86: The Truth About Running & Longevity | With Brad Kearns

Brad Kerns: With marathon runners, when they cross the finish line, if you took them over to the emergency room, they would present as if they were having a heart attack. That's how messed up their blood work and their liver enzymes are when they cross the finish line. 

Extra: Brad Kearns is a New York Times best selling author, former two time U.

S. national champion. And number three, world ranked professional triathlete, 

Brad Kerns: Yale University School of Medicine contends that 50 percent of all regular runners get an overuse injury every year, and that 25 percent of all dedicated runners are injured at any given time. The truth from evolutionary biology is that humans are born to walk.

Extra: His B rad podcast is a top 10 ranked Apple podcasts, fitness category show. Covering diet, fitness, peak performance, personal growth, and longevity with Brad's carefree style and lively sense of humor. 

Brad Kerns: And if you extend out to like a hundred miles or beyond, the human is the superior endurance creature on earth.

Michael Kummer: Welcome to the Primal Shift Podcast. All right, Brad, thanks so much for being back on the show. Um, I am aware that you're an avid runner. You absolutely love running and you think running is the best thing humans can do, uh, to sustain optimal health, right? 

Brad Kerns: Well, it's been a long journey. Especially with my transition from being a hardcore endurance athlete in my youth and competing on the professional triathlon circuit for nine years, traveling all over the world and training my butt off and racing like crazy in this extreme endurance sport.

And today, as I near the age of 60, I can't wait to bump into the higher age group. I'm obsessed with sprinting and high jumping, which is so fun for us to connect on our previous podcasts. You as a guest on my B rad podcast and, uh, me on the primal shift where we talk about that, that background of sprinting and how beneficial that is for all manner of peak performance, anti aging disease, prevention, longevity.

So I am completely embracing, uh, a new paradigm of fitness where I'm pursuing this broad based functional fitness with. power, explosiveness, muscle strength, muscle mass, and all that, which is entirely disparate from my previous experience where I was focused on going very fast in a straight line in three different sports at great expense to my overall general health and longevity prospects.

Fortunately, that phase of my life was a nice phase of my youth where I. Race from ages around 20 to around 30 when I retired, beat up and worn out, even as what would be considered a young man, but that extreme endurance experience now informs. I look back and I realize how ridiculous it was and what fitness really means fitness for life.

Michael Kummer: Right. You know, and there is this, well, there's this book and the concept, I guess, behind it, Born to Run, right? Humans are supposed to be, we are born to run because of, you know, physical attributes, because of, you know, our ability to sweat and cool down, you know, so we don't overheat and there are a lot of Um, to be made that, you know, we are supposed to be runners, you know, endurance runners, um, and, and then there are those who say, well, actually, that's not true.

You know, if you look at our, you know, physical capabilities, we are sprinters. We are walkers. We are, you know, yes, of course we can run, but that doesn't necessarily mean running for hours. And, and I think where I'd like to kind of bring the discussion is because, you know, there are those who are, you know, it's like in the, in the dietary world, there are the vegans and then there are carnivores.

And there, and there, you know, in between, you know, People either don't think about what they do or they have no opinion. But if you have an opinion, it's typically very polarizing. And the same, I think is true for running versus not running, walking, sprinting, lifting, you know, high intensity kind of workouts.

But I think there is probably room for all of that. You just have to understand, you know, what's the purpose of, you know, going for a 30 minute jog in the woods because you enjoy, you know, how you, how it makes you feel. Right. Versus running 10 miles every single day, because you're competing, you know, for a triathlon or whatever the case might be.

And so let's break it down a little bit. I mean, first of all, what are some of the reasons of the pros of running and some of the reasons why people might want to do that? Um, what are some of the reasons why people might want to. Not do it. And instead rather go for a walk of the same distance and just take a little longer.

Right. Uh, what are the pros of, of sprinting and some of the other more explosive high intensity type of workouts, and how can you, you know, leverage all of those in a way that doesn't destroy you from a joint. Back knee, you know, longevity perspective. 

Brad Kerns: Yeah, that's a great, uh, setup. Thank you. And I think you're kind of describing today's, uh, fascination with the so called hybrid athlete, which is so amazing, uh, for me to look at these achievements of people who are pursuing these, these crazy goals where.

It's a disparate skills of incredible strength and power as well as endurance. Um, I've seen the guy on Instagram, uh, Michael Miraglia, who is the only person in the world so far to deadlift 500 pounds and then run a mile in under five minutes. And he did the whole thing in four 46, including the time it took to lift the weight off the ground and drop it right there on the running track and then run four laps.

And it's, it's, it's an amazing. Achievement to develop those disparate skills now, that's the, you know, the high level elite person, but you propose the question of like, what is the average recreational fitness enthusiast? What should they do and how should they allocate their pie slices toward? Broad based functional fitness for longevity, which by and large would seem like a really great goal for most everyone, unless you have really distinct competitive goals.

So when you were training for the world junior championships at 100 meters, you were not jogging 30 minutes in the. I don't think, or an hour because this was changing your fast switch muscle fiber over to, to oxidative. And when I was training for triathlon, I was either going for long distance workouts, or I was eating or sleeping.

I didn't have time or energy to go and do a CrossFit session because I had to get up the next day and bicycle 84 miles. So if we make the assumption that you just want to be fit for an active energetic life, then it makes sense that you would kind of check off. Uh, a few important boxes rather than dedicate almost all of your time and energy to, for example, cardio, which is what I see a trend in fitness world when you go into the gym, even a huge gym like you see in the big cities, there's like 87 machines stacked up in a giant floor space.

And then you go, oh, where's the weights? And there's they're crammed into the corner where everybody's bumping into each other doing the machines. And it kind of should be the opposite. Especially when you can exercise outdoors. But anyway, a lot of people are spending a lot of calories and a lot of sweat building their cardiovascular fitness with steady state endurance exercise.

And it's another steady 

Michael Kummer: state, 

Brad Kerns: a steady state, meaning like you're maintaining the same heart rate. Or the same pace throughout the workout. And so like in the running community, uh, the group meets up on Tuesday night and they say, Hey, let's run eight minute pace per mile. And we're going to do the five mile loop through the park.

And so it's the heart beating in a metronomic manner for the duration of the workout, rather than having breaks for rest, as you might find like in a sprint session where, you know, you're jogging for a bit for warming up and then you're doing. Uh, four times 60 meters with two minutes rest and all these protocols that we follow, uh, for example, in a, in a typical swim workout or a track session, so the, the devotion and the popularity of steady state cardio is what we're attacking in the new book, born to walk that Mark Sisson and I.

have just published. You talked about there he is. If you're watching on video, he's given us a cameo on the on the video. That's great. Um, but you also mentioned, uh, the 2009 bestselling book titled Born to Run. And this was a really great story told by Christopher McDougall. It's been a perennial bestseller for many years, and it glorified our natural genetic attributes for extreme endurance performance.

And indeed, you mentioned being bipedal, being able to have a cooling mechanisms to sweat. We have non opposable toes, the toe pointing forward. We have the Achilles tendon, which our ape cousins do not. Um, a primatologist, Bill Sellers, called the Achilles tendon the primary. Evolutionary adaptation that allows the human to be human and to be able to carry on for long distances.

Um, there's a cute YouTube video where they have a simulated race with all the different animals. And so the cheetah, the horse, the antelope, the human, they all line up on the starting line. And you can see as the video goes, you know, the cheetah is kicking everybody's butt for 200 meters. But then when you get up to a mile, the antelope is the fastest.

And if you extend out to like a hundred miles or beyond. The human is the superior endurance creature on earth. They have 100 mile races here in California, where the horses compete on the same course as the humans and the human record is faster than an endurance horse for the Western States. 100 mile run.

Now, we're just like you mentioned, we're capable of great endurance achievements, but that has. That does not mean that we are designed or evolutionary adapted to get up and run long distances day after day after day in pursuit of completing a ridiculous event like a marathon. And the marathon has been glorified for many years as the ultimate achievement in the running community.

But it's far too long for almost everyone on the planet today to train for in a healthy manner and even contest. And so what you see. With marathon runners, when they cross the finish line, if you took them over to the emergency room, they would present as if they were having a heart attack. That's how messed up their blood work and their liver enzymes are when they cross the finish line.

So they've basically destroyed their body in the name of getting this finisher mental and saying that they're, they're able to run 26. 2 miles. I mean, If it's a bucket list achievement, I see the smiling faces. I see people overcoming challenges and accomplishing something awesome for their body. But we'd all be better off if the marathon were only 13.

1 miles instead of 26. 2. It's just too extreme to align with health. 

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Right. That that makes a, makes a lot of sense. So, you know, and here is the thing for people who are. incredibly motivated to do hard things. I mean, you know, something as simple as, you know, getting into jumping into ice cold water, right? A lot of people, you know, think they cannot do it, you know, or they don't have the mental capacity or, you know, the physiological response to the cold, whatever the case might be.

And then those who overcome that and jump in, it's like an accomplishment. And, and for me, you know, I, I, So I think that's a good thing, right? How do you figure out when one of those good things is maybe not that good anymore? Because getting into ice water, what's the worst that's going to happen? You know, you're going to gasp, you're going to feel terrible, you get out and nothing is broken.

You know, you, you're still good. You're probably better off than you were before. Right? Yeah. But that's different to running a marathon, right? And accomplishing that and feeling good about it because there is a consequence to that. 

Brad Kerns: Yeah. What you're describing with the cold plunge is an appropriately brief.

natural stressor and fight or fight stimulation. And we become, uh, stronger and more resilient both physically and mentally from these appropriate stressors, such as a 47 minute CrossFit session or a one, my, uh, an all out one, one lap around the track, 400 meters as my race coming up in my first track, many of the year is going to be, uh, it's, I dread it.

It's painful, but it's over and so quickly. And so I become. a fitter, more resilient, more confident person. All that's wonderful. And then we compare and contrast to the chronic stressors of modern life. So sitting in the traffic jam and getting frustrated, having a dysfunctional relationship where you're arguing on a daily basis or running too many miles at slightly to significantly too high of a heart rate.

Such that you are adding more chronic stress piled on top of a lifestyle that is already chronically stressful. And that's when you break down and have suppressed immune function. And by the way, one of the biggest goals that most endurance athletes share is dropping excess body fat. Most fitness enthusiasts.

And it is actually proven that long distance running does not contribute to the reduction of excess body fat. Instead, it sends the genetic signals for fat. storage, especially the accumulation of visceral fat, because visceral fat comes on when you have that chronic overproduction of stress hormones.

And not only does it promote the accumulation of visceral fat, it promotes the loss of lean muscle mass and it suppresses the adaptive hormones like testosterone and estrogen so that you're not as healthy and vibrant as you can be all from an inappropriate approach to endurance training. 

Michael Kummer: But what would you say then if someone says, Well, but if I go for a run for half an hour, you know, it just makes me feel good.

I get, you know, a rush of all those feel good hormones, you know, I'm, how can that, how does that then, uh, play with, with what you said, you know, the release of maybe cortisol or other stress, you know, associated hormones that, uh, you know, put you at the end of the day into a, you know, stressful situation rather than in a, You know, feel good situation.

Is there a threshold? Like, is there a, a point in time where you're switching over from the feel good to the chronic stress? 

Brad Kerns: Yeah, that's a great question. And we're, we got to look at this with a big picture perspective. So the damage and the destruction is caused by. patterns that become overly stressful.

So we're all allowed to pursue outlets and physical exertion and get those endorphins flowing after. But we do have to realize what the endorphin rush is all about and You're probably familiar listeners with the endorphins or the feel good chemicals that are actual very strong. Endogenous morphine is where the term comes from.

They're very strong chemicals that give you a sense of euphoria and dulling of sensations of pain after you push yourself with a hard physical effort. So the harder and longer the effort, the more endorphins flood your bloodstream and give you this chemical high. And so if you start chasing the endorphin high on the regular, you transition from someone who's engaged in healthy lifestyle practices to many symptoms of an addict.

How do you know if you're an addict to exercise? The definition of addiction is where the the addict needs a hit a dose in order to feel normal It's not this notion that the guy on the street looking Is looking to get high because he likes to get high after a while when you're in the throes of addiction You need a drink or the drug in order to feel normal.

And if you don't get it, you feel terrible So if you're an exerciser out there listening watching thinking I feel moody cranky and irritable If I don't get my workout in every single day You are now tiptoeing into the area of addict. Same for if you are chasing this endorphin high and you are demonstrably going for that chemical sensation after the workout as a reliable way to kind of disengage from the stress and frustration that you're facing during the day.

So it has to be. very carefully managed. But of course, the endorphin high is allowed once in a while would be ideal. Just like going out and having a few extra drinks with your buddies because they're visiting in town. You haven't seen him in 20 years and you're going to get an alcohol buzz that's beyond that threshold of healthy if you were to do it frequently, right?

So that's where Extreme or grueling exercise should fall into the picture rather than, and we see this in the CrossFit community too, where people, they love CrossFit. It's a super challenging workout. People are clapping your name at the end. Come on, Mike, you got this. Boom, boom. And you're going and doing that.

3, 4, 5 days a week is different than managing your resources and your energy and going for the Saturday WOD where everyone's going to try to put their name on the board and, and put up a better time than they did last month. 

Michael Kummer: Gotcha. So, I mean, listening to that, I mean, it, it, this really applies to almost everything in life.

You know, I mean, there is a lot of the good things. There are people addicted to probably to cold plunging, to sauna bathing, you know, it's very easy to. To use that. Oh, this makes me feel good. So more must be better, 

Brad Kerns: right? I wonder if anyone's overdoing cold plunging, like they're going four times a day, cause they just get such a rush.

That would be super funny to like investigate because that barrier of entry is so tough. But, um, I'm curious, you can probably be addicted to. Um, biohacking in general, and we have this condition of orthorexia as related to diet, which is defined as an unnatural and unhealthy fixation on eating correctly or living correctly to the extent that if you can't find anything that meets your high standards when you're going through, uh, Hartsfield airport on your, on your flight connection and you get frustrated and stressed because you have to lower your standards of a meal, that's when you know that your commitment to healthy eating has gone overboard as well.

So back to that first, back to that question that I haven't answered yet. And where, where's the cutoff where, uh, going out for a run in the forest is healthy versus where it can be potentially counterproductive. And it's really simple. It comes down to, you know, getting permission to run is all about this important concept called fat max heart rate and fat max heart rate is the intensity level at which you are burning the maximum number of fat calories per minute.

Now, if you identify this, uh, you can identify it in a laboratory, or you can use the widely respected Phil Maffetone formula of 180 minus age in beats per minute. So what are you, like 30 now, or you're, you're probably, 

Michael Kummer: how old 

Brad Kerns: are you? Yeah. 43. So 180 minus 43 would be 137, would be your magic number. And 137 represents.

With close accuracy, uh, the maximum number of fat calories per minute. Now, if you were to speed up And go faster and your heart rate increases. Of course, you're burning more calories per minute, but you trade that maximum fat burning starts to drop in favor of a quick spike in glucose burning. It's also a quick spike in ventilation that's noticed at fat max heart rate.

That's how they identify it in a lab. And so what happens when you drift beyond fat max heart rate, you have turned the workout. Uh, from energizing, refreshing to something that's slightly too significantly too stressful. So it becomes a training session where yes, people have to run hard to prepare for the competitive events of whatever distance, but you're changing the metabolic effects of the workout and the stress impact of the workout.

If you drift beyond fat max heart rate, because when you're fat max or below. Basically, you're getting some refreshing exercise. You're out there in nature. Uh, you're emphasizing fat burning. You're teaching your body to become good at fat burning around the clock. And honestly, the more, the better. So if, if you and I decided to take a break from podcasting this summer and walk the Appalachian trail, 2, 200 miles in a hundred days or whatever, that would be by and large, an incredibly.

Healthy thing to do is being on our feet for hours and hours every day hiking at a comfortable pace. But if we tried to go and break the Appalachian Trail record by pushing our bodies to the extreme, the average is like 52 miles a day. And the person did it. I think it was a female did it in like 50 days or something.

Some amazing pace. Um, that would be too much and be highly destructive to push the body too hard for hours and hours a day. So that cut off point represents when you can have permission to go jogging or whether that outing would be better served to be a medium or brisk walk. It's all about what your body's doing at the various paces.

In other words, how fit you are. So we have a lot of Commentary in the book about the greatest marathoner of all time. His name is Eliud Kipchoge from Kenya. He's the guy that ran an hour 59 for the marathon. He does the vast majority of his training. 83 percent of his weekly mileage is conducted in the so called zone one heart rate.

Not zone two, which we all hear about is so wonderful and you got to get your zone two and you got to get your zone two, but what about the love and respect for zone one, the best athlete in the world is training at a pace that's so comfortable that it's like a brisk walk or a medium walk for you and I.

Michael Kummer: Interesting. Yeah, that's something to think about. Um, now walking, you know, if we have a, let's say I, I want to, you know, cover three miles, you know, every day and I choose to walk instead of. Running now, my walking, even a brisk walking might, or might not get me into that, uh, magic zone, you know, where I burn.

Yeah, I don't really, you know, my, my goal is not burning fat regardless, you know, but if, if that was someone's goal, would you say, well, then, you know, rather, you know, run a little bit, then walk briskly again, run a little bit, or just run the entire thing, or forget about that, that heart rate zone. It's better, you know, in the long run.

to just walk briskly as fast as you can. 

Brad Kerns: Well, if you have competitive goals, we have to simulate the experience in training. And so if you're training for, and you want to, you know, excel in a 5k half marathon or marathon, you have to plunge into this very. High risk training protocol because we have breakdown, burnout, illness, and injury.

That's prevalent in the running scene. There's stats that we published in the book that are just shocking and embarrassing. Yale University School of Medicine contends that 50 percent of all regular runners get an overuse injury every year and that 25 percent of all Dedicated runners are injured at any given time, and these are the overuse injuries like the Achilles tendinitis or the shin splints or the knee problems that put them on the sideline because of the constant pounding and the overly stressful nature of their training programs.

It's basically, uh, it's called micro trauma to the joints and tendons and muscles day after day after day with insufficient recovery because they're going too quickly as evidenced by their heart rate. So you What you want to understand is when you're heading out for the workout for, in order to be an appropriate training session, that's within your stress capacity.

You've got to keep it under fat max for the entire workout. So maybe you could run the first mile and your heart rate still at one 30 to one 37. But if I asked you to go for five miles, what's going to happen is you're going to have to slow your pace. As the workout gets longer, because it's called cardiac drift, of course, the heart rate gets higher because you're getting tired over the course of the workout, so people can mix it up if they want to do jogging, walking, jogging, walking, but it's really important to stay in that aerobic zone throughout the workout in order to feel refreshed and energized and give your body the proper physiologic stimulus to become competent at endurance and that aerobic conditioning.

And I think people mess this up routinely because it's so incredibly frustrating. If you haven't measured this, Michael, yourself, you go out there and see how fast you're going at 137. You'll be surprised how comfortable it is because you don't really feel the strain until you get quite a bit higher than fat max heart rate.

And you're up near anaerobic threshold where you're really starting to breathe hard and realize, well, I'm really getting a workout here. So that's one. big mindset and strategy we urge is that, you know, you need to respect the importance of aerobic conditioning, which happens at comfortable heart rates, not mild to significantly stressful heart rates.

Michael Kummer: All right. So you're saying that by staying in that, in that zone for me, that would be around one 37. I can actually improve my. my cardio respiratory fitness. Um, yeah, the best way. 

Brad Kerns: Yeah. And this is not, um, brad on your podcast yapping about this. This has been proven by the performances of the world's greatest endurance athletes for the past 60 years.

Uh, 65 years now, dating back to the 1960s in New Zealand, when this great coach named Arthur Lyddiard trained his endurance runners with over distance training, where they'd run for miles and miles at a comfortable pace and climb the sand dunes for, you know, these huge long workouts, but they were.

comfortably pace. And then the guy stepped on the track and broke all the world records and won gold medals in the Olympics. And no one could believe what was going on. Uh, this great runner named Peter Snell, who was double gold medalist in the Olympics. He shattered the world record in 1960 in the 800 meters.

Which is a race lasting for a minute and 44 seconds was his time, but he was training for over 100 miles a week of running, and that was the first notion that this over distance training where you build this amazing, amazing aerobic engine is the thing that fuels you. to performances at the, uh, shorter, shorter duration and faster speed.

Um, Chris Hinshaw with aerobic capacities, big in the CrossFit scene. He's a former pro triathlete that I raced with way back in the day. He realized that his CrossFit athletes were so powerful and explosive and strong. But they lack the aerobic conditioning to, for example, stay strong through the entire 47 minute workout, or forget about the CrossFit games where they're asking you to do over and over, over another set of 20 handstand pushups with your 25 pound weight vest.

You need that endurance base for anything in any sport that you're doing. And that comes when you exercise at a comfortable pace. 

Michael Kummer: Gotcha. Now, you know, if you, if you take this, you know, too hard and you're gonna, you know, go for that slow, comfortable run, you know, and you do that overtraining, obviously, you know, if you want to compete, you know, that, that's probably a good idea.

But for the average show, there is still the issue then of, you know, joint abuse, you know, knees, ankles, lower back, et cetera. Right. So you, the truth is, you know, if you want to do this every so often, it's probably fine. Stay within the threshold, but doing it every day is still a bad idea. 

Brad Kerns: Yeah. The pounding on the joints and the impact trauma is a concern.

Now, if you run with good form. You're not going to be plunged into this chronic injury pattern, but what happens with the running community in the running boom of the last 50 years is the invention of the elevated cushion shoe allows people to shuffle along with poor form that generates huge impact trauma, and these people are not fit enough to be running, but they are able to run because they're wearing the elevated cushion shoe.

And so what the elevated cushion shoe enables is this Uh, very common heel striking, breaking, jarring, over striding pattern. Uh, it's often referred to quickly as the heel strike pattern, and it's indicative of when you land with the tibia at an acute angle to the ground. So you land in a breaking pattern for many reasons.

The shoe doesn't cause you to land in a breaking over striding pattern. It enables you to run in this pattern. The reasons for running with poor form are you're simply not fit enough. So you have dysfunctional, you get dysfunctional glutes. That don't don't fire. Well, you have tight hamstrings. You have tight hip flexors.

You have poor core strength. You have insufficient ankle mobility so that you can't dorsiflex the angle properly. You have insufficient forward lean of the trunk because of your weak core. And so all these things happen from a sitting based lifestyle or a lack of general athletic fitness to the point where.

As a runner, you're shuffling down the street and slamming into the ground with this heel strike pattern that Harvard research, Dr Daniel Lieberman, author of exercise and many other great books that one of the world's foremost experts on barefoot running in his lab. He shows that you can incur up to seven times more impact trauma with crappy running form, wearing the cushion shoes as you can when landing barefoot.

And oh, my gosh, this cool thing that we've done at. Our retreats and seminars is, uh, ask people. And I can ask you to do this right now. Listener the next time, find a smooth, hard surface, like a really clean sidewalk or perhaps an indoor gymnasium floor or marble floor down the hallway. Take off your shoes and take off running barefoot.

down the very, very hard surface. And what happens is for almost everyone, you immediately exhibit perfect running form. You run like a deer with this beautiful explosiveness and balanced body weight because you can't. pound the ground with bare feet on the sidewalk, or you'll have immediate pain sensation after one or two strides of heel striking.

You simply can't do it. So you will teach your body immediately with your nervous system, getting the feedback from your bare feet, hitting the ground to load the body properly and have just the amount of joint bending and, uh, correct impact and flattening of the arch and tightening of the. Arch and the Achilles tendon to help you spring off the ground.

Now, I'm not saying you can now get rid of your shoes and go run five miles on the sidewalk because, of course, you'll get injured and blown out in a matter of minutes. But the fact that we can do it when we don't have shoes on and we have that immediate penalty is amazing. And then what you want to do is like.

Understand what that stride feels like. You probably have it wired into your brain because of all the sprinting where you know how to land on your midfoot and balance the body perfectly for an explosive takeoff. And of course you can take those mechanics to a slower pace, but for many people, it's an awakening to realize, wow, I can run light on my feet like a deer.

If I just think about my technique. I don't really need the big cushion in the heel of the shoe because I'm landing on the midfoot like the human is adapted to and that's when you can learn how to run properly. But guess what? It takes a lot of musculoskeletal resiliency. Therefore, most people can only run with correct form for, let's say, 30 seconds or a minute.

Then they should walk. rest and then try another burst of correct running form or jogging farm. I'm not talking about going fast. I'm just talking about using the correct form. Then you can go out in the forest for 30 minutes and have a productive workout that's interspersed with a lot of walking. If you're interested in learning how to run 

Michael Kummer: Right.

It makes a lot of sense. Now, if someone says, okay, I get it. You know, running every day for the purpose of losing weight, fat, improving my cardio, whatever the case might be, is not the greatest thing I can do. I want to do something different. What are alternatives that. yield the same results and benefits without any of the downsides.

Brad Kerns: Well, we've been talking about this for 16 years now, when we first released the book, The Primal Blueprint, Mark Sisson and I in 2009. And it's the primal or the ancestral inspired fitness patterns. And what evolutionary biology shows us is that the human is obligated. to move frequently throughout the day at a comfortable pace in order to be healthy.

And of course, the centerpiece would be walking. That's our primary, our quintessential form of locomotion, but it can also include all other types of gentle movement, uh, a Pilates class or a yoga class, or, um, taking the, the bags of chicken feed and spraying them on the ground and then, uh, stacking them back up on the shelf.

You know, you're moving throughout the day to be healthy. So that's the. foremost requirement for human health is increased general everyday movement. And then when it comes to fitness, we have those big pillars of resistance exercise as well as brief explosive all out sprints. And you don't have to be sprinting on a on a regular basis.

Just, you know, once every 7 to 10 days is fine. whereby strength training, resistance exercise. A lot of the experts are recommending, you know, a couple of times a week where you have a proper session that perhaps last between 10 and 30 minutes. It doesn't have to last an hour and 20 minutes or any of these things that are risking becoming too stressful in a big picture perspective.

So it's like putting our muscles under resistance, load doing something explosive. When I say the word sprint, you and I are thinking of sprinting down the track, but you can sprint in all different modalities where if you're not adapted to Doing a high impact right away. You can sprint on your rowing machine or your stair machine or your stationary bicycle.

You can sprint in the swimming pool and just tap into that top end performance, because that is the essence of use it or lose it. The natural law of fitness. If you can become competent in sprinting, you become better at all lower. Levels of exercise intensity, not only physically, but psychologically, your perceived exertion is lower when you're out there doing a brisk walk or a slow jog because you are good at sprinting as well.

And you teach the body what it's like to, to really maintain that explosiveness and that power. And unfortunately, we lose that at a much more accelerated rate. Then we lose our cardiovascular endurance. So, uh, the elderly populations, many of them who are dedicated to healthy living, they get out there and walk like my mom walks a mile to two miles every morning.

And then I have to give her the, the other news is that you're doing great. Congratulations. She's 87. She feels great. And now you got to get into the gym and you got to keep that appointment with that personal trainer to load up those machines and push, you know, 

Michael Kummer: But you know, someone might say, well, and that's all well and good, but I feel like I'm, I mean, I'm not burning any calories.

If I don't sweat like a pig, you know, I feel like it's not working. It's not enough. 

Brad Kerns: Yeah. Um, I appreciate these follow up questions and I know you're getting some good content because I'm loving your newsletters and your shows where people are now expanding their perspective of this flawed and dated perspective of calories in and calories out.

So we know that the body engages in an assortment of compensation behaviors. When the exercise is too stressful. So when we're talking to the running community who are putting in all these miles and chronically overproducing stress hormones in the bloodstream, because the workout is too stressful, that's what causes the accumulation of visceral fat and the dysregulation of appetite and satiety hormones.

So, yes, indeed, you can go on your internet calculator and notice that your super difficult spin class that you did at 6 a. m. Indeed, burned 750 calories or whatever they're going to tell you. But, over time, as you're lazier throughout the day, and as you reach for more pints of Ben Jerry's as a habit in the evening, these are the compensation factors that take away from any attempt to drop excess body fat, which we know is coming.

The main way this is achieved. The way this is achieved is hormone optimization. You can call it. So that means staying strong, energetic, healthy, being able to burn body fat yourself because you have nutritious diet and you have good sleeping habits and you have stress management. That's the secret to getting the physique and maintaining it.

for the rest of your life. So the calories burned with stressful exercise are not going hand in hand with fat reduction. Otherwise, what we could do is chart our weekly mileage, right? Hey, I run 30 miles a week. I'm a marathon runner. That's this many calories I should lose. Let's see. Hold on a second. Oh, 47 pounds of excess body fat every year should be melting off my body because I'm running so much.

And of course, we're now unwinding this story and realizing that it's complete folly, even to measure the calories burned during your workouts. It's all about living that healthy lifestyle and putting everything together for hormone optimization. 

Michael Kummer: Now, a lot of people don't have a lot of time or don't prioritize movement throughout the day enough.

You know, ideally you want to be constantly or almost constantly moving in whatever shape or form, right? For most of us and to a degree that's, you know, applies to me as well. You know, I sit in front of the computer for extended periods. And so when I don't have time to move. I feel like I need to compensate for the time that I've set, right?

And if someone has it as an eight to five, you know, some, you know, if you're a consultant or whatever, traveling a lot, you've spent countless hours in the office and then you have that one hour in the morning or in the evening. Where you can crush it and kind of try to compensate for everything that happened or did not happen during the day.

What would be a good strategy, you know, um, for that? Obviously, we can ignore or at least not going to, you know, don't cut your sleep short to exercise. I think that's a stupid idea. But besides of, besides of that, you know, just from a pure movement, uh, moving the body, burning calories, scaring your heart rate up perspective, what would be a good exercise regimen?

to be most effective in such cases? 

Brad Kerns: Well, the first thing I would, uh, reflect on is the great research on sleep and brain productivity. And so the experts know there's Stanford University research that we publish in the book where, um, your cognitive function declines after 20 minutes of intense focus on a peak performance task.

It, it drifts away. And so if you do not give yourself a movement break every 20 minutes of hardcore, intense work, the break will be taken for you. What happens to me, Michael, is I sent, I tend to, I tend to be watching high jump videos. All of a sudden they appeared on my, on my, on my tab from, from YouTube rather than continuing to focus on my book manuscript.

The breaks are taken for you if you don't take them. And so these little bouts of, uh, brain refreshment and physical movement throughout the day also help with your fat metabolism and your ability to stabilize appetite, energy level and cognitive focus for the demands that we place on it. And so if you don't have time to take a minute break every 20 minutes or take a five minute break every hour throughout the day, you are by definition going to be slower and less productive.

And the research on sleep is that if you, this might not be exactly the, the, the accuracy, but it's like, if you are 20 percent deprived on sleep, you're 20 percent slower on all your cognitive tasks. So you have to stay late at work because you woke up early, uh, to, to get more work done. And so that's kind of funny to me.

Um, it's pretty easy for us being, you know, immersed into the athletic and fitness lifestyle for our whole lives to realize this. But, um, I'm really fond of taking afternoon naps because, uh, A lot of my work is really cognitively demanding, um, starting from a blank screen and cranking out a 300 page book is no joke.

And I need to be as sharp as I possibly can. And I will notice at two and 30 in the afternoon when I start to feel a little goofy or I drift over to the YouTube video and realize. Now it's time for my nap, because when I come back from that 20 or 30 minute nap, I'm going to kick some butt at level nine instead of cruising along.

Um, the, the researcher from Britain, uh, James Hewitt calls it the cognitive middle gear and the cognitive middle gear describes many people's jobs in essence, where they're just going through the motions and they're answering the phone all day. And I love it when I, when I go like this, I say, Uh, hi, this is Brad Kearns calling to check on my appointment time next week.

And they say, Oh, okay. Can I have your name, please? I'm like, okay, you're stuck in the cognitive middle gear. And, um, I want you to get out of it right now. So I'm going to, I'm going to wake you up with a few jumping jacks and some. Some deep squats in your cubicle right there as we talk over the phone. So the first tip is you got to stay moving so that your brain can work at its best.

And then another thing I like to discuss and recommend is this concept of micro workouts whereby we demystify what a workout really means and how complex it needs to be. You don't have to get in your car and drive. Down the road to some parking lot to check in at the front desk and, and beep your pass and get a towel and go line up and, and get ready for this elaborate thing.

Of course, that's a fun part of life. And people who adhere to a workout schedule is great, but you can take 20 seconds right now in your cubicle, even if you have no space and do a set of deep squats. And even if you're fit, when you get to number 20, it's a strain and you start to feel a little burn in your muscles and you get your, your breathing up.

And if you add these up over the course of a year, you're And I come back on the primal shift 365 days from now, and we say, yeah, you mentioned those micro workouts back in 2025. It adds up to a tremendous fitness benefit. So I have these rules in my life. And one of them is when I encounter a staircase during my daily life, I rush up it every time.

Oh, I do fast feet like the little sprinting drill, or I just make a point of sprinting up the staircase rather than walking at a normal, like a normal person. Um, there's also a hexagonal deadlift bar over in my side yard, right next to the garbage camp. So when it's time to empty out the garbage from the kitchen, I pass by that bar and I do one set.

Of six to 12 with very low weight. So I don't have to warm up and do the whole protocol, but I'm getting a little bit of stimulation with the hex bar lift, uh, as part of my day, I'm not writing it down in my journal, did a set of six at 97 pounds, you know, it's no big deal, but it's sprinkling in fitness opportunities throughout your busy day.

Michael Kummer: That's, that's a, that's a very good idea and I've, uh, I really like those micro workouts and, and I've, you know, had, I started implementing them and then I realized I'm doing a lot of micro workouts, you know, throughout the day, unconsciously, you know, you mentioned before lifting feedbacks, you know, there's always almost every morning we have to, you know, bring a bucket and like a farmer's carry kind of workout across the lawn with the fermented feed for our chickens.

And it weighs, I don't know, maybe 40 pounds or whatever, not super heavy, but heavy enough that it's, it's, uh, An effort, you know, to a degree and you know, all of the things I'm like, you know, I, I really, that was one of the benefits really of, of, of, uh, of raising animals because you gotta, you have manual labor involved if you want to or not.

And it's really a nice contrast. To all of the other things that I'm, I'm doing here in the office. And I also, I think that might've started when we first talked, uh, was maybe, was it last year it was definitely last year, even the year before I remember it was a while ago. Uh, the concept of walking, you know, just walking more.

And ever since we've, we've gotten, you know, a lot of people get dogs. Okay. They, they, they're going to help me work out more. I think that's a very bad idea to get a dog, to help you do something that you're incapable of doing because chances are. You're going to starve the dog of, of, of its exercise because you're not going to go, you know, when it's rainy or when it's not perfect weather outside.

But I've noticed that because I like to do be outside and do things anyway, and now it's even more so, you know, I walk at least 45 minutes, sometimes one and a half hours every single day. Just because of of him, you know, and wow. 

Brad Kerns: Now, when you're walking, even as a very fit person, your heart rate is most likely double or more than double your resting rate.

So you're getting a fantastic aerobic training session along the lines of Eliud Kipchoge running eight minute miles at high altitude for 13 miles. So you're training for a marathon. While you're walking around with your dog and, uh, you know, going and taking it to the next level and preparing for a grueling event requires more training and specialized workouts.

However, when you have that base, now you're able to go into the gym and do those awesome CrossFit sessions with much more competency than if you were just sitting in your office for eight hours and then going to CrossFit at 6 p. m. and trying to be a hero there. It just. It's tough. And most people, if they have that insufficient daily movement, it dramatically compromises their fitness potential.

And it's not that big of an ask to get out there and put in a little more time just moving around and pulling the stretch tubes that are hanging from your door. It takes 30 seconds and it's a great fitness stimulation. 

Michael Kummer: Yeah, and I never thought about that, but I have noticed that, especially in the last 12 months or so, my work capacity at CrossFit has improved, whereas in the past, you know, I could maybe hold a certain pace for a seven minute workout.

Now I can suddenly do it for a 12 minute workout, you know, I don't know, you know, don't get too hung up on the exact numbers, but I know that I can keep the or maintain the same intensity for longer than I used to. And I never connected it with, you know, just something as simple as, as, as going for that walk once or twice a day, every single day, sometimes even wearing, you know, the white vest, you know, to make it a little bit more challenging, um, and getting my heart rate just up a little bit, but not to the extent where I'm like, Oh, I need to sit down.

Brad Kerns: Yeah, that's incredible. And now I want to figure out how I can achieve the opposite because you're this sprinter guy who has the tremendous genetic gifts for power and explosiveness. And I have plenty of endurance and I go out and do my sprint workouts and I'm like, dang, man, why can't I break 60 for the 400?

How do I get there? Faster and more powerful and explosive. So you have that, that training base and that, uh, genetic potential. And now you're layering in the, you know, to, to perform with, um, you know, great intensity for seven minutes. Wow. That's awesome. But then if you can put it out to 12 minutes, that's when you're going to the CrossFit games finals, instead of getting knocked out in the regionals, you know, it's the, it's the endurance to generate that power.

Michael Kummer: Right. Yeah, that's fair enough. Um, going back to the book, who is that book for? For runners? For people who have never worked out in their lives? For, who is it for? Who should read this book? Yeah, thanks for, 

Brad Kerns: thanks for asking the question because we were trying to accomplish a lot with one book title and The subtitle says the broken promises of the running boom and how to slow down and get healthy one step at a time.

So it's kind of a two part book. And the first part is challenging our prevailing notions about what fitness really means and what cardio cardiovascular endurance. Means and how to get there and how we've been brainwashed and succumb to marketing hype by profit driven enterprises that are glorifying races like the marathon and teaching us that we're born to run and we should run every day and that running 30 miles a week is a path to health and fat reduction and all these things that it's been proven not to.

We also have a chapter talking about the addictive nature of high level recreational sports, especially the endurance scene. And we see that in the gym culture to where, um, you know, the fitness freak is celebrated in culture and society because their dedication, but it's becoming unhealthy and over into the category of addiction.

So we kind of set everyone straight with these flawed notions of struggle and suffer that pervade the fitness community. And then the second part of the book is celebrating the benefits of a walking oriented lifestyle. There's a chapter on foot health and foot functionality. And you had Mark Sisson on, he did a wonderful job talking about, uh, his launch of the Paloova shoe company that you're a big, uh, you're a big promoter of, and we appreciate you so much.

And you're embracing of this barefoot technology, uh, compare and contrast to the disastrous effects of elevated cushioned shoes that have had. on, uh, not only in sporting and running shoes, but, you know, wearing them around all the time. So it's a multifaceted book that I think everyone would appreciate reading and picking up these great tips, especially, uh, with the end, the last couple of sections, we talk about what it means to have a broad based functional fitness program, promoting longevity.

And that's when you get into the fun stuff of. Realizing, Hey, if you're going out for a 30 minute jog in the forest, guess what? You can stop at the tree stump and do five box jumps and then walk it off and recover and then jog a little bit and then stop at another obstacle and do some pushups against the fallen tree trunk.

And, you know, get a more beneficial, broadly beneficial workout than thinking that you have to just peg that heart rate and stick to some pace that's too stressful to even help. Reducing excess body fat. So it's putting everything together and leading a healthy active energetic lifestyle. 

Michael Kummer: All right I appreciate that and I appreciate you making the time and sharing everything, you know, I know it's a lot uh, you you have quite the experience and I and I much appreciate that and Um, I link everything down below in the in the show notes where people can find the book I assume you can buy it on amazon or anywhere books are sold.

Yeah, we have a cool 

Brad Kerns: website Uh, called born to walk book. com. And we have all these, uh, promotional excess goodies, uh, where you get, uh, shopping discounts and PDF downloads that are really valuable resources. So it's, it's a bonus offer. If you start there and, uh, just come back and, uh, you know, confirm your purchase, wherever you like to, uh, order books, whether it's at the neighborhood bookstore or online providers.

Michael Kummer: All right, sounds good. Cool. Well, we're gonna wrap it up. And again, thanks so much for joining me again today. 

Brad Kerns: Oh, any time on the Primal Shift, man. I love your show, and it's an honor to be a part of it. 

Extra: Cool. Appreciate it, man. In the next Primal Shift podcast episode, we're cutting through the noise surrounding beef.

Is it really a heart killer? Does it cause cancer? Harm the environment? Or lead to weight gain. We're tackling these myths head on and uncovering the truth about one of the most ancient nutrient dense foods on the planet tune in as we explore the science, the myths, and the facts you need to know, don't miss it.