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The Dose Transcript for January 11, 2024

Host: Brian Goldman

BRIAN GOLDMAN: Hi, I'm Dr. Brian Goldman. Welcome to The Dose. When it comes to fitness, I've learnt not to take the easy way out. I've been a jogger for many decades. I run 40 minutes to an hour four or five days a week, so I put the time into it. And yet, it turns out that you may not have to put that kind of time into your fitness routine. So this week, we're asking something counterintuitive and maybe even a little bit subversive. What's the least amount of exercise I can do to get the benefits? Hi, Jane. Welcome back to The Dose.

JANE THORNTON: Thanks for having me. Nice to talk to you, Brian.

BRIAN GOLDMAN: Jane, what's the shortest bit of exercise that you do that could still be called exercise?

JANE THORNTON: Probably getting out on an ice rink with my kids. They're not quite skaters yet, so I feel that even though I'm trying to track the activity, I am likely not raising my heart rate much at all and just trying to stay off of the ice in terms of staying upright.

BRIAN GOLDMAN: So you don't leap up out of your desk and just start running around the office apropos what we're going to be talking about.

JANE THORNTON: Yeah, not at all. I mean, I was sedentary for up until about the age of 15, so I wasn't a sporty type of person at all. So I actually resonate, I think, or relate more to the audience members today that are sedentary instead of that kind of Olympic training that ended up defining a lot of my career.

BRIAN GOLDMAN: So good for you. Good for all of us. Before we begin our conversation, can you give us a hi, my name is? Tell us what you do and where you do it. Just adlib.

JANE THORNTON: Hi, my name is Dr. Jane Thornton. I'm a sport medicine physician and a Canada Research Chair in Injury Prevention and Physical Activity for Health at Western University in London, Ontario, and a former sedentary teenager turned Olympic rower.

BRIAN GOLDMAN: Before we start talking about brief intense exercise, bits of exercise, remind us what the standard fitness guides tell us about how often we should be exercising daily per week.

JANE THORNTON: Right. I think it's really interesting, especially as a medical professional, because I think it's one of the few things we agree on in medicine around the world. The WHO has put out guidelines about a decade ago, and they've recently updated them, but they're very similar and adopted by Canada, U.S., European countries, Australia, you name it. And essentially, what they look at is the guidelines being 150 minutes of moderate to vigorous physical activity per week, and the upper range of that is 300 minutes. So what that means is essentially, if you're working out kind of at a brisk walk intensity about half an hour a day, you're meeting those international physical activity guidelines. And they also suggest a couple of sessions of muscle strengthening. But by and large, those are the ones that most people adhere to as best practice.

BRIAN GOLDMAN: Okay, let's get to the topic at hand. Explain what researchers mean by short bursts of intense physical activity.

JANE THORNTON: Yeah, it's interesting that the exercise scientists out there and researchers have essentially tried to break down some aspects of how our energy systems work in terms of activity. We think of things like high intensity interval training. So that could be very short bursts of activity, usually intense or relatively intense, followed by periods of rest and repeated a number of times. We can also think of the very kind of generic things like movement snacks or exercise snacks, which is something slightly different. That's more in the sedentary research, people trying to say, let's break up sedentary time by just moving around a little bit. But essentially, we think about these short bursts of intense physical activity as being something that's lower volume. So it doesn't take up quite as much time, but it's usually a little bit more intense than what maybe a longer workout might look like.

BRIAN GOLDMAN: Exercise snacks. That is a phrase I am going to remember. Can you give us some examples of that?

JANE THORNTON: Yeah. So it's basically… the premise is it's interesting. So it's just that idea of trying to break up times of sedentary behaviour. We're all there. I'm there myself as well, just needing the reminder sometimes to get up out of the chair while you're at work, away from your desk. And it could be things like walking around for a couple of minutes. It could be doing some squats in your office, or walking to the printer, or parking your car a little bit further in the parking lot and walking into a building. Those types of ideas that thinking, you know what, I'm not really ready. Or I don't have this period of time to do a full programmed workout, but what could I do to just take a little bit of time to incorporate a little bit of movement into my day?

BRIAN GOLDMAN: When you do it, is it just a little bit of movement, or should you be attacking it with a bit more vigour than usual, a little faster, a little harder than usual?

JANE THORNTON: Yeah, I think it depends on people's goals and where they are from their health perspective. So I try to tailor my advice to either if it's the patients that I see or general public, if you're healthy and you're trying to have, you have a specific goal in mind, if that's better fitness, maybe you have an upcoming surgery you want to be prepared for, versus someone who's in hospital trying to gain functional independence before going home, it really does vary. But I would say for the individual trying to get a little bit more fitness and trying to improve their fitness for their health, the intensity does matter. And usually, if you can push the intensity a little bit. So we use something called the torque test, and basically meaning that, you know, if you can hold a conversation with someone beside you, imaginary or real, you're walking down a street, for example, if you can hold a conversation, but you're still kind of breathing a little bit more shallow, maybe you've got breaking a sweat, you're probably in that brisk moderate intensity zone. When we're talking about higher intensity, we try to think about vigorous, but that's very relative for people. But that's, you know, maybe you're not fully able to form full sentences and you're just being able to still talk. But that can help people determine what kind of intensity they should be participating in.

BRIAN GOLDMAN: But that's a really good practical test. Can you talk and do whatever you're doing at the same time? That's a really good thing to know. You mentioned sedentary a couple of times, and I want to ask you about that, because one of the things, I had this moment of clarity that aside from my runs, which are pretty vigorous and, you know, they're long, 40, you know, 40 minutes, 45 minutes, sometimes an hour, I'm pretty sedentary the rest of the time. And you know how I know that? I just came back from a trip where my family and I walked every day a lot. And we probably put in, you know, 15,000, 18,000 steps every day. And I'm more fit than I was before I started the vacation. And yet, I run. So this is a thing, isn't it, that you can be a sedentary runner, for instance?

JANE THORNTON: Exactly. I joke a little bit. So even this morning, I was out rowing with our rowing team. And, you know, I'm doing a very vigorous workout like you're suggesting as well for an hour. But then the rest of the day, I'm sitting at a desk. I'm thinking I'm even worse because I'm sedentary even in my training, in my session sitting on a rowing machine. But essentially, this idea of trying to incorporate physical activity, actually being upright, moving around, walking around does have benefits. And what studies have shown is that it's indisputable that we have negative health impacts that they increase with total daily sedentary time. So there's an actual field of research specifically devoted to sedentary behaviour. However, the good news about that, though, is that even if we can't reduce that total sedentary time because potentially, we are in long commutes, long days at work, sitting for various reasons or maybe unable to, you know, maybe we're mobilizing with a wheelchair or some kind of other aspect that we're not actually standing upright and walking around, that concept that we can still put in some physical activity does actually offset those adverse effects. So absolutely, it's great that you're doing a run still. So I'd say if that's what works for you, fantastic. But I felt the same way that I actually do feel better if I'm active throughout the day. And I think the research bears out on that as well.

BRIAN GOLDMAN: So let's talk about the science. What are the benefits of getting in some short bursts of intense activity versus being completely sedentary?

JANE THORNTON: Benefits vary, but it seems to have some benefits, particularly for motivation for people. If you can't fit in a lot of physical activity, so some people will give up and thinking, well, do I really have to be active for 30 minutes at a time? Can I actually do that and fit that into my schedule? And I think where we've gone wrong as an international community has been thinking about this, that these are a generic 150 minute to 300 minute per week. But is it that actually reasonable for someone who may be holding two or three jobs, or trying to raise kids, or trying to commute back to work? There's a lot of socioeconomic issues with trying to suggest that, yeah, you just do your 30 minutes per day. So I think that that ability to think outside that and saying, can we actually get the same cardiovascular benefits with shorter intense work? And the research does bear out again that, yes, we can. And I think so for those benefits, there's actually larger benefits and just on health, of physical health alone by having these shorter workouts. But we do see that even if it's short intense bursts, you still have those same cardiovascular benefits for the most part. Still better sleep, mood. It still can impact from a healthier weight perspective and lower risk of chronic disease. So when we look more carefully at those guidelines, it says 150 minutes. But if you're actually going vigorous, that means that you can have that. So all of a sudden now, you've gone down to 75 minutes per week. So I think those are things that maybe we don't pay as much attention to but are well worth considering on a number of different levels.

BRIAN GOLDMAN: In addition to the motivation, the health benefits are real. Like some of these studies that I've been looking at, like one published fairly recently in Nature suggested that short bursts of intense activity can have positive benefits in terms of diabetes control, lipid metabolism like cholesterol and lipid metabolism, triglyceride metabolism, and can even reduce all-cause mortality.

JANE THORNTON: Exactly. And that's what we look at. We look at about a 30% decrease in overall risk of mortality and morbidity. So the effects are very large. And when I think about it too from that physician perspective, we've currently doing a study with cancer patients as well. And the same things bear out that it's actually quite significant even for patients undergoing cancer treatment, to think about it. Now, a caveat to that is that high intensity interval training is very relative. So for some people, a brisk walk may be intense exercise. And that's okay. But I think we're demystifying or kind of debunking some of these myths that people with chronic conditions and health conditions of various types, they can still benefit from this higher intensity interval training, particularly under the guidance of a medical professional. So I agree. I think it's really interesting to see and good news for everyone.

BRIAN GOLDMAN: So how important is it then to have different levels of activity in your day?

JANE THORNTON: I think it really does depend on people's… like you said, I mean, the movement snacks are a great idea that's breaking up sedentary time, but that can be done with light physical activity. There does seem to be benefit with increasing that intensity to at least moderate physical activity. And some vigorous does change up the routine a little bit, but does create a different stimulus on the heart and oxygen demand and so on. Still, if one person could only do moderate physical activity, I'd be very happy with that, and I wouldn't say that someone has to necessarily do something vigorous. At this point, we're still trying to differentiate and tease out all the very, the details around that. But we do see that these overall effects for health can come at a variety of intensity levels.

BRIAN GOLDMAN: And this is really important for people who think it's all or none, that either they're devoting a significant chunk of their life to fitness or it's not worth it. What the research is saying is that even a little bit is better than nothing, and a little more than that is better than a little bit.

JANE THORNTON: Yeah, exactly. The most benefit we're going to see is if someone is completely sedentary and starts to put a little bit of activity into their lives, I mean, we start seeing that diminishing returns probably after the 300 minutes per week. But for athletes, of course, those might be well worth the investment or for people trying to target specific fitness goals. We actually interestingly, even though we see this kind of minimum benefit, we haven't yet found a upper threshold. So you can still do at least 10 times the guidelines and still, that's still okay for your health. But where we come to this kind of fairly arbitrary number of 150 to 300 is that's where you see the most mortality and morbidity benefits. Meaning that the biggest bang for your buck, the biggest decrease in mortality and morbidity and morbidity, I mean, just in terms of disease and so on.

BRIAN GOLDMAN: Let's address sitting. How often should we be getting up if we're seated at work or at home?

JANE THORNTON: Ideally, we try to kind of get up every hour. I know that's a bit arbitrary in that advice as well. It's important to just… I mean, sometimes, people will set reminders on their watches or phones, those kinds of things. But just that ability to get up and move around is often a good reset, not just for your physical health, but also mentally for concentration and so on. So that's probably the advice that I would give to people. Now, if that varies a little bit, if people are getting up every half hour, fantastic. If they wait two hours and that's all they can do, if they have a long commute and so on, and just do what you can and every little bit counts. And really, that is one of the main messages, that really, every move counts. And I think that's really nice because it makes physical activity much more accessible to people as we've started to realize that it doesn't need to be this big program or intense exercise program that you can derive benefit from, but it's really just moving around.

BRIAN GOLDMAN: I'm thinking about ways to amp up everyday activities. One example might be if you're used to kind of strolling to the corner store, for a change, maybe once a day, walk there as fast as you can like your life depends on getting something in the store. Like I'm really, I really got to get this. I got to get this now.

JANE THORNTON: The nice thing about, you know, some of these applications on your phone or throughout communities and free activity resources, free community meetups and so on is that you do have that ability to potentially increase your goals, increase the speed that you're trying to do something, measure something a little bit more accurately for those people, or even just having a sense of is this harder for me today? Is this my best that I can do today and see if I can push it? We tend, as a human society, to engineer physical activity out of our daily lives, and I think it's where we can be a little bit creative and find solutions. How can I start incorporating a little bit of movement into my daily life? And maybe it's taking the long way home through the forest, over the streets, those kinds of things. Little, little tweaks, but they do end up making a measurable difference.

BRIAN GOLDMAN: How about in the home?

JANE THORNTON: Yeah, I mean, there's a few things. I mean, stairs are interesting, right? If you're injured, those are more difficult. People who are at a fall risk or those kinds of things may have more difficulty. So maybe it's things like just making sure that you're incorporating a little bit of housework that you might have delegated to somebody else. Maybe it's that idea of walking around the house a little bit more or doing some increased gardening, which would even in just increased light physical activity, but has a whole wide range of benefits as well. But I do like that idea of can we make our neighbourhoods more walkable? And that's not on the listeners per se. But as a policy perspective, it’ll be fantastic to be able to have those how are we making our cities and neighbourhoods more walkable or bikeable, those kinds of things.

BRIAN GOLDMAN: How should we be structuring our days so that we make sure to get the necessary minimal physical activity? How do you recommend doing that?

JANE THORNTON: Yeah. You know, in my practice, I do a lot of counselling on physical activity, and I again try to listen to the preferences of the person I'm speaking with. And I'll give you an example, is just some of us are morning people and night people. So I know that even though I've been used to physical activity for a long period in my life now, it didn't come easily to me. So I still need that ability to get up and first thing I need to do is exercise. Otherwise, it's much, much harder for me to motivate myself to do it. On the other hand, I have colleagues who just want to get to work, get through their day. And they find that some exercise, even something like a walk home or going for a run, really clears their mind to be able to separate that day and what they want to do in the evening or to be able to relax. Other people find that their best time is during the lunch hour, for example. So it is really trying to figure out yourself. When is the best time for me to be physically active? When is it easiest? So you don't have to spend that extra kind of cognitive load to motivate yourself on a daily basis. I still make sure even now, even though I'm used to exercise, I still put my clothes out the night before so I know exactly what I'm getting into and make sure my bag is ready to go to the gym and so on. And so I make sure it's so easy that I don't for some reason kind of tempt myself out of going to practice.

BRIAN GOLDMAN: How can tools like fitness trackers help us increase our physical activity?

JANE THORNTON: Yeah. For some people, they work. For others, they're not great. I can tell you, for most of my career with the national team, I didn't like using measurement tools. I didn't use a heart rate monitor. I loved just going by the feel, and I felt that was really good for my body to understand how I was performing and kind of listen to my internal cues. For other people… So now, interestingly, getting a demo watch, I started looking at my metrics. All of a sudden, now I can't stop looking at it. And so in the sense of trying to measure, you know, getting those reminders to stand up every hour or trying to look at whether or not I'm meeting my goals for my activity that day. So again, it's whatever kind of helps people try to meet their goals. Some people use daily activity logs. With the patients that I see in counselling exercise, we set up follow up visits every few months to see how their goals are helping them. And so it's a bit of a check in or accountability. And sometimes, apps can provide that as well. You don't need a physician for that. But certainly, those accountability that you might be able to have someone, you know, someone around the world that you have as a team-mate kind of checking in on each other. So for some people, those really spur them on and help them be physically active as well.

BRIAN GOLDMAN: I guess as a final word, you know, since we kind of jokingly refer to this as the sloth episode of The Dose, for those people listening to us, to you and I talking about this, who are thinking that they want to try to get away with as little movement as possible in a day, what do you say to them?

JANE THORNTON: Well, I think great that you're even thinking about putting movement into your day. I would say the first step is see when that movement can occur. So plan that when you're in a kind of a motivated mood and try to orchestrate that. Put something in your calendar. Make just some way of experimenting and being curious about a way that you might be able to incorporate those movement snacks or those high intensity interval sessions. Or is it something you prefer to do alone or with a group? Try to kind of understand where it might best work for you. And also, just I think I would say to most people is just be reassured that any movement helps. Every move counts. And the biggest benefit is just from starting to move. There was another study that came out not too long ago even about weight training and just even doing one session a week. So really, this idea of probably more like minimalist training is actually quite healthy. And I think we can actually learn a lot about the idea of let's really just try to incorporate, do what we can, celebrate those moments, and just at least start from there and see that hopefully those long term benefits, like actually enjoying what we're doing and the mood benefits and so on are the thing that keep you going back.

BRIAN GOLDMAN: I intend to indulge in more movement snacks.

JANE THORNTON: Me too.

BRIAN GOLDMAN: Dr. Jane Thornton, thank you so much for speaking with us once again on The Dose.

JANE THORNTON: You're welcome. Thanks for having me.

BRIAN GOLDMAN: Dr. Jane Thornton is a sports medicine physician at Western University's Fowler Kennedy Sports Medicine Clinic. Here's your dose of smart advice. When it comes to exercise, the World Health Organization and other bodies say we should get 150 to 300 minutes of moderate activity per week, think brisk walking or raking leaves, or 75 to 150 minutes per week of vigorous activity such as jogging or swimming. There's little doubt that the best health outcomes come from regular exercise four or five times a week. On the other hand, as little as 10 minutes a day, 60 minutes a week, benefits your health. Even shorter bursts of activity for a shorter duration can produce similar results. A recent study found that young adults who pedaled a stationary bike as fast as they could five times every hour for just four second bursts over an eight hour study period had improved fat metabolism, comparable to doing 30 minutes of continuous exercise. People who engaged in at least four one to two minute high intensity physical activity bursts every day had a nearly 40% lower risk of dying from cancer and a roughly 49% lower chance of dying from a cardiovascular disease. And the more you do things like that, the lower the risk of premature death. Four second bursts of rigorous physical activity can also offset the harmful effects of prolonged sitting. What to do depends on your lifestyle. If you've got the time, do at least 150 minutes per week of moderate exercise, or 75 minutes per week of vigorous exercise. But if you don't have a lot of time in your schedule, then shorter bursts and shorter activity duration can be very beneficial. Experts like Doctor Jane Thornton call those movement snacks. That's one kind of snacking that comes free of guilt. It's not all or none. Get off the schneid and your body will thank you. As always, if you have heart disease or other chronic ailments, check with your health care provider first before giving this a try. If you have topics you'd like discussed or questions answered, our email address is thedose@cbc.ca. If you like this episode, please give us a rating and review wherever you listen. This edition of The Dose was produced by Sameer Chhabra. Our senior producer is Colleen Ross. The Dose wants you to be better informed about your health. If you're looking for medical advice, see your health care provider. I'm doctor Brian Goldman. Until your next dose.

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What's the least amount of exercise I can do to get the benefits? - Transcript

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