 Alright, good morning everybody and welcome to day two of the Ancestral Health Symposium. My name is Ben Greenfield and I've been tasked with the job of tormenting the presenters for the first half of the day today. So I'll be introducing James Steele, our first presenter. James is, as you will find out very soon, a foreigner. He studies at Southampton University. He's a PhD candidate there with a particular focus in the realm of resistance training. And among other things, James actually has, as I learned at last night's dinner, a very asymmetrical and dysfunctional pelvis from falling over on his bicycle at a stoplight. So you can try to get that visual out of your head while he's presenting today. It's also James's birthday, which I also just found out. So we'll refrain from seeing you happy birthday, James, but we'll at least say it. So on three, one, two, three, happy birthday, James. Alright, take it away, man. Okay, right. Okay, so just to give you a kind of overview of what I'm going to be covering in this talk. When I first started putting it together, I kind of had this idea that I knew what I wanted to say. I was familiar with some of the literature around the area by guys like Lauren Cordain, James O'Keefe and Boyd Eaton, some of the earlier review papers where they had kind of proposed these ideas of, you know, hunter-gatherer-type fitness, evolutionary fitness, paleo-fitness, whatever you want to call it. But when I started really getting stuck into the literature, I started to see that things weren't necessarily as rosy or romantic as these authors have kind of portrayed them. So what I'm going to hopefully do is give a bit more of a kind of sober view of this notion of evolutionary fitness. And whether or not some of the ideas we have about hunter-gatherer physical activity patterns actually tie up with recommendations from modern exercise physiology in terms of best ways to kind of optimize our physical fitness. So in terms of background, we've got a lot of, you know, a string of recent academic papers which have kind of discussed these topics. As I said, some of the more recent ones are like James O'Keefe and his colleagues. We've also had some recent papers in sports medicine looking at applying these kind of ideas to training athletes. And within the lay press as well, we've got, you know, a number of kind of more popular manifestations of these things. We've got like Darryl Edwards with his Paleo Fitness. We've got various other things. I found this book, it's quite old, Instinctive Fitness. We've got Move Knot. And CrossFit as well, various things which kind of use this kind of evolutionary justification in some way for what they're doing. Although I've recently learned that CrossFit are actually suing the National Strength and Conditioning Association. So we'll pretend I didn't actually talk about CrossFit. Just in case this gets out to Greg Glassman and, you know, I get a lawsuit on me. So we've often got this notion that kind of hunter-gatherers were fit. They were strong. They were healthy. They were robust. You know, we've got all these studies which are rolled out time and time again to indicate that they were, you know, they were fast. We've got analysis of the footprints laterally from TA suggesting that he was as fast, maybe if not faster than like Usain Bolt. Modern hunter-gatherers tend to have higher VO2 maxes than the average population. Studies by like Sean Stock at Cambridge and earlier stuff by Ruff suggest that hunter-gatherers were strong and robust based on their skeletal remains. And obviously, you know, they've got lower body fat percentages and generally better body composition than us. And these are the studies that kind of continuously rolled out to kind of justify these kind of romantic pictures. But I wonder whether or not that is kind of a bit of a romanticised, you know, a romanticisation of it. And whether or not the majority of the literature actually kind of supports that idea. So in terms of what kind of, you know, we're seeing in terms of the importance of physical activity in everyday life nowadays is that we all know that being physically active is important. And being physically active reduces or cause mortality in a kind of dose-response manner. The more we're physically active, the more we get an effect from it. But recent research is starting to question this idea that the amount of physical activity is the most important factor. And actually, the intensity of all, you know, I'll touch on what I mean by intensity because it's a kind of touchy topic nowadays in exercise science. But certainly the physical fitness that people have, which seems to be related to the intensity of the activity that AHA engage in, seems to be the more important factor. So for example, people who have higher physical fitness measures such as VO2 max or strength, muscle mass, they tend to be more strongly predictors of all cause mortality. And as an example as well, I actually added this study in a couple of days ago, which I came across. It was a study in Finnish men that looked at the intensity of the activities that they were engaging in and found that the more intense their leisure time physical activity was, the more their cancer risk was reduced. But interestingly, the lower intensity activities, which didn't provide much of a protective effect, would be considered to be typical foraging hunter-gatherer type activities. So there was a lot of berry picking, there was a lot of foraging, fishing, hunting and all these sorts of things, which we think, oh, you know, that's what hunter-gatherers did and that's what made them fit and healthy and robust and free of diseases. But this recent study suggests that actually they don't provide as strong a protective effect as we potentially think they might do. So in terms of evolutionary fitness recommendations, that's kind of asking the question of what should we do? And looking back at the literature, they seem to have focused on the following questions in determining what those recommendations are. So looking at what evolved traits we have that determine our physical activity capacity and limitations. So asking, as homo sapiens, what can we do? And looking at either extinct or extant hunter-gatherers physical activity patterns and asking the question of what did we do? And kind of trying to draw recommendations from them. But what I think is a more appropriate way of doing it is to kind of synthesize that with what modern exercise physiology research suggests. And now I'm going to kind of limit the talk by saying the premise of this talk is that I'm going to focus on what effect these physical activity patterns have on physical fitness measures, because as I've just noted they have quite a strong association with all cause mortality. And I'm going to be looking at kind of synthesizing some of the observations we have about these hunter-gatherer physical activity patterns with what modern exercise physiology says. I also want to kind of make a note beforehand to say that although in the past our physical activity was directed predominantly towards survival, in modern society physical activity is kind of differentiated certainly from exercise. So exercise is what I'm going to be focusing on, what exercise recommendations we can draw from the literature in terms of physical activity patterns of hunter-gatherers. So what recommendations can we make for directed physical activity exercise in essence for improving physical fitness factors? So the question is, what exercise should we be doing? So as an outline I'm going to try and answer these three questions. What can we do? What did we do? What should we do? And then provide some conclusions and potentially some recommendations. So in terms of answering those questions of what can we do, I'm going to look at what sort of activity repertoire we seem to be evolved for. What capacity do we have? In terms of what did we do, I want to look back at some of the physical activity patterns in our evolutionary past. So we'll look at some of the physical activity patterns of other primate species, what the literature suggests in terms of extinct human populations, and what it suggests in terms of extant hunter-gatherer populations as well. And then try to tie that up with what recent evidence suggests in terms of whether we should or should not emulate these patterns, if we can actually determine what they are. Okay, so I'm going to steal some concepts from Dan Lieberman's talk at Harvard a few years ago, just to keep in mind when we're talking about what activity repertoire we're kind of adapted for, what physical capacity we have. So obviously what we're looking at is what adaptations do we have, what useful features do we have that have improved our evolutionary fitness, our reproductive fitness? Because it's important to remember that although we may have adaptations that promote reproductive fitness, they don't necessarily promote health and they don't necessarily promote what we would typically consider in modern exercise physiology as being physical fitness. So there's a differentiation to make between reproductive success in terms of evolutionary fitness and physical fitness. It's also important to remember that just because we can do it doesn't necessarily mean we should do it, and that's where the tie up with modern exercise physiology is going to come around. Okay, so one of the key things, and it's obvious to everyone, we don't even really need to go into the literature in depth with it, but we're obviously bipedal. We're adapted to bipedal locomotion. And I talked about this last year in my talk in Atlanta where I covered some of the literature revolving around the emergence of different locomotion patterns and how we've kind of transitioned from a predominantly quadripetal arboreal locomotion pattern through semi-terrestrial quadripetalism into more habitual bipedalism. And with last year's talk I was focusing on some of the changes within the lumbar spine and the pelvis and how that might impact on lower back pain. So there are a number of different adaptations, though, obviously, which promote our ability to move bipedally. And we obviously have adaptations, and some of you will probably have seen this in Dan Liebman's paper, Bramble Liebman's paper in Nature. There's a whole list of different adaptations which promote both efficacy in terms of walking bipedally, but also running as well. So we can walk and we can run, and there were reasons for why we may have adapted those physical traits in terms of environment, increasing food availability, increasing range, reducing cost of transport, certainly for walking, although not so much for running. Our cost of transport for running tends to be on average higher than most other species, although we tend to have a flatter curve when we increase the velocity of transport. And there are a number of adaptive advantages to that as well. So obviously, being bipedal, increased visual field as we were moving into new environments. As I said, there was a reduced cost of transport for walking, so our daily range could have expanded considerably as well. Obviously, we're all aware where, hopefully, if we're familiar with Dan Liebman's stuff, that being bipedal confers a significant thermal regulation advantage as well. And also, having the hands free means that we can start to carry more objects. We've evolved tool use, increased our ability for food acquisition in terms of movement and berry picking and foraging and that sort of thing as well. We've also obviously had adaptations in terms of our upper body physical capacity as well. And we've lost potentially a lot of our specializations for our boreal quadripedalism, so our upper bodies aren't necessarily the same as some of our earlier ancestors. We've lost that specialization for our boreal locomotion. But, and again, this is going back to some of the studies from rough suggests that Neanderthals, early Homo, they looked as though they potentially were quite heavily muscled looking at their skeletal robusticity. But there's quite a lot of difference as I'll go into shortly in terms of what the results of other studies actually suggest. There's quite a lot of variation in samples which might be related to climate environmental differences. But it's reasonable to say as well as Cordane and colleagues speculated in one of their earlier papers that because of the lack of hafted tools, compound levers, we probably had quite a lot of our body physical capacity in terms of strength and endurance for the tool use as that adapted. But over the years we've also seen a reduction in that musculature. If we look at some of the stuff from Shawn stock, which seems to be coincident with more advanced tool specialization. So as hafted tools were created, needs requires less in terms of our body physical capacity to use them. So we see a kind of trend towards a reduction, a potential reduction in the musculature based on the robusticity remains. But, and again, it's difficult when we look at these types of data, when we're looking at skeletal remains in terms of trying to determine what muscular capacity look like. Because they can be a reflection of physical activity patterns themselves and not necessarily an adaptation in terms of an evolutionary adaptation to those physical activity patterns. So it's kind of difficult to kind of draw chicken and egg scenario that which one came first. It's obviously also important to remember as well that we have adapted as an adaptive system. So our bodies do respond to the demands we placed on them and our capacity broadly matches the demands we place on it in everyday life. The body doesn't want to waste energy, excess capacity is costly. So it's an evolutionary advantage to have an adaptive system that responds to the demands that we place on it. Okay, so we'll move on then to what some of the physical activity patterns in our evolutionary past were. Now, a lot of the earlier papers are focused on energy expenditure, trying to determine what our physical activity levels were as such. So if you look at some of the earlier papers, you'll see tables like this where they look at what the total energy expenditure was. Activity energy expenditure may have been working out physical activity levels based on the ratio of resting metabolic rate and total energy expenditure. Or you see tables like this which make suggestions as to what kind of modern activities result in the same sort of energy expenditure. But as we're kind of aware as well, energy expenditure isn't necessarily that important when it comes to exercise. Exercise isn't great in terms of the energy expenditure it provides. And I think it's more interesting to focus on what exercise variables and what manipulation of those variables actually promotes adaptations or changes in physical fitness that promote longevity, health, reduce or cause mortality and so on and so forth. So this synthesis is going to kind of consider what we can draw in terms of how frequently active were hunter-gatherer populations, what sort of volume of activity did they engage in, what intensity of activity they engaged in. And I discussed this recently in a paper where in this talk I'm going to be referring to intensity as the effort, how hard the actual work was, not necessarily the typical definition of intensity that you see in resistance training literature which often refers to the loading. And it's difficult sometimes when we're looking at physical activity patterns to determine what the actual loading was. So in this I'm going to focus more on what sort of types of activities and what sort of modes of activities were actually engaged in. And then obviously the important thing is what can we draw from the data when we look at in terms of providing some sort of overall picture of how frequently, how much, how hard and what types of activities hunter-gatherers were engaging in and how we can use that to potentially provide some recommendations for promoting fitness. So we're going to start off looking at other primates and the data is a bit sporadic on this. So there are some studies where it's difficult to determine some of those variables I was just talking about. In general when we look at it the frequency of activity is very, very seasonal in other primates although the types and kind of modes of activities that they engage in tend to be relatively consistent. So you see a lot of activities which you'll see in kind of some of the more kind of primal play type sessions that Daryl was doing this morning and yesterday. A lot of kind of clambering, climbing, sitting, walking, running, bounding, brachiation which is kind of swinging from the arms although we've lost that kind of specialization to be as good at that. In terms of volume of activity though they tend to not be anywhere near as active as this kind of romantic picture of primates kind of tends to be portrayed. So their range around the daily range tends to be very, very low. They tend to on average move around about half to one and a half kilometers a day. And when you look at some of the data on how much time they actually spend resting or what we would probably consider to be in sedentary activity, it's actually very, very high. So they spend a lot of time lounging around, resting, sitting, standing. They sit a lot which is surprising because sitting kills you apparently. And they spend very little time actually moving around. But yet they tend to be fit, strong, healthy, low body compositions and so on and so forth. So again is the volume of activity, the frequency of activity necessarily important. These are other primates though so it's difficult to say. So that was looking at kind of arboreal quadrupeds. If we look at, obviously that varies by species as well. So you do have some species which spend a lot of time lounging around. And other species which don't spend anywhere near as much time. But on average they tend to spend a fair amount of time just chilling out. If we look at semi terrestrial quadrupeds, so like the greater apes, chimpanzees, bonobos, gorillas, again we see as body size increases there's an increase in range. But again they do tend to spend a lot of their time kind of chilling out, sitting, eating, although as we know with some of the greater apes that might be related to their gut physiology and they need to actually perform that type of activity regularly. But again the types and modes of exercise are what we would typically expect to see in this type of species. And again if we look at for example changes in our ability to perform certain activities, as I said we've lost that kind of upper body specialisation to engage in specialised arboreal locomotions such as brachiation. And we tend to see there's kind of a gradient in terms of our ability and the frequency of brachiation that you see in the great apes species as you move closer and closer to humans. So primates spend a lot of time sitting around, not doing a lot. Interestingly as well they actually spend what I thought was less time than I would have expected to see socialising and playing. They just kind of chill out a lot and then occasionally they'll play a little bit and then they might move a little bit and then they might eat and then they'll just go for a nap again. So they spend a lot of time being sedentary. Okay, so let's move on to what physical activity patterns we can try to draw from extinct hunter-gatherer populations, what the skeletal remains kind of suggest to us. Now the idea of reconstructing physical activity patterns of extinct hunter-gatherers has been termed by Germanic colleagues as the bioarchaeology Holy Grail. It's this mythical thing that's really hard to determine. But people try and attempt it by looking at skeletal remains, looking at changes in articular modification, musculoskeletal stress markers which indicate potentially the types of forces that are being placed on the musculature, skeletal robusticity and changes in the geometry of certain bones that might reflect engagement in certain types of loading or activities. So I thought to myself, great, right, I'm going to look at the literature and I'm going to try and draw out these variables again and see what we can get. Because I had this image in my head that hunter-gatherers were going to be really active, really fit and we were going to be able to draw out these amazing recommendations. But when I sat and tried to look through the literature I felt a little bit like it was doing this at me. It was fadding in my general direction. So it was almost impossible to try and draw out a physical activity level or pattern specifically. And even two decades ago, authors in the paleoanthropological literature were kind of saying there is clearly no particular physical activity pattern that categorizes hunter-gatherer populations. It varies massively by geography, their culture, their technological advancements, for example, after the last glacial maximum as environment changed considerably, there was a decline in physical activity. Although the actual populations haven't necessarily changed, they just got more sedentary. In some studies you see that there's a sexual division of labors and men and women tend to perform different activities although their physical activity levels remain relatively similar. But in some populations you don't even see that sexual dimorphism. You don't see differences in males and females. So again, it makes it difficult to determine what kinds of activities they were doing. Also, and even more interestingly, when you look at studies of skeletal robusticity and other skeletal stress markers, there are some studies that suggest that hunter-gatherers are no different than agricultural populations. Some studies where they clearly are greater and some studies where they're actually worse than agricultural populations. So again, it's really difficult to try and determine whether or not they were more, less, the same, active, and it starts to question whether or not there are really differences between us and modern populations as well because some studies actually show similar skeletal robusticity when you bring the whole body of literature into account. Also, the idea that we can infer that they engage in specific types and modalities and then try and draw recommendations for engaging in certain activities is a bit folly as well because cultural materials don't always correlate with the musculoskeletal stress markers that we see. So the stress markers that you expect to see from engaging in certain activities doesn't necessarily tie up with the cultural remains, the archaeological kind of evidence that you find with those populations. And even though we have ethnographically recorded divergent physical activity patterns between different populations of hunter-gatherers, you don't always see differences in the skeletal morphology. Also, some of the recent research from sports medicine as well has started to suggest that actually maybe we can kind of determine whether they were engaging in linear running or more intermittent kind of sprinting, whether they were endurance running or spending more time kind of intermittently sprinting, or whether they were doing a lot of running that involved changes in direction because some studies have suggested that tibial and fibula morphology differs between those different types of activities when you compare different times of sports. But then again, other studies don't show that difference and it makes it very difficult to determine what kinds of movement patterns we were actually engaging in. So, were we engaging in these types of activities? Should we still be engaging in them? I don't know. Being a bit facetious, maybe we should be engaging in this kind of activity because some of the evidence suggests that we clearly spent a lot of time around large ungulates, and I just love this because I wanted to put it in, unkindly disposed to the humans involved. So perhaps we should be spending more time rodeo riding because clearly that's the type of activities that early humans engaged in. Maybe not. So I just wanted to read out this example to kind of highlight this quote, to highlight the folly of kind of trying to draw recommendations or even draw any conclusions of what those physical activity patterns were. So, Mayor and colleagues kind of highlighted that inadequate sample size, too far reaching conclusions and neglect of other possible explanations are among the problems easily recognized in the literature. Many assumptions are lacking a sound experimental basis and it becomes increasingly evident that there are many more problems and limits of interpretation than have been usually acknowledged in the recent past. It also appears that many results which have been interpreted in terms of sexual division of labour may in fact be expressions of the intrinsic sexual dimorphisms of homo, homo sapiens, and not cultural populations specific peculiarities. Also acknowledging the results of many studies from the field of sports medicine, it appears doubtful that the adult activity pattern, patterns of activity, can truly be isolated from those which stem from the formative years of human skeleton during the sub-adult growth period. And that's an important point as well because sometimes when we look at skeletal remains, they don't necessarily reflect adult physical activity patterns, they reflect what the sample was doing during their formative period because that's when there's the most bone adaptation in response to physical activity patterns. Okay, so moving on to extant hunter-gatherers then. And we have a lot more data for this really. So what I wanted again was to figure out what manipulation of these variables produces this. So in terms of frequency, most hunter-gatherers tend to spend a lot of time physically active, but not necessarily doing things that we would consider to be exercised, probably more like chores, a bit of housework here, a bit of foraging here, very low intensity stuff. They were normally active but not active in the way that we were considered to be active during directed exercise. Also, if you buy into the idea that we've evolved to perform endurance running, the frequency of that is hard to determine as well in some cases because if you look at some of the data that is available on it, they would probably maybe do an endurance run every three to five days when they were successful. It's a little bit more difficult to determine how frequently they did it when the hunts were unsuccessful. But there was a very low frequency in terms of engaging in that more intense type activity. In terms of the volume of activity, as I've said, there was a lot of daily activity, and the fact that we engage in kind of random type power law distribution walk patterns does indicate that hunter-gatherers have a large daily range. So they do spend a lot of time moving around, just not necessarily moving around at high intensity. For example, hunter-gatherers do tend to kind of have regular movements of their camps and stuff as well throughout the year, so they on average move every couple of weeks or so, and they might move an average of kind of 10 miles or so in terms of moving their properties. But then some populations around their campsites and their current bases, they tend to have, again, quite a small range. So if you look at some of the recommendations from Cordain and O'Keeffe, I kind of recommend a range of 6 to 16 kilometers of daily movement in terms of locomotion, but it's difficult to determine whether or not that's really the range of locomotion that we should be engaging in. Again though, and this harkens back to the other primate species, when you observe hunter-gatherer populations and foraging populations, they spend a hell of a lot of time resting. They spend a lot of time sedentary. They spend a lot of time lying around, sitting down, just chatting with each other, laughing. Children tend to spend a bit more time being active, and when children are involved in foraging activities, they do tend to go on quite long walks and spend a lot of time foraging, picking berries and that sort of thing. But again, as we said, that's not necessarily associated with improvements in health outcomes and fitness outcomes. Now, all of the presenters have been invited to provide an accompanying paper to the Journal of Evolution and health for these presentations. So one of the things I've done for the paper, so you'll be able to see the raw data in there, is I tried to pull together all of the studies I could find that actually report a physical activity level, a ratio of total energy expenditure to resting metabolic rate for different hunter-gatherer populations, both male and female, agricultural populations and modern populations as well. And then to compare that to what Eaton and Eaton suggested was the paleolithic standard for the physical activity levels. And when I plugged that into SBSS and actually ran some stats on it, there was no significant difference between the two. I mean, if you look at the hunter-gatherer in agricultural populations, it does seem to be slightly higher, but in terms of whether or not those differences and certainly compared to the paleolithic standard as Eaton and Eaton kind of suggested, there's not as much difference as we would expect. So hunter-gatherers are probably a little bit more active than we are, but how much more, you know, are we romanticizing how active they actually are? I think potentially we are. Now, the intensity of the activities or the vigorousness of the activities that they're engaging in I think is the more interesting thing to look at. So again, as you said, these are studies looking at the Bolivian Amerindians, which suggests that they spend the majority of their time engaging in what were considered to be kind of lifestyle activities. So housework, you know, camp work more likely, a little bit of foraging here and there, all very, very low intensity. Kind of what Marxism suggests, you know, move a lot at a very low intensity, but they do also spend a little bit of time engaged in very, very vigorous activity. In fact, you probably can't see it on this, but I thought it was quite amusing that when you differentiate between day and night and look at the male populations, there's a couple of minutes each night that the males are engaged in very vigorous activity. The women aren't, so it doesn't lead me to question what the males might be doing at that time of night. So anyway, the point is that the hunter-gatherer populations do spend, you know, probably a little bit more time on activity than we do. They're probably a bit more active, but more importantly, I think, is that they do spend time engaged in very vigorous intensity activity. So for example, even Dr. Kim Hill's kind of observations suggested that, you know, the average speed that hunter-gatherer populations tend to move around is of, you know, 1.5 to 3 km per hour is a really slow stroll. It's just mowsing around. But then every now and then they would engage in sprint-type activities, very high-intensity-type stuff. Again, if you look at persistence-hunting average speed, 6.1 km per hour is actually, you know, just a bit of a route march. It's still walking. It doesn't indicate that we should necessarily be engaging in kind of endurance running or that type of activity. I'm sorry, and there was another one here. So this is a study that's looked at physical activity levels within children populations in... I can't remember what group these were now. But anyway, again, it highlights the point that although there's differences between sort of different hunter-gatherer groups, they spend some portion of their time engaging in very, very high-intensity activity, which I think is the point that we've kind of been missing a lot in terms of activity recommendations. So what kind of types of activities hunter-gatherers, excellent hunter-gatherers are engaging in. And hopefully you're all kind of familiar with Peter Gray's stuff. He suggests that they spend a lot of time playing, but that the play that they engage in is more kind of in spirit than what we would consider the physical activity type play. So there's a lot of humor. There's a lot of laughing, joking, that kind of thing. There's a lot of kind of creative activity, but not necessarily play as in what we see kids doing in the playground, running around, doing that sort of stuff. So apart from the children, adults do play, but it's more kind of what we would expect to be doing as adults, rather than what we would expect to be doing as children. They spend a lot of time walking, as we said. They do walk around a lot. They spend a lot of time randomly walking in various directions when they're foraging, looking for different things, trying to expand their range, expand the amount of return they can get on their actual foraging expeditions. And a lot of time walking around their camps, huts and that sort of thing as well. But again, as we said, the range is necessarily as large as we expect it would normally be. Running, though, is a bit more difficult to kind of decide whether they did run. We can run, as we said. We're adapted to run. But do we actually run? Don't know. Certainly when some populations have been looked at, none of the tribe were observed running at any time. They spent a lot of time walking, but they were never seen running. So whether or not we can recommend that is it necessary for us to run? Maybe, maybe not. And obviously we've got the normal kinds of activities which we expect to see in hunter-gatherer populations, which are necessary for the types of lifestyles they lead, which differ between men and women. So hunting, trapping, women are spending more time gathering food preparation and that sort of thing. But interestingly, in a recent study it showed that some hunter-gatherer populations do spend quite a lot of time engaging our boreal locomotion, despite the fact that we're not that specialised for it anymore. So that's an interesting point to look at as well. Okay, so obviously all of these kind of things that we see in extant hunter-gatherer populations are going to be affected potentially by their environment, habitat quality, hunting, logistical mobility, that sort of thing. So if they're in a rich environment they tend to be more sedentary because they don't need to engage as much physical activity in procuring energy. Whereas if they're in a poor habitat location they'll either spend time moving and relocating or they'll spend more time foraging and engaging in physical activity for those reasons. Interestingly though, modernisation doesn't seem to have affected their physical activity levels as much as we expect it to. And that might be because actually their physical activity levels don't differ as much from ours as we generally think they do. Okay, so what sort of things can we conclude from this and then how do we tie it up with modern exercise physiology? So looking at it, there seems to be no one physical activity pattern typically ancestral. It's really difficult also to determine whether or not something is an adaptation and thus has resulted in us engaging in those physical activities or whether or not we engaging in those physical activities has produced an adaptation which we see at sea. So we tend to see as well there's very low to moderate and inconsistent relationships between physical fitness and actual physical activity levels so the amount of physical activity they do. Also it's difficult to determine whether or not for example changes in brain size actually facilitated increases in physical activity or whether it's the other way around. And I'm going to suggest that you all hang around for Skyler's talk as well because he's going to talk a bit about how resistance training can enhance cognitive capacity and change our brains as well. So again, it's a chicken and egg kind of scenario. Which direction does it go? Is it bi-directional? Who knows. And can we draw any conclusions from that in terms of exercise recommendations? I'm going to have to go pretty quick about that at that time. So let's move on very quickly there then. So the current evolutionary fitness recommendations most up-to-date ones from O'Keeffe and colleagues in their recent papers are along these lines. And I'm going to focus obviously on which ones determine physical fitness adaptations. So how do we corroborate these with modern exercise physiology? So do the recommendations that are currently being made agree with evidence regarding manipulation of those training variables for improving fitness outcomes like cardiovascular fitness, strength, hypertrophy so on and so forth. So the current public health guidelines have been questioned a lot recently because they focus more on the volume of activity but yet they don't seem to provide the benefits that we would expect them to. And what we're starting to see is actually that physical fitness measures seem to be more closely associated with reduction in all cause mortality and that higher intensity activity seems to have a closer impact on this as well. So maybe what we've been focusing on in terms of the high volume of low intensity activity that hunter-gatherers engage in, what we should be focusing on is the more intense stuff. We should be focusing on the fact that they engage in these activities whereas we tend to not engage in those activities, certainly in the general population. So there's growing evidence that higher intensity exercise significantly improves cardiovascular fitness. We may not even need to engage in interval type training, just single bursts of high intense activity seems to be important for that. In terms of strength and hypertrophy as well, you can bin all the other variables. They're important kind of but the most important factor in terms of determining strength and hypertrophy outcomes from strength training is the intensity of effort put forth. Obviously in terms of frequency we know that varying that based on physical preparedness of the individual is important so auto-regulation is one of the only kind of periodization programs that seems to be consistently supported and shock horror, the mode of exercise doesn't even seem to be as important as we think it is for producing improvements in physiological fitness measures. So on that topic of modalities and very, very quickly even in the kind of skills and activities that modes of exercise that hunter-gatherers engage in we tend to see that physical fitness tends to impact them quite considerably but actually it's more about practice makes perfect and in today's society do we really need to spend time practicing to perform certain activities that hunter-gatherers perform when we don't need to perform those skills in today's life when perhaps we should instead just be focusing on improving physical fitness outcomes. So and again just very quickly recent work from myself and other areas are starting to question this idea of a mode type dichotomy between resistance type exercise and endurance type aerobic exercise so if intensity is high enough both activities can produce improvements in cardiovascular fitness strength and hypertrophy and so on and so forth so modality and the external resistance type type engagement doesn't seem to actually matter that much for the physiological outcomes that we're interested in looking at. Obviously very quickly it's important to consider though that certain modalities may have inherent injury risks associated with them so when it comes to actually deciding what physical activity to actually engage in you need to consider those as well. So to quickly wrap up evolutionary type fitness has become very, very popular in both the lay and academic press and I think from looking at the evidence reliance on suggested physical physical activity adaptations is a bit premature because the evidence is very light in terms of drawing recommendations from extinct and extant hunter-gatherer populations. Also hunter-gatherer populations don't seem to be as active as we generally think they are, we've been romanticizing that a bit and what we tend to focus on is the fact that even though they may be a little bit more active what's been focused on when really it should potentially be the intensity of that activity irrespective of the modality that seems to be the most significant contributor to improving physiological fitness adaptations. So to sum up and recommend then what sort of things can you do and what sort of recommendations can you take away from this. So one select an exercise mode that's based on personal preference or if you're an athlete sporting requirement is important but it's important to consider the risk-reward ratio as well and whether there are inherent injury risks associated with that and whether or not you're willing to take those risks when it comes to improving those physiological fitness outcomes. Two, focus on utilizing a high intensity of effort preferably maximal or near maximal as opposed to focusing on increasing volume or frequency that seems to be the most important factor for actually determining those outcomes. And three, when it comes to undulating figuring out what sort of frequency see how you feel. If you feel well recovered then train again exercise to a high intensity and then rest. Hunter-gatherers primary populations spend a lot of time chilling out because they every now and then engage in high intensity physical activity. So it's important to make sure you auto-regulate what types of activities you're engaging in. Thank you very much for listening and I think we've run out of time for questions so we'll say. We actually do have about five minutes for questions if you guys want to ask that's fine and just say curling is probably not considered appropriate exercise right? I know he was going to ask that question or golf. Just a second. Hi. Hi, thank you. That was great. Before I ask the question is it possible to get those slides somehow? It was a lot of information. Yes, absolutely. I have a research gate profile where I tend to upload any publications or presentations on there. So I'll put that on there. Also I've got a full reference list for all these citations as well. So I'll upload that so you can follow through, reference check and do what you like. Great. Now my actual question. There was a comment in there about training on uneven surfaces. I'm assuming that was sort of referring to running on a street versus maybe on a path. Right. What is the supposed gain from that? Is it more physical and proprioception related or is it just simply to keep you more keen on what you're doing? Obviously that was on the recommendations from the recent papers by O'Keeffe. I was trying to focus on the physiological outcomes in terms of cardiovascular fitness strength and hypertrophy. I'm not aware of any evidence that that type of activity the whole barefoot running thing and running on uneven surfaces promotes them. But there's some suggestion that there may be changes in proprioception and benefits from doing that. That's a whole other talk as well as to the pros and cons of barefoot running and how you should go into that. In terms of what the talk was kind of focusing on and like I said, there's not really any evidence unless you're a runner that you need to run. You can get the same sort of improvements in cardiovascular fitness strength and hypertrophy from engaging in other activities if the intensity of effort is high enough. What you get from performing running is you improve your ability to run and if you're a runner then you need to do that. But whether or not anyone else needs to do it is questionable and obviously running is associated with quite a high injury risk in terms of the studied exercises and physical activity patterns running seems to be quite high up on the injury list as well. Unless you're a runner I don't personally recommend that people should run unless you enjoy it. One of the points I wanted to make was that the reality doesn't necessarily matter as much. Person preference should come down to it because it's making sure that people actually adhere to physical activity programs seems to be the far more important point at the moment and certainly I'm starting to find in the research that we're doing in our lab that it's really easy actually to make an exercise program that's effective, it's harder to make an exercise program that people stick to certainly for the general population. Obviously most people here are probably quite motivated so I think personal preference is a big impact on that sort of thing. Thank you. You mentioned intensity is being really important. Is it the intensity important because of overall general health that yields from that or are you talking about increased performance and hypertrophy? What we're finding is that the physical fitness kind of outcomes like VO2 max and strength and those sorts of things are becoming, we're finding more and more that actually they're stronger predictors of mortality outcomes and disease type markers than a lot of the other kind of stuff that we tend to look at. So the intensity seems to be very important for optimally promoting improvements in those fitness markers and those fitness markers seem to be very closely tied to like all cause mortality and those sorts of things. So in terms of optimizing that aspect, that fitness marker that's predicting those things, I think it is important to focus on those. Obviously there's a whole kind of there are risks and rewards associated with increasing the intensity of exercise primarily dependent on the modality so you kind of have to keep those things in mind as well. Pick a safe exercise that you can do to a high intensity of effort and you're good to go. Thank you. Cool. I can answer questions at any time during the day just come find me. I'm approachable. It's approachable. Funny accent. We'll start with