tim Ferriss: And with the active recovery in this case, so we’re doing three sets, per se, of three- to five-minute intervals; let’s just say five minutes. If the warm up was at 75 watts, what would the wattage be on the active recovery?

Martin Gibala: We would keep the active recovery quite low as well, so maybe even going back to 75 or maybe 100 watts.

It goes to then you don’t want to work to hard, frankly, in the recovery periods because that’s going to take away from your ability to put out the hard efforts when you’re really going for it. Surprisingly, you’re heart rate, your oxygen uptake; your metabolism stays up very high during these recovery periods, even though the actual workload setting can be quite low.

This saw tooth pattern of going hard and then taking a break, and what I mean by taking a break is keeping the recovery periods active but the workload setting quite low; that’s important because that allows you to sort of refuel a little bit, recharge and be able to go hard in the subsequent interval.

Tim Ferriss: I’ll just call it the rest period, even though we’re talking active recovery; how do you decide on optimal rest period? The reason I ask is for instance in strength training, if you’re looking for hyper traversas maximal strength, the rest periods can vary dramatically.

You might have power lifters who take five to ten minutes between sets because the want to, among other things, completely regenerate creatine phosphate and so on. How do you determine the optimal rest period in between these intervals?

Martin Gibala: It’s a really good question. Part of it is definitely the metabolic considerations you alluded to there. Are subjects able to restore their phosphocreatine reserves within their muscle? Generally speaking, you can replace about 50 percent of your phosphocreatine within a minute or so. And if you get four minutes of recovery, you can have near complete restoration of phosphocreatine, and that of course depends on a couple of factors.

Part of the consideration then is how much we want to allow the individuals to refuel. But the considerations that go into it, and this is where it comes back to that first question that I asked you, what’s an individual’s goals?

What time do they have available for the workout? Because you can allow ample periods of recovery but especially if you’re talking about this notion of time efficient exercise, recovery periods can’t be too long. So, sometimes there are practical considerations that we will take into play there.

The other is the fundamental question, and we honestly don’t have the answer to it, and that is, is it the absolute power that drives the adaptation or is it the relative stress? So, to put that in another way, I could have people do intervals in a glycogen depleted state, or with full carbohydrate restoration. If they’re glycogen depleted, their power outputs are going to be lower and they’re going to feel a lot crappier. But the adaptations may, in some respects, be a little bit better.

To put that in the context of recovery, if we don’t allow “full recovery,” the subsequent power output in the other intervals is probably going to be lower but the relative stress on the individual is going to be higher. So, I think it comes back to this idea of variety. Variability is a good thing because we’re just hitting the body in so many different ways. So, for most individuals, there is no single best program and varying up the intervals is a good strategy.

And just to add there, obviously if we’re talking about an elite athlete and we have a very specific coach who knows this very specific athlete very well, the program is going to be very tailored and very precisely figured out. But more generally speaking for an individual even like yourself, I think varying it up is a good approach.

Tim Ferriss: How frequently would you do the three times five minute effort workout? How often, meaning how many times per week, for instance? Or how many rest days in between?

Martin Gibala: This is where again it goes to the goals of the individual, but I would say these intervals can be challenging; clearly mentally demanding and fatiguing. So, if you’re an individual who can tolerate three sessions per week of this type of training, great.

Tim Ferriss: Oh, that’s right; three times a week is what you said.

Martin Gibala: But some individuals can’t tolerate that so that’s a consideration, as well. What I will say is in the vast majority of our studies, we use a protocol of three times per week in our interval training for two, six, or 12 weeks; however long the study is going to be.

Tim Ferriss: How does what we just spoke about differ from the namesake of the book, which is the one minute framing? What does that refer to?

Martin Gibala: The one minute workout, which is the title of the book, again it’s more of a teaser headline but it specifically refers to a protocol that we devised where the work involved is three 20-ssecond efforts. So, the total amount of hard work during a workout, if you will, is only one minute and that one minute is broken up into three intervals that last 20 seconds in duration. Now, those intervals are truly all out exercise. So, the workload setting on a bike is very, very high, and the pace I would use to describe it is sprint from danger pace, or the pace you would cycle at to save your child from an oncoming car.

This is very demanding exercise. But what we’ve demonstrated is that type of exercise can be extremely effective. There’s clearly an intensity duration tradeoff; the more intense you’re willing and able to work, the smaller the volume of exercise you can get away with and still reap benefits.

And it’s not necessarily a linear relationships; it’s almost an exponential relationship. So, we’re talking about very short, very, very hard efforts. It’s a surprisingly small dose that you need in order to trigger a lot of these adaptations.

Tim Ferriss: What type of rest intervals do you have between these 20-second efforts?

Martin Gibala: We had done a number of these studies with I mentioned Wingate exercise before, these 30-second, all out efforts. Then we would give people a couple minutes of recovery, and they’d repeat that four or five times. We were sensitive to the criticism, the legitimate criticism that when you do these Wingate training protocols, they require about a 25 or 30 minute time commitment. So, yeah, it’s only two or three minutes of exercise but it’s a half hour of time commitment so it’s really not that time efficient, especially when we place it up against the public health guidelines, the lower end of which is 75 minutes of vigorous exercise.

[So, we wanted to come up with protocols that were unquestionably time efficient. So, the standard one-minute workout, if you will, involves that two-minute warm up and three-minute cool down, so that’s five minutes of warm up and cool down. And then the hard work is a 20-second effort, two minutes of recovery.

The second 20-second effort, another two minutes of recovery, and the third and final 20-second sprint. So, you basically have a five-minute work period which involves that one minute of hard exercise. So, bottom line, the protocol including warm up and cool down is ten minutes start to finish, but within that ten minutes you’re doing one minute of very vigorous exercise.

Tim Ferriss: In subjects who are deconditioned, or let’s just say relatively untrained; these are not people who engage in any type of regular leg dominant or certainly leg inclusive workouts; these are not people going for steep hikes three times a week, or doing any type of cycling, or high rep squat workouts or anything like that. If you were to take a huge sample of, say, a thousand people, what type of improvements would you be looking for or expect on average and in what markers?

Martin Gibala: First point to make is most of these studies are relatively small, and so that idea of the large study with 1,000 people, those are really some of the studies that need to be done in interval training research; maybe we can get into that later. But in our studies, to give you one specific example, we’ve compared that one-minute protocol so involving one minute of exercise within a ten-minute time commitment, and people do that three times per week.

So, the sprint group, if you will, is doing three minutes of intense exercise within a 30-minute time commitment each week. We’ve compared that protocol to a group who does traditional cardio, or the type of continuous steady state training that’s reflected in the public health guidelines. So, the other group that we compared them to is doing 50, five-zero, of continuous exercise three times per week.

So, one group doing 150 minutes of traditional, moderate intensity cardio; the other group doing a 30-minute interval workout but within that 30 minutes, it was only three minutes of very intense exercise. In our most recent study, which was 12 weeks in duration, the key outcome measures were V02 max as we’ve talked about, we measured citrate synthase so a marker of muscle health by taking biopsies.

And we also measured what we call their glycemic control; an index of their insulin sensitivity, basically how well the body utilizes blood sugar using a test called an intravenous glucose tolerance test where you literally infuse a bolus of sugar into people’s veins and you watch how that sugar is handled over a period of time. It’s a relatively robust marker of insulin sensitivity.

What we found after 12 weeks is despite the huge difference in time commitment, all of the markers improved by the same extent on average in the two groups. So, the improvement we saw in V02 max was 19 percent on average over 12 weeks, and that was the same in the two groups. We saw about a 30 percent increase in that marker of their mitochondrial content; again quite similar in the two groups.

If anything, it was a little bit higher in the interval training group and the same for insulin sensitivity; the improvement that we saw statistically was the same but it tended to be a little bit higher in the interval training group. So, a real striking example, I think, of the potency of interval exercise, especially these short, all out intervals to elicit changes that we more traditionally associate with public health guidelines-type research.

That’s not to say at all that we’re criticizing the public health guidelines. It’s just a striking illustration of the fact that you can elicit a lot of these traditional cardio responses and muscle metabolic responses and health responses using these short, very hard bursts of exercise.

Tim Ferriss: How would you suggest people begin a program like this? And maybe the answer is what we already talked about. Whether it’s the three- to five-minute intervals. What would you suggest as a starting rest interval?

Because we talked about the benefits of potentially replenishing phosphate creatine but then also the potential improvement, the magnitude of change if you’re operating from a deficit, per se. Where would you suggest I start, for instance, if I’m doing these three five-minute efforts; how much rest would I take in between with the easy pedaling?

Martin Gibala: If we’re going to the 20 minutes that we were talking about there, if you built in five-minute intervals with two minutes of easy pedaling, or I guess it would be two and a half minutes of easy pedaling; that would add up to your 20 minutes. So, five minutes, two and a half minutes of recovery, another five minutes, two and a half minutes of recovery; and then the third and final five-minute effort.

If we were doing three-minute repeats, you could do a series of five by four. So, three minute effort, one minute of recovery, and repeat that five times and that would add up to your 20 minutes.

So, again, I think someone like yourself, I would lean maybe towards the shorter recovery because you’re already in relatively decent shape, of course. And so ideally you want to do as much high intensity work as you can within that 20-minute timeframe. Now, if we were to move you to the one minute workout, of course you’re going all out so the efforts would be extremely demanding and the peak power outputs that someone like you could elicit are obviously going to be much higher than someone who’s not in as good a shape or someone who is more deconditioned.

So, there are a couple of ways to answer your general question. The first is what we’ll generally tell people is just get out of your comfort zone. So, if you’re new to intervals, maybe starting with the gentle interval walking approach or utilizing that strategy of going hard for a couple of minutes, and then backing off for a couple of minutes; that’s a beginner interval workout. In the book we lay out some examples.

We have 12 different workouts that we lay out, all based on science so people would know the basics of these workouts are grounded in good science. But we present them as providing individuals with some ideas and different varieties of interval training protocols that they might used, depending on if they’re just starting out, depending on if they’re a more highly trained individual; again providing some of the science behind that and some ideas for how to structure it.

Tim Ferriss: Outside of certainly starting with the first study you’ve been innovating in this space and experienced some blowback or criticism, or not even criticism but maybe skepticism…

Martin Gibala: No, we’ve been criticized.

Tim Ferriss: Yeah, you’ve been criticized; you certainly get skepticism. Outside of what you’ve written in this book, what are things you believe that other people might think are crazy?

Is there anything else that comes to mind where you disagree with conventional thinking or conclusions as they stand right now? It doesn’t have to be limited to physiology but certainly could be in physiology.

Martin Gibala: I almost hesitate to say this a little bit because I’m sure I might get some blowback even on this. But in some ways, I see a move to demonize traditional cardio, if you will. Or you will read things like: traditional, modern, intensive exercise is ineffective, or it has no place. I disagree with that. Clearly I’m big on interval training; I’m a proponent of it. I think it can be widely applied and I think it can be extremely beneficial for a lot of individuals and so I think it’s underutilized and it’s very effective.

But that’s not to say that there’s no place for traditional, steady state exercise. And certainly it’s erroneous to suggest that that type of training is completely irrelevant or it won’t provide you with any benefits. So, I guess that would be one example where I might take exception to some advice, common advice that I will often hear.

Tim Ferriss: A few other questions – or actually I’m going to jump into the callisthenic component. I’ve read that you’ve said before if you had to choose one exercise, you would choose the Burpee. I’m a big fan of Burpees. I’ve done a lot of Burpees in my life from wrestling and jujitsu and so on.

Puquees are a nice variation of that as well, with the pull up bar above you. Do you still feel that way about Burpees? And then I’ve read that in the resistance training that you do, you train to failure, but you’ll do cycles so you have three sets to failure of each exercise. So, I’d be curious to know A) do you still feel that way about the Burpees, and then B) why three sets to failure as opposed to one or two?

Martin Gibala: I do feel that way about the Burpee, and let’s frame the question, here. The question that I received was what is the single best exercise. Which really means if you were only restricted to one exercise, what would you do and why? Obviously it’s even hard to fathom the question but I would pick the Burpee. Because 1) it requires no specialized equipment. It’s a body weight style movement so you can do them anywhere. 2) It’s going to build both strength and cardio-respiratory fitness.

So, if you do Burpee sets, obviously you’re going to have some pushup motion in there, you’re going to have some leg strength development. But if you’re doing Burpee sets, and it goes to the second part of your question; why would you do three sets; because I think applying Burpees in an interval manner and doing a couple of sets of them allow you to keep the heart rate up, which is going to provide the cardiovascular training.

So, I would stick with the Burpees. It can be done anywhere and if you do Burpee sets, it provides both a cardio-respiratory boost as well as a strength boost. If I can just say, I think I also said at the time when I was asked the question, I don’t ever see anyone sticking with a Burpee workout over time because let’s face it; Burpees suck. Burpees are really hard to do. But if I could give a shout out to this individual who contacted me, his name is Josh Spodek. He lives in Manhattan. He’s a PhD in astrophysics, he’s got an MBA. And he contacted me to say I read the piece in the New York Times and I sort of took it up as a challenge.

And I’ve been doing Burpees every day for five years. It’s basically become his go-to exercise. So, clearly some individuals could keep it as their sort of go-to exercise. So, good on you, Josh; I certainly couldn’t keep that up even though I said it would be my go-to exercise.

Tim Ferriss: Yeah Burpees, I wouldn’t give them a very high ranking in the physical recreation category, for sure.

Martin Gibala: If I could just make a comment, too, Tim. I just said Burpees suck; they hurt. This is something around interval training where there are definitely very visceral reactions around the potential translatability So, my colleagues who are in the exercise and health psychology area who talk about things like mood, affect, motivation, long term adherence; there’s a real visceral debate going on right now around the potential long term translatability of interval training.

Clearly I’m someone who is in the camp of yes, I think this is very much a viable public health strategy. Certain types of interval training are highly suited for many different individuals. And again it goes back to this idea that people think interval training only means extreme style training. But there’s a large segment or there’s certainly an opinion out there that this is not a viable public health strategy at all. I happen to disagree with that because I think the more menu options we can give people, the more exercise choices the better. But this idea that intervals can be an uncomfortable way to train and that might turn people off exercise, that’s certainly a sentiment in some quarters.

Tim Ferriss: If we were looking at, at least as I think about it, the three legs of the stool for a sustainable, beneficial exercise program, if you have at the top, if we were trying to look at a hierarchy adherence, would the subject actually perform this routine over time? And then you have effectiveness; does it produce the results desired in any shape or form; and then efficiency, as we’ve talked about a number of times, time efficiency.

How do you increase the longer term adherence to interval training? Is it just a matter of starting off very moderate and then conditioning people over time, both psychologically and physically to the sometimes uncomfortable stimulus? Are there other aspects to program design that you would encourage people to think about?

Martin Gibala: There’s a chapter in the book where we talk about this; the psychology of interval training. I interviewed a couple of experts who provide some tips. Even things like, for example, starting out early in the day, avoiding comparisons, rewarding yourself; giving yourself a little treat and celebrating success. Don’t beat yourself up.

Some people can get down on exercise if they don’t have a big block of time or if, for example, they are unable to sustain a moderate intensity jog for four to five minutes or so; they start to beat themselves up. I think with intervals, you can do a short interval and experience a sensation of success; hey, I did that.

Going back to the cardiac patients, almost any of these individuals as they go through their lives, life is an interval exercise for these individuals because just moving around can be quite challenging so. Even just to get around and go through activities of daily living, they have to perform it in an interval manner. So, I think my answer is there are certain types of interval training that are suited for certain types of individuals.

And we also know – again, I’m not a health psychologist but when I talk to my colleagues who are experts in this, going back to this idea of menu choices, the more options we can give people, the better. And I think interval training offers, as we’ve been talking about, almost an infinite variety of ways to structure the workouts. There are only so many ways to jump on a treadmill and jog at a moderate pace for 45 minutes or an hour.

Tim Ferriss: You can watch a lot of different shows on Netflix while you’re doing it, though.

Martin Gibala: The other thing is intervals provide a way to structure exercise into your life, rather than having to fit your life around exercise. People talk about stealth interval workouts. As corny as it sounds, taking the stairs; lots of us live in apartment buildings or work in office towers; that’s a stealth interval workout, just doing a couple of stair flights throughout the day.

There’s this concept of exercise snacking. We’re learning, for example, that it might be better to do three ten-minute bouts of exercise through the day rather than a single, structured 30-minute bout of continuous exercise, at least when it comes to things like your blood sugar control. Intervals are well suited for this concept of exercise snacking, as well.

Tim Ferriss: Marty, a couple of non-physiology questions, although they could end up producing answers that have something to do with that. What books have you gifted the most to other people?

Martin Gibala: This question, I’m going to sound like a scientist here but one of the books that I’ve given out a lot is called The Craft of Scientific Writing. It’s certainly something that I’m working on but when I’ve gifted books, it’s often been either to a colleague or definitely new, up and coming people in the discipline of science.

The way you write scientifically is obviously different from other writing. If you want to write scientifically but in a compelling way for individuals to try and translate the science into the lay public, for example, that’s really what I try to do with The One Minute Workout is boil the science down, write it in a compelling and accessible manner.

Certainly I’ve had tremendous assistance from a colleague, Christopher Shogen who is just a tremendous writer. And we know we are on the right spot where I was happy from the scientific message, and Chris was happy with the writing, or at least the readability or the accessibility of the writing style.

That’s a real challenge, of course. It’s an art as much as it is a science. So, a book like The Craft of Scientific Writing helps provide some tips there because if you’re a scientist coming up, you’re constantly writing. You’re writing grants, you’re writing papers and you want to convince people with the point that you’re making. You don’t want to bore them and you want to do it in a compelling manner.

Tim Ferriss: What are some of any science writers or science books that come to mind as good examples to you? Atul Gawande comes to mind for me; Checklist Manifesto and others, certainly. Do any particular writers or books come to mind that have a scientific accuracy to them that are compelling?

Martin Gibala: Obviously I have a ton of respect for someone like Gretchen Reynolds at the New York Times. She’s obviously a big proponent of interval training; she’s been a supporter of our work. Her book, The First Twenty Minutes, provided a really good example or set a bar for us in terms of trying to structure The One Minute Workout where you’re trying to boil the science down, present it in a compelling manner.

There’s a Canadian named Alex Hutchinson who writes for a national newspaper, The Globe and Mail. He has a book, Which Comes First; Cardio or Weights?

Same thing; where I think there’s a gift there in terms of boiling this complex science down into compelling narratives that people can read and understand. That’s initially two names that come to mind, at least in terms of people who are taking science, taking scientific studies and trying to boil it down into accessible messages that people can use in their everyday lives.

Tim Ferriss: Speaking of everyday life,. This one is not always the easiest question but we’re probably going to wrap up on this. If you could put a message, a short message on a gigantic billboard and of course metaphorically, you’re just getting a message out to people; anything noncommercial, what would you put on that billboard?

Martin Gibala: I don’t want to fail miserably on this last test because part of me is like, oh, my God, what would I have that’s so compelling to say but I’m going to put it out there on a billboard?

We were talking offline earlier a little bit. As a scientist, getting out of your comfort zone a little bit as a scientist, you tend to be so cautious. You’re like almost everything you say are “studies end with,” “we need more research on this,” or you write a grant and you’re afraid to get out of your comfort zone. Certainly as I’ve gone through the process of writing this book by collaborating with Chris Shogen on the book, it was really a matter of ‘you’re welcome’?

We do have something to say, here. There’s an audience out there that needs this. Because I would often get questions around where can I go for more information? Where can I go to learn more about interval training for health? I really couldn’t point to a specific website or book that was out there. And so in some ways, we tried to fill that void with the book in boiling it down.

So, I guess going to the billboard question, it would really be a matter of telling people, not to steal something from Nike but just get out there and do it. Or you know what, if you don’t have a 45-minute block of time to work out, that’s okay. Build intervals or build exercise, build movement into your life because we really, really need that. You look at the profound influences that that could have in terms of boosting health, lowering healthcare costs.

When I talk to my students, it’s about where could all of that money that we’re otherwise spending on drugs and pills go? Well, we could use that investment in other places to better support people. It’s almost like I’m stealing other people’s lines here but this notion of exercise as medicine, it’s absolutely true. Exercise is the best medicine. It has so few side effects associated with it but the benefit that we can get from it is tremendous.

I think some people are afraid of exercise, or obviously the No. 1 cited barrier for why people don’t exercise is lack of time, or perceived lack of time. People have it in their heads that if I don’t have this big block of time to exercise, it’s not worth it, or they blow it off. So, if there’s a message, it’s really no, time efficiency we understand is important but even if you have a ten-minute period of time in the day, get out there and move. Intervals provide an extremely effective way to build time-efficient exercise into your day and of course, the benefits that are profound.

Don’t think of it as you need to exercise to lose weight and that’s what confers health. As we’ve been talking about, there’s a direct line there between exercise boosting your cardio-respiratory fitness, lowering your risk of dying, lowering your risk of developing many of these chronic conditions.

Tim Ferriss: I have an idea also that you can use, and I will not charge my typical royalty for this. It’s one minute disappointing in the bedroom, plenty in the gym, and you have your URL. Marty, where can people learn more about you, find you, the book, say hello on social media or whatever you’d like to mention?

Martin Gibala: I’m on Twitter, @gibalam. The book will be published by Penguin Random House. It will be out on February 7. You can preorder now from all the usual book sellers.

Tim Ferriss: Fantastic. Any parting words otherwise that you’d like to request? I think you probably hit it in that last answer but anything else you’d like to say or request of the audience?

Martin Gibala: I guess if I had to come up with something for that billboard then, maybe it’s “life is an interval workout.”

Tim Ferriss: Ooh, I like that.

Martin Gibala: Maybe that’s the way to go. Maybe that’s the name of the next book. Obviously, I’m big on exercise. I really appreciate this opportunity to talk to you a little bit about that. Exercise is fantastic and if we could just get more people moving, the enormous impact and benefit that would have on public health.

Tim Ferriss: Agreed, and personal health which is what it starts with, in a sense. Marty, thank you so much for the time; I really appreciate it. And to everybody listening, you can find show notes, links to everything we discussed as per usual at You can find links, resources from every episode including this one. And until next time, thank you for listening.

The Tim Ferriss Show is one of the most popular podcasts in the world with more than 900 million downloads. It has been selected for "Best of Apple Podcasts" three times, it is often the #1 interview podcast across all of Apple Podcasts, and it's been ranked #1 out of 400,000+ podcasts on many occasions. To listen to any of the past episodes for free, check out this page.

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