The Cardio Myth with Dr. Doug McGuff
Mike Rogers leads an enlightening discussion with returning guest, Dr. Doug McGuff, a full-time emergency room physician and owner of Ultimate Exercise, a high intensity, personal training facility in South Carolina. They examine the history of Cardio and how it became such a widely misunderstood concept. We learn how the cardio movement, aka aerobics, began and why many believe Cardio is more beneficial to the heart, lungs and blood vessels than other types of exercise.
What is the actual definition of aerobic and anaerobic pathways and how are they linked? Can a certain type of exercise be more ‘aerobic’ than another? Does strength training improve the cardiovascular system? Dr. McGuff answers these questions with such elegance and clarity that even a caveman would understand.
Arlene [00:00:01] The Inform Fitness podcast with Adam Zickerman and co-host Mike Rogers is a presentation of Inform Fitness studios a small family of personal training facilities specializing in safe efficient high intensity strength training. On our bi monthly podcast Adam and Mike discuss the latest findings in the areas of exercise nutrition and recovery with leading experts and scientists. We aim to debunk the popular misconceptions and the urban myths that are so prevalent in the fields of health and fitness. And to replace those sacred cows with scientific based up to the minute information on a variety of subjects. We’ll cover exercise protocols and techniques nutrition sleep recovery the role of genetics in the response to exercise and much more… On this episode Adam and Mike welcome back Dr. Doug McDuff one of today’s leading high intensity experts and author of the bestseller Body by Science. Together they ask can a certain type of exercise be more aerobics than another and is there a new emerging exercise paradigm?
Doug [00:01:18] The only way to get at the cardiac or vascular system is to do mechanical work with muscle and it turns out that the higher the quality of that mechanical work, the higher intensity of that mechanical work. The greater the benefit to the cardiovascular system.
Adam [00:01:37] I’ve known today’s guest Dr. Doug McGuff now for over 20 years. He’s a doctor he’s a practicing E.R. doctor in South Carolina and Doug is one of those few doctors who actually happens to run his own gym. It’s called Ultimate Exercise and it’s in Seneca, South Carolina. In 2008 Doug co-wrote the groundbreaking book Body by Science. It was and really is a really important book because it comes from a theoretical understanding of basic physiology and for the first time properly applies it to high intensity exercise. I can’t emphasize enough what his book has done to our industry and bringing high intensity excise to the mainstream. Doug thanks for joining us again for a second episode with Mike and I. I’m going to let Mike drive this session.
Doug [00:02:24] OK.
Adam [00:02:24] So Mike please…
Mike [00:02:27] Hey Doug…
Doug [00:02:27] Hey Mike, good to see you!
Mike [00:02:27] You know, at Inform Fitness you know we say that we are a high intensity strength training program for 20 minutes once a week. And of course in almost every consultation from every new client we get the question 20 minutes once a week. That’s it. Don’t I need to be doing some cardio. And even in the last decades with all the research and scientific studies available there’s still so much confusion about cardio. The word cardio the concept of cardio. What people think it is what it actually is. You know how cardio is still interchangeable with the word aerobic. It’s still thought to be very necessary for achieving fat loss cardio exercise what’s necessary for a healthy heart. And Adam and I love getting into the weeds of the biochemistry but we also want to communicate clearly with the lay person who just wants to be healthy and doesn’t want to doesn’t have the time to read all the scientific footnotes. So in the simplest terms what is cardio. How should we be thinking about cardio. What should we be thinking about when we use the word cardio.
Doug [00:03:32] You know the honest answer is I don’t even know what the hell to do with that term because it’s been so distorted and it’s in our zeitgeist. But I don’t think anyone can actually define what they mean by it. I think they have some sense that there are certain types of exercise that are more beneficial to the heart and blood vessels than other types of exercise. And that’s built upon a huge pyramid of mistaken premises that go all the way back to the 1960s. So when exercise was first researched the only measuring tool you had to see about anything the quantitate and exercise effect was to measure oxygen uptake or to do vo2 max testing. And basically you’re measuring the amount of oxygen consumed relative to the exercise that’s being done that involves wearing a tight fitting mask that connects to some hoses and a box that measures oxygen going in carbon dioxide going out and trying to correlate that with a specific amount of mechanical work that was being done on an apparatus. But you know like the old vacuum tube computers that occupied a whole room this was a big box and the big machine that required the subject being tested to be kind of tethered to it. So as a consequence the only thing you could really do was to have this thing set up next to a treadmill or a bicycle odometer. And because it was set up to measure oxygen uptake it tend to perform better at lower intensities. So the exercise that happened to be tested at that time was a relatively low intensity for long durations that would produce measurable results within the measuring capability of the tool that was cataloging how much oxygen you were using over a span of time. So that became the testing tool to quantitate exercise with and then over time research was done and they showed that people who exercised had fewer cardiovascular events than people who did not. So the type of exercise that was done on this apparatus was measuring predominantly the aerobic or oxygen using subsegment of metabolism because we had a machine measuring oxygen uptake. So we’re measuring the aerobic subsegment of metabolism. So that type of exercise became known as aerobics. Because that exercise was linked in studies to improve cardiovascular outcomes which we now know are just a result of performing mechanical work with muscle and the myokine signaling that’s going out. The two became linked aerobic exercise became linked to cardiovascular health and that link over time became solid enough where people just called aerobics cardio.
Mike [00:06:29] Yeah, the interchangeability…
Doug [00:06:30] and then the interchangeability was cemented. What people don’t recognize is that the aerobic subsegment of metabolism is carried out in the mitochondria little powerhouse with the cell. But that little Mitochondria is actually an ancient bacteria that got incorporated into the cell a long time ago because it was an organism that ate the waste product of single celled organisms. That waste product was created anaerobicly in the absence of oxygen so you take glucose take it through 20 steps you get a little bit of energy out of that and you make pyruvate. Pyruvate then goes into the mitochondria and that gets metabolized in the presence of oxygen to make some more energy. But when it comes to improving the aerobic subsegment of metabolism the only way you can do that is by delivering anaerobic substrate as quickly as possible and under high intensity exercise circumstances you can deliver that as quickly as possible to the extent that the pyuvate can’t be shuttled into the mitochondria anymore and it starts to stack up. When it stacks up. It gets acted upon by an enzyme called lactate dehydrogenase and turned into lactic acid. That’s why we breathe hard. That’s why you feel this burn and this kind of ears ringing metabolic effect of high intensity exercise. But in so doing we’ve driven the aerobic subsegment of metabolism as fast as possible so we’ve gotten the best aerobic benefit out of high intensity exercise also. Key though is that there’s no way that just that aerobic subsegment of metabolism is hooked up to the heart and blood vessels. The heart and blood vessels serve the entire cell not just part of it. And the only way to get at the cardiac or vascular system is to do mechanical work with muscle. And it turns out that the higher the quality of that mechanical work the higher intensity of that mechanical work the greater the benefit to the cardiovascular system.
Adam [00:08:42] Is that… The body doesn’t differentiate between what’s causing that that high intensity mechanical work the body doesn’t differentiate that you’re getting that high level of intensity through a leg press versus a bicycle for example.
Doug [00:08:54] Correct. And not only that the cardiovascular system the adjustments that are made. Very small amounts of it are actually made in the cardiac and vascular system. Mostly what’s happening with the cardiovascular system when you’re resting heart rate goes down all those other variables. It is basically an autonomic or automatic response to the metabolic improvements that have occurred out in the periphery predominantly in the skeletal muscle, so the improved metabolic capabilities of the skeletal muscle and the increased strength of the skeletal muscle is what has changed the behavior of the cardiovascular system. So if you take someone that’s you know their muscle has a force out capability of 200. And you have someone that has muscle capability of 100 and they’re both gonna walk a flight of stairs. The amount of work that the cardiovascular system sees in the weaker person is doubled. And that’s just you know a hypothetical mathematically simplified concept but that’s basically it when the capability of your skeletal muscle is doubled the amount you have to rely on the cardiovascular system to support it is spared. So a lot of what the cardiovascular adaptation is not central to the cardiac Ambassador system but it’s an adaptation made out on the periphery.
Mike [00:10:22] That’s actually in consultations how we direct and try to answer that question as to even through the example of like walking stairs and…
Doug [00:10:32] Yeah you know it was in the 60s they actually did a really cool baby hill that was kind of one of the early pioneers in vo2 max testing they did a really cool study that just got lost. And what they did was they took subjects they trained them on an ergometer where they worked only the right half of the body let’s say half the body right arm and right leg did steady state exercise. And they had a vo2 max improvement. But compared to people that did both sides of the body that improvement was only half. One more interesting thing is if you tested the trained side of the body. You showed the vo2 max improvements that were assumed to be central cardiovascular improvements. If you tested the untrained side of the body there was no improvement in vo2 max, proving that the vast majority of the improvement that you’re seeing is going on in the skeletal muscle itself out on the periphery and it’s not a central cardiovascular adaptation that’s occurring.
Adam [00:11:41] Has that study been repeated but by any chance?
Doug [00:11:44] I think it has been repeated but not in the recent past at all. I mean this is way back in the late 60s early 70s.
Adam [00:11:52] You think that was shut down the whole aerobics industry as we know it.
Doug [00:11:55] Yeah. It’s almost like a meme. Once it gets a foothold and takes off it’s hard to unwind and it’s really hard to unwind things that have become you know in the in the popular mindset of a, you know a meme or zeitgeist. You know look how hard it’s been to unwind the whole cholesterol hypothesis of coronary artery disease and diets that have too much fat at home are gonna be harmful of those sort of things. Look how the Women’s Health Initiative came out and said Oh look. Twenty six percent increase in breast cancer rates and women on replacement hormones when it was really just bad science and it was a relative risk reduction not an absolute risk reduction but I mean it just killed it and now they’re trying to kind of unwind that a little bit. It’s like let’s be a little bit more sensible about this. And it’s almost impossible to do. For some reason once it gets that nationwide foothold it’s just very hard to unwind that sort of notion.
Adam [00:12:53] And that’s what’s worrying me about this anti-vac stuff that’s happening now that I don’t in this way. But you know that reminds me of what’s happening right now I mean hopefully that doesn’t become part of the zeitgeist too that vaccines aren’t safe anymore.
Doug [00:13:05] Yeah. Yeah.
Mike [00:13:06] Doug are there circumstances where someone perhaps should be doing some steady state exercise in addition to their resistance training for the purpose of improving their cardiovascular health.
Doug [00:13:16] Well here let me put this as the backdrop. Adam and I both came from a background in super slow. We really thought that the only thing to do was to do high intensity strength training and that any activity outside of that was only going to consume precious recovery resources. We really literally wanted clients to train really hard and then go into suspended animation chamber until their next work. I’m sure Adam can attest. I certainly found it. It was the most frustrating exercise to try to sell that to clients because what happens. I think this is largely through myokine signalling and energy signaling is once you’ve got a client that started with you at baseline once they got somewhere between 25 and 40 percent stronger their activity levels spontaneously just went off the chain. All of a sudden people were taking up sports that they’ve given up their going out running 10 k’s they were getting a mountain bike and going out and riding every evening. Their activity levels went off the chain. I think that we awaken an active genotype and we get people adequately strong. I think the mark of a healthy organism is a large amount, a large background of low intensity activity with intermittent spikes of high intensity activity.
Mike [00:14:39] Which feels more like recreational fun than it does then exercise.
Doug [00:14:42] So I would say the context in which I would artificially introduce that is if for some reason either because of employment lifestyle or just a negative inclination towards being physically active the person was not expressing that sort of activity level then it might be worthwhile to go ahead and try to artificially introduce that. But I found that that almost never occurs. I find that most clients generally become very active and a lot of them do end up for spontaneous and recreational or pleasurable reasons taking up activities that Adam and I in our previous paradigm would have classified as steady state or aerobic or bad which actually in this context turns out to be quite good. And in context of a myokine expression and adequate physical conditioning is probably not nearly as dangerous and injurious as we once thought because the injuries that we were seeing were from people that were obsessively and artificially doing massive amounts of steady state training.
Mike [00:15:59] Because they felt like they did do it.
Doug [00:16:01] Yeah.
Mike [00:16:03] How do you manage clients who have a difficult time dealing with intensity and still put a meaningful stimulus on the muscle.
Doug [00:16:11] I used to worry about that a lot and now I almost don’t give a crap.
Adam [00:16:15] laughs…
Doug [00:16:17] And here’s why.
Mike [00:16:17] That’s my problem… I worry about it still. How do you stop worrying about it?
Adam [00:16:23] After 20 years Mike still gives a crap.
Doug [00:16:24] Yeah. So here’s the deal. So we made reference in the previous podcast of the Simon Melov study that showed these massive improvements in gene expression back to youthful levels and elderly clients. And I made mention if you dig into the methods section of the paper and the actual resistance training workouts that were done it was at best mediocre and we still showed these incredible improvements. So clients that are averse to intensity or exertional discomfort the first thing that you have to tell yourself is however far you can get them is so many light years beyond what they would do under their own tutelage or under the tutelage of a workout caddy at Gold’s gym. Even though it’s frustrating to you the trainer you are bringing them so far ahead of where they would have gotten otherwise that you are probably well within the territory triggering the stimulus that’s going to produce these beneficial adaptations.
Mike [00:17:28] Yeah I don’t. I don’t really worry about it so much as much as I used to actually just like you because you know so they are exactly what you just said we could take them as far as we know we can take them. It’s still out of their comfort zone to a certain reasonable degree. They’re still getting some gain maybe they’re not getting 100 percent of what they could get out of the workout but they’re getting 40 percent which is still better than zero percent.
Doug [00:17:52] Right now I think the important thing is just to stay consistent and not give up on them. Once you start producing any adaptation at all that their aggressiveness in terms of exertional discomfort starts to increase somewhat over time. Even when it doesn’t, what you’re doing is you’re giving a stimulus that’s a little less intense and severe. So especially in the early stages rather than being a stimulus organism response and then the next workout stimulus organism response and in the early stages of a client you’ll see that they’re on a very steep curve. When someone doesn’t give you quite as much…it might be a stimulus organism nothing stimulus organism nothing stimulus organism nothing stimulus organism boom response I really got the gut feeling that the benefits are still there it’s just operating on a timescale that’s a little bit more drawn out and slow and the results may be a little more granular than we’re able to detect to our satisfaction. But if we just stick with it the benefits still come. You know when you’re training 25 30 clients in a day you know you really look forward to that one client that’s just an animal that’s going to come in and kill it. But anyone that’s trained twenty five clients a day one hundred clients a week knows you’ve got to kiss a lot of frogs to meet that Prince. But in terms of the benefit you’re providing the people you know the fact that you’re willing to plod through it and just suck it up and do it offers huge benefit to these people over time.
Adam [00:19:33] I’m glad. Good question Mike. And I’m glad you said that sometimes because I can’t get them to go to the intensity that I would like them to go through that I’m shortchanging them or they’re not getting anything out of this and it’s good to remind myself that it’s still a lot better than they’ve ever gotten. It was good to be reminded that that the Melov paper actually like you said there wasn’t the greatest workouts in the world that were causing these benefits. So good. Very good there.
Doug [00:19:56] And you know Mike sometimes my trainers the schedule just kind of meets itself out the way that it does and sometimes the trainers and the clients they can have a real dry period where they don’t have a really intense client for four or five days. You know it’s not uncommon to have trainers like, man can you just come down so I can put you through a workout. If you’re in a dry spell and sometimes trainers just training each other or you training Adam.
Mike [00:20:24] It’s a… I have the patience and a lot of our clients have the patience and I know every day I’ve been doing this for a long time also and I know that there is an impact that’s what gets me very excited to come to work every day is that on a small level on a profound level people who used to be in chronic pain aren’t anymore people who you know added a ketogenic diet but didn’t do any cardio had lost 50 pounds. You know we see these types of things and there is a prince among all of the frogs. Like every single day. You know…so.
Doug [00:20:58] Yeah, this is part when you’re a professional trainer this is part of being professional. You know you look at the military you look at fighter pilots you look at snipers and they train and they train and they train and they rehearse and they rehearse and they rehearse. The vast majority of fighter pilots. Will never be in a dogfight. The vast majority of snipers will never shoot anyone.
Mike [00:21:21] Right. Yeah.
Doug [00:21:22] But you still trained AND trained AND trained you know and we get a lot more usage of our skills than most people ever do. You know it’s still a cool thing but it does. You know it’s just the reality of any job is there. Yeah I know that just you know you just got to suck it up and plow through it you know.
Mike [00:21:39] Right… well Doug thank you very much for being on the podcast.
Adam [00:21:44] Yeah thanks Doug. That was really good. Hope to see you soon again.
Doug [00:21:47] Yeah likewise.
Arlene [00:21:48] This has been the Inform Fitness podcast with Adam Zickerman. For over 20 years Inform Fitness has been providing clients of all ages with customized personal training designed to build strength fast. Visit informfitness.com for testimonials blogs and videos on the three pillars… Exercise nutrition and recovery.