Your guide to Zone 2!

Hello and welcome back to another episode of the Physiology of Endurance Running podcast. Today we are giving you your guide to zone two training. Zone two is literally everywhere. Every influencer, I was in their barbers before Christmas and the guy next to me was talking to his barber about zone two training. This is either running, it's got two mainstream, or zone two was just reached levels of hype for this shouldn't have reached. And mostly just been named zone two. It just annoys me for details, which we'll get into in the podcast. But yeah, I guess the whole idea of this episode is part of a series where we're going to go through with different training zones or intensity domains and really give you the science on what actually, how do we actually define them, how can we define them with and without a lab. And then what training adaptations you expect to get from them and how can we apply that in your own training. So that's, that's the aim of the episode. Hopefully we're successful and you've got a bit of an idea of, you feel a bit more clued up about zone two by the time we finish. But yeah, I think that's basically what we're going to cover today, right, Owen? Yeah, and I hope, I hope no one's ever listening to this podcast thing and they're going to get like definitive answers because that's not how sports science works, is it? Yeah, I guess you're going to come to the end of this and you're not going to know exactly what zone two does and doesn't do because we don't know. Well, again, again, I think that's why I really wanted to do this episode because people who have no science background influences whatever go, yep, zone two is going to do X, Y and Z and sometimes they're right, sometimes often they're not right. Or maybe the evidence isn't there to support what they claim, especially around the potency, I think, when it comes to zone two. It's effective. It does do what it says on the tin. It improves loads of different variables, but I guess one of the arguments we make in this episode is comparing it to higher intensities and what's the effect of a no-subzone two versus three, four, five, etc. There's definitely some things that the Instagram meals are getting right. You're probably going to enjoy your running more if you're absolutely smashing out every run. That moderate, right, that heavy intense that we're talking about, like scientific zones now, but really smashing all of your runs and you slow down a bit, you're probably going to enjoy your running a bit more. I think it's always a lot more enjoyable. You're probably going to be running for longer, you're not going to constantly be injured and ill, but then beyond that, I think, any concrete claims should raise an eye brow. Yeah, we're very much pro, easy running. I think it's the argument of what zone two is going to do for you and what it isn't going to do for you and where it fits into your training programme. That's what we're trying to get out of today, as I said, what and also just considerations for different populations. If you've only got four days a week to run, should you be doing zone two every day or not? Because a lot of people would say, yeah, just run easy, but maybe the balance fair shouldn't be easy. Maybe we're not even going, I polarised in what we're doing, 80 easy, 20 hard. I don't know, that's sort of the debate we're going to have over the rest of the podcast. But yeah, the start of a series where we're going to go through all the training zones and just do a bit of a digest and hopefully we don't give you all the answers, but you come out of it with a bit more clarity than when you went into the episode. Yeah, and I think at the end of it we're thinking about sort of talking about how we yeah, programme it for ourselves and for the people we coach as well. Because I think part of the part of the like reason we decided to do this episode was from breaking down the Valencia block. And I think it was more in the in the next episode we're going to do where, you know, I divide that zone up a bit different to you and there's not a right or wrong way to do it. But you know, that's going into like coaching, but that's sort of where it came from, right? And that's sort of what we want to discuss over a longer format than just this is what we did for Valencia and sort of leave it. Because we did have a few questions, didn't we? We got quite a few actually Instagram messages about how you divide up. Yeah, and just distinguishing intensity domains, which is how science goes about it and training zones. And there's probably not a right or wrong way to do it, but how do we do it and why I think it's really important. And I guess like continuing on from that like exciting announcement, we launched Patreon. So if you want to find out a bit more about how we apply what we talk about on the podcast in our own training, then we've launched Patreon. There's going to be bonus episodes coming out each week, which we will me, myself, Owen and Jen will go through our training and building towards all the races we've got coming up. So I'm training towards reveal at the minute. Owen's not quite sure what he's training towards at the minute. Potentially a hundred K. We'll see. And then Jen's training for Rotterdam. So we cover it. We launched that, or we announced that on Sunday, on the hour to come out on Sunday, the last episode. So if you haven't listened to that already, you can go listen to that. But yeah, episodes coming out weekly bonus content on their resources, but will help support you in your training. So thank you for all of those who have already signed up. We really, really appreciate it. And your support is greatly appreciated and helps us just provide you the listeners with more content, which is, you seem to think we're popular. People seem to like us, so we'll keep, if people like us, we'll keep making stuff for you. So that's, yeah, we appreciate it, really grateful. Yeah. Did we want to say thank you to a couple of the first sign-ups? I think we should. I think who is number one on our list here? Who was the first person to sign up for our Patreon? Do you want to give them a shout out? Yeah, I don't know why he's signed up, because I think we actually had people asking to get them back on. But yeah, thank you, thank you, Disco Dave, for signing up to Patreon and the company on the Long Runs. Yeah, he was a good company on Sunday. He was Dave. Even when he was getting dropped, he was a good company. Well, you know the concept as well. He did moan a lot to be fair. I mean, I think the course that the loop I made was like a K-long wasn't it? So he wasn't happy about that. But if you want to hear more of that chat, yeah, sign up for Patreon. I guess our real first person, because Dave was a bit of a test run to the whole system, but our real first person all the way from Norway was Morton Wenas, which I hope I pronounced your name correctly. Apologies, if not, but thanks for your support. Really appreciate it. And yeah, if you want to check out our Patreon links in the show notes. I guess one thing we need to make is a little bit of an apology, and that there was a bit of a confusion around the price. And we're still working at our Patreon works as well. This is very much a bit on my side for us, not a day job. And so what am I trying to say, oh, you need to rescue me here? Yeah, so we found if you sign up through the IOS app, there's an extra charge applied by Apple that we weren't aware of, because none of us have, maybe Jen and Dave have an iPhone, but yeah, they didn't sign up through that, but yeah, so just be aware, if you're signing up through the IOS app, they add an extra charge. And then you get that local VAT and stuff as well. Which we can't avoid that one, but yeah, we can't get it, it attacks off, unfortunately, for you, but maybe heads of a website rather than going through the Patreon app if you're using an iPhone, and you might save yourself a bit of money there if you're interested. I think if you've already signed up, then you could most likely cancel and then maybe worth re-signing up via our website instead, just go to Patreon, search for Physiology of Injurance running podcasts, slash be endurance collective, and you'll find us, or just head to the link in our show notes. So thanks for all your support, really appreciate it. And yeah, I guess anything else to say before we let them use to this episode? I'd rather thank you to Saw, as always. Yeah, yeah, so I was head to Tohensaur apart from the very old Hillingden vest, very old, but actually really good. You know, you get some of those old club vests that are actually really good quality. Yeah, I was in OG Ron Hill. I might have been, yeah, I had that little triangle logo. The fit, the cut was really nice as well. Yeah, it was good, but everything else was sore, that I wore for the Metley cross country at the weekend, and I felt like really comfy, because you know, you stood on the start line of a cross country freezing cold, because it's two degrees and windy, and then 30 minutes later at the end of the cross country, I'm pretty warm, but I'm not like drowning in sweat, so that was nice. I thought I looked alright as well. There was, there was a lot of sore getting about on the, there was a lake where I warmed up, and I think you basically had to have an item of sore clothing to be warming up around that lake. Metley is sore, sore country, I think. Yeah, yeah, I think you were, a few of the people who worked for sore in those clubs, aren't they, were completely sorry, we've got a little bit of an influence. Yeah, but you know, I can definitely say, yeah, the long sleeve top and the gloves and the split shorts that I wore at Valencia were perfect for cross as well. Yeah, I thought I looked good, and felt good when I was running in it, yeah. Yeah, well, I still think the best investment you can make is in those marathon half-tides or the split shorts, but I'm now in favour of that. I've moved from the split shorts to the half-tides, they always used to be a split shorts kind of guy, but now I'm in the half-tides, and they are just better for gels, I think. They're just, they're just so good, and it is an investment, but if you're thinking about, if you don't got to spring marathon records, and you're going to be carrying gels, it's just, it makes such a difference knowing you're not going to lose them out of your pocket, they're not going to be bouncing around. It's just, it's most annoying thing ever. I've had shorts in the past, especially split shorts, but notoriously bad for it, and they just, you can't hold enough gels, they're bouncing everywhere, and it's just annoying. You just can't wait to get through them, so they're not bouncing around on your shorts. So yeah, really good investment, go check them out. Thank you very much to Soar for continuing to support us, sorry for nearly forgetting about you. I guess like, to dive into the episode and sort of leave the groundwork's been, zone two is absolutely everywhere now, like I went to the barbers the other day, I think I said I'm a podcast, they were talking about zone two training in there, and even my dad, who is, is 17 now, he's talking to me about zone two training, and it is just exploded, just about, it is just easy running, right? It's just easy running, rebranded as zone two, but I personally hate the term zone two. It makes me cringe just a little bit when someone says I'm doing my zone two training, because I've not come from, I've come from background where I wouldn't have known what zone two was when I was starting to run with my wrong club, running club, doing my easy runs, it was just, it was just go for a run, sometimes it was a bit faster, and sometimes it was a bit slower, but it has made waves, everybody is talking about it on YouTube and podcasts like ours, but even like low, low level, and Instagram reels, you tag, put zone two in it, it's just going to explode, so we better get GM to do that for this episode, so we're hitting most big numbers, but what's your first impressions of zone two? What do you think of when someone said zone two as you were running? Normally seeing it like on Strava and thinking that's not zone two, I think just, because yeah, it's not really being used as, well, it's not being, yeah, it's not being used in terms of a precise measure that a zone would suggest, like a discrete zone, it's just now become a catchal term for easy running, like you said, and yeah, for some instances where I see it on Strava, I'm like, oh no, you're running way too fast, that's not zone two, yeah, you think, that's just like a classic club run, a pitfall, isn't it? Just bash out all your easy runs, and then for other people, it's like, now it's way too slow, you're really good running, you're like shuffling, probably below zone two, and then that opens up, we'll how do you define the bottom end, which is what we're going to sort of come onto, that's one of the big pitfalls of zone two is, again, we're making out like it's just discrete zone, but we don't actually know how to measure one end of it, so that sort of falls flat as face straight away, doesn't it? Yeah, thinking a bit more deeply, why I don't like zone two, I think you're right, but it's most people, zone two is actually something that's reasonably precisely defined, like zone two is an excise intensity, which is measured by looking at different physiological variables, whereas most people just are putting zone two on anything and saying, yeah, it's best to pass zone two when it's maybe faster, slower, somewhere in between in reality, but there's no, it's adding false precision to something, I think, it's about irritates me. The second bit is zone two is polarising in that some people are obsessed with it, it's saying, all you need to do is zone two, and I think especially the influences, just zone two, all the time, every run, zone two, you get super, super fit, and then you've got other people in other camps who are polarised in the opposite direction, and that it's a waste of time, it's just junk mileage jogging, and I think we've moved away from that, but I feel that with the likes of hierarchy and stuff like that crossfit, it's more going back in that direction, maybe that's my perception, but I do feel like zone two is polarising, and that people think you can get everything from it, or they think that actually it's not much of a good use of your time, maybe especially if your time limited. Yeah, yeah, there's different applications of it, isn't there, like beyond, beyond like we said, like a defined zone, yeah, how it sits in your training week and how you should be like, yeah, using it, which I think will come on to later in terms of our, so I guess like practical takeaways, but yeah, yeah, yeah, I guess people just, yeah, like we said, taking a precise, or a precise sounding term, and everyone has a different use of it, which sort of isn't the point of a precise term, is it? It's like when you, you know, if you say to one person, you're going on a tempo run, that means something counts, or it means something's for one person and something different. Don't give me a start on tempo, isn't it? Because tempo runs, tempo runs really worse, it's like, what does tempo even mean, like at least threshold is a little bit more precise, but people don't understand what it actually means, and we'll get to that in our episodes probably, and maybe touch on it today too. Oh, episode on tempo runs? I know, I know, tempo runs are just a time trial, aren't they, but you'd say it's a tempo run to make yourself look better on Strava, is that right? Yeah, when it's not as hard as it's worth it. I did a tempo run this morning, and I wouldn't be hard on the end. Right, so number two, points, second part then, let's get to actually defining zone two. So this is actually something that in some ways sport science has got a reasonable consensus on, I would say, a lot of thresholds, there's a lot of argument about best ways to define it, and there's a little bit of that in defining zone two, but I think there's much more of a consensus and agreement compared to yet other physiological variables. And again, you protection it briefly, by defining it, by consensus, I mean, we're good at defining the top of zone two, and that would generally be by looking at the first lactate threshold or LT1, often called aerobic thresholds, but basically looking at that highest speed you can run at without lactate accumulating in the blood. So if we're doing a test with U-O-I, you're running at 10 kilometers an hour, you lactate it's 1, 11 kilometers an hour, you lactate it's 1, 12 kilometers an hour, you lactate it's 1, where are we going to get to about 14, 15, 15, 15, 16, if I'm fit. Yeah, it's a 15 kilometers an hour, it's 1, 16, 16, 16, 16, 16, it's 1.8. So we're taking 16, then there's the highest speed you can run at without lactate, meaningfully increasing above your resting level. So for you, that's your LT1, your first lactate threshold, the top of your zone two. Do you agree with that? Yeah, you can use gas dates as well, but most people nowadays I think are probably going to be using lactate measurements, because you said like you can do it in a lab, you could do this on a track, you could do it on a treadmill at home, like you can actually self-test this. Yeah, so that's pretty easy to define. Like we said, it's the bottom end of the zone that's harder to define, right? I guess there is no consensus on where you put the bottom of your zone two. I don't know, I guess it's a chicken and egg thing, we're going to mention it, there's not loads of research on zone two, but does someone need to define zone two before there can be more research, or does there need to be more research before someone defines zone two? And even then people probably wouldn't stick to it, like it's sports science, there's like there's 20, 27, what is that, 27 different LT2s, or ways of placing that sort of metabolic sort of maximum points. Yeah, so yeah, we wouldn't agree anyway, but someone hasn't written a paper yet defining it, so yeah, exactly. So I think yeah, that first, like the top of zone two, normally LT1, you can use gas thresholds like then say through threshold one or gas exchange threshold, but actually for the the consensus is that lactate is a better marker, I would say. And there are debates about where exactly you put LT1, some people don't have a really stable baseline, like I described for you, oh, and some people sort of still are drifting upwards of their lactate levels before you see a marked inflection point. And then that becomes a little more difficult to define where it is, but for the site, but actually compared to compared to most thresholds, I think it's quite easy to identify, but then like you said, what is my bottom on zone two? And if you talk to scientists or researchers, they're not really talking about zones, they're talking about intensity domains. And for them, anything below LT1, first lactate threshold is just a moderate intensity domain. It's coaches that have come in and split that up into zone one, zone two, zone zero, I hear, get floating around a bit sometimes these days. I don't even know what that means. Not being dead, maybe, I don't know. That's standing at your standing desk, isn't it? That's zone zero. That's not standing at your standing desk yet. Yeah. So that is a massive issue with researching it, so to researching zone two and just actually doing interventions that are going to properly assess what the effectiveness of different training zones, because there's no physiological difference in terms of the lactate levels, your pH, your stress hormones, your breathingness to too much, dependent on where you are below LT1. There's going to be sort of a continuum that there's not going to be a clear break point in a different response between zone one, zone two, whereas there is between zone two and zone three, or the moderate and heavy intensity domains. So that becomes confusing. Because when I'm prescribing zone two and where the differences between zone one and zone two lie, I'm just thinking about making a zone that is useful, because if it's five beats wide, then that's not a useful zone. You're never going to spend any time there. So it needs to be meaningful, and I think it becomes even more important when you're talking about someone who's really well trained and got a really high LT1, because then there's a massive range of speeds, but ruling one intensity domain. So it makes sense to break it up, right? You, I'm LT1 of 16 kilometers an hour. Well, if we were just talking about moderate intensity domain, everything from walking up to 16 kilometers an hour is the same, whereas you're going to feel, it's going to feel different in terms of your RPE, how long you could go at that pace, if you were just going to sustain it indefinitely, it's obviously going to be different. So it makes sense to break it up, but then it's how'd you break it up? Yeah, and I guess that's like that interaction of relative intensity for the individual, and then absolute intensity. Like you said there, 16 kilometers an hour, or even faster for yourself, and other really athletes is really, really fast. Like I remember a few years ago hearing Robinson, it's like a 208 Mathena, 208, yeah, 208 I think, saying he can easy run at like 350 a.k. He is running easy, but that's just too fast. That's too fast for a 208 Mathena to run at that speed, but metabolically he is still operating at an easy intensity. So that comes into play as well, that absolute intensity of the speed that you're going, and I guess what you'd call it, like biomechanical, musculoskeletal sort of impact of that training as well, because I guess maybe again to say that we're really focused on the metabolic and cardio respiratory physiology of this. We're not really necessarily thinking too much about the load it puts on like your Achilles. That's not really our world, is it? But that's going to be massively different. Again, like using you as an example, like if you can run at 340 a.k. and it's an easy run, that's like a way different load through your Achilles to 430 a.k. But they're both both still metabolically an easy run. So, yeah, there is a lot like that. They both be pretty much the same. They're going to come at about one millimeter. And if you look at my muscle pH, it's going to be a baseline. I'm not going to be producing any stress hormones most likely unless I've gone in in a fasted state or something like that. So adrenaline, cortisol, bed, going to be looking pretty normal. But there are things that are going to be different when you said that loading pattern. The energy expenditure is obviously going to be different and how much glycogen you're using. So, I think that's when it comes into play, like what speeds should you actually be using for your everyday run? Because I don't tend to break it up into zone 1 and zone 2 days. I just go and run easy, which is one of the reasons why I don't like zone 2. Because there is just no difference between zone 1 and zone 2. That's in terms of, there's a difference, but not a difference. That makes sense because you've just said there are differences, but metabolically there aren't differences differences. So, yeah, it's not clear where the boundaries sit. But then when I've got my training zones for analysis afterwards, like we did that road to lenses series, it is nice to be able to quantify how much of it was faster, easy running and slower, easy running because you're spending so much time in your week doing easy stuff, but it is nice to have a better lens for analyzing what you've been doing. Yeah, and I guess the other thing I'd say is that you've through years of training, sort of, that you could, I guess, privilege or benefit of having this scope to do a massive amount of a huge range of easy running and we sort of joke about on the road to lenses series, you come and run, I'm pushing it for a long run and you're like, yeah, this is essentially zone one. Like, you know, you get comments on your driver, right? Like people can't believe like, how low your heart rate is for like a run sort of thing. Like, you've earned that right or that, that benefit of having that huge range, whereas actually there are going to be some people where it is, you know, the difference between running 530 aka and 515 aka probably doesn't, like, doesn't feel like much, but there are going to be runners where actually that's going to be crossing the boundary. So there is way less scope and it may be that's maybe a benefit of zone to is it is a little bit more precise because actually it doesn't feel that different because it's not a sort of, if you don't have a huge range, you know, where if like, being realistic like 637 minutes of K is like, you know, just about running, then you sort of have a much much smaller, you know, you have a much smaller like absolute range of speeds, don't you, to sort of operate in. And that once you start compressing the zones, then actually being a bit more strict is better, whereas I guess that's what I'm trying to say. And then you've, because you've got such a huge range of like paces you can run at before your, yeah, before you're crossing that metabolic boundary. It's almost like you don't have to think about it as much, not to say you don't think about it, but yeah, you, you can just sort of go through, I guess, whereas yeah. Yeah, well, because, because my RT1 is so high and the same for you as well, right, it's not like you have to be super, super elite to be have this phenomenon, but you're never going to accidentally go out the door and be running in zone three. Just because I've never gone out the door for an easy run and accidentally started running three, twenty a K pace. I'm just not going to do that because A, that is going to feel like hard-ish. I can go into 40 K at that pace in a training run, and that's going to be hard at the end, even though lactate's quite low. But it's just, it's just, you can feel that you're working, and it's just so much, so far away from what I would normally go and jog at, whereas if you are someone who's less fit, then their threshold is going to be a low percentage of their max. They have got less just speed to play with, and they are so far away from what they could run at for 30 seconds, a minute, but it's just going to feel very comfortable from a muscular skeletal standpoint. So I do think, but I think zone two is useful in the context of having a zone one, zone two, if you are someone who's moderately fit to very fit. If someone's more than you a runner, I think just breaking it down into easy, moderate, and hard makes more sense, and that probably means most runners. Maybe not most runners, but listen to this podcast, but most runners don't need to be thinking about zone two. They go, well, you should just be thinking, is this easy? Is this moderately hard or is this hard, I would say? I would argue. Should we get onto defining zone two, then, if you haven't got access to a lab or a lactate meter? Yeah, we can try. We can try. What are your thoughts? How would you go about it? So, somewhat, an athlete's come to you. They're like, how, what pace should I be doing my easier runs at? Yeah, so again, I guess we're talking about zone two. This is why, again, I wouldn't bother with zone two. I would just sort of talk to them about their training and just say, okay, when you're out jogging, I think once you've been running for a while, I think you do actually get, I guess, running for a while and thinking, like, actively thinking when you're running and reflecting afterwards, I do think you can pick up where you are running easy. And I'd say, actually, you should, I think you can pick up the top of zone two quite easily, then the bottom of it. I think you can innately sort of pick up, but yeah, it's just, like, you know, like you say, that talk test, and I always think it's like, if you get to a traffic light, like, you don't feel like you, you're happy that the traffic light's red and you've got to stop. Like, you can just sort of keep running, I think is a good test. You're more frustrated that you've got to stop rather than glad that you've got a breather. Yeah, yeah, once, you know, once you're getting, once you're running towards, yeah, crossing and you're like, oh, I hope, like, especially if you know the traffic light sequence, you're like, oh, I hope it stays red a little bit longer. Like, you're probably, probably getting towards the top if not hour zone two. That's I think another good, yeah, just because you're not thinking about, like, oh, I'm in zone two at that point, you're just, that's just your, like, natural instinctive reaction. And I think that's a better guide than, like, oh, like, yeah, what's this, what's this online, like, calculator said, like, actually, just, yeah, if you're like, oh, I'd like a break for 20 seconds, probably too fast. Yeah, yeah, no, I like that. Well, let's start on that theme, then let's start with one of the things that I think is the easiest way to see where your top of your zone two is, where that LT one is. And I, I would just go to RPE as a starting point. So having done loads and loads of lab tests, like hundreds and hundreds, one of the key things I would report is, what is your RPE at your threshold? The thing that tells you quite a lot, but there's remarkable consensus, I would say, but the most people LT one is a five out of ten. And so you want to be below that for your easy runs. There's obviously some range. And I think people who are more middle distance athletes, people who are less fits of their thresholds, are at low percentages of their VO2 max, like I was talking earlier, or people who just haven't done much training and haven't got a good calibration of RPE. Maybe that breaks down a bit, but for most people, I would say for most of people listening to our podcast, if you are a two or three out of you ten on your easy run, you're probably all right. If you're a four, you're probably okay, but you're starting getting towards the top of that zone two. If you're a five, you're probably crossing over it. I think that would, that would be my starting point. Yeah, yeah, I think that's a good, a good way to start. I guess also just, you know, if you are looking at this, like you're probably using heart rate, and I think again, looking back at data from multiple runs, like not just one run, and just looking at what your heart rate does, especially if you're running somewhere like fairly flat, and just seeing like a caves. Across the whole run is my heart rate drifting up, and I'm running up roughly the same pace, then you're probably out of zone two. Whereas if it's staying stable and and maybe even like, you know, you do the first KO two, and then your heart rate actually drops a little bit. That's probably again a good sign that your, yeah, you're in zone two, and you know, there's other factors like if you're stressed, like your heart rate's going to be higher, but I think, yeah, doing that over a number of weeks can also also be a good way of, yeah, like rather than using an absolute heart rate number, looking at the heart rate behavior, I think is another good way to look at it. Yeah, no, I definitely agree. I mean, if your heart rate is stable over the course of a one hour run, then there's a good chance that you're in the right place. If it's drifting upwards, like steadily, and of course that run and pace is staying the same, you're probably above your LT1. Not necessarily if it's super hot, then you are going to see more drift, but I think the heart rate, dynamics are a good tell. You can look at the percentages of max heart rate, and Matt is basically what your Garmin is doing to assess where your thresholds are or your core are, so whatever, they are looking at percentages of your max, but there are obviously caveats with that, and the first big one is do you actually know what your max heart rate is? That is a massive, massive factor, and if it's using 220 minus your age, but Matt's absolute nonsense, if you've got your heart rate max from running a 5k as hard as you can, like you've raced a 5k and you can see what it's peaked at, that gives you a better starting point, but even then I've seen athletes who just have a really narrow heart rate range, easy running, they can be easy running at 170 beats per minute, but their max is 200 beats per minute. That's probably unusual, but I've seen it, and likewise I've seen people who have massive heart rate ranges, where they are seeing big, big jumps from small increase in speed, I'd say on average, somewhere at about 78, 77% of your max heart rate is a good guy, and I think that is what, if you're going to look at calculators online or looking to the literature on a bit more detail, that's the sort of ballpark number it's going to give you, and that works quite well for me, and actually my Garmin zones do match up quite well, just incidentally from what I would, you know, generic Garmin zones match up quite well to what I would get lab tested at, but there's going to be some variability there, so it's a guide, but not perfect. You can use things like heart rate reserve, which have been suggested as being better, which effectively looks at, instead of like what's your max heart rate, it's what beats range have you got available to use, you can do max heart rate, minus resting heart rate, and say that range is 150 beats, then doing a percentage of that is maybe a better way of quantifying and controlling, the take into account like different factors there, and in which case I've seen a number of like 72, 73% floated around, which again sort of matches well for me, but I don't think that will be my first point of call, it would be doing things more obvious, like how hard does it feel? What's your heart rate doing? Is it drifting upwards? I'm the same for your effort, if your effort is drifting upwards as well over the course of that run, then that's a good sign that your physiology isn't stable and you're above your LT1, but good ultimately, if you're below your LT1, lactate, heart rate, RPE, that's all going to remain pretty stable over the course of an hour, 90 minutes. Of course, eventually you are going to fatigue and you're going to become glycogen depleted and heart rate is going to drift up as you can dehydrate it, but you should be pretty stable for quite a long time without seeing massive changes in just your perception of effort, let alone anything else. I think one final method to define it, or to find the top of your zone too, if you go run an evenly-paced 40-mile ultra, it comes out pretty much bang on from what the lab measures. So four and a half hour time trial evenly pace it and you'll get your LT1 from that. There you go, there you go. That's your side quest is to go and establish a field test for your LT1 four and a half hour time trial. Yeah, nice. And then at the bottom, we've already said there is no bottom to zone two, there's no way of defining it. It's sort of you just want a zone that's useful for you. So I don't think, I think if you're setting your Garmin zones, then yeah, I put in a zone two, don't just make it all the way down to walking, spit it up in the zone one, zone two, that makes sense, but then just choose a range, but it's actually going to provide some benefit to you when you're analysing your training. I would normally say something about 20 beats is a good range. If it's 10 beats, I feel like that's too narrow to be any use. If it's 50 beats, then that's just too bigger, a range to, that's probably going to encompass anything from walking, very slow jogging all the way up to running at a reasonable pace, what are you able to do? So I think 20 beats, I would say is a good ballpark off. You're talking about speed, like two kilometres an hour, like 30 seconds, 40 seconds a K, would you say something like that? Yeah, yeah, I guess so, yeah. I guess it depends how fit you are, doesn't it? If you push your RT1 up because you train in a certain way, then it's going to be a really big gap, I think. If you have a relatively weak RT1, then it's going to be a bit smaller. Yeah, I mean, I was going to add with the heart rate zones, I think this is where some trial and error and just some yeah, reflecting during and after a run. You start to instinctively know like, okay, you're running somewhere nice, you're not stressed. There's not much life stress and there's not much within run stress. You sort of know like, okay, this is really easy, this is nice, and then, okay, this is getting a little bit harder, it's still easy, but it's getting a little bit harder, and the boundaries probably, I think practically, somewhere in there, for me, in my head, if I'm in zone one, it's a real recovery run and there should be low physiological and psychological stress, but then if one of those is off, like, if I've had a stressful day at work, then yeah, my heart rate might be a bit higher and it's probably not going to be in zone one, it's still going to be easy, but I don't know, that's just the way I think about it is, is yeah, like if you are really nice and relaxed and enjoying yourself and not pushing, I think you do, you can figure out a useful place to put the boundary. I think the other thing just to add as well is like, again, going by heart rate, even 10 beats below, you know, 5 to 10 beats below LT1, and like, I've got it from lab measurements, so I'm fairly happy with where it is. Like, 5 to 10 beats below, you do still feel like you're pushing, like, you're not necessarily really hammering it, like, you would be right at LT1, but you know that you're still going through it, like, that's a fairly fast, easy run, whereas, like, another 10 beats below that, it should be fairly relaxed, I think. So, I think that's maybe just another thing to think about, it's like, okay, if you decide, if you decide 160 BPM is your LT1, and then you're going to put the boundary at 140, what's happening if you're running at 150 BPM? Like, what's that feeling like? So, not just thinking about the absolute, like, lines where you're putting these zones, but what's also happening in the mid, like, just the whole way across the zone, to be honest, like, what's your RP, how do you feel? What pace are you running? And just, yeah, thinking about the whole zone, not just the top and bottom. Yeah, yeah. I think people sometimes miss the zone in zones, in that it's, you know, it's an area and there's scope, even within that, you're breaking up a continuum, aren't you? Speed is a continuum from walking to maximum sprint speed, and you're dividing up into zones, hopefully using physiology to guide that because we have discrete physiological responses, dependent upon if we are above our threshold, below our threshold, between the thresholds, but even men, it is a continuum of speeds and we are going to be subtleties in, as we said earlier, like energy expenditure, carb, fatal gestation rates, muscle recruitment, obviously, the faster you go, the more muscle fibres you recruit, that is going to be true even within a zone. So it's definitely, it's still a crude method of breaking up intensity, really. Yeah, yeah, it's definitely not ideal, and I think that's maybe the other thing is, it's not, there's not a right answer. Not that necessarily, even, like LT1 is always going to be exactly right, like it's going to change day to day a bit, but you can be pretty certain with that. I think with this, it's just a case of just always going back and thinking about it, and that, you know, it's perfectly fine to change, slightly change the boundary that you set on the Garmin every few months. See, I disagree there. So my, my LT1 is consistently 155 beats per minute, and LT1, I think, yeah, I've seen the bottom, yeah, but I've, yeah, my, I've set my top of zone one at 135 beats per minute, at 20 beats below, and I can't change that now, because of age, because then I actually, that is fixed. If I'm going to do any training analysis, I'm not comparing like with like, so I want to keep that anchored to 135, which, if I was going to do it again, start again, I would probably put it a bit lower, because I actually don't go and spend much time in that 135 to 155 window. These days, I'm pretty much jogging at 120 every run, and if I go, if I get into the 130s, that is feeling like I'm working reasonably hard, and then if I'm doing a more harder long run, I might, I'm probably going to be around that LT1 area, or getting up to that sort of point by the end. But now, that's it, I've locked him, it's just been, it's been out for 10 years now, I reckon, so it's just going to be stay at that for me. That's my take on it. You can play around with it, but I, I just like to be able to compare across multiple training cycles, how much time did I spend them at different zones, even if it is an arbitrary number, I prefer to be consistent arbitrary number than just a constant moving target arbitrary number. But I do think one for me, like one through five, that is a meaning, I could go and spend a whole run in zone two without having to really think about it, and making sure I don't go into zone three, or dropping to zone one, so it's a usable zone, and there's also a big enough range in terms of paces, so I think, currently, if I was going to run at 155 beats per minute, I'm probably at 320 UK, and if I'm at 135, I'm probably at about 340, so maybe it's a bit too narrow, but yeah, so I think if I was going to go back and do it again, I'd set it 125 or 135, I think, but I'm too far in now, I'm too far in. Anyway, yeah, I'm too committed, let's move on then, so that's, that is how we would define it, zone two, although I still hate zone two. Let's now talk about trading adaptations, and I think this is the part of a podcast where maybe it gets a bit controversial, and I think there is a lot of nuance, but it's not understood that well, and what people think they know about training adaptations from zone two, on necessarily what the literature suggests. Do you think that's fair to say there's a starting point to this part? Yeah, and I guess everything we say that might be a benefit, like should have the caveat of there is really not much good research. It's either there's one or two papers, or it's sort of being inferred from what we know about it's siggling pathways and how they're measured from like heavy and severe intensity exercise, then being applied to the bits of research on zone two, or you know, so I say zone two, like a lot of the research isn't necessarily even on zone two, that's one of the drawbacks as well. So I think that's, that's, yeah, view everything through that lens, everything that we're about to say. Yeah, yeah, so I mean, I think a lot of the, I think the controversy isn't in, but what zone two, does and does not do, it's just in how effective it necessarily is at driving these adaptations. And there's no doubt that zone two, I mean, zone two of a minute, I think, is touted to drive mitochondrial biogenesis, mitochondrial efficiency, and there's some really big proponents of that, like an ego, Sam Malan, who used to coach Tadeh Pogaccia, Tour de France winner, if you didn't already know, multiple times Tour de France winner, he's massively into this zone two, and he's both a coach, researcher, practitioner in terms of, as a physiologist, and done some really good work with the, his PhD supervisor, George Brooks, interlactic clearance, etc. And they're really big proponents of the effectiveness of zone two to drive these mitochondrial adaptations. And that is true, they do drive mitochondrial adaptations, and that in turn is going to lead to performance advantages, it's going to allow you to burn more fat, it's going to allow you to be less reliant on your glycolytic system, so you just don't need to produce lactate because your mitochondria are sufficient to rely pretty much solely on oxidative phosphorylation, so carbohydrate and fat oxidation through aerobic means, and so you're not producing lactate, and you're not having to recruit those fast, which muscle fibers and not producing waste products, such as hydrogen ions. The controversial thing is actually how effective is zone two at driving these adaptations versus higher intensity. And there's a recent, well recent, when's it come out, in the summer of 2025, a paper that got a lot of publicity criticism maybe, but it was called much ado about zone two, and it was basically a, it was a narrative review that assessed the efficacy of zone two versus other intensity domains. And the main finding from this review, which has been echoed by lots of other papers is, but yeah, zone two works, but actually higher intensity works better. So in a, in a pretty much stepwise fashion, so you've got moderate intensity domains or below LT1, we've then got that threshold zone between LT1 and LT2, which is super popular for a minute, yet a matter is better at driving these adaptations than zone two work, but actually if you do more view to a max style training, so above LT2 and up to that view to max intensity, that was more effective at driving adaptations. And then sprint interval training, so work we doing a stuff above zone two. So scientists would call it extreme intensity domain training. That's not quite as effective as view to max type training as severe intensity domain training, but it's still much more effective than doing moderate intensity zone two work in quotation marks. And that's, people didn't like that really when it came out. A lot of the, a lot of both practitioners, athletes, it sort of goes against this idea of volume being super, super important. Yeah, and I guess, you know, in preparation for this, obviously like read the paper, and I don't know, like I was, I said to you before, like I thought it was a really good paper in terms of like they're quite clear, and maybe that's the benefit of a narrative of you as a paper type rather than like a meta analysis, but it is quite clear throughout, like yeah, it might do this, there's not really the evidence, and they do constantly talk about, well, elite athletes are still doing loads of zone two training. So obviously there's something to it, it's just not clear, yeah. Yeah, I quite liked it. I guess it's just the same pitfall that we talked about at the start in terms of if you really like boil something down, then you sort of lose all the nuance and, yeah, I don't know, the main sort of thinking and reasoning and the logic behind it. So, yeah, I guess, you know, yeah, if you read the, or if you see the paper, you see the abstracts, and then you say, oh, well, you know, my favorite athletes, Dan Nash is doing 200k a week, surely zone two is doing something. You're right, but I guess you miss it, what is it, missing the word for the trees or missing the trees for the wood? I think there's, there's some expression in there somewhere, yeah. There's, no, and like, you know, they say it throughout, right? Like, yeah, you, you get more, you get as a, as a single dose of, well, I guess a single under, you know, repeated dose of training, higher intensity does more, but this is maybe where we are skipping ahead a few episodes to, to the how to apply this, like, you, you can't do a view to max session every day, plenty of people try. You know, there's, there's the odd outlier that like, you know, the one that always comes up is, is nil is van the poll, right? The speed skater, which has some differences to running, but he was doing like five intense days a week, two days off. Um, you know, that, that got him an Olympic gold thing. And world record. Two world records. Yeah. So there is, there is other ways to do it, but, um, yeah, I guess again, like chicken egg, like, the, you know, all of the best athletes in the world, all of the best runners in the world are doing a lot of zone two. Um, is it, is it that they're doing it wrong? Or is it that science hasn't caught up yet? And then when you read the narrative of you and there's not much evidence, it's, yeah, chances are the science just hasn't quite got the answer right or clear yet. Yeah, yeah, 100%. There's definitely other things going on because elite athletes are doing lots of easy running and they wouldn't be doing that for no reason. I mean, one other paper that I think breaks this down quite nicely, uh, is this, I will blink at my show notes, but it's titled heavy severe and extreme, but not moderate and tense to exercise, increased view to max and thresholds after six weeks of training. And basically what they've done is they've got groups of 14 athletes, nicely, actually, half of them in each half of each group were women. So seven men, seven women, uh, and they did, I, but three times a week for six weeks, they did either a heavy, or they either did a moderate intensity zone two session, a heavy domain session, which is basically a threshold session, or they did, uh, there was two breakdowns about as well. So it was a low heavy, and then a high heavy, so basically closer to LT1, but above LT1 and then closer to LT2, but below it. Uh, then there was a, a due to max type training session, which was between LT2 and the U2 max, and then there was a sprint in school training. So I think there was 84 participants by maths is right there, uh, which is a big old study. And after following the programs for six weeks, there was a stepwise progression in response, both in terms of VL2 max, but also that, that, uh, maximum metabolic study state as well, and that the ones who have the biggest response were those who did the high intensity interval training. So it went back VL2 max type zone, and they had a 6.2 mil per kilogram per minute increase in VL2 max, whereas the moderate had a 1.8, which is probably not statistically significant. I may be just on that borderline. So moderate did work, just actually it was only, um, it was three and a half times less effective than doing high intensity training. And I think you'd probably expect that with VL2 max because we know that VL2 max is a cardiovascular measure of primarily. It's more to do with pumping capacity at the heart, but the same was true of maximum metabolic study state. So the thresholds where they sit was more improved by doing VL2 max type training than it was by doing threshold training. And people wouldn't normally go on and improve my thresholds by doing VL2 max work, but actually it's just that the stimulus is bigger. Uh, and the body is very clever in, but these signaling pathways are all linked. And I would say at the most broad sense, but there is really just a couple of signaling pathways, but all wrapped together. And it's basically this isn't, we need better endurance. We're going to switch on this signaling pathway, which is going to drive mitochondrial biogenesis. I increased in, uh, fat oxidation enzymes, increase, increase include glucose transporters, increase in lactate transporters. They're all sort of stemming from this one signaling pathway. And so we want to, if we, if we need more endurance, we're going to switch all of them on. And that's, uh, and any, any high intensity endurance tape based activity is going to turn that signaling pathway on to a greater or lesser degree. So it does make sense, but even VL2 max type training could increase our fat oxidation rates, for example. And that's been, I've I've been showing them a literature multiple times. Doing sprinting is full training. It's been shown to increase fat oxidation rates. So doing, uh, wing gates four times 30 seconds as hard as you can with three minutes rest, but it's been shown to increase fat oxidation rates, probably in a lesser well-trained population. And someone who's already, um, probably needs someone who needs a bigger signaling response than just two minutes of really hard work, uh, but it has been shown. So there is a connection between all of these intensity domains, uh, I've lost where I was going with that. But, uh, I was going to jump in and say, so, so not to like, I, I, I read this paper as well. I think I've read it before as well. And, you know, it's, it's a, it's a really, really nice light and really intensive piece of work. I think us, um, something we say about a lot of sports science research, isn't it, um, knowing how much it takes to do? But, um, I guess, I guess to, um, to not counterpoint it, but to say at the same time, each group was work matched. And it was three sessions a week. Um, and I guess like my, my response, like, you know, the, the paper is high in, um, in, uh, internal validity, I'm trying to remember my validity is now, and it's low in like ecological validity. So internal, internal validity is that, like, you're, you're measuring the groups. I've done a similar amount of work because that work matched. So it is possible to compare them. But if, if you said to me, oh, I'm going to, like, if you, if you said, I'm, I'm doing this new training plan, I'm going to run, uh, well, they were cycling, but you know, I'm going to do three times a week, 50 minutes, easy cycling. Like, you know, that's not going to get you fit. Like, you, you know that you could do, you could do that, what, you could do 50 minutes twice a day. Sort of thing, not with at least 24, like they had 24 hours between sessions and a 48 hour rest per week. That's not how, that's not how runners train. Whereas if, if you said, oh, yeah, three times a week, I'm going to do two max intervals. I'd be like, well, that's a lot of work. And like, I wouldn't raise my eyebrows as much if you said, I'm going to take a day off in between the sessions. So I guess you just, you just, like, you know that like, their work matched, but they're still quite different. Um, and they're not, that's not how you would train, right? Like, you, you, you know, because, because you are keeping the intensity really low in the, um, in the, you know, zone two, or in this case, the moderate, um, intensity group. Like, that just means you can do more work. Like, and a substantial amount more work. So yeah, it's like, you know, like I said, it's so really like, it's, it's the type of work that has to be done. Um, but I guess there's always going to be the responses. Well, it's not got, not good ecological validity. Yeah. Because that's not how runners train. So yeah, and just to clarify on how they've matched it, it's matched to kilojoules of work. And I guess in the sense, if you were going to think about in running terms, it would be, well, you're going to do the same amount of energy expenditure, the same amount of distance effectively, because you don't, it takes pretty much the same amount of energy to run a kilometer in four minutes as it does three and a half minutes or three minutes, broadly, depending if it's the same person running it. So actually, you could effectively think of doing, well, of course, if you're doing 20k a week of easy running, well, 20k a week of harder running, he's going to give you a bigger, bigger, a bigger and better response. Uh, so I think it's, I think it's a good paper. And it tells us a lot about what really can drive adaptations, but it's how you're going to apply it to the real world, which probably brings us onto our next section, then, uh, of, I, why do elites do so much their own two stuff of his rubbish, basically, which have alluded to already. Uh, and we started talking about it, but it's obviously, but, you know, you've said, I'm doing 200k a week. And in our rotablensis series, both we all documented that we were doing pretty high volumes and 90% of it was easy-marriage below LT1. And that block went pretty well for all three of us. And my training hasn't changed very much really over the last five years on a, on a macro level. And I've had a lot of success from high volume. So it's not just the world's elite, it's sub elites and a lot of our training philosophies are well, as well, based upon volume, I would say, it's been a key part of it. No one is, I definitely wouldn't be in the camp of, yeah, you can, you could get really fit doing 20k a week. So we know from just looking at what people do, but we need easy running as part of our training. Yeah. Yeah. I get, you know, come out, like keeps saying that chicken and egg, right? Like, there's, there's a reason people are doing it. Um, and I guess, I guess also, um, as, as running's become more popular, sort of, everyone's almost like converged to the same point, like it, you know, historically, you think about like Zatapek doing, was he doing like 40, 40, 200, so 40, 400s or whatever it was? Was he, he was doing doubles as well, right? Was he? I think, yeah, you know, in, in, in army boots, right? Yeah. Like a, um, a dirt track. Yeah. That was, you know, at one extreme and then at the other extreme, you had people just doing easy running and they still ran the same times and, you know, I think we would know if there was people in, you know, the 5k 10k final at the world champs that were doing 20 by 400 twice a day, multiple times a week. But there's not like they're all, um, they've all sort of gone the same direction. So, yeah, I guess there's a survivorship bias in terms of that's, that's what's happened. Um, just a natural evolution of training, isn't it? People aren't going to keep doing things, but don't work. Um, we've got to this point where most people are following not exactly the same program, but broadly the same, but there's a good chunk of easy running in there. I, you know, we've, everyone's heard Stephen Siler talking about polarized and pyramidal training approaches and there's a, you know, most of the training is easy, some of it's moderately hard, some of it's quite hard and that's pretty much much what people are doing and normally they go in hard two or three days a week. I'm not going to say sessions because we've got double threshold now, but typically two or three days a week a hard and the rest are easier days and pretty much everyone is following that plan. Uh, so there's certainly an emphasis on the easy running and I'd, I'd, I'd, I'd say if anything, the direction is going in higher volumes, not lower volumes. So why is very mismatch, a potential mismatch between what the science is saying and what we see with our eyes when we're looking at running in a wild. Yeah, and I guess, I guess it, you know, at least part of the answer is, is a theme that we've talked about with other episodes, isn't it? That's, and what we said a minute ago, it's really hard to do research and you're, you're maybe manipulating one or two variables and measuring the difference and actually there's, there's tens, if not hundreds of variables a week for a runner in terms of intensity, duration, um, of a, of a single run and the week as a whole and then how that week interacts with the next week, um, that you're constantly manipulating and you can't really capture that in, in research, it has to be, you know, like we just said with that paper, you, really, you have to work match a group to compare them, you, you know, you can, you can be a bit more ecologically valid, but it becomes way harder to do the analysis and you sort of them wonder like, okay, is there something that's causing the difference that we're not measuring? So it is, you have to be really, really controlled and very gradually make process or make progress and ideally, you, you know, Dan does a paper and then someone else, even does the exact same paper or does it slightly differently, but is essentially measuring the same thing to sort of validate Dan's work and that's, that's the progress that science makes whereas if you have a group of 20 runners you're coaching, um, you can, you can slightly manipulate the variables and you can just, oh, this is like, and just change it sort of thing whereas you can't do that midway through a paper that then takes you six months to write afterwards. Yeah, unfortunately, well, fortunately, um, scientific papers to be good and I need to be very precise with the question they're asking, but unfortunately, like you said, there are so many variables in, but go into constructing a training program for an athlete and what is optimal for them that you can never encompass all that into a study because studies only work when it is right, asking a very precise question with a very limited range and focus. Otherwise, they become, they just don't have a statistical power to answer a question really and they can't be that conclusive with the answers. It just becomes, and I've done papers like this before, uh, and I think I would change how I'd approach research if I was going back into that world, but you just end up with more questions than answers, which, you know, maybe that is science, but it shouldn't really be. You should come out of the other paper knowing, knowing more about an area, not less, which is, uh, how often I've felt when I've, I've got something published. I guess I'm not. Yeah. I was going to say, you know, there is, there is some case studies out there as well. I know, I know a few journals are pushing a bit more for case studies, so maybe we'll see more and at least, um, at least you were, you know, we're with a case study and like we're always going to mention the pool of adcliffe case study that, um, Andy Jones wrote. I, yes, it's, it's one person's training, but the measures through that through a high level athletes career are pretty decent, um, and you, you know, you have a pretty good idea there of what, what was happening and the changes that were being seen, um, you know, across someone's whole career and I think that is, that's a really good resource. There's not, there's not loads of them sadly. It's sort of a shame because I think that's, um, yeah, quite, quite interesting. I don't know, you could call it like temporal data in terms of, you know, just these changes over time. Um, that maybe, maybe it's being missed. Yeah, maybe, maybe, yeah, maybe it would have been cool if, if someone had been able to write that about like, Kipchoge, across, you know, the last 20 years of his career. Maybe it's coming soon, but, um, yeah, just, just, just to see it and, and it's a bit more objective, um, in terms of, you know, like, yeah, you could, you could just list pool of adcliffe's times and, and say, okay, well, well, here's, here's the progress, but actually with that paper, you have the three determinants of performance, there's, there's maybe, you know, a fourth for the marathon, especially, um, and how they've changed over her career. And that's, that's also really useful as well. I think in terms of saying, like, okay, like, you know, she did loads of easy running blended with other things, but, you know, this is the change in her measurable variables that we saw across her career. And, yeah, maybe some more that would help as well. But, yeah, there is a few case studies, I guess, to see. And you can sort of infer from them, can't you? And that's the problem, though, isn't it? You're always in furring and going, well, Paula, I lifted high volume and her economy got better, so it must have been the high volume, but she also did string for plyometric training, so maybe the volume did nothing, and it was string for plyometric training that really helped her economy. And maybe that was just unique to Paula. And actually, if someone else followed a similar approach, they wouldn't have the same response. And that's why case studies are really interesting. And I love the case study, but also it's, it's, you can't change the world with a case study either. So, we're getting a little bit sidetracked, I think. I would say why, I think before we started recording, oh, I and I was discussing that a lot of the reasons why easy running is beneficial, because I don't think any of us are going to disagree that it is beneficial in a necessary part of your training, but the why is less clear, but I think we can have some pretty good guesses as to why it is a crucial part. And I'm going to start off with the first point, but even in those studies we mentioned before, easy running didn't do nothing. It was still adding to the training adaptation, and it was still giving a response. It was just less per unit of time than high intensity training. So, if you want to maximize your potential, you want to maximize the adaptation response. Matt is going to come from, yeah, doing the intensity, but also doing a lot of the easy. Yeah, and maybe it's a case of thinking about your training as, although they all interact, but almost discreet training. If you do a hard session on a Tuesday and a hard session on a Friday, like those are discreet, and then the rest of it's the easy running, and they do fit together, but actually it's like different things as well. I guess there's maybe one way to think about them. They do link together, but you have the dose of hard running that you think you can take across those two days, and I guess we'll talk about that more when we talk about heavy and severe intensity domains and intensity and time interaction, but you have those, and then you have your easy running, and okay, how much of that can I tolerate across the five other days? Is one way to think about it as well? Yeah, absolutely. And I think also we've discussed the story already, but I think that a lot of studies do easy running and disservice because of that matching for workload, because in reality, you can do so much more easy running than intensity, and there's obviously going to be a limit to how much intensity you can add into a program, especially in a sport like running, where it is your load, your loading, your weight bearing, there's high impacts, and that is going to have more than just a metabolic response, but a mechanical response as well, whereas easy running, which brings us on to one of the other points I had written down here is it is low risk. People don't tend to get injured from easy running. I mean, you could argue maybe stress fractures, but most of the time that is more energy intake issue, rather than an energy expenditure issue, I would argue in most runners, and people aren't pulling the hamstrings jogging around. Most of the injury is coming from high intensity training, so it is low risk, so it means you can do high volumes of it, and you can also do high volumes of it for a long period of time, and so that is going to stack over months years, but adaptation response in the long term, I think it's the easy running, but it's going to make the biggest difference to your fitness, rather than the intensity. Yeah, like you said, I just looked at my night, I did 86% of my running before Valencia is easy running, so that's, you know, orders of magnitude higher than the more intense running. So yeah, you can just stack so much more, and that's what's being missed in the, I guess in research, is they're not, as far as I'm aware, there's not a paper that has someone doing, you know, two hours a week of heavy intensity excites, and eight hours a week of easy in comparing it, but maybe the response is closer when you get to that sort of number, or that sort of, yeah, dividing up of time between the zones. Yeah, and I also think there is a, I knew we were saying they were discrete, like easy running and your hard running, but I think the easy running compliments for harder running, but you're going to build structural and probably metabolic resilience through doing easy volume, that is going to allow you to handle more intensity. So I know that if I try to do some of the sessions in the days that I do now 10 years ago, I wouldn't be able to walk for the next day, I would be broken, but now I can handle it this morning, or today, for example, I did 15K a morning with a 309K, with a warm up and cool down, so that became 23K for the morning, then in the afternoon, I went on a treadmill and did five times six minutes, going around three minute a K pace, and that became 16K, so I've done 39K of running with, what was that, about 25K of hard running in there, but I'm confident that I'll be able to get up tomorrow and do a double day and probably run for two hours of easy, two hours of easy duration, well below LT1, probably zone one, and be fine, but obviously some of that resilience has come from intensity, but you need to first be able to run for two hours easy before you can think of a day which is two hours with intensity in there, I would argue, and I think the easy days are really good for building that more structural resilience in terms of bone mass, your tendons and ligament strength, you could get that from strength training, but not in the specific way, and you see this when you're a cyclist, it's really fit, they've got a great view to your max, they've got good thresholds, and they try and run, they're not, it comes to something like a marathon and they just break down. Yeah, and I guess you would look at them and you'd say okay, if you're coming from long, long duration cycling, a lot longer than any of us run, you should be able to handle those long metabolic or metabolically challenging long duration efforts, but it's actually a musculoskeletal failure. I don't know if that's the right word, we sort of talked about this before, didn't we? We don't know what the actual term for tendons and ligaments and bones, bones can't handle it. I think that's good, I like that. What did you say, musculoskeletal failure? I think that's a good term. So yeah, definitely that, and I'm running economy, I think is linked to that. Running is a skill, and the evidence does suggest that actually we just get more economical as we do more years of training, and most of that training is going to be easy, so my bet would be that it is the volume that is important for driving those adaptations rather than the intensity. Intensity is going to help economy, and I'm not going to deny it, I'm not going this to pretend it doesn't, but I imagine but for that longer term increase, how much you're running, probably is really important. There's case studies going back to case studies, there's case studies of masters athletes who have got world class running economy, and they're in their 60s and 70s. So it's not something, I think it's something that you can accumulate and maintain just by running for a long period of time. Should we leave the people with some takeaways? Yeah, yeah. I think we're ready for that, yeah, I think we're ready. So how would you then decide upon how much easy running you're going to put into a week? Yeah, how would you structure a week based upon what we've talked about? So I think it's looking at your harder sessions, so those one, two or three sessions a week that are going to be above LT1, so not easy running. It's programming those and then fitting the easy running around it to not take away from them, but like maximize the amount of easy running that you can do. I think if we're talking in an optimal, we're not bringing in work, life factors into it. You plan your harder sessions and then the easy running that can realistically fit around it and based upon your training experience and training age and how much you've done recently. So we're not saying like go from like 60k a week to 200k a week next week. There is a building up element, but yeah, start with the hard sessions because they are the most important thing if you're just looking at the value that like one thing, one session in a week gives you and then fit the easy running around it. I think at the same time like we're not saying that you just got to smash loads of hard sessions, that's what'll make you fit. It's the blend of all of them. That's the most important thing, but in terms of structuring a week and how you balance own two or easy running and harder running, I think fit the harder running in first and then there's the easy running around it. Yeah, 100%. I think it's prioritizing those harder days and knowing what you want to do on those days and then going, what do I need to be able to execute and perform at the right intensity on those days? Because we've all turned up to sessions, I certainly have, excuse me, where you've gone to do your race specific 10 by a K at 10 K race pace and there's just nothing there. You're just too tired, you're too fatigued, you've done too much for a day before, probably too much volume in a week before and it's all caught up with you. And if you've not, I'd be able to execute your session, then that is most likely a planning failure in, but you did a bit too much, which is fine, or if it's a one off, you then learn from Matt and go, right, I need to put, make some adjustments here. But if you're never actually hitting the intensity as you need to in your sessions, because you're just doing too much training, then that is an issue. So the easy running is really important, but you need to get that intensity in. And if you're doing too much easy running, that's not going to make up the missing your harder sessions. Does that make sense? I think so. Yeah. Yeah. And that's how I, how I work. I choose a Friday. I want to be able to, in a normal training block, I'm going to choose a Friday. They're my harder sessions. They are the priority. And I want to get as much volume in as I can, but I still want to be able to do those sessions. And normally very warning signs aren't there, but if you're following a similar pattern each week and you notice that actually it was pretty hard to get through that last session, you did it and you got your heart rate where you wanted it to be and the splits were all right. But the next session, it comes around and actually just can't, you can't get the heart rate up. The splits are way off. You just can't actually put out that intensity. That is the sign that you're doing too much easy, and put it back a bit. So my recommendations always actually start off with a hard, be conservative of the easy days and then just build it up over time. And then you can monitor what your tipping point is in terms of when does it start to interfere with the harder days. And that will change over time as well. Your tolerance for training volume is going to improve. But you don't want to sacrifice the intensity for the duration, because both are important, but the intensity is especially important. Yeah, and I guess, I guess previewing what's to come down the line, but then we'll talk about the intensity and how you balance that in, I don't know if it'll be the next episode, but an episode soon to be released. Yeah, yeah, we're definitely lots more to talk about. I just, I just think the mix. I was going to say as well, just that, you know, we talked about like takeaways in terms of like training prescription, but I think the other things I thought about in terms of like if you see people or just things to bear in mind if you see zone two, and I guess maybe it sort of sums up what we've talked about by is there's not, there's not a scientific definition of zone two. So that's the first thing. So if you say, if you see someone saying science says this about zone two, like it's probably not actually saying that about zone two will be talking about moderate intensity exercise, which is different, which is different. Income says a lot more than just zone two. And because of that, because there's no definition, that means that people use different definitions of it as well. So it's not a, yeah, like we said, it's not on agreed upon zone, like in the same way that the zones used in research are. So it's just something to bear in mind when you, yeah, when you hear or see, you know, see an Instagram reel about zone two. And then also there's, there's not much research. No, no, no, it's definitely, it's something we're still learning about, isn't it? And I think I can't see us developing a lot of knowledge in this area very quickly to be honest, because it is a hard to, it's hard to study because we're also in the interaction of things. But one thing before we do wrap up that I wanted to cover, and I said we would at the start of a podcast was I personalization. So how does zone two, or how much zone two training you should do? Or how does it fit into a week for someone who's doing 200 K versus someone who's doing 30 40 K a week? And I think actually that is where the science does give us some good answers. And but to an extent, you probably can compensate with intensity versus duration. And so, yeah, obviously to really maximise your potential, you need high volume training and lots of intensity. But if you are someone who's can only run four times a week, then I would probably be still doing two harder sessions a week, as long as you're able to tolerate that, you're not getting injured. And you are, you're ready to handle those loads. That is probably going to be more powerful than going, I need to do my zone two. So I'm just going to do four days a week of zone two work. Or maybe you go see inside or go right up on 80% easy, 20% hard. So three easy sessions, one harder session. You can maybe do you can actually maybe do a bit more intense in there. The other thing I would say about your easy days is, but if you are time limited, then you probably can push those easy days a bit harder, especially if you know exactly where your LT1 is. So you can push that up at your easy days closer to LT1. Whereas if you're doing 200K a week, or if you're Jake Barraclough doing 280K a week, then you need to be so far away from LT1 to be able to get through the mileage. Because if you tried to do that in zone two, whatever that means, you would just be putting too much strain on your body, both from an energy availability standpoint and a glycogen standpoint and a loading standpoint. So I do think there are, I think science often gets poo-pooed for not giving us clear answers, but I think it can guide us in some direction and help us answer some of these questions. And I think a wrap up from this is, intensity is really important. But easy running needs to complement that. I mean, you need to work together to really get the most out of yourself. Yeah, yeah, I'd agree. Yeah, they interact, don't they? Oh, yeah, 100% they interact. It's definitely going to be, I think they complement each other. You can't have one without the other. There's no way we're going to go back to a time where people just do intensity or they just do volume. And I think the secret to mastering your own training is just finding that balance. If someone is doing just intensity, let us know because we do, we work it well for you. We're not broken all the time. We would love to hit it, but most people aren't, are they? That's, yeah, we sort of figured it out with enough bodies thrown against the wall in terms of how to train properly that they have a pretty good idea, and it's just that the new wants for each individual is the margin that everyone's in now. Yeah, definitely. So I hope this has been an insightful episode and it's given you some questions, but I think we both agree that if you've got questions coming out of a podcast episode or it's made you think that's the sign that it's been good. Hopefully we've been able to follow along with our ramblings, and then yeah, I didn't look out for the upcoming episode for the next few weeks and months where we're going to dig into other training zones and intensity domains and clarify what the literature says on what that can provide you with. And we've sort of laid with foundations, I think, with this episode, but basically just trying to work through all the training zones and how that should be incorporated into your week and probably dependent upon, we haven't even talked about different events that someone's training for here, or we haven't talked about older athletes, which is still an episode we want to do, but we're trying to get a specialist on who knows a bit more about that area than us, but there are so many frameless that you could look through training zones in, but I think just trying to cover them over the next few weeks and months. Look out for those episodes if you've enjoyed this one, and hopefully by the end of that series, you'll have a better understanding about intensity and just structuring your week to really optimize things for you. So thanks for listening, I hope you've enjoyed, and we'll catch you again soon.