Gladden longevity — Episode #52

Steve Reiter: Welcome to the Gladden Longevity Podcast with Dr. Jeffrey Gladden, MD, FACC, Founder and CEO of Gladden Longevity. On this show, we want to help you optimize your longevity, health, and human performance with impactful and actionable information by answering three questions: How good can we be? How do we make 100 the new 30? And how do we live well beyond 120?

I'm Steve Reiter, and Dr. Gladden we just wrapped up interviewing Sten Stray-Gundersen with B-Strong Bands and talking about blood flow restriction. You're a big fan of the B-Strong Bands. I'm going to be ordering them. Talk about what they are and-

Dr. Gladden: No, I've been a big fan of blood flow restriction ever since I was introduced to Vasper. I think one of the things I loved about this conversation is that we go into the physiology of why blood flow restriction, all the cardiovascular benefits, but also ways that you can use it in really creative ways to actually optimize workouts, whether it's weight workouts or bodyweight workouts or aerobic training or just walking around, quite honestly. So, it's going to be a fascinating conversation. I think you're going to love this.

We're really excited to welcome Sten Stray-Gundersen to the show today, the Gladden Longevity Podcast. Sten is an expert in blood flow restriction, which we have a fair amount of experience with, beginning with Vasper years and years ago. And then we actually did a research paper on Vasper and compared it to KAATSU and some other things, but now we're really enamored with these B-Strong Bands, and it turns out that Sten is not only interested in B-Strong, but he is actually done a master's in blood flow restriction at the University of Austin and also is a Ph.D. candidate now. So, I think we're about to really learn some things on another level when it comes to blood flow restriction. So, I'm very, very excited to welcome you to the show.

Sten Stray-Gundersen: Really happy to be here. I've been listening to you guys for a while now, and so it's exciting to be on.

Dr. Gladden: Great. Yeah. Great. So, tell us a little bit about it; I saw that you were a D-1 soccer player at Dartmouth, I think undergrad, and I don't know, what was your introduction to blood flow restriction? Did it happen in college or high school, or what's the story there?

Sten Stray-Gundersen: Yeah, that's actually exactly how it happened. So, just to go back a little bit, my dad has kind of been an expert in the world of exercise physiology for the past 30 years or so, and his kids are great guinea pigs, and he really likes to experiment.

Dr. Gladden: All kids are good guinea pigs.

Sten Stray-Gundersen: And he also, from a very young age, using his kind of studies involving high low training, [inaudible 00:02:49] high altitude, train out in low altitude. We lived in Park City, Utah, for a while, and he was implementing that on his kids with the idea that this was going to help propel them in athletics. And so, was a long history of listening to him and realizing just how much he did know and how useful it was. And so, in my junior year of college, when I was playing on Dartmouth soccer team, this was back in, I guess 2015, 2014, he introduced at the time, which was KAATSU, even this methodology coming from my dad, I was a bit skeptical as he was, but there was some validity behind it and research papers behind it. So, we gave it a good try. And just from a personal standpoint, it just changed the game for me and-

Dr. Gladden: So, let's describe for the audience what KAATSU is. That's a term that most people probably are unfamiliar with, KAATSU. It sounds very Japanese.

Sten Stray-Gundersen: Yes, and it is. So, it developed in Japan, and to my understanding, ‘kaatsu’ means additional pressure. So, in a very sort of simple way, it's applying additional pressure to the vasculature tissues in order to restrict blood flow and make relatively light intensity or lightweight exercise be perceived as high intensity or a heavy exercise.

Dr. Gladden: So, for the audience, just the analogy, you're putting a tourniquet on your thigh or putting a tourniquet on both thighs and maybe both upper arms, but with a tourniquet where you're trying to actually stop blood flow, you're not trying to stop blood flow with blood flow restriction, you're just trying to slow it down, so to speak, so you're not going to lose your arm over it, but it's the same idea as you're putting a tourniquet on and just tight snugging it up, so to speak, right?

Sten Stray-Gundersen: Exactly. And in other words, you're not going to lose an arm or leg over this, you don't have to give an arm or leg to reap the benefits here. So, originally, the way that this was developed, and it's important to go into the history of it a bit because it sort of sets the stage for blood flow restriction as it is today. This was really originally invented by a doctor named Dr. Sato, who actually was in a [inaudible 00:04:54] position at a funeral.

And that involves basically sitting on your calves, and he is also a bodybuilder. And he noticed that as he was sitting in this position, he felt the same sort of pump in his calves that he experienced with a heavy body-building session. His calves got a nice pump to him and things like that. And so, this started turning the gears in his head a bit. He actually started experimenting with bicycle tubes and straps and various things to actually restrict his blood flow.

Dr. Gladden: Let me understand this. He is at a funeral, and he's sitting on his calves. How do you sit on your calves? Is that-

Sten Stray-Gundersen: So, it's a sort of traditional meditative position.

Dr. Gladden: Like a lotus position?

Sten Stray-Gundersen: Say again?

Dr. Gladden: Like a lotus position or no?

Sten Stray-Gundersen: So, not lotus. He has his shins touching the floor, and then basically his-

Dr. Gladden: [inaudible 00:05:42].

Sten Stray-Gundersen: [inaudible 00:05:43] hamstring-

Dr. Gladden: ... onto his calves.

Sten Stray-Gundersen: Right. His hamstrings would be on his calves, and his bottom would be on his calves. And it's essentially making some of the calves ischemic. Now, again, this is not the end of the story because if he were to just end there, this would be sort of dangerous. He experimented with bicycle tubes-

Dr. Gladden: Ischemic, tell me, just define ischemic. Ischemic is a lack of blood flow to a tissue. So, ischemia is a lack of adequate blood flow to a tissue, just so you've got that. Okay. So, he is making his calf muscles ischemic. They don't have quite the blood flow they would have.

Sten Stray-Gundersen: Right, and people have experienced this before. If you sit down on something for too long, you can kind of get that tingling feeling or-

Dr. Gladden: Going to sleep feeling.

Sten Stray-Gundersen: Going to sleep. Exactly. That sort of sparked this idea. And he then experimented with bicycle tubes, like I said, tourniquets, straps, belts, stuff like that. And he actually ended up giving himself a pulmonary embolism because he was doing this and making the actual muscle ischemic while contracting. And so, there is this risk associated if you're not using the right things because ischemia in our field is not good for the tissue.

Dr. Gladden: Well, there are a couple of things that happened with that. So, if you're really cutting off blood supply in the veins, in other words, you put the tourniquet, let's call it tight enough, and there's no blood flowing in the veins, then you have what's called venous stasis where the blood is just sitting there, and when it's just sitting in the veins and not flowing, it's prone to clot. And so, you get a blood clot in the vein and your leg, and then it breaks off and travels up and goes to your lung, you get a blood clot in your lung, which can be a life-threatening event, quite honestly. So, he just about killed himself trying to figure this out, is what we're talking about.

Sten Stray-Gundersen: You got it. Yeah, you've explained it well. And he ended up realizing that what you truly need is an intermittent venous impediment or venous occlusion where you're having intermittent flow throughout the vein. You're never creating what you just described as this venous stasis. And that is critical. He ended up going skiing on Mount Fuji and broke his malleolus.

Now, at the time, they put him in a full leg cast, and as we well know, when you're in a full leg cast or any kind of cast, you get a large degree of atrophy. And at the time, he was still experimenting with this, but he thought he had sort of figured it out. He knew that muscle contraction was key. He knew that an elastic tourniquet system was key so that you're not creating hemostasis. They went to take off his cast to replace it with a smaller one, and the margin of atrophy was extremely low. And in a sense, he attenuated the atrophy that he would otherwise experience.

Dr. Gladden: Okay, so he's got a cast on, he's got a cast, he's broken his ankle, his medial or lateral malleolus, and then he's got a cast on, which should cause atrophy, particularly in his calf muscle, but he puts a tourniquet on his thigh or on the calf, somewhere on-

Sten Stray-Gundersen: High up on the thigh.

Dr. Gladden: High up on the thigh. So, he is intermittently decreasing blood flow. Now was he also walking around? Was it a walking cast, or was he moving around or just intermittently just restricting blood flow?

Sten Stray-Gundersen: He was restricting blood flow while doing isometric sort of contractions, or not even isometric, but just flexing essentially within the cast as much as he could.

Dr. Gladden: Okay, so he's exercising inside the cast-

Sten Stray-Gundersen: Correct.

Dr. Gladden: ... with his blood flow restriction. Fascinating. Okay, cool.

Sten Stray-Gundersen: Correct. And so, this was really the epiphany that sort of sparked what we understand today as KAATSU, and he was also a bodybuilder, so he used it in his own training and had extremely great results. Now, this was back in the late '50s or early '60s; people out there might scratch their heads and say: “Well, how has this been around for so long, and I haven't known about it?” Well, I think it's a multifold issue. This was, in part, dangerous. He had a negative experience with it initially through the improper use of it. And that led him to employ the certification program, and basically, a lot of obstacles for the common person to be able to use this consistently. And also it was sort of kept sort of as their secret weapon if you will-

Dr. Gladden: Secret weapon.

Sten Stray-Gundersen: Yes, in their back pocket. And actually, in the '80s and '90s, there were some European bodybuilders who started using tourniquets and knee wraps and things like that, but it never really, really took off. And it wasn't until I would say 2010 through 2012 maybe, where it started really coming to the US, and that's when my dad kind of got involved, and he was involved with KAATSU for a bit, but there were just so many obstacles still, and it didn't seem to be optimized for the common individual, the lay individual. And so, he felt he could be able to build a better mouse trap. And so, we came out with the B-Strong Bands, which employ a semi-elastic application of BFR. And in the midst of this also, there was also a group in San Antonio working with blood pressure cuffs and tourniquet-style rehab, particularly in military populations. And they showed great rehab benefits from that. So, that kind of sets the stage for where we are today.

Dr. Gladden: Right. Yep. I'll just mention Peter Wasowski; you may know Peter Wasowski, the guy that kind of invented Vasper, and he also adapted into the Vasper system with putting cooling water into the cuffs and doing interval training on a new step with cuffs on the arms and legs and got some nice results too. So, I think there are lots of different ways to kind of apply this, if you will. The thing about Vasper is that the machine's expensive. You get the whole system; I don't know what it is, 50-60K, and it sits in your house. And then there's a KAATSU system out there, too, that I think is electronically inflated and deflated, if I'm not mistaken, right?

Sten Stray-Gundersen: Correct. Yes.

Dr. Gladden: And then there's B-Strong, and so maybe you can contrast a little bit between these different systems and advantages or disadvantages you think you might have with a B-Strong.

Sten Stray-Gundersen: Part of the reason we came out with B-Strong is, first of all, the cost. The cost is in the hundreds of dollars rather than in the thousands. And secondly, there were a lot of protocols that were necessary leading up to the use of KAATSU and perhaps [inaudible 00:11:55]. I have less experience with [inaudible 00:11:57], where you need to go up to an inclusion pressure, or not an occlusion pressure rather, but a period of restriction, you deflate the cuff, you increase the pressure again, you deflate the cuff. It sort of primes the vasculature to be able to handle a beat of blood flow restriction session.

Dr. Gladden: This is called ‘preconditioning’, and it's used in all kinds of cardiovascular experiments, either in the periphery or cardiovascular. And what happens is, let's say you're working in a heart attack model, and so you want to see what's the size of the heart attack going to be, you could just go in and ligate or close off the artery, in which case you'd have a very large heart attack. But if you precondition by actually constricting it, releasing it, constricting it, releasing it, constricting, releasing it, and then close it, you get a much smaller heart attack because you've preconditioned the collateral blood flow, you've preconditioned the heart to actually tolerate ischemia. So, when you're thinking about your limbs, you can kind of precondition the limbs in a way by utilizing these techniques. It's kind of interesting. It's a way to increase nitric oxide production, quite honestly, which then dilates the arteries and gets things going. So, anyway. Okay.

Sten Stray-Gundersen: And one of the ways that we think about ischemic preconditioning in that case, we're using actual cuffs to do that, you're changing the environment more favorably to handle excessive increases in oxidative stress, which kind of start the cycle of inflammation and damage and all this other stuff. And actually finishing up my dissertation now, in one of my studies involves the use of hypoxia or systemic hypoxemia and its ability to actually precondition the vasculature to handle excessive increases.

Dr. Gladden: So, just so the audience understands this, so you probably have people breathing a lower concentration of oxygen than they normally would while they're exercising, right?

Sten Stray-Gundersen: Correct.

Dr. Gladden: Are you using-

Sten Stray-Gundersen: So, actually, and this is actually at rest. So, I encourage people to check out Hypoxic Preconditioning: Attenuates Ischemia-Reperfusion Injury in Older Adults, which is what the title is for that paper.

Dr. Gladden: And so, let me ask you a little bit about that. So, if somebody had coronary artery disease, in your study, do you show that if they do hypoxic breathing or low oxygen concentration breathing for a number of minutes a day, that it actually, over time, will improve their ability, it'll decrease their chest pain or their angina or anything like that? Or are you jumping all the way to those kinds of conclusions, or where are you?

Sten Stray-Gundersen: So, as a conservative scientist, I would say we can't jump quite there yet. We have not studied that population, specifically. This was in the same aged match controls, but they were healthy individuals. So, I can't speak to coronary artery disease, but I can speak to their age match controls where they did see an attenuation in this, what we call ischemia-reperfusion injury. Now we were using the brachial artery as a surrogate measure, which is typically used as an index of coronary artery function, slightly different, and I don't want to jump to any conclusions quite yet.

Dr. Gladden: Right. Okay. So, nonetheless, it's sort of counterintuitive to think that if I'm going to be cutting off the blood supply that, I might be damaging my arterial system, but in actual fact, you're actually making it stronger in a way. You're actually making it more resilient. You're preconditioning; it's training, it's like another form of exercise, it's hormetic stress, if you will. It's a hormetic-

Sten Stray-Gundersen: Precisely. And it's the intermittent nature that is really the key here. Chronic exposure to ischemia, chronic exposure to a lack of blood flow is one definition of death, it’s a lack of nutrient supply. This intermittent nature, and acute intermittent nature, that's key here. One thing to distinguish between different blood flow restriction systems is there's sort of two approaches. One is what we call a limb occlusion or arterial occlusion pressure approach, where you're going up to a limb occlusion pressure and to kind of explain that is the pressure required to completely collapse the artery itself.

You're going up to that pressure at rest, you're backing off anywhere from 40 to 80% of that pressure, and then you're going throughout the exercise. So, in all BFR, you're never trying to completely occlude or cut off that artery. And really what you're trying to generate is an intermittent venous occlusion where you have a patent artery, you have blood flow coming in through the artery, you have a certain degree of blood pooling in the limb, or you're having intermittent flow of the venous side of things out of the muscle, across the band, back towards the heart. And so, we're never trying to completely stop blood flow. So, that's a key distinguishable feature of different BFR.

Dr. Gladden: Yeah, it's interesting; the way I think about that is that you're actually creating a more hostile environment for the muscle to try to function in. You're not really limiting inflow, it's still getting oxygen, but its ability to flush out CO2 and flush out other toxins related to metabolism is limited. And so, it has to adapt and basically upregulate its mechanisms for handling, say, lactate or handling acidity or oxidative stress or whatever else, different enzymes that will do that. So, in essence, you're kind of training that to function in a hostile environment. So, then when you go ride your mountain bike without the bands on, all of a sudden, it's like: “Oh, this is easy.”

Sten Stray-Gundersen: Which, by the way, happens with high-intensity exercise. The adaptations currently in place are not sufficient to maintain that high-intensity environment. And just to clarify, there is probably a little backup of flow. And so, you do desaturate the tissue, but you likely never desaturate the blood flowing through the artery itself.

Dr. Gladden: Yeah. Yeah, there's a device called a moxy that you can put on and measure actually tissue saturations oxygen. You've probably done that in your studies. Did you show that when you put the B-Strong Bands on that, you do desaturate?

Sten Stray-Gundersen: Yes, exactly. And this was more of a sort of pilot study or case study type situation, but we did have someone perform simple bicep curls with and without the bands, and typically your muscle tissue sits around 70 to 80% saturation at rest. And then, once you start doing bicep curls without bands, it might get down to 50, maybe 40, depending on how far you take it. And then it very quickly recovers back to baseline. And what we found with BFR bands is that you go down to on the first set to about the same level, but it's this pseudo rest. So, in between that interset period, you're not getting back up to baseline. And so, the next set, you're going down by probably about the same amount, but now your new baseline is lower, and so each successive set, you keep getting into trouble.

Steve Reiter: So, Sten, describe for the listeners what the B-Strong Bands are because I'm looking at the website, I see that they go around your arms and your legs. I assume you don't have bands for the chest or any big muscle groups other than arms and legs.

Sten Stray-Gundersen: Right. And that is intentional. In part, the limbs are the easiest to restrict and the most comfortable to restrict. So, a lot of feedback that you likely get from BFR is that it's very painful and not just the actual muscle burn, but the actual placement of the band, the band's pressure on the tissue. We've optimized these to be narrow enough to not impede movement and athletic movement but wide enough to sort of displace that pressure and be comfortable when using these. And there is some debate, say the jury's still not out in that we haven't found biomarker evidence of systemic effects per se, but we do see increases in muscle size in the areas that are not blood flow restricted, if you will. And I think there are a couple of things going on there. So, just to kind of clarify, what I'm saying is when you put the bands on your arms, and you do a pushing exercise, like a bench press, for example, we see that the pecs also grow in size compared to the triceps.

So, they are growing in a similar amount, and there are likely a couple of things going on there. For one, you're likely fatiguing those triceps a little bit faster, you're likely desaturating those triceps a bit faster. So, then you then have to depend more and more on the pecs to actually move that pushing movement. And second, there are likely some systemic effects that you're eliciting from the brain; most notably and most kind of talked about is growth hormone. This is kind of an overarching hormone that everybody loves to talk about, and any muscle that is undergoing contraction and fatiguing contraction, specifically, is going to have their growth hormone receptors come to the cell surface to actually pick up circulating growth hormone. And so, those two kinds of likely work synergistically to be able to grow the muscle and make the muscle stronger itself.

Steve Reiter: Dr. Gladden, you actually take these B-Strong Bands when you travel and use them-

Dr. Gladden: Yes.

Steve Reiter: As part of your travel kit, so that way, you're getting workouts in the hotel.

Dr. Gladden: No, exactly. I really like them because they fit in your suitcase and they don't take up much space, and they come with a little insufflator, which looks kind of like a blood pressure handle and sphygmomanometer is what it is. And basically, it's lightweight, it fits in your travel case, and I take it with some resistance bands. And then, I use the resistance bands to do isometric training for legs and arms and things like that with the B-Strong Bands on. And then I also do some knees-over-toes type exercises with one-legged split squats and things like that and pushups. And really, literally, within 20 minutes or even 15 minutes, you can get a total body workout that feels like you just were in the gym for an hour. It's very efficient, and it's very portable. So, it's kind of like my travel kit; I take it with me wherever I travel.

Sten Stray-Gundersen: Absolutely, we profess anywhere, anytime, anyone can perform this type of exercise. And I think you said it best, you can get a full-body exhaustive workout in a very shortened timeframe with relatively light weights, and the knees-over-toes stuff is awesome. I can't promote that as much any more than possible. And the idea there is you're slowly building progressive overload to these muscle groups, these stabilizing muscle groups with these pre-rehabilitation type exercises. And generally, that can be a gradual process. With the bands, you can really stress those muscles to an extreme degree, and I think more than otherwise possible.

Dr. Gladden: Yeah, we have a Nordic bench here at Gladden Longevity, in the office here, up in the gym, and I've been working on trying to do a Nordic curl, which I can't pull off yet, but I find that using the B-Strong Bands actually gets me closer to being able to do them. So, if I'm doing Nordic curls, and just so the audience understands, this is a bench that basically you kneel on, and then your ankles are kind of secured with, it's not a plate, but it's basically two rollers that come down on the back of your ankles. So, you're kneeling in, and your ankles are fixed, essentially.

And then the idea is to basically lean forward and go down and touch your chest to the bench and then come back up. So, it's a hamstring curl, but you're actually lifting the entire weight of three-quarters of your body, maybe more, probably more. It's more like, I don't know, 80% of your body weight for sure. You're trying to do just with your hamstrings, right?

Steve Reiter: Wow.

Dr. Gladden: And your glutes. Yeah, it's a full-on pro exercise. Most pros can't do it. Maybe you could do it, Sten, I don't know. But anyway, it's a great exercise because it really builds that posterior chain as part of the knees over the toes, basically protocol, if you will. So anyway-

Sten Stray-Gundersen: Just to jump in on that, there's a lot of regressions you can do-

Dr. Gladden: Hundred percent.

Sten Stray-Gundersen: ... if you use a resistance band, you don't have to do 80% of your body weight. And actually, if there's anyone out there who is just starting out with BFR, I would not recommend that intense eccentric type exercise for them. They can kind of do regressions of that. They can do concentric hamstring curls, for example, and build up, and then without the bands, they can go ahead and try that. As something to gather about BFR, you never want to jump into an exercise that is extremely intense right off the bat, always do exercises that you're sort of familiar with, and that's a better way to go kind of gradually.

Dr. Gladden: And since I can't do the curl, what I do is I do a regressed form of it. So, I have a BOSU ball that I reach out for or that I just allow my chest to plop onto, and then I use my arms to help myself come back up, so that I'm on the edge of what I can do, but I'm not going to complete failure. So, anyway. Yeah.

Sten Stray-Gund...: Excellent.

Dr. Gladden: Yeah. But it's great. I've also done it in combination with an ARX; I don't know if you've tried that.

Sten Stray-Gundersen: Yes, I have, actually. That was quite an experience; I have to say. I was just recently at a convention or a symposium, and I tried that for the first time, and that combination, it was killer. It was great. It's-

Dr. Gladden: It's killer, right? Yeah. ARX, it's a great exercise machine for both full concentric, in other words, pushing something away from you and then eccentric as it comes back to you, you're a hundred percent on through the full stroke of the exercise in both directions, and you add the B-Strong Bands to that and all of a sudden it's a really great exercise. You just feel like you're completely engaged with the exercise, and since there's no weight to the thing, you're just pushing as hard as you want to push, so to speak. So, you're not going to hurt yourself, but you feel like you're just right there, kind of a maximal clean effort the whole way. It's just a good feeling like you're getting the real exercise that you always wanted, where the whole stroke of the exercise is optimized, and it's a great feeling, quite honestly.

Sten Stray-Gundersen: Oh yeah, it works the muscle throughout its range of motion, right?

Dr. Gladden: Absolutely.

Sten Stray-Gundersen: It's great. And just on that note, you mentioned it comes with a sphygmomano- never say that word properly, sphygmomanometer.

Dr. Gladden: Sphygmomanometer.

Sten Stray-Gundersen: Essentially, one of the main reasons we actually have that is its sort of a low-grade way to do it, but we like that you don't have to charge a device, you don't have to carry around batteries, you can just really take this anywhere. You don't have to have an electric cable that's attached to anything. So, it's a really nice thing. You could do it, theoretically, on the top of a mountain or out on the beach.

Dr. Gladden: So, I have a question for you. So, the armbands and leg bands are different circumferences, of course, and the kit comes with armbands for smaller arms and armbands for larger arms, and then leg bands for smaller legs and leg bands for larger legs. So, it's pretty adaptive when you get the kit, but when you're blowing them up, when you're pumping them up with this sphygmomanometer and you have gradations on there, like 100, 200, 300, 400, I think it goes to 500.

Sten Stray-Gundersen: Correct.

Dr. Gladden: What should people be going to, and what do those correlate to? On a blood pressure cuff, it correlates to millimeters of mercury, but obviously, this is not millimeters of mercury because we're not going to 400 millimeters of mercury. So, what's actually going on with that? What's going on?

Sten Stray-Gundersen: So, this is a point of confusion for many, so I'm really glad you brought it up. First of all, to answer the first question, the width of the bands were really determined by the size of the limb. And through a lot of series of process of elimination, we came on to the sizes that we have now, which is about three centimeters for the arms, for the upper body, and about six centimeters for the lower body. Otherwise, larger individuals, they can even use what we call are blue bands, which are generally used for smaller-esque legs.

They could use those on their arms, for example. And it really has to do with the limb girth. And subsequently, the pressures that you talk about are also having to do with limb girth. So, we really have recommendations for pressures associated with each band. And so, if you get a size one, which is a green band, or a size two, which is a red band, it'll have recommendations based on that band for you as a starting point. And one thing we always stress is start small and kind of build up from there. So, to answer your third question, the millimeters of mercury question, it is actually millimeters of mercury. So, we are using up to 500 millimeters of mercury pressure.

Dr. Gladden: Really?

Sten Stray-Gundersen: Yes, but this is not the pressure that is exerted on the vasculature, and this is an important point. Typically, as you know, Dr. Gladden, systolic blood pressure is the pressure required to collapse an artery and to stop blood flow. And we typically hear of the 120 over 80 models where 120 millimeters of mercury is required to collapse the artery. And so, obviously, if we're going up to 500 with these bands, that's not representative of what's directly being placed on the artery. Now, if you were to use a rigid cuff or a blood pressure cuff, tourniquet, or things like that, that does not have any give to it, and that does not allow the muscle to expand with exercise. And not only that, that's the exact pressure that's being placed on the vasculature. So, really, what this represents in the band-

Dr. Gladden: So, it's the elastic nature of the band as opposed to the actual fixed nature of the band in a blood pressure cuff that's making a difference here. So, you can go to a higher pressure, technically, and put less pressure on the artery than you would with the other band. Okay, that makes sense.

Sten Stray-Gundersen: And specifically, we can think about it as sort of compressive BFR. And as we increase that pressure, the circumference of the band gets smaller and smaller, and it's kind of hard to articulate without just showing a diagram or something like that. But the more pressure that we put into there, it's sort of on this sort of upside-down U-shape curve where if we were to just use the bands with no air in them and you really, really cinch them down, you might be able to, not stop blood flow, but be really, really tight and actually inflating it just a little bit to 150 to 250 millimeters of mercury actually gives elasticity to the band itself. And then anything above that up to a point, you're going to have a greater degree of elasticity with more pressure. But as you get closer to 400, maybe 450, 500 millimeters of mercury, now you're creating a little bit stiffer environment within that band.

And so, this is the reason why we have different recommendations for sort of limb size. And as you get more and more used to this stimulus on the body, you can go to a little bit stiffer and stiffer and stiffer band of pressure to accommodate that. And one example of this is if you have someone who has a lot of dense muscle, they're going to use higher pressures. If you have someone with quite a bit of subcutaneous adipose fat around it, you probably want to go a little bit higher pressure, so that you're actually enacting pressure on the limb properly.

Dr. Gladden: Got it. If you do get the [inaudible 00:30:48], start slow and build up, this is one of those things where your body needs to adapt over time, and you don't want to just try to be Hercules and pump it up to 500. That's the wrong answer here, quite honestly.

Sten Stray-Gundersen: Exactly. And the real key here, one thing to say about BFR, is I think we often get lost in numbers and measurements. And although those are important, it's really not necessarily the pressure that matters, and it's the perceived development of fatigue. And what BFR is really hacking into, if you will, is the brain's perception of the exercise.

And as you're creating an environment that's similar to a high-intensity environment, you mentioned it before, a drop in pH, a more acidic environment, a drop in oxygen concentration and partial pressure of oxygen, and an increase in things like lactate. Those are all associated with high-intensity exercise, in which the brain's job is to respond to that and send the necessary healing and adaptive anabolic hormones to address that. And what BFR is doing is really kind of short-circuiting that system. And by doing that, the real key is a high perception of fatigue, a high perception of effort.

Dr. Gladden: Yep. Interesting. Have you ever combined this with any electrical stim devices?

Sten Stray-Gundersen: Yes. Not necessarily in the lab, but just sort of within my own athletic population-

Dr. Gladden: [inaudible 00:32:05] or [inaudible 00:32:08] or any of those kinds of things.

Sten Stray-Gundersen: So, I haven't worked with those products specifically, but just general stimulation, it's a really good way to perform rehab because even if you're not able to have a full range of motion, but you're trying, and maybe a muscle is not turning on as it should, using the bands in concert with this electrical stimulation, I think I've used [inaudible 00:32:26] before, it was really profound just the degree of muscle contraction you're able to elicit and with muscle contraction you're getting all those things I mentioned previously, drop in pH to increase in oxygen to drop in oxygen concentration, et cetera.

Dr. Gladden: Right. I will admit to the fact that I had the B-Strong Bands on, had the [inaudible 00:32:45] on, my glutes, and my hamstrings. I think I had it on my quads and my low back too. We had a couple of different devices at the same time, and then I was doing the Nordic curl.

Sten Stray-Gundersen: Wow, the bionic man.

Dr. Gladden: Yeah, I felt like the bionic man. What was interesting was it was like cranking up the [inaudible 00:33:06] to give the e-stim for the contraction was enabling me to do the Nordic curl better than I could otherwise because I could recruit more musculature to come into play. And it was a really interesting sensation. I still couldn't do the Nordic curl, even with all my bionic hacks, but I could tell that-  I'd been traveling quite a bit, and I haven't actually been in Dallas all that much, quite honestly.

But my plan that I'm going to be here a bit more is to actually work into that and see if I can actually accelerate my progress into being able to do a Nordic curl. So, the reason I'm bringing it up for the audience is that there are ways to get somewhat creative with this, and let's say that you are injured or let's say that you can't move or something like that, you can use something like e-stim along with B-Strong Bands and you can start to rehabilitate or pre-habilitate or mitigate the decline in a limb by actually using techniques like this to kind of get things back again. So, you can think about it in a creative fashion. Yeah.

Sten Stray-Gundersen: Absolutely.

Dr. Gladden: So, tell us a little bit about cardiovascular health. I know this is one of your areas of expertise when it comes to blood flow restriction. And we talked a little bit about preconditioning, but are there other effects that you've been measuring or looking at?

Sten Stray-Gundersen: Yeah, so as the old adage goes, I think it was coming up back in the 1600s, “a man is only as old as his arteries”, or “a man is as old as his arteries”. And that still holds true. And that's kind of one of the reasons why I'm so interested in cardiovascular health and fitness is maintaining that. Now, just like regular exercise or just cardiovascular exercise, one thing that we're doing is we are, as we mentioned before, acutely increasing oxidative stress in an intermittent and sort of contained manner. And that is going to be to the good as far as preconditioning and developing a strong cardiovascular system. And again, the old adage of “if you don't use it, you lose it” really applies directly to blood vessels. If there's no blood flow going through the vessels, if there's not this pressure gradient going through the vessels, these vessels are signaled to for apoptosis, and they degrade.

So, it's extremely important to increase the shear rate, increase what's called shear stress, and how much actual force is going across the artery itself. Things like saunas do this. And that's one of the reasons why this has picked up so much in popularity is we're able to induce an increase in shear stress and an increase in blood flow with exposure to sauna and heat. The reason why that happens is, as you well know, your blood gets redistributed to your skin to actually dissipate that heat. And that's actually why you sweat is actually it's sucking the moisture out of your blood into your skin to then evaporate and actually cool you down. Another way to do this is through hypoxia or systemic hypoxemia, you're breathing low oxygen level or low levels of oxygen, and that actually causes an increase in blood flow. And this is sort of what my dissertation is sort of centered around right now.

So, we've looked at it in the ability for hypoxia to protect the vasculature, but also to sort of get around people's lack of desire to exercise. One of the biggest issues is cardiovascular. I think it's still the number one killer in the "developed" worlds or developed nations, and we know the antidotes to this, and it’s exercise. So, something is going on where people don't want to exercise. So, there are many, many ways to be able to stimulate increases in blood flow, which is really the precedent to all the other beneficial adaptations that have merged from that. And just again, to expand on this, what we're doing with BFR is we're creating this local hypoxia within the tissues, which is a big stimulus for an increase in blood flow. When something becomes hypoxic, that says, hey, there's not enough blood flow going to this area; let's increase that. And so, there's many ways to do this.

Dr. Gladden: Yeah. So, basically, when you don't have enough oxygen, either because of blood flow restriction bands or combination with low oxygen concentration, kind of like trying to exercise at 8,000 feet or 10,000 feet or something, blood flow has to increase, but there's also a stimulus in the body to actually build new blood vessels, so that you actually increase vasculature into the muscle. So, now you have more vessels going there. So, instead of an atrophy of the whole system, you're actually building the system. And that's the beauty of exercise. We know that diet will sabotage arterial health, so you've got to always take care of that, but being able to get increased blood flow and then have the muscles get to a point where they can't get what they really want in the moment is critical. And so, many people don't exercise "to that point" or hard enough.

It's like: “We walk”. Well, okay, you're walking, that's great, but when we measure your VO2 max, it's not that great, quite honestly. You actually have to push the system. And so, having a technology where you can push the system and particularly where you can use in combination with, “I don't feel that great today” or “I'm injured”, or “I don't want to lose muscle mass, I don't want to lose my circulatory system expanse that I've created with exercise I've done”, this becomes very, very important for optimizing health and longevity. We're not just talking about a bodybuilder in Japan. Now we're talking about how do you optimize your cardiovascular health for the rest of your life. This is big deal stuff.