124. Best of Strength Training: Why Strength Determines How You Age

Welcome to Extend with me, Dr. Darshan Shah, a podcast dedicated to cutting-edge science, research, tools, and protocols designed to help you extend your health span. Having become one of the youngest doctors in the country at the age of 21 and trained in board-certified at the Mayo Clinic, I've accumulated three decades of practice as a board-certified surgeon and longevity expert. Over that time, I've discovered that a mere 20% of health knowledge yields 80% of the results when it comes to your health span. We're living in a new era where we are creating a new healthcare system no longer focused on disease management but achieving optimal health and vitality. Join me as I interview world-renowned experts, offering you a step-by-step guide to proactively avoid disease and most importantly, extend your health span. Over the past year on Extend, I've had conversations with some of the smartest minds in strength training, human performance, and how these fields tie into longevity. One theme kept coming up over and over again. Strength changes everything. So today, I'm putting together a best-of episode focused entirely on strength training. This is a curated collection of one of the most important moments from five different conversations I had last year. Pull together to give you a clearer, more science-backed understanding of why strength training is foundational to how we age. In this episode, you're going to hear how muscle supports metabolism and hormone health. As you know, I always say, your metabolism lives in your muscle. You're also going to hear about why bone density mobility determines independence later on in life. You'll hear about how strength and movement protect the brain and why daily habits outside of the gym matter just as much as your workouts. These clips highlight the ideas I believe are essential if you want to build a body and brain that stay capable, resilient, and strong over time. If you missed some of these conversations in 2025 or you want more of these impactful insights, go back to the episodes where you hear these guests speak in long form. There's an incredible amount of information there. Let's get started. First, we'll start off with JJ Virgin, and we're going to look at why muscle loss is one of the earliest and most overlooked drivers of metabolic decline and why JJ Virgin believes that strength is foundational to long-term health. When you get strong, you will also lose weight. You will also have a better body composition, and you'll have all the benefits you're looking for things without having the metabolic disease aspect of things. Right. Without having to try to maintain your weight, I'm sure you've heard of TOEFI or sarcopenic obesity, thin outside, fat inside, where they found that the people who were struggling with that were the people that were trying to maintain weight through diet alone. When you put on muscle, your metabolism is so great, you don't have to worry about it. It's a non-issue. You can actually eat. If you're eating correctly, you're not going to be hungry anyway. Absolutely. I always say that your metabolism lives in your muscle. We think it's somewhere else. That's a great statement. It lives in your muscle. I'm going to quote you. You can use that one for sure. Yes. The more muscle you have, the better your metabolism works, the less chance of metabolic disease. It's all about the muscle mass. Which means we should be packing on. I think of it so much as a retirement account. It is. We should be packing on as much muscle as we possibly can. I just want to emphasize to women, you'd be lucky. You'd be dancing up and down if you could put two pounds of muscle on a month. Absolutely. This is no easy feat to put on a bunch of muscle. It's not. I want to go over some specific protocols that you give for men and women about putting on muscle. That's really where we need to hone in on because there's so much misinformation out there and people are just confused. People don't know what's the right dose, how does protein play into this. We should go dive into each one of those topics. Before we do that, you talk a lot about aging powerfully. I want to tie in the longevity conversation as well. Tell us what you ... Why do I say that? Why do you say aging powerfully? Why do you say aging powerfully? Yeah. I was like, for gay, aging gracefully. I still hear this all the time. I'm like, no, we do not want to age gracefully. We have two distinct types of muscle fibers. We have slow twitch and fast twitch. We have these hybrid fibers that can convert to either one. Women tend to have more slow twitch than fast twitch. We're all different snowflakes, but we tend to have more. It's the fast twitch that's really capable of more hypertrophy. As we age, we start to lose more fast twitch than slow twitch. Here's why this is important. Women, when you look at a lot of the activities women tend to do, they tend to do more things that are not going to really work their fast twitch muscle fibers. Most women are not doing sprint training, power training, that type of thing. CrossFit would be a great example of things that are going to work fast twitch, but things like yoga and walking, these are slow twitch muscle fiber activities predominantly. If I'm focused on those, then those hybrid fibers are going to move into slow. Now I'm atrophying and losing my fast twitch. I'm just making myself slower. That is the opposite of aging powerfully. That is why when you look at what do we need to do as we age, we need to prioritize fast twitch muscle fibers because if we don't use them, we do lose them. I think the important thing here is the less you do, the less you can do. The more you do, the more you can do. I have a very different idea about training than I see most people doing out there. This really started back when I was working in physical therapy. Most of my grad work was in spinal lifting biomechanics. What I saw in physical therapy and what we were taught in school, we were taught two really dumb things in grad school. Number one, don't lift weights until you lose the weight. That is so wrong. I remember hearing that back then. It's still out there. It is. It is still out there. It's sad that people still think that that's reality. The other bizarre one was, and this was especially so obvious to me, being focusing on lifting biomechanics, they were like, if you have a bad back, avoid extension exercises. Don't work your back. Just do flexion and work your abs. I go, that would make you worse. That would make you weaker. We have this thing in muscle physiology called reciprocal inhibition. If you're flexing forward to work your abs, your back muscles have to not do anything. Otherwise, you would be static. You couldn't move. If you focus on one area at the expense of the other, that other area gets weaker. When you look at why people tend to not exercise, the number one reason is time, of course. That's an excuse if you don't have time, fine time. Just make time. There's nothing more important than this. The other reason is some type of an injury. When I was 17, I blew out my knee. When I was 21, I broke my foot. Just dumb sports injuries. Those became my why. For so many people to go, I have knee injury, so I can't work out. I was like, I have a knee injury. I have to work out. I literally had a bone-on-bone, very bad knee that they're like, you must have a total knee replacement. I put it off for 30 years because of how strong I had everything around it. That's what I want to emphasize. If you're listening, you go, oh, I can't do these things because of arthritis, because of an injury. No, that's why you want to do these things. Right? Absolutely. Now, we're going to hear from Andy Galpin. We're going to shift to why strength matters, and especially in how you train. We're going to talk about how you can train in a way that actually fits your physiology. Incredible insights from Andy Galpin. It's kind of counterproductive to compare muscle versus VO2 max. You really need both, right? It's kind of like saying, what's more important, my front wheel, my car, my back wheel. Exactly. No, no, no. This is not an either or thing. This is that you're not going to drive well without both of these things. Exactly. I know. We've done studies on lifelong exercises in many of these things. We've done things on, we did actually a twin study on monozygous. Oh, wow. Yeah. So this is great for translation. That means you have the exact same DNA, right? So egg is fertilized and split into two. You get to clone. And so we don't want to longer have the, well, what if their genetics was different question? We know that they are identical. However, they have 30 to 35 years of discordant physical activity patterns. So this is the ideal scientific study, right? Awesome. Complete genetic control over that. Well, the exercises in this particular case were mostly steady state endurance type of exercises with no lifting compared to sedentary twin. And most of the things that you would predict were improved in the exercising twin, cardiovascular health, blood lipid markers, VO2 max, body composition, all of it better. However, muscle strength, muscle functionality, performance, muscle quality as identified to be a imaging all not any better or worse than a lot of exercises. Wow. That's incredible. And so the clue, I mean, there's a number of conclusions that paper, but one of them was simply that endurance exercises phenomenally good for your health. It's tremendous. But if you don't also do strength training, you're leaving many physiological adaptations on the table. There have been many studies again on lifelong strength trainers and you see the same thing create and a number of areas and limited in other areas. There's been lifelong endurance exercises. We've done other work. I went to Stockholm, Sweden years ago, did did research on cross country skiers who have been training and competing and skiing since the 1940s and 50s and compared them to 80. These are all 80 to 90 year olds, by the way, compared them to aged matched individuals who didn't compete in sports. Lots of improvements in VO2 acts and other markers equal, if not worse, muscle function. So the story is very, very, very clear here. You're going to want both of these things, two things on board. And so if we look at what's going to determine the most about how people look, feel and perform throughout their life, give you the longest life, the most high quality life, health span, you know, all this stuff. Number one is staying out of disease, right? So don't get cancer. Great. Okay. I'm going to leave all that off the table. That's stuck. You're part of the equation. I'm not an MD. Okay. So the equation what we're left with now is things like, okay, do we have an appropriate metabolic function, right? Is our metabolism running without major cause, major problems, right? What's that mean? Either completely compromised thyroid function, very low metabolic rate, extremely high fat utilization or extremely high. Some dysfunctional thing, right? Can it just be like, don't be terrible. You mean the bell curve here, right? That's all we have to be in this one. Can we have it a functioning immune system, right? And then we can, we get ourselves through the world, right? And that really all three of those are going to be regulated by skeletal muscle. Skeletal muscle is what's going to determine your ability to move throughout the world and to not get hurt. If you're VO2 max, half that is skeletal muscle, right? There's a central and there's a peripheral component to that. You're VO2 max and you know what we already talked about. If you don't have enough muscle, we're going to struggle to support the immune system. We're going to struggle to support recovery. Metabolism is going to be compromised. And so I mean, I could go on and on about these things, but globally, you don't have to have any specific phenotype from a muscle perspective. You don't have to look a certain way. You don't have to have enormous muscle or be a professional power lifter or weight lifter, but you just can't be in the bottom 25th percentile in terms of muscle size. In this next segment, we're going to talk about one of the most important overlooked aspects of why strength training matters. We're going to explore how strength protects bones, joints, and long-term independence with Dr. Vanda Ray. F-A-C carry a load, meaning weightlifting. Now when you weightlift, you got to know why you're doing it. In Unbreakable, I'm talking about building strength and power. We need to be strong as we age and we need to have power. It's not to say that lifting for endurance is wrong. Lifting for endurance is picking up the Mambi-Pambi pink weight and doing it 30 times so that you fail after 30 times. There's nothing wrong with that. If your goal is endurance, it's not my goal. There's nothing wrong with lifting for hypertrophy, which is the big muscle, tearing up muscle, healing the muscle, building bigger muscle. Nothing wrong with that. That range is 10 to 15 reps. Our goal is strength and power. We're going to work up from wherever we're starting to lifting really heavy weights, low reps to failure. It's always to failure. You have to condition your ligaments and tendons. You have to get your form really well. This is where I think of all the lifting techniques, you probably need to hire a strength conditioning coach to teach you first. I did it and it was critical. That is in the literature, a range of three to six. I'm going to tell you as a clinician, but in general, people need specific instructions. I prescribe four reps, four sets of really heavy lifting in the compound lifts. Push pull with the upper body, push pull with the lower body. You supplement with the single muscle lifts at slightly higher reps. It sounds like a lot. I can accomplish this in 30 minutes on the gym. That's how to lift for strength. Then finally, F-A-C-E equilibrium, which is balance. I'm teaching people to stand on one leg when you're brushing your teeth. Do the balance reach and foot speed. I also happen to have an Olympic agility coach, foot speed and agility coach in my building. She has taught me and all the people I take care of agility drills, like you see athletes doing, to rebuild the coordination for our type two muscle fibers. The interesting thing is when you first start doing these alternating drills, heel-toe, heel-toe, your brain stops you. It's a little hard to coordinate because you're rebuilding those coordinating pathways. Imagine in a real life situation when you're about to fall and you haven't had to have a coordinated pathway. You're not going to catch yourself versus if you have, you're like, got it. So F-A-C-E are the four components of building physical resilience in midlife. A quick note before we dive in. If you've ever been consistent with your habits but still dealing with low energy cravings for food or slow progress in your weight loss journey, there's likely a microbiome component to what's happening. And supporting that foundation can change how your whole system functions. So I want to take a brief pause because I want to talk about something I see all the time. A lot of people have the discipline. They're exercising. They're mindful of their sugar. They're trying to eat real food, but they still get the low energy cravings and slow progress with their journey in weight loss. And when that happens, it's easy to think, I just see to keep trying harder and harder. But this might not be an issue with motivation at all. You really need to look at your microbiome. There are certain key strains in the gut. And when these are depleted, especially one called acromancia, the body has a harder time maintaining the lining of your gut, supporting healthy GLP-1 signaling, which reduces your cravings, and also producing reliable, stable energy. So you can be doing all the right things, but your body doesn't have the internal support to benefit from it. This is where Pendulum comes in. Pendulum was the first to bring live acromancia to the market. This is a strain supported by thousands of scientific studies that I've talked a lot about in my podcast. And the metabolic daily formula combines acromancia with other strains to support energy production, metabolism, appetite, digestive comfort, and just resistance to stress. So in other words, it's going to be a foundational support for your body to respond to all the work you're already doing. So if you're feeling like you've been pushing hard, but you're not seeing the return, I would actually start with your microbiome and pendulum acromancia. If you go to pendulumlife.com and use the code extend, you can get a 20% off your first membership order. That's pendulumlife.com code extend. In this next segment, we're going to break down the direct connection between strength training and brain health explained by Luisa Nicola, neurologist. Now let's move on to the importance of resistance training. This is where I think many people go wrong because A, it's difficult. B, it's intimidating. So adherence is hard for a lot of women. C, who's got time for it? I can only imagine. You said you've got kids. I mean, it's you're, you're going away this week for it's a long, a lot of time, right? Who has time to hit the weights? So best case scenario is setting up a gym in your home. But what does resistance training to do? Well, it improves strength. We know that strength, grip strength is one of the risk factors for all cause mortality. It increases muscle mass. Muscle mass is, or muscle is an endocrine organ. So we need this for longevity. But in terms of brain health, what happens is when you stimulate your muscle, you contract it, it releases something called myokines. These are these muscle based proteins. Once they go into the bloodstream, they go into the target organ. They cross the blood brain barrier. If you will, they go to the prostate, they go to the liver, the kidneys, and they have positive effects on the brain. They can help your brain function better. They can help grow the brain. They can help with blood flow. They can help with the amelioration of amyloid beta, which is a hallmark of Alzheimer's disease. So you could paraphrase it and say that your muscles are the pharmacy and the myokines are the medications. So if you want the antidote or the elixir to brain health, it is exercise in my opinion. Very powerful. So the muscles are actually an endocrine organ because they are sending signals to the brain with the myokines that are secreted. What specific effects do the myokines have on your neurons? So let's take lactate, for example. Lactate is a molecule, it's a hormone, and that can help with glycogen replenishment. That helps with the way that we utilize our brain energy. So our brain is fueled by glycogen, but it's also fueled by ketones. It can be also fueled by lactate, so you get more brain energy. So your brain is able to produce energy at higher speeds. We have something called irisin, it's another signaling molecule that acts as a messenger molecule, so it actually helps with the expression of BDNF, which helps grow new neurons. It helps preserve new neurons, and it helps with something called synaptic plasticity. So we have something called synaptogenesis, so you can grow new synapses. Coincidentally, if you look at depressive-like symptoms in patients, or if you look at patients who have got major depression or even mild depression, they lose the ability for the neurons to communicate with each other. So you can get this natural antidepressant effect from exercise as well. The most exciting part right now, though, of this line of work, so I'm now just doing it, I'm onto my second systematic review, which is crazy if anyone's written one, it's a big process. It's a bear. But I'm actually looking at the relationship between exercise on cancer, and it turns out that just 30 minutes of exercise per day can down-regulate 13 types of cancers and help prevent 13 types of cancers. And one way it does this is through natural killer cells. So what happens is when we are exercising at our maximum, I'm talking like going 85 to 90%, but you can also get it from aerobic training. 85 to 90% of your maximum heart rate, you are first of all, you're shunting blood through your system at maximal force. Now, if you have a tumor at one specific site in your body, we'll call this stage one. That tumor is really intelligent. It needs blood supply, and it's a hungry little beast. What happens is it gets blood supply, so it basically recruits these tumor cells. By the way, I'm not an oncologist, but this is what I've been reading and researching. It recruits these other tumor cells, and it basically says, guys, we need to take over the system, the system being the body. So it pushes out what we call circulating tumor cells. These circulating tumor cells go and they try and migrate to another area of the body. That's what we call metastasis. When one tumor site from one organ in the body goes to another area and metastasizes it goes around the body. It turns out that maximal exercise can help ameliorate these circulating tumor cells, and it does this via natural killer cells. And Ben DePeterson, she's a wonderful physician and a chronologist in Copenhagen, and she was one that found this, that during exercise, natural killer cells get shunted to the tumor and they kill them, because that's what natural killer cells do. They go in and they kill the tumor, and she showed this in prostate cancer. So we're now seeing that exercise can help downregulate and inhibit the growth of tumors, but also once being diagnosed with cancer and you undergo treatment via chemotherapy, it can actually help the prognostic status of that. And finally, let's look beyond the gym and focus on how movement quality and daily habits determine long-term resilience and why your mobility matters so much with two of my favorite people, Kelly and Juliette Starrett. There was a great research that was talked about in David Epstein's wonderful book, The Sports Gene, where they took these mice and they researched and started to notice that some mice were running about a mile a day, and that every once in a while, a mouse would pop up and run three miles a day. And they were like, oh, that's weird. It's about this mouse. So they started breeding those three mile mice. And pretty soon they had these super mice that were running like 67 miles a day. They just loved to run, loved to run. And the other mice, one mile a day. But when they give those mice Ritalin, they ran one mile a day. So the hypothesis there is that we actually have, and we know this, there's a larger genetic drive to move. And that's different for all of us. Like we're not weirdos, but we've tested our kids' genes. And we have one daughter who has low sort of genetic drive to move. And if given her preference, she would love to bake. She started subscription cookie business. She's an entrepreneur. But she'd be like, I'm just going to watch TV and bake. And we were like, knowing this about her, we're like, okay, what sport are you going to be in? We had to really sort of motivate her. I, my genetic drive to move was like 99th percentile. I'm like, oh, what are we doing? Where are we going? So what we're often seeing is that for some of us, it's easy to move. And for some of us, it's difficult to move. So what we need to do is be thinking, how do I shape my environment so that the environmental constraints sets me up to do what my need to do. Look, I know you don't want to brush your teeth and eat vegetables and fiber, but that's what human beings do. So let's go ahead and get, pull on your big boy pants to eat the berries. And figure out how to make that happen for sure. All right. So we've, we're not going to be sedentary. We know that we're going to incorporate movement into our day to day life. However, that's not the whole story because I can tell you, I have a lot of patients that come in and they're not sedentary. They're getting there eight to 10,000 steps a day. They do the test on your app and we find movement issues. And, you know, I kind of go, I look at the human, I see their neck, I see their shoulders, I look at their back, hips, knees, ankles. And so that's kind of how I look at a person's movement deficits. And it could be, you know, maybe just her neck. Maybe it's her neck and their hips. Maybe it's their knees. And you see these weird patterns of movement deficits. And so I'd love to hear what you find. I mean, you have a ton of data because you guys have the app. I would love to hear where you see the most movement deficits, why those are and what people can do about them. Were you just ready to cue Kelly up to talk about his favorite subject, Arshen? I had no idea this is. Hip extension. Well, in this situation, remember that. Is hip number one? Yes, right. I think hip extension is number one. Yeah. You know, ultimately, if you're a movement nerd, you're probably going to start at the spine and the pelvis and then eventually become obsessed with the feet. And then you're like, okay, well, the whole thing matters. You know, we call it complex regional independence. And which means is, for example, if you have neck pain, but you don't have complete shoulder function, can't put your arms over your head. Right. It's difficult to put your bra on. You have no internal rotation. And we're never, ever going to actually solve the neck problem. Until we restore the function of the system. So we should see the neck, the upper back and the shoulders of system the same way now we're beginning to see the lumbar, the pelvis and the femur system. So if you go to see your physician and she isn't asking you about your hip range of motion, you should leave because that's like, Hey, you know, I'm going to look at how your car is functioning, but I'm only going to look at the steering wheel. You know, we need to understand how these things, these things comport. And what we've, what we found to be useful was that if we could come up with some really easy assessments for people, quick, quick tests. And, and what we're, we feel like is when we're talking about high performance or limits of human performance, it's one or zero. Either can be full range of motion or you're not. But for everyone else, we say red, yellow, green, right? Like, cause you know, my life doesn't depend on my body, you know, to make the catch. So what we find is when we work first on the big primary engines of the hips and shoulders, the spine is the first engine of the body. And that's all we talked about breathing and, and you know, how are you using your spine and how are we loading and playing? But then the next sort of, you know, valence out is looking at the hips and the shoulders. And it's an easy way for people to understand sort of where they need to begin to start to restore those ranges of motion. The disconnect is that we fail to look at people's, how people's movement practice Pilates does an amazing job of touching the shapes, exposing isometric. So if you're doing Pilates on the regular, you're more likely to have complete positions yoga. Again, same thing, a movement practice. Now let me be clear. Pilates and yoga do not work on VO two max. They're not going to build strength, right? They're going to get some strength, some, some tissue loading, but not the kind we need from kettlebells and deadbell and deadlifting. But also you can't go to the Olympics doing those two things. But they're movement practices, modern GPP practices like CrossFit or some of these other practices, or we're asking people to express the normative ranges of motion in the language of modern strengthening, conditioning, pull-ups, being able to squat all the way down, snatch some of the root. What we see is turns out that the formal language of strength, conditioning is actually the root language of the body. And now we can say, well, how much of that do I need or how much do I want to lean into this piece? But it's a really easy way of making the invisible visible. And that's what we're trying to do is say, instead of doing something and then testing, I should be testing myself every day through my movement practice. Right. So sort of because your range of motion is going to be a dynamic change. It's going to be a sort of a dynamic system. So if you run a marathon, jump on an airplane, you know, pull a red eye, I'm going to measure your hamstrings and guess what? It's not going to be great. The hip flexure is not going to be great. Right. But, you know, so what we want people to do is start to think every day, how am I feeling today and which positions do I need to add in? So when we're asked to come into complex, you know, sports environments, we look at how people are moving, what movements are there, where do we need? Hey, we need to spend a little bit more time loading hip extension or, Hey, I see that you're not doing anything truly overhead or we need to do something where this leg is a little bit more midline. So suddenly the universal root language of human is the push up. It's the deadlift. It's the pull up. And now we all can agree. It's not how much hip flexion do you have? It's do I have enough range of motion to put my arms in my head? Got it. Got it. I really hope you enjoyed that best of episode all around strength training. In 2025, we've episodes on multiple aspects of your human physiology. And I believe strength training really came to one of the top three topics that we talked about over and over again. Like I said, if you really enjoyed these speakers, please go back and listen to their full form episodes. Thank you so much for listening. And here's to a great strength filled 2026. Thank you so much for listening to the podcast today. Please remember to subscribe if you like this episode and give us a good review and share a link with your friends. It really helps to support all of our efforts. I also want to remind you that the information shared on this podcast is for educational purposes only and is not intended to replace professional medical advice, diagnosis or treatment. Please consult with your healthcare provider or physician before making any decisions or taking any action based on what you hear today, especially if you have any underlying health conditions or on any medications. Your doctor knows your personal health situation the best and it's always important to seek their guidance.