00:03
Welcome, hi, I'm Mikki and this is Mikkipedia, where I sit down and chat to doctors, professors, athletes, practitioners, and experts in their fields related to health, nutrition, fitness, and wellbeing, and I'm delighted that you're here.

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Hey everyone, it's Mikki here. You're listening to Mikkipedia, and this week on the podcast, I chat to Professor David Dunstan about the dangers of sedentary behavior and prolonged sitting. We discuss what sedentary behavior actually is and how this just differs from general sort of inactivity and physical inactivity. We discuss the physiological changes that occur when we are sedentary and how it impacts negatively on

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cardiovascular and respiratory health, fat deposition, and at a population level, the percentage of people who could be considered sedentary. We discuss interventions to help reduce sedentary behaviour. We discuss the appropriateness of physical activity guidelines and if these are potent enough to offset the risks associated with being sedentary. And we also discuss recent research investigating the relationship between quality of life markers

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psychological health and sedentary behaviour during the Covid lockdowns. Prof Dunstan is a wealth of information and really is at the forefront of the research in this space so I'm super thrilled to be able to have a conversation with him. Professor David Dunstan is the head of the Baker Deakin department of lifestyle and diabetes within the Institute for Physical Activity and Nutrition. He also holds the positions

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of Deputy Director and Laboratory Head for Physical Activity at the Baker Heart and Diabetes Institute. His research focuses on understanding the adverse health consequences of too much sitting and the potential health benefits resulting from frequently breaking up sitting time with active countermeasures. In particular, he has developed effective strategies to reduce and break up sitting time in adults with or at risk of developing chronic diseases.

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and to support office workers to reduce sedentary behaviour in workplace settings. He is also interested in how best to implement efficacious, sit-less, and move more interventions at scale within healthcare settings for those living with or at risk of chronic disease. Professor Dunson has a number of research grants that he has won over the years and is involved in many international studies alongside UK, USA, Sweden, and Finland.

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where they have been awarded millions of dollars to study this area. Professor Dunstan also was a clarivate, highly cited researcher in 2018, 2019, 2020 and 2021 and he is in the top 1% most cited for his subject field and year of publication, with published research of over 340 peer-reviewed papers and 5 book checks.

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We have included a link to Professor Dunstan's research gate page for you to get a place to go to have a look more in depth in his research. I think you're really going to enjoy this conversation that I have with Prof Dunstan and I've also included his staff profile at the Baker Institute as he is able to translate that science into languages we understand so brilliantly.

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Before we crack on into the interview, just a reminder that the best way to support the podcast is to hit the subscribe button on your favourite podcast listening platform. That increases the visibility of the podcast out there and it makes for literally thousands of other podcasts so more people get the opportunity to learn from the guests that I have on the show like Professor Dunstan. So please enjoy this conversation.

04:17
David Dunstan, thanks so much for taking the time to speak to me today. And funny that you recognise my name as someone that you examined my PhD, which was fun to go back down that memory lane, that's for sure. But I really appreciate your expertise, because I've spent a lot of time talking about physical activity and exercise and health with a number of experts. But on the flip side, haven't really had

04:47
much time discussing sedentary behaviour which is similar to inactivity but as I understand quite different so I'm really looking forward to the discussion this morning. Oh well thanks for inviting me and I'm looking forward to our chat. So can we begin David by just getting a brief sort of background from you as to how you got into the field and looking at well first sort of I guess the broad area but more specifically that sedentary behaviour?

05:15
Yeah, I've been involved since my PhD in looking at the benefits of physical activity for the treatment and prevention of type two diabetes. And I think many of us are well aware that for those types of population groups, getting people to do regular exercises, you know, a big challenge, particularly when there's many barriers to doing regular exercise.

05:42
The origins of me working in the sedentary behavior are really inspired by people that I work closely with still now, and Professor Neville Owen, who's at Swinburne University, and Professor Joe Salmon, who is with me at Deakin University. And back in 2000, I was running a national diabetes prevention, oh sorry, diabetes prevalence study, and there was an opportunity to

06:11
explore different health risk behaviors that were emerging as potential risk factors for many diseases. And fortuitously, in that study, the OzDiab study, we included just a simple question about television viewing time. Now we've since known that television viewing is just one of the many sedentary behaviors that people...

06:37
can undertake on a daily basis. And in fact, even since doing that study, the landscape has changed dramatically in terms of TV and then now there's live streaming, et cetera. But it really has formed the foundation to look at this in epidemiological studies about the relationships that are independent of whether or not a person does physical activity, or regular exercise. And...

07:04
Since 2000, there's been an explosion or a rapid accumulation of evidence in the scientific literature that's really just highlighted that sedentary behavior is a risk factor in its own right and a health risk behavior that we need to address in addition to getting people regularly moving and engaged in physical activity.

07:33
or health. It then led to experimental studies where we put that into a laboratory situation and really showed that imposing long periods of sedentary behavior is detrimental to, for instance, blood glucose control. And then the next big step obviously is to start to look at behavior change interventions. So these are the interventions that are focusing on reducing sedentary time. And we've done a lot of that work and I'm sure we'll get to discuss that.

08:03
Awesome. And so I think people under appreciate the, what you've said about that independent nature of sedentary behavior as a, as a risk factor. You know, I do a lot of work with, uh, people who are, who are physically active, who might be athletes and they might get up, go for a run, but then go to their office job and sit down for eight or nine hours a day, come home. But because in their head they've done, you know, 10,000 steps on their run that actually they're

08:31
they've done what they need to in terms of activity. Now, what would be your sort of opinion with that? Yeah, well, increasingly the focus is on the full waking hours that people are exposed to. And so what you just described that for instance, if a person is meeting the recommendations of 30 minutes, let's say of moderate activity, that still leaves for a typical person that sleeps out hours a day.

08:58
that still leaves about 15 and a half hours of other activities. And for many people, um, they wouldn't be familiar with this, this risk behavior or sedentary behavior or, you know, sitting, sitting or sedentary time, because that can, um, occupy for the Australian. I average Australian adult occupies around about nine hours per day. And so if you're thinking about proportion of time spent in the day, um, it, in fact, sitting,

09:27
for many people occupies more time than sleeping in a 24 hour cycle. And so for many people, it's just that's what's done sort of thing. It's the norm. But we're now starting to understand that you can be active, that is meet the recommendations, but you can also sit for long periods of the day. And the amount of sitting that you do throughout the day or excessive sitting,

09:57
can essentially undo some of the benefits that can be generated from doing regular physical activity and alternatively that the risks associated with excessive sitting are most pronounced in those that don't do a lot of physical activity. So there's that real interrelationship and that's why we now see guidelines that are physical activity and sedentary behaviour guidelines to really focus on both of these.

10:27
Yeah. And David, what is your opinion on, I wonder if you can share your honest opinion actually, on the physical activity guidelines. Like I'll just say, you know, I look at them and think 30 minutes a day of activity doesn't seem to be enough for people to shoot for in light of a lot of the health problems that we see out there at a population basis. Yet I understand the risks of.

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telling people that they need to do more and making it almost unattainable. Like, I guess it's hard to find that balance of the thing that should be recommended, but maybe we have, and I'm just, I don't know, I've just got a bad opinion on that. No, I think that, I mean, many people do think along those lines, but I think what we're talking about here is population health and...

11:19
I think that there's been so much evidence, and even just recently with the device-based data, so much evidence showing that the greatest public health gains that we get are taking people who are doing nothing to doing something. And that appears to be the greatest benefit of pushing people more towards that 30 minutes. Yes, that's good. And of course, you're going to get better, even better health outcomes if you do more.

11:49
It's really thinking about shifting that whole risk curve so that we can get the greatest benefits. Yeah, yeah, that's such a great point. And what is the data on sedentary behavior? Like, what percentage of, and I know you'll obviously be familiar with Australian, but maybe some global statistics as well, I'm not sure, but what is the percentage of people who would...

12:14
who you'd consider to be sedentary or the definition would determine a sedentary. And how has that changed over the years? Yeah, it's a good point. And there's not a lot of countries that are reporting on the prevalence of sedentary behavior because the issue there is that we still have not got definitive cut points of what defines high sedentary behavior. But

12:39
What I can say is that increasingly with studies using the devices like the research accelerometers, et cetera, it's really quite consistent seeing that across different countries, the average time spent sitting. Now this is much truer of what a person does than what they would self-report is between that nine to 11 hours per day, which is a huge volume of time.

13:09
And so there's many people that are exposed to this excessive time spent sitting, particularly those working in office environments, et cetera, and those working in transportation, where you're sitting is a requirement of the job. One key piece of evidence that has been published from the US in the NHANES study is they looked at...this is based on self-reported data. They looked at people in the US population.

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who are inactive, that is not meeting the guidelines, but also sitting from eight hours or more per day. And the evidence in the US is that one in 10 people are in that category where they're not only not doing the right thing about physical activity, but they're also sitting for high amounts. So that's quite a substantial, it's likely to be an under-reported measure as well. So that probably gives you a flavor that

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it's quite prevalent. Now, the other thing that we really have seen in the last three years is the impact of COVID on physical activity and sedentary behavior. And this consists in evidence showing that, you know, at least during lockdowns, et cetera, that sedentary behavior did increase, fortunately. And we have seen this residual effect.

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post COVID as well as that sedentary behavior has gone up in that time. Now I think what has happened is that shifts in working arrangements, for instance, working from home, et cetera, has really taken out a lot of that commuting that people would typically do and typically could get movement, daily movement. And there's some evidence showing that there's a tendency to

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longer working hours while working at home. Longer working hours is often in a seated position. So it's really, we've seen a lot of shifting and changing over the years, but clearly that centenary behaviour has gone up over the last 20 years or so. Yeah. And I also think about the environment, like not just the commute that people are missing out on, but often most people's houses are smaller than the offices that they're

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working on or the campuses that they might be sort of, you know, working, working on, which you just, you just get so much more incidental activity than the small amount, you know, going from your office to your kitchen to upstairs and back down. You have to be quite deliberate about getting steps in. That's right. And, you know, back in 99, within the Australian physical activity guidelines, they had one broad recommendation of think of movement as an opportunity, not an inconvenience. And,

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So that was really the sort of foundation for focusing on that incidental type of activity and getting more daily movement. And when we come back to guidelines, I think one of the major shifts that we've seen in the last three or four years is we used to have this stipulation that to accumulate a number, amount of physical activity to meet the guideline, you had to do it at least in 10 minute bounce.

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So you'd have to go for at least 10 minutes. But the real shift now is that every single minute counts. So you can, this is really important for a public health message is that you can accumulate this across the day. You don't have to get your exercise gear on and do at least 10 minutes at a time. You can accumulate it. So that's where that active commuting could come in to this because if your nine minute walk to the bus stop,

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in the past wouldn't have counted towards your physical activity. So I think that that's a real positive change in those guidelines. Yeah, completely. And even if I think about how people view physical activity, I know a number of people I speak to are like, well, I don't have 45 minutes to get to the gym or to go for my walk. So in their mind, if they don't have that set amount of time, then it's just not worth it.

17:28
you're right, that message that it all accumulates across a day, making that snactivity as part of that sort of everyday, just what you do is really going to help with regards to being less inactive and have less of that sedentary behaviour. And I think the other thing that there's been a real shift in some of the language used in guidelines with a deliberate shift away from

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a sole focus on exercise. Um, and that's really essentially being replaced with physical activity, which of course is any form of, you know, um, body movement of which exercise is one component of that physical activity. So outside just getting your structured exercise, like, you know, doing a 30 minute, um, uh, workout, et cetera. There is opportunity to achieve your physical activity guideline.

18:28
outside that structured exercise by simply moving more and for instance in active community. So I think that that's a real positive message and for many people the term exercise can conjure up some unpleasant previous experiences that I think that that's what has impacted some of those chronic disease populations for instance those with type 2 diabetes who have real issues like

18:57
Exercise is a bit of a non-option for them, but getting out and doing a little bit of accumulating light walking is likely to be highly beneficial for that group. Yeah, sure. So David, moving into some of the health issues associated with sedentary behaviour, could you elaborate on some of the mechanisms as to how sedentary behaviour leads to problems? You mentioned blood glucose, but

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insulin resistance, vascular dysfunction. So what are some of those physiological outcomes? Well first of all, I should highlight that comprehensive reviews of the evidence have clearly shown that excessive sedentary behaviour is linked to firstly, premature death. It's also linked to increased risk of cardiovascular disease, type 2 diabetes and some cancers as well. So I think that's...

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pretty well known now that there is a strong evidence base that there is that link. But what there has been in recent times is a lot of studies to attempt to unpick that. And this is what you're talking about in your mechanisms. Okay, well, if people are sitting for long periods of time, what is it actually doing to the human body? We recently published probably the most comprehensive review on what are the likely biological impacts

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prolonged sedentary behavior or increasing amounts of sedentary behavior. And I think if you, you can simply break it down by effects on different systems. And firstly, the one that you alluded to where probably the most consistent evidence is that we do know that when people see it for long periods, particularly in really large chunks of sitting time, we call that prolonged sitting. It is

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quite detrimental to the control of blood glucose to a meal, especially. And in particular, for those groups that already have disturbed glucose metabolism, like people with type 2 diabetes, it's where we see it most magnified in those groups. So glucose is one. Now, the other key sort of mechanism is the impact on blood flow.

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Um, so what we do do show is I'll see is that when people are seated, there is a reduced blood flow that occurs particularly in the lower limbs because when we sit, essentially our muscles switch off. Um, and so our chair is doing the work that would be undertaken by the body. Um, uh, when we're standing, for instance, to minimize the effects of gravity.

21:48
So what we do see is a lot of studies showing that reduced blood flow can impact, subsequently impact blood pressure. And so it can have adverse consequences for blood pressure with rises across the day with long periods of sitting. Of course, the reverse is true if you break up your sitting time more frequently. Then there's also relationships that have been shown with inflammation.

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the longer people sit that the greater tendency for inflammation to develop and inflammation is a complex consideration. But we want to try and minimize the amount of inflammation that is developing throughout the day, particularly in response to meals, etc. And then we also have started to see studies showing the impact on blood flow to the brain, for instance.

22:44
So what we do see is that when people are sitting for long periods of time, that there can be adverse consequences to the blood flow to the brain, which is really important because we need those nutrients to get to the brain and for our ability to concentrate and perform the daily tasks. So I think if we break it down into those four key sort of mechanisms of

23:13
glucose control, the blood pressure and blood flow impacts inflammation and also on potentially the blood flow to the brain, et cetera. They're the key mechanisms so far that have been revealed that potentially explain those relationships with those health outcomes that I mentioned earlier.

23:43
risk factors that then lead to issues with blood sugar regulation and type 2 diabetes and cardiovascular events and all that kind of thing. So that makes perfect sense. In that paper, David, which you sent me that I'd seen that the review that you mentioned, and we'll pop a link to that in the show notes for people who are interested to have a look.

24:12
the intermediary metabolism. Are you able just to describe what that actually means? Yeah, it's all those, you know, well, where the body is regulating homeostasis, for instance. So, you know, the control of glucose for one, and then the control of blood fats. So this is in response to daily meals throughout the day, how well our body is responding.

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to that control and that also can include, you know, the control of insulin in terms of regulating blood glucose throughout the day. And also, as I mentioned, those inflammatory markers. So it's all those markers that are impacting on the control of those essential physiological mechanisms like

25:08
blood glucose control, which we need to have such fine control or things start to go awry. And David, what studies are out there that show that a break in that sedentary behaviour can impact favourably on some of these markers? Yeah, so what I've just described and all the effects of what occurs with increasing sedentary behaviour, there is accumulating evidence from studies that have looked at this experimentally.

25:35
So some studies use bed rest, which is probably the most extreme form of sedentary behavior and probably not simulating what typically occurs in society. But other studies have looked at when limbs are immobilized for orthopedic injuries, et cetera. But more recently, there's been dedicated studies that impose sedentary behavior versus

26:01
breaking up of that sedentary behavior. So when I talk about breaking up, some studies have used every 30 minutes, just getting up and moving around. Some of you say every hour or so getting up and moving around. And not surprisingly, many of the effects that I described on for sedentary behavior, the reverse is true when we actively break up sitting times throughout the day, that is reductions in blood glucose throughout the day.

26:28
And that's really important in response to meals, reductions in insulin, reduction in blood lipids, increased blood flow and reductions in blood pressure. So it's almost the flip of what occurs when we see what we see with increasing amounts of sedentary behavior throughout the day. And so I think it really highlights that it's not only about how much time you spend in total throughout the day,

26:57
but it's how you accumulate your sedentary behaviour throughout the day with a breaking up pattern more favourable than a prolonged pattern. Yeah, so in your view, if there was a practical recommendation around breaking up sitting time, is it every half an hour for a couple of minutes? Is it every 90 minutes? Is there a recommendation around it? Yeah, so we've based it on the studies undertaken so far. A minimum would be to break up every hour.

27:26
But ideally, I think what we are really encouraging is to every half an hour, just take a short break from the computer screen. And so one of the golden rules that I often talk about when talking to media, et cetera, is to maybe use the clock as your guide. So at the 12 and the six mark of the clock, take an opportunity to just simply get up and break up that sitting time, essentially turning on the body's engine again.

27:56
which has become idle for at least half an hour or an hour. So. Yeah, nice. That's awesome. One of the other things which I read was that sensory behavior leads to an increase in sort of visceral fat deposition. And is that through the mechanisms that you described earlier with regards to the changes in insulin and blood glucose and things like that? Yeah, it's a very.

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very complex area to understand what's truly affecting the visceral fat, etc. But there has been some studies that have shown associations of high amounts of sedentary behavior in visceral fat, for instance. But there's a lack of consistency in the evidence that truly pins sedentary behavior as a true independent risk factor on body weight per se.

28:52
And I think we need more studies that look at this over longer periods of time to be able to get more definitive of is this cause or is it associated with other factors, which is highly likely given that there's a lot of influences on body weight that occur. Yeah, yeah, for sure. Because if I think about sedentary behaviour, like people either at the desk or watching television, like they may also be.

29:20
having popcorn or eating snacks or doing other things, which even though they're adjusted for in statistical analysis, sometimes I wonder how much of that stuff you can actually adjust away, I don't know. Yeah, yeah, yeah, that's so true. But what we do know is that if we look at energy expenditure, we know that a seated posture, there is ever so much less energy expenditure

29:49
to, for instance, just standing. But of course, once we move, and of course, when we move faster, that energy expenditure is substantially increased. And remember what I mentioned earlier is that the average Australian adult sits from nine hours per day. So that's nine hours spent in a very low energy expenditure throughout the day. So it's likely to be a contributor, but very difficult in epidemiological studies.

30:17
as you say, to factor out those other influences. Yeah, sure. And has your research changed your own behavior, David, and that in your labs and stuff? Oh, definitely. And what we see is that, well, for me personally, I spend a lot of time up on my feet throughout the day. So I really avoid those sitting periods of 30 minutes or more. In fact, I use sitting as a break

30:46
being upright throughout the day, whereas a lot of people use it the other way around. What we also see is that in many of our meetings that occur within our laboratory at least is that our meetings are active type meetings. So some meetings will include a walking meeting that can occur outside when we don't have to take notes, et cetera.

31:15
But even in those longer meetings, we actually highly encourage people to stand up and move around where it's, you know, in, in, in our society, it's, it's, it's essentially a, um, a social norm that you should hit. That's when you're concentrating, but in fact, you actually a lot more likely to concentrate better when you, you are interspersing some, uh, upright time with, you know, when you're sitting. Yeah.

31:45
Yeah, for sure. I have a standing desk and there are certain tasks I do easily standing. However, I am the person who if I need to think I actually have to sit down to do it, I can't stand and think I can do tasks. But then I also try to look at me showing off, not really showing off, like almost like making sure that you don't think I'm too sedentary. I try and take laps around my house, actually, every so often to sort of break up that.

32:15
that sitting time. So I appreciate what people think. Yeah, and I think it's really important to highlight that they're not standing desks. We call them height adjustable desks. So it allows a person like what you just described, to work in different postures, you can work in a seated posture or a standing posture. And of course, we don't want to be conveying this message that you should just stand all day, because that potentially could introduce other health problems.

32:44
So I think it's important to have a balance between the sitting and standing throughout the day if you are using one of those height adjustable workstations. Yeah. Do you remember those? I'm trying to think of what those bulls were now. They're everywhere. Those, I'm going to say yoga. Yeah, yeah. And people, there was all the rage that everyone would have one of them to sit on as opposed to a chair. But then I think there was some health and safety issues. So that didn't last very long. But is that actually?

33:13
like a better option from an energy sort of standpoint, David? Well, potentially from an energy perspective, but I also have many of my physiotherapy colleagues that really caution the use of such footballs, particularly for people who already don't have great core strength. And so what it can do is actually introduce

33:39
musculoskeletal issues you've done for long periods of time. So it's one that I don't really highlight as a potential solution to just getting up and moving around. Well, I think the preferred option is to just getting up and moving around frequently is more likely to be, you know, more safer without the risks associated with sitting on those balls. Yeah, actually, yes, that makes perfect sense now as to why it's not.

34:08
the ideal scenario. And you mentioned sort of accumulating activity across the day. And obviously I'm thinking about steps, but, and I don't know whether this is your area or not David, but what about like, I have a strength training session to do. I don't have 45 minutes at the start of the day, but like, is it still worthwhile doing that kind of thing in a snack-tivity type way across your day? Are you still gonna get the same sort of benefits? Do we know that? Well, I think...

34:36
the benefits that you're going to get is the benefit of doing something rather than nothing. So obviously it's a more positive approach to health. I don't know whether we have the evidence for instance for strength training that say if you do half of your session in the morning and then half of the session in the afternoon, what are the impacts there for strength?

35:05
you know, musculoskeletal health. But of course, that's going to contribute to you meeting the guidelines because you're accumulating that time over the time. So I think, I often, no, I often quote probably one of the most famous persons in physical activity research, Steve Blair, when he gets asked, what's the best exercise that you should undertake? And he says, it's the one that you will do regularly.

35:33
And so I think that that's a really important point that you find what works for you and what can be undertaken on a regular basis. Yeah, no, that makes a lot of sense. So David, obviously your lab does a lot of these type of studies in and around sedentary behaviour. What is some of the research that you were quite excited about over the next couple of years to further our understanding on this?

36:01
Yeah, what we are really working on now is two key aspects. One is firstly to identify who is more at risk because of their sitting and their physical inactivity. So can we get better ways in which we can screen people by simply asking about their sitting time and their physical activity? Because to ask either in isolation, you're not getting a true picture.

36:30
what we're working with is our healthcare professionals to streamline that risk identification approach because we know that we need to focus on both of those behaviors. But what the other aspect is from the research is a real shift in our thinking towards the promotion of regular physical activity, particularly in people who have those conditions like diabetes, et cetera, of what we term a staircase approach

37:00
regular physical activity participation. And when I talk about a staircase, we're often dealing with people who are doing nothing or very little activity. And so the barriers for these people of taking them to doing nothing up to what would be considered to be guideline, you know, exercise is a real big challenge. So the staircase model operates on this principle of taking transitional steps.

37:30
towards that. So in the first instance, if a person's sitting for a lot of time, but they're not doing much activity, let's just start thinking about reducing your sitting time throughout the day. Can you get less sitting throughout the day? Okay. Well, once you achieve that step, can you progress to the next step of increasing the amount of light movement that you do throughout the day? So, you know, then you're progressing the sitting less and moving more. And the idea is to provide a foundation then.

37:59
to encourage that more moderate intensity activity like the brisk walking, et cetera. So in the current sort of traditional model where it's a one size fits all, you need to get more exercise, but the staircase model really operates on this principle of taking people through a transition towards then having a base to be able to engage in that, that what is considered to be the more healthy.

38:26
type of physical activity, moderate intensity type activity. So I think that what we're really wanting to work on in healthcare settings, for instance, is can we first identify people at risk, but then can they be referred to interventions that can essentially be delivered remotely? And probably what we have a new era with is the wearables that

38:54
do exist. So for instance, the Fitbit, the Apple watch, the Garmin, et cetera. We now have this opportunity to use that data to inform our interventions on a daily basis. We can actually get the data, you know, for instance, in some of the devices, we can get minute, every minute we can get that data and we can actually provide cues and prompts to people.

39:21
depending on their context. So if you're at work, it's going to be very difficult to put on your exercise gear and go up a walk, but you may be able to get a walk around the corridor. So when smartphones, et cetera, know where a person is located, they can tailor that message to the actual context. So that's probably what really excites me the most is that we are now into this new era of being able to deliver behavior interventions that focus on both.

39:51
sedentary reduction and increased physical activity and remotely delivered, which has the potential to increase that maintenance and long-term maintenance of regular physical activity. Yeah, and I think about that, David, like so many people feel a little bit disheartened if they're in that position you mentioned of being both very sedentary and being physically inactive, that they're so far from

40:21
where people are telling them they need to be, that it's almost insurmountable. Whereas that so, and, or they go from zero to hero and injure themselves in the process. So that sort of stepwise progression to ultimately what is optimal for, you know, minimizing risk sounds much more sensible and achievable. And everyone, and everyone loves to sort of, well, maybe not everyone, but to reach a goal and feel good about that. Like there's nothing better than

40:50
feeling amazing from doing something like that. I think you've said it better than I said it and that you've hit on a lot of those considerations. And I think what our job now is to generate the evidence base to show that those types of approaches, staircase type approaches are actually beneficial for health. And so they're the longer term studies where you can go for 12 months or more to be able to demonstrate that

41:18
Yeah, you can accumulate activity across the day and you can transition through the steps progressively to get to the benefit of regular moderate intensity activity. Yeah, no, that sounds awesome. And is there funding in Australia for those types of studies, David? I don't know, you probably have asked me, not a great time because our funding climate is substantially, well, highly competitive is probably what I...

41:48
should say. But I think what I refer to of the staircase approach is looking at this from a different angle. And so I think we really have to start thinking about our approach to the promotion of physical activity because here in Australia at least, we have just seen a flat line or plateauing of the participation levels in physical activity. So we really

42:17
Despite all our public health efforts and our wonderful climate, etc., our environment is highly conducive to physical inactivity for a large segment of the population. So we have to think about other ways in which we can approach this to bring that line up a little bit from a flat line of just under half the population and not getting the benefits of regular physical activity.

42:47
thinking about the holistic approach to physical activity and reducing sedentary behavior across the day for people. Yeah, and you mentioned earlier that or sedentary behavior was more pronounced post-COVID. Has COVID in part changed that physical activity behavior as well? Yeah, and largely at the...

43:15
incidental type activity. So we've just touched on before about if people, well, I think from a behavioral perspective, when people are sedentary, it displaces physical activity. So just by simple definition, sedentary behavior is the low energy expenditure activities in the day that don't require any real movement. Okay. So any, if you transition from sedentary

43:44
you are sort of re replacing with physical activity. So behaviourally, I think we have to start getting people thinking that any time that we are spending sedentary, we're losing that opportunity to be physically active. Yeah, yeah, for sure. Yeah, you're right. Everything's like a trade off, right? And opportunity costs when it comes to what you decide to do. David, you

44:09
We're also, and I don't know the extent to which you were involved in the study, but you were an author on a study around psychological health and COVID and sedentary behavior, which is, you know, we've been talking a lot about the physical health outcomes of being sedentary, but what do we know about sedentary behavior and psychological health as a sort of kickoff into this conversation? Less.

44:36
Less is probably what I should say, less than we know for physical health. Um, but, um, what we are starting to see is some, you know, really interesting studies that are showing that there are detrimental impacts of sedentary behavior on mental health and, you know, relationships with depression, anxiety, um, et cetera, but what the work that you're referring to, what, um, that has started to uncover is that not all sedentary behaviors.

45:05
have the same effect on mental health. And what I mean by that is that there are some sedentary behaviors, and I'll use television viewing as an example, where what we would call as a passive sedentary behavior, you're not really having to do much thinking at all. Whereas as opposed to using a computer to work, you're sedentary, but you have to use your brain.

45:31
And so we call them mentally active sedentary behaviors. And what's really interesting is that once you start separating those sort of passive sedentary behaviors versus the mentally active sedentary behaviors, it's quite clear that the passive sedentary behaviors have a more detrimental impact on mental health outcomes like depression, cognitive functioning, et cetera. So it's really early days in this area of research, but I think it's just the evolution

46:01
research in that we found that there are relationships with physical health with sedentary behaviour. Now we're starting to see it with mental health, but now under the surface of that, there are different types of sedentary behaviours that are more detrimentally associated with mental health outcomes. And I think we're going to start to see a lot more as research groups start to look at the different types of sedentary behaviours and the impacts. Yeah, it's interesting. And of course,

46:29
people who are interested in this field will be well familiar with the beneficial effects of physical activity on mental health. So I guess this is just, this is potentially just another string in that sort of bow of research and understanding, which was a terrible analogy actually, I'm not sure quite why I use that. But there you go.

46:56
In light of this research, David, what is the next steps with regards to understanding this relationship more? Well, we're now starting to look at various groups that have collected this type of data in their epidemiological studies, because I think it's important to look at this not cross-sectionally, so one point in time, but to look at this prospectively. So...

47:19
changes over long periods of time. So research groups are starting to look at this in prospective studies, which is going to get us a little bit closer to understanding that sort of pathway and the relationships. But importantly, we are seeing some groups, and including our own, that are wanting to start taking this back to the laboratory again. And so when you expose people to...

47:45
mentally active sedentary behaviors versus passive sedentary behaviors, do you get different impacts on, for instance, cognitive functioning? Do you get different impacts on cerebral blood flow, blood flow to the brain, et cetera? So looking at some of those mechanistic aspects, and I think that that's exciting. It's going to start to provide a more solid evidence base that we need to channel our attention to.

48:12
those passive sedentary behaviors for improved mental health. Yeah, yeah, for sure. And David, like, just lastly, like, I wonder about your opinion or how you feel about, like, children today versus, you know, what it was like when I was growing up with regards to the exposure to much more opportunity to just be passive to just that sedentary behavior. Like, is that...

48:39
Like, do you often sort of sit back and go, God, you know, we're in for it in the next 20, 30, 40 years with regards to health outcomes, or have you got a bit more of a positive view on it? I get in trouble a little bit at home about this because I've got, you know, teenage children and whenever I say all back in my day, it's a hyper-farting. But I think what's clear is that there has been this huge revolution of

49:09
the instant access to passive sedentary behaviors that, for instance, the mobile phone provides, the screens provide. And even if I think about 20 years ago when we were doing our OZDiAP study that I showed to at the start, television probably was the predominant source of screen time. Now we have multiple forms of screen time. And what really does worry me substantially is that...

49:37
We've got now streaming services, for instance, where people can essentially binge for long periods on those. Yeah. And in the past, when we had television, we used to have our commercial breaks that provided a prompt to get up and move around. Now we don't have that opportunity. So we have seen a real, real dramatic change in our landscape. And it does leave me a little bit pessimistic for the future, unfortunately. Yeah.

50:07
Yeah, I feel much the same about that. I also remember seeing data, and I can't remember, I don't know whether this is still true or if it's been updated, but the metabolic equivalent factors of the energy cost of different activities. And I'm sure I remember seeing that watching TV had a lower metabolic cost than sleeping, for example. Did I imagine that?

50:31
not substantially lower, but it's getting closer to that sleeping sort of energy cost. And so again, it comes back to the volume that people have throughout the day. So nine hours, some of which might be watching two hours, two hours of TV per day, is at low energy cost. And so I think that we have created, well, there's an environment that we are exposed to.

50:59
that is highly conducive to low energy expenditure. Yeah, and what importance is placed on physical activity and physical education in the school system in Australia? David, do you know? It could be better, but I think that we're starting to see some positive signs. And I know, for instance, my colleagues at Deakin have embarked on research to really shift the teaching practices.

51:28
the learning environment to be more active learning. And through the Transformers program, it's about shifting what has probably existed for hundreds, a hundred years, where you must have kids sitting to learn in classrooms and really shifting that culture towards, well, yes, can they be more active in that learning activity?

51:56
And it's likely to, for the various reasons that I mentioned before, it's likely to be more beneficial for the concentration, et cetera. Yeah, yeah, no, for sure. Well, it sounds like you and your lab and your colleagues are doing what you can to help from like, both in that research space, but also heavily involved in that sort of public health space. And I know that you're often called upon to comment in that media space as well. So.

52:23
you know, some of that message will be out there. How else, David, can people find out more about your research and what your, are you wearing a dual hat, I know, but where can people find out more about what you do and the research and stuff? Sure, I direct people to our Baker Heart and Diabetes Institute website, where it describes our physical activity research. And importantly, we provide a lot of summaries of the media that is generated from that research.

52:53
And then the other hat within the Institute for Physical Activity and Nutrition at Deakin University, I head up the Baker Deakin Department of Lifestyle and Diabetes. And so there's again, summaries of recent achievements, etc. that can be obtained from there. Yeah, awesome. And then lastly, you mentioned a conference, which is not just an academic one, but a practitioner.

53:20
conference that's going on in Wellington this year. And I know that I'll have a lot of personal trainers and other people who might be interested in that. Are you able to share any of those details? I'd love to, because I wear a third hat, which is the vice president of the Asia Pacific Society for Physical Activity and Nutrition, where we are three years old, the society. And importantly,

53:48
The society is to bring together all the players in the promotion of physical activity in society. So not just people working in academia, but importantly those people that are on the ground and working in practice and those that are informing policy. So the Asia Pacific Society for Physical Activity and Nutrition this year's conference will be in Wellington, November 27th and 28th.

54:16
The sessions are really targeted across both research, practice and policy. So I think it's, we're hoping to fill that gap that has existed for a long period of time where we can bring together those that are working out there in the field with those working in research. Yeah, I think that's fabulous because it's one thing to do the studies and

54:42
make recommendations based on that, but it's quite another thing to translate it into recommendations that people can actually follow. So, well, I'm super excited by that, David, and I'd just like to thank you for your time. I really appreciate it. Thank you again for examining my PhD and making that possible. And I really look forward to seeing more stuff from your lab over the coming years. It sounds really great. Oh, thanks so much. It was great to have a chat.

55:11
I look forward to hopefully seeing you in Wellington. Thanks David.

55:25
Hopefully you enjoyed that and if nothing else it gave you pause to think about your own sedentary behaviour during the day and what you can do to potentially increase it. It certainly makes me think more about it when I'm engaged in the research and talking to experts like Professor Dunstan. And as I said his research links are in the show notes. Next week on the podcast I have another professor, Professor Scott Lear.

55:52
who talks all about his own journey with mental health and just some of the interventions he explored when going through depression and anxiety and some of the lessons that he's learned. So it's a mixture of the research behind it but also his personal story and I really think you're going to want to tune into next week. Until then though, catch me on Instagram, Twitter and threads @mikkiwilliden

56:22
or hop on to my website, mikkiwilliden.com, book a one-on-one call with me. You guys have a great week, see you later.