Resistance training: How to stay strong as you age

0:00Welcome to ZOE Science & Nutrition, where world leading scientists explain how their research can improve your health.

0:15Today, we learn how to keep our bodies strong as we age, and why this is so crucial for a long and healthy life. As early as our 30s and 40s, our muscles start to shrink, and we begin to lose strength. This puts us at major risk of frailty, falls, and fractures, which an older age can even lead to death. But there is good news. This future is not ineptable.

0:44I'm excited today to speak with Professor Brad Schoenfeld. Brad is a professor of exercise science at Lehman College in the Bronx, New York, and a world-leading expert on building muscles and strength. He's published over 250 peer-reviewed papers and written numerous fitness books.

1:04Brad, thank you for joining me today. Now we have this tradition on the show that we always start with a quick fire round of questions from our listeners. And we have some very specific rules, Brad, which we know are really hard for professors. And the rules are you have to say yes or no, or if you absolutely have to, you can go as far as a one sentence answer. So the first question, do my muscles matter for my health? Yes. If I have more muscles, will I age more slowly? As a general rule, yes. Is strength training more important than cardio for health? In my humble opinion, yes. I mean, they're both.

1:44I think that does an injustice to the either or question because they are complementary. Can weight training fight loss of bone density after menopause? Yes. is it ever too late to start increasing muscle strength? No. All right. And then finally, and you don't have to say yes or no, what's the biggest myth about strength training that you often hear? So many. Women feel it'll make them too bulky. Athletes often feel that it'll bind them up so they become less athletic, that it takes a lot of time. And I could go on and on. There's just so many myths. And none of those things are true, Brad? None of them are true.

2:25That's amazing. Well, look, I look forward to unpacking this. So before we dig into sort of actionable advice for our listeners, I'd love actually just to start at the very beginning and understand. And I think the starting question for me is like, how do our muscles work? Muscles attach to bone via tendons and muscles shorten and linten. So when they shorten, they will bring bones up to carry out a movement. And ultimately that allows you to ambulate, to walk. It allows you to pick up packages, pick up your kids, and it allows you to do resistance training, of course. And so they're obviously essential, right?

3:02We'd be sort of like jelly on the floor without that description you just described. It doesn't seem obvious why they would be important to our health, providing they're functioning enough that we can walk around. So can you help to unpack that for me? The idea is that when muscles begin to shrink and they get weaker, you do not have sufficient strength to carry out basic tasks. And then you lose your functional independence, which is the primary reason that most people go into nursing homes to care facilities as they age. It also can lead to falls, hip fractures, which often are fatal over time.

3:40That mortality in those in elderly individuals who undergo falls is close to 50 % over a period of a couple of years. The functional disabilities, of course, are far reaching as far as people's ability to carry out activities on their own, which not only is really bad as far as their ability to engage in life, but it's also demoralizing mentally. There's aspects far beyond that that also are important. Muscles store glucose. So glucose, of course, is stored in muscles as a glycogen. If your muscles start to shrink, you have less ability to store glucose. That tends to lead to diabetes. Also, the functionality of the muscle themselves in terms of their insulin receptors, their ability to get glucose into the muscles, so it's not just the size and their ability to store a certain amount of glucose, but it's their ability to take in the glucose.

4:39And by the way, you mentioned earlier, also by pulling on the bones, they help to strengthen bones or when they weaken, they facilitate the decrease in bone density. So there's just really all organ systems kind of can be affected by muscle. I mean, I guess I really want to follow up on that first part, because I guess for many people listening to this, this idea about having freedom for as long as possible and having good health for as long as possible is really central. And I grew up just basically sort of understanding, Like as you get old, you get wrinkly and you get weak and you stop being able to do things and that's just how it is.

5:15And this is going to happen to you anyway. To what extent is that true as far as your muscles are concerned? And is there anything that you can do now when you might be in your 40s or your 50s or your 60s or whatever that is going to affect that loss of muscles that is having this effect on losing freedom as you get older? Yeah, so the age-related loss of muscle is called sarcopenia. It's actually now a diagnosed medical condition. And it is not inevitable that resistance training is really the key. Now, certainly other activities can help in that regard, depending upon what they are. But ultimately, resistance training, which can be defined as the activities that promote muscle working against a given force.

6:08And that can be accomplished through lifting weights, as often thought of as the most common view of it. But I mean, it can be bodyweight exercise, can push-ups, bodyweight squats can be forms of resistance training. You can use bands, resistance bands. You can use cable machines and other types of units. And it can be integrated. I mean, there's yoga that involves resistance where they do various. So anything where your body, your muscles are working against a given force. And to answer your question then, if you engage in resistance training that substantially challenges the muscles over time, you can not only stave off sarcopenia, but you can maintain more.

6:54There's certainly people in their 60s, 70s, and even 80s that have more muscle than they had when they were 20, when they started resistance training later in life, and that have more muscle than 20 year olds do at a given age. So I would say that the key in my humble opinion to Stevenloff's sarcopenia is resistance training. Well, I love that. It's really positive, right? Because I think often in this area, everything's very depressing about the idea. There's nothing going to do. You're going to get older. You're going to lose everything. and I think what you're saying is actually there's a lot you could do and it's not too late, right?

7:31If you didn't do any exercise in your 20s, you're saying it's not, oh, that's too bad. I love this idea of being in my 60s or 70s and having more muscles than I had in my 20s. I just want to interrupt and say there is research. We actually carried out a meta analysis on the oldest of old, which were people 75 years and older who were sedentary and given resistance training and a meta-analysis is a pooling of all the studies on the topic. There was marked increases in strength, and we see hypertrophy increases in muscle growth differences. And these are short periods of time, by the way. We're talking 8 to 12 weeks.

8:12Again, 75 plus. So these are minimum 75 years old. Could you explain a little bit, because I think we sort of jumped over a little bit, this link between doing this resistance training and preventing your muscles shrinking? Why does that happen? How does these two things fit together? When you resistance train, so you're applying force to the muscles, the forces that you're applying to the muscles are converted into chemical signals. These chemical signals carry out protein synthesis. They create more protein to the body to produce more muscle proteins, which give you larger muscles. When you are resistance training at an intense level, you are challenging the muscles to a greater extent than when you are walking.

9:05So will walking be better than lying down all day? Of course. So if you're just lying down all day, if you're bedridden and then you get up and walk around, that will help to build some muscle. but it's going to be very minimal. The body only builds muscle to the extent that it's challenged. To achieve greater muscle, you have to provide a greater stimulus to it. All the body cares about is survival. So maintaining muscle is energetically expensive, and we are still living in the bodies of our paleolithic ancestors. So the body doesn't realize that we can just go out for food whenever we want, et cetera, and it tries to be resourceful.

9:43So to maintain muscle will be energetically expensive, which would have a negative survival impact when you are scavenging food in the start days. So to bring this back home, when you're lying down, although let's say you're just not doing anything, you're very inactive, the body realizes it doesn't need this or thinks it doesn't need this extra muscle and it's energetically taxing to keep it. So why bother? Why would we need to maintain it if we're not going to be using it? That is the use it or lose it principle. When you're lifting weights that challenge the body, because you might want to talk about, you don't necessarily need to lift heavy weights, but when you're lifting weights that ultimately become challenging, the body realizes that, or thinks that it needs to be able to maintain muscle to carry out these activities for survival.

10:32And again, everything revolves around what the body is perceiving as its survival needs. It's really interesting, Because it's very similar to a lot of discussions we have about nutrition, where also we have this problem where we sort of have these bodies that were built for this permanent fear of starvation and famine. And we live in an environment where, you know, there's a Starbucks and a McDonald's on every corner and it's all misset. And I think you're saying exactly the same thing about exercise in our muscles, that our body is worried about the cost of supporting these muscles. So it's constantly trying to shrink them, whereas actually we'd really like to keep them really high.

11:11And sadly, there is no magic pill and you've got to do something that really puts them under strain if you want to keep the level of muscles that will keep us healthy. Correct. And I would add too, since you bring up nutrition, that consuming protein is an important component as well. That protein, the consumption of protein is used, the amino acids from it are used to build muscle. So when protein is deficient, you will, at least up to a certain point, you will compromise your ability to gain muscle. But the most important factor is resistance training. You can still build muscle even with quite suboptimal protein intakes, but it will compromise the magnitude of your gains.

11:58And does that mean that as people age, you think they should be conscious about increasing the amount of protein they eat than they might be thinking about otherwise? Well, yeah. So, there's several things. Number one, there's something called the leucine threshold. leucine is one of the amino acids, essential amino acids, and it's been shown to kind of kickstart the protein synthetic process after resistance training. And thus, as you get older, your body becomes less sensitive to leucine and that generally speaking, you need to consume more protein in a given setting, in a given sitting, to hit your leucine threshold.

12:42The most important thing is the resistance training. Again, you will compromise gains to an extent, but it's not like you won't get gains if you don't hit your leucine threshold. But it is important that as older people get older, you want to try to squeeze out as much as you can because it becomes harder to build muscle. And Brad, is that like a steady decline over time or is that more... I have a 15-year-old and he's basically putting on muscle by the week, just watching him. And I, on the other hand, train all the time and I feel like I completely plateaued and it's incredibly hard to put any muscle on.

13:15I'm in my late 40s. Is that going to be much worse in my 60s and 70s? What does the science say? It's very gradual. So generally speaking, and there's not much you could do, let's say hormonally, men will generally lose 1 % or so of testosterone after about the age of 40. These are averages. Different people have genetics that's going to enter into that and other factors. Women, it's even more pronounced because women, when they go through menopause, lose estrogen. Estrogen basically is considered to be the female component of testosterone to facilitate muscle building. At least there's some good evidence to indicate that.

13:59And the reductions in estrogen are huge. So it's a tenfold reduction in estrogen production for women, which compromises their ability to build muscle even more. So that in itself is going to be a factor. Chronic inflammatory effects, so the body produces these inflammatory cytokines as people get older on a chronic basis. And injuries can affect that. conditions such as osteoarthritis can be involved. So there's just a multitude of factors when you age that are kind of working against you. And it sounds like particularly as a woman going through menopause, that there's like a big shift then in your ability to maintain or grow muscles after menopause compared to before.

14:44Is that, did I understand that right? The men are going to have a more gradual decline in testosterone. Let's say from the age of 40, you just start seeing a shift. It does seem to accelerate, though, when you get into your, when it gets into his 70s plus, can have even a greater downward linear trajectory where women over a period of several years during menopause really have this drastic drop in estrogen. And that seemingly does, again, compromise to a greater extent muscle building ability. But as I said, it does not mean you can't build muscle. Both men and women equally can achieve very good gains.

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17:33You've scared us all with this idea that your ability to hold on to them gets worse and worse over time. I'd love to start to talk about the actionable side about this because I think everybody is like, well, I would like to have more muscles. I don't want to fall over and break my hip. I want to be able to stand up and get out of my chair. Just before we go into the details, I just want to start at the highest level because the terminology around exercise can be very scary for non-experts and quite confusing. So you've generally talked about resistance training. A lot of people talk about cardio and we had this question in the beginning.

18:06And I'd love just to understand, because I think for a lot of people, they'd be like, well, my doctor just tells me I should do more exercise. Can you help me to understand this difference between lifting something heavy and going out for a run or a cycle? Cardio implies that you're involving the cardiorespiratory system where it's oxygen dependent. So it's just, you're generally training in a manner that's submaximal where you can continue doing it over very long periods of time. Resistance training, you're going to be limited. You're not going to be able to lift weights continuously for 20 minutes.

18:47I mean, then you're essentially doing cardiovascular exercise. So, you know, outside of a minute, 90 seconds, a little more, it ceases to be resistance training and you start entering into cardiovascular where it becomes more of an aerobic endeavor where your body utilizes oxygen. Now, we've heard lots of people talk about the benefits of cardio, that this does have lots of health benefits in sort of long-term studies, but it sounds like it's not giving you the muscle-supporting benefits that you've been talking about. Could you just help us to unpack that? And I think you said something quite interesting in the beginning, that on balance, you actually think, you know, if I've got 20 minutes to decide what I'm going to do, that actually the resistance, if I had to do one or the other, the resistance is actually going to be better for my health than the cardio, which I think for a lot of people will be really surprised.

19:40Could you help to explain that? Yeah, sure. We kind of touched on this before, but when you're doing cardiovascular exercise, you are not challenging the muscles substantially to need to develop and to increase their strength. All they need to do, again, the body is looking for survival. If your cardio consists of walking a couple of miles a day, the body will adapt to be able to do that. But that's a very low bar as far as the muscle needed to accomplish that. Whereas if you're lifting weights, the body is going to perceive a threat to its survival and it's going to substantially increase its muscle size and strength and the various neural factors as well to accommodate those types of changes that happen over time and to consistently be able to carry out those functions.

20:42Because the body's looking forward. If you're walking, well, the body thinks you're going to need to walk on a regular basis until you stop doing that. And then the body starts over a period of time and then the body regresses and says, all right, now we don't need to do this anymore. Strength gains can happen within a few weeks, two, three weeks, you will start to get hypertrophy, which is the building of muscle tissue, increases in muscle size usually start to become evident in about a month or so, four weeks. Now, again, it depends upon what you're doing and genetics to a certain extent you're going to enter into this.

21:22But those are general, I would say general guidelines. This is quite nice, right? Just a few weeks, you're saying you'll get the benefit. It's nice. Many of the things we do, I think, in our life that are supposed to help our long-term health, you don't really... And we see this, for example, even with your microbiome. it might take you three to six months before you really start to see any shift. So there's actually a very fast adaptation, I think, compared to many of the things that I've heard people talk to us about. So I think everybody's going to listen to this saying, so, okay, what is it that I should be doing?

21:53And so I'd love it if you could talk a little bit about the type of exercises that people could be doing and what's, I guess, best in terms of this strength training. There's a lot of muscles in my body? Do I need somehow to be doing like an exercise for each of my muscles? Or if I'm worried about my hip, do I just worry about my hips? Like what should people be thinking about? What's required in order to get these benefits you're describing? So, you know, these are questions that always are individual specific, but I can give you a general recommendations is that you should be doing overall training the whole musculature.

22:31If you're looking just for, let's say no specific issues. You just want to get healthier. You should be training the major muscles of the body. You generally should be resistance training a minimum of twice a week. Again, that's a bare minimum. And depending upon how you're structuring it, there can be other guidelines there. But let's just go with the minimum of twice a week. and you should look, if you're looking for time efficiency, and I will say this, two half-hour sessions a week can give you very potent gains. You're not going to step on stage as a bodybuilder. I think I've missed that boat already, Brad.

23:15But from a functional standpoint, from a health standpoint, from even just certainly looking better, you can achieve literally one hour a week. You don't want to do it all in one session. You'd be better off splitting that up into, let's say, two half-hour sessions. But I'd say at a bare minimum, that can give you good gain, decent gains. And if you want a little better gains, maybe three days a week and doing 45-minute sessions. So even the time, there's ways of time-saving. You can do what are called supersets and other types of techniques where you can reduce rest time between the exercises and achieve time efficiency.

23:57So, again, working the major muscles, think of the chest muscles, the shoulder muscles, the back muscles, the quadriceps, the glutes. People a lot of times will focus on bicep curls and tricep press downs. Well, you get substantial involvement of those muscles when you're doing rows and presses. So literally doing minimalist type routines that involve these multi-joint exercises can work the total musculature. Again, not to the extent that you're going to be stepping on stage, but most people, as you point out, are not looking to be bodybuilders. I do a lot of consultations with elite level athletes and bodybuilders and the recommendations for them are going to be much different.

24:46You need to be much more not only disciplined and conscious of your routine, but you need to be focusing on a lot more scientific principles when it gets to that level. But a very basic routine can achieve very, very potent effects from a health and fitness standpoint. I think that's really exciting. And look, Brad, I know you used to be a bodybuilder and a personal trainer. So I'm going to assume that you enjoyed the exercise and that you enjoyed sort of like the physique that you were building. But there are a lot of people out there who asked a lot of the questions that I'd like to go through now who aren't regularly in the gym or, and I would put myself in this category, don't actually get a lot of pleasure from it.

25:36So I do the exercise, but I'm not really having a lot of fun in the exercise. I feel very good afterwards that I've done it in part because it's done. But I would be really interested maybe to start with a question that came up quite a few times, which is we had quite a few listeners saying they feel really intimidated by their local gym and the idea of getting started in this idea of strength training. Do you have any advice for someone who's listened to this and saying, like, wow, okay, I'm really convinced. This is important. I have to go and do this, but I'm really not sure how to get going.

26:17Yeah. So the most important thing is making sure you have a good idea of what you're doing. I would say it is generally a very good thing to find a qualified personal trainer if possible. There's going to be an expense to that, but take several sessions just to get a feel for what you should be doing. You don't have to stay with the trainer for long periods of time, but I would say at least several initiation sessions. Most gyms, when you go there, give one free session with a personal trainer. That can be a start, but usually people need several sessions to get a feel for what they're supposed to be doing.

26:58if the money's an issue there. There's plenty of videos online that they can look up. And so you can, for free, you can go online. But I mean, if you're, you know, look for qualified people, that's what I would say. And make sure you know what you're doing and then map out a plan. The most important thing is to have a plan. There's an old adage, Chinese adage, that says those who fail to plan, plan to fail. Adherence, of course, is the most important factor. So you need to be regimented. You need to commit to a couple days a week minimum, like I said. And ultimately, it should be like brushing your teeth.