Should you train cardio and strength on the same day?

Australia Broadcast Center

01-06-2025

Tegan Taylor: Norman…
Norman Swan: Tegan?
Tegan Taylor: You have told me in various guises over the years the different things that you do for exercise. I know that you cycle at the moment. I know you've been a fan in the past of high intensity interval training. I know that you've been doing Pilates. But what I want to know is, across a typical week, what's the mix?
Norman Swan: Well, I cycle a lot into work, so almost every day I'm getting what you call endurance or aerobic exercise cycling, which is quite a lot of exercise. And almost every day I'm doing some strength work as well, whether it be Pilates, gravity-based stuff or stuff with weights.
Tegan Taylor: Look at you just fulfilling the Australian guidelines on physical activity. What a guy.
Norman Swan: Yeah, but I still look like the guy you'd kick sand in his face. That was an ad that used to be for Mr Universe, you know, be like Mr Universe. 'I was once the guy who had sand kicked in his face and look at me now,' and he looks like Arnold Schwarzenegger's dad. Anyway…
Tegan Taylor: I love your timely references, and also how you reenact things so briefly.
Norman Swan: That's right. You can't see my arm movements here, but yeah, that's right.
Tegan Taylor: Well, the mix of physical activity on a certain session or on a week is the topic of this week's What's That Rash? and I'm super excited to get into it because it's a rich seam to mine.
Norman Swan: It is, on What's That Rash? , which is where we answer the health questions that everyone's asking.
Tegan Taylor: So today's question comes from Vicky, who says, 'I'm wondering if there's benefit to training cardiovascular fitness like jogging and swimming on a separate day to weights and strength training, or is combining the two in the same training session best for maximising results?' Norman, this is something I hadn't ever really thought about much before. But, as we've discovered, there's actually quite a lot in this.
Norman Swan: There is a lot in it, and there's a lot riding on it if you are an elite athlete and you're trying to get the optimal training regime, and that's where you've got to separate this out, because most of the research is actually not into people like you or me, or shall I just say 'me' because you are much fitter and stronger than me, but in the elite sport context, what's the best way of doing that? And we've probably got to get some definitions right up front, so…
Tegan Taylor: Well, I think we should start with some groundwork as to…if we're not talking about elite athletes, which we will probably talk about quite a bit in this chat because, as you say, a lot of the research is in that space, but for the average Australian who looks like they might get sand kicked in their face, what are the recommended amounts of physical activity across a week?
Norman Swan: Well, the physical activity guidelines, it depends on whether you're having moderate or vigorous activity. Moderate activity is activity where it's actually hard to have a conversation while you're doing it, so it's not relaxed, low-level things. So if you can gossip about the kids or your friends on a walk around the park, that is not moderate intensity exercise. You've got to be walking fast enough or jogging so that it's hard to have a conversation. Vigorous is just one step up from that, where you really couldn't even think about starting to talk because everything's going into the exercise that you're doing.
So if it's moderate intensity exercise, it's two and a half to five hours a week, which really means on most days of the week you're having about 45 minutes of moderate intensity exercise. It's a bit less than that with vigorous. Vigorous activity means you can probably compress that into a shorter period of time. But the recommendations also (and going to Vicky's questions) say that at least two days a week you should be including muscle strengthening activities, and that includes push ups, pull ups, squats, lunges, lifting weights or household tasks that involve lifting, carrying or digging. So none of it is mild exercise, it's all at a level which you're feeling a bit of stress on your system.
Tegan Taylor: And there's nothing in there saying that you can't do them as part of the same thing, although I guess depending on how you read it, you could say, oh, I have to do this. And also the strength training separately. It doesn't say that.
Norman Swan: To the contrary, they're saying that in your 45 minutes of cardio type exercise, aerobic type exercise, you should take some time out. And I think if you look at it it's maybe 15 minutes of the 45 minutes, I can't remember exactly, that is associated with muscle strengthening. So yes, it is part of that aerobic 45 minutes that you're having. And remember that muscle strength is a really important part of our wellbeing, particularly as we age, because as we get older we lose muscle mass, and that's a route to frailty. So you really want to be being as strong as you can, within the limits of your ability to do exercise, going through life.
Tegan Taylor: And there's a term for this mixture of cardio and strength-based activities, it's called concurrent training, where you're doing strength and cardio in the same workout. The thing that I find interesting about this is that I find it very difficult to do cardio without involving my muscles in a pretty big way and doing the sorts of things that you would consider to be strength based, and I find it really hard to lift weights and not get puffed. So can you really separate these two things from each other anyway?
Norman Swan: Well, you can in terms of what's dominant, but it's true that a lot of muscle strength exercises…I mean, just try doing squats. Squats do get your heart rate going, and if you are doing reps with weights, that gets your heart rate going, so it's very hard to separate them, and that's where the goals of your exercise start to come in.
Tegan Taylor: Muscle strengthening is quite an ancient thing that men especially have done for a really long time. I was actually shocked to discover how recently it was that we realised that cardiovascular exercise was good for us. I was really surprised that even for the first half of the 20th century doctors often believed that strenuous exercise would perhaps cause a heart attack rather than prevent it.
Norman Swan: Yeah, and it was a fellow Glaswegian who really pioneered this research. A good Jewish boy from Glasgow, actually he was from Liverpool originally, but then trained at the University of Glasgow…
Tegan Taylor: You'll claim him.
Norman Swan: …and then a public health researcher at the London School of Hygiene and Tropical Medicine, really a pioneer, Jerry Morris, and he did this seminal study which was looking at double-decker buses in London and comparing the health and wellbeing of drivers to the conductors who were running up and down the stairs.
Tegan Taylor: Such an interesting controlled study, because it's controlling for so many different things, socioeconomic factors, by choosing two groups of people working in the same industry, working probably the same kind of shifts, but the real difference there is their physical activity levels.
Norman Swan: Yeah. I mean, not perfect, because it's likely that bus conductors were a bit fitter to start with because they were able to get up and down the stairs, but nonetheless it was a pioneering study in its day, and it showed drivers were much more likely to die of a heart attack than bus conductors, and if bus conductors got heart disease, it tended to be milder, they tended to develop more angina rather than suddenly getting a heart attack. But going back to Jerry Morris, he showed conclusively really that cardio (in other words aerobic exercise rather than muscle strengthening) helps your cardiovascular health and reduced the risk of heart attacks and strokes.
Tegan Taylor: Do you know what's really lovely? At the Olympic Games in 1996 he got an honorary Olympic gold medal in recognition of his excellence in the science of sport and exercise. How cool is that?
Norman Swan: Super cool. And what's also super cool is that he didn't die until he was 99 years old.
Tegan Taylor: See, he knew what was up. That's so cool. So let's talk about cardio exercise first then. Do we have specific definitions of what constitutes cardiovascular exercise?
Norman Swan: Yeah, it's about your heart rate, in many ways, it's about an exercise that stresses your cardiovascular system and gets your heart rate up into a proportion of the maximal heart rate, usually round about between 50% and 70% of your maximum heart rate, which is age adjusted. And what's been shown is that if you do that on a regular basis, you reduce your risk of coronary heart disease, but not only that, your blood pressure tends to come down, your resting pulse rate comes down. And really the only way you can get your pulse up to that sort of level for a reasonable period of time is by exercising all your muscle groups. You're not going to do it necessarily with a pair of weights in your hand, trying to strengthen your biceps.
Tegan Taylor: So vigorous physical activity, getting your heart rate up into that space. And in addition to giving those long-term health benefits, you're also increasing your endurance, if performance in a cardio based sport is important to you (for example, long distance running).
Norman Swan: Yes. So this is where the issue of the research being done into sportspeople, because concurrent training is good idea in theory because you knock off two things at the same time, but do you work against it? And what the research shows (and it's taken a long time to get back to Vicky's question, but it's an important question) is that if you are an ordinary person training for benefit, concurrent training increases both strength and endurance and aerobic fitness. It doesn't necessarily improve power.
Tegan Taylor: So, strength based.
Norman Swan: It's strength based, but it's also about being able to recruit power quickly. So if, for example, you are training, even though you're not an elite sportsperson but you're training for tennis or squash, that power thing is affected by aerobic training. Now, it's thought that it's about which parts of your body you're training. So if, for example, your aerobic training is mostly your legs and you're wanting power in your legs, then there is interference.
Tegan Taylor: Oh, I thought you were going to say there was going to be benefit there, but are you saying…
Norman Swan: No, it's interference. Your power goes down when you are doing it. It's probably that you are exercising the same muscles, they're tired and not getting the same benefits. So for example, if you are rowing as your aerobic exercise, which is more of a whole-body thing, and you're wanting to train for power in your lower limbs, it looks as though you do not compromise power. You might get more strength by separating out the two, but who's got time for that? In a practical sense, you will improve strength and aerobic fitness if you want to do them both at the same time.
Tegan Taylor: Well, you say 'who's got time for that', but let's say you are trying to optimise, let's say we are talking about an elite sportsperson, Vicky's writing to us from the AIS. What is the optimal…is there a certain order that we should be doing things in? Should we be separating it by days, like aerobic training on one day, strength-based training or power-based training on a different day?
Norman Swan: The literature is mixed on this. For example, if you were doing it on the same day, you would watch what aerobic exercise you're actually doing. So if you're wanting to get power, and the power is particularly in the legs, you might focus for your aerobic training on rowing, or indeed cycling, static cycling, because cycling is a concentric exercise which is different from the muscle movement you might want to get if you're going from scratch to a full sprint.
Tegan Taylor: But for the average person, we're going to come back to one of our little refrains, which is the best exercise to do is the one that you're going to do, it's the exercise that you enjoy and that fits into your lifestyle, and to not overthink it too much.
Norman Swan: Yes. Well…
Tegan Taylor: You like overthinking.
Norman Swan: I don't think this comes naturally, so I think you've got to think about it. You've got to think about you're out for a walk and you pass a bench where you might do push ups and where you stop and do squats, you've got to think that through so that you're doing all of that in one session, and you will improve your strength, and you will improve your aerobic exercise. It might not make you the fastest on the field, but very few of us want to be.
Tegan Taylor: Yeah, you want to live the longest, then you can out-lap everyone. So Norman, we've talked a lot about sports performance in this chat. What we haven't really talked about is some of the other reasons why people are keen on exercise, apart from longevity, i.e. weight loss.
Norman Swan: Yeah, I'd rather talk about fat loss.
Tegan Taylor: Okay, yes, good distinction.
Norman Swan: There's pretty good evidence in the scientific literature that if you do concurrent exercise, in other words strength training and aerobic exercise in the same session, you burn more fat. So if fat loss is your aim, you want to be doing the concurrent training, it's really good for that.
Tegan Taylor: Let's say you are doing concurrent training, you're going for your walk or whatever, does it make a difference…what do we know about whether you should be doing your cardio first or your strength-based stuff first?
Norman Swan: It doesn't seem to make any difference, from the literature that we've got together for this program, although I'm sure people would argue about it. I mean, in the days when I could afford a personal trainer, the personal trainers would actually vary depending on what they would do. Some of them would get you running on the machine and then do the strength training, and some people will get you to do the running on the machine afterwards, and some people would get you to do none at all. And I don't think it makes any difference, which is why I don't have a personal trainer anymore.
Tegan Taylor: So, the bottom line for Vicky then?
Norman Swan: A bottom line for Vicky is that if power is what you're after in elite athletes, then there is an issue with concurrent training. It doesn't mean you can't have it, but you've got to think through what aerobic exercise you're doing, that it doesn't interfere with the muscles you want power from. If you're just ordinary people like you and me who want to live as long as possible, as healthy as possible, strong muscles, concurrent training is fine, but you've got to think that through so that you're actually doing realistic exercises. And what we haven't spoken about is progressive exercise.
Tegan Taylor: Oh, better talk about it quickly then.
Norman Swan: You've got to have a consistent level of difficulty, and for that you've got to pile on the weights as time goes on, or pile on the extra exercise. But the good thing is if you're tight for time and you do the exercises faster, the aerobic ones, you get through more burning in less time.
Tegan Taylor: At a training session I was at the other day, they finished us off by doing bicep curls. And you'd start with a weight, and then when you couldn't get to do any more, then you'd switch to the lower weight, and by the end you had two-kilo weights, and even lifting those, it felt like they weighed about 20 kilos each. I was cooked and I could barely move the next day.
Norman Swan: So a lot of people think that exercising to muscle exhaustion is the trick, rather than necessarily piling on really heavy weights. So doing multiple reps rather than three or four reps with a really heavy weight, because that will tear your muscle fibres. But this whole issue of tearing muscle fibres just for bigger muscles is not necessarily strongly equated with strength that you need for the future.
Tegan Taylor: And actually on that, if you want more about muscle strengthening, muscle hypertrophy, we did do a What's That Rash? episode on that in January last year called 'why no pain no gain is bull', so you can check that out on the ABC Listen app.
Norman Swan: And you can also check out our protein intake What's That Rash? because to strengthen your muscles and do well, you need an adequate protein intake, so you can go to that What's That Rash? as well, and we'll have both those in our show notes.
Tegan Taylor: There's a What's That Rash? for everything. And I've got to know, Norman, what's your next exercise that you're doing? What's your next workout going to be?
Norman Swan: I've got to get on my bike and cycle home.
Tegan Taylor: And I'm planning to go for a swim tonight. Well, Vicky, thank you so much for the question. If you've got a question that you'd like us to dig into and get super nerdy about, we love it, and the email address is [e-mail].
Norman Swan: Let's go to the mailbag.
Tegan Taylor: Yes. So Nat has messaged in. So we talked a few weeks ago now…Norman, we're always talking about N-equals-one studies, where people have self-experimented, and then when we did our live show on knuckle-cracking, we talked about an N-equals-one that won an Ig Nobel Prize a few years ago, about someone who cracked the knuckles of one hand only for 50 years to see if it developed arthritis, and it didn't. Nat has done an N-equals-one study for us similarly. Would you like me to share what it is?
Norman Swan: I would. I love these pioneers of medical knowledge.
Tegan Taylor: So this one is in relation to our episode on acne that we did a little while ago. Nat says, 'In my early teens my mum repeatedly told me that if I squeezed my pimples, they would get worse. I decided to test this theory at about age 13, and for the next five or so years, I only ever squeezed or popped pimples on the right side of my face…'
Norman Swan: Oh, unilateral plook popping.
Tegan Taylor: '…leaving those on the left side to fester unhindered. At the end of my experiment, at around 18 years of age, I had to concede that my mum was right and that the right side of my face did in fact get far more pimples than the left, and the skin was more scarred and uneven than the left.'
Norman Swan: What a sacrifice to make for medical science.
Tegan Taylor: Thank you for your service, Nat. Nat goes on to say, 'It was one of the rare occasions when the many medical myths spouted by my mum did turn out (for me at least) to have some credibility, though I'm unsure whether the cause was the pimple squeezing action or the transfer of a cocktail of bacteria via grubby teenage fingernails.'
Norman Swan: Yeah, my bet's on the latter.
Tegan Taylor: It could be a bit of both, I think.
Norman Swan: We love N-of-one studies, keep them coming.
Tegan Taylor: Nat, thank you so much for that. And you can always send your feedback, your N-equals-one studies, your body building tales of woe, all of it can come to [e-mail].
Norman Swan: See you next week.
Tegan Taylor: See you then.