Am I Doing Zone 2 Wrong

Zone 2 training is low-intensity, aerobic-base running — but the hardest part isn't the science, it's one simple question: how do you actually know when you're in Zone 2?

Most runners rely on the heart rate zones their watch hands them. The problem is those zones are built on an estimate of your max heart rate that can be off by 40 beats per minute, which throws the whole calculation off.

In this solo episode, Evan breaks down what Zone 2 actually does for your body, why your watch is probably getting your zones wrong, and the no-gadget “talk test” that's more reliable than the numbers on your wrist. He also shares what nine weeks of real Zone 2 training did to his pace — and the injury that taught him to build smarter, not just faster.

What you'll learn:

•  What Zone 2 is doing inside your body (mitochondria, capillaries, and the aerobic base)

•  Why “220 minus your age” makes your watch's zones unreliable

•  The talk test: how to find Zone 2 with no watch at all

•  How much Zone 2 you actually need at your weekly volume (and why 80/20 isn't a universal rule)

•  Why your heart rate spikes on hills — and why that's fine

•  How long Zone 2 takes to work, with real before-and-after pace numbers

•  The cardiovascular-vs-structural trap that led to an Achilles injury — and how to avoid it

Evan isn't a doctor or a coach — just a runner who reads the research and shares what he finds. Nothing here is medical or training advice.

Studies referenced:

Storoschuk et al., “Much Ado About Zone 2,” Sports Medicine (2025): https://link.springer.com/article/10.1007/s40279-025-02261-y

Persinger & Foster et al., the talk test and ventilatory threshold, Medicine & Science in Sports & Exercise (2004): https://pubmed.ncbi.nlm.nih.gov/15354048/

Nes et al., max heart rate accuracy, The HUNT Fitness Study, Scandinavian Journal of Medicine & Science in Sports (2013): https://onlinelibrary.wiley.com/doi/10.1111/j.1600-0838.2012.01445.x

Mølmen et al., mitochondria and capillary growth, Sports Medicine (2025): https://pubmed.ncbi.nlm.nih.gov/39390310/

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Until Next Time: Just Keep Running

Transcript

SPEAKER_00 0:00

Yes, I can speak a nice little sentence without having to stop for breath. I said that out loud to myself on a run. And then I needed about four or five breaths before I could say anything else. That weird little experiment, answering out loud a question that I had asked myself in my head, that's how I know when I'm in zone two. And if you've been confused about what zone two actually is or whether you're even doing it right, you're not alone. I was confused too. And honestly, I'm not sure I was doing it right until pretty recently. Welcome to Just Keep Running. I'm Evan Blakeney, and today we're talking about zone two training. You've probably heard about it. It's all over running podcasts, YouTube, Instagram, Facebook. Every coach and every algorithm is pushing it right now. I heard a lot of people talking about zone two, and while I was able to understand the concepts and what I was trying to do with zone two, the actual execution part wasn't quite so clear. People would say things like, run at a conversational pace. And then I'd be out there on a run wondering, okay, but what does conversational actually mean? Because I'm clearly not able to chat the way I would sitting on my couch. Or they would say, most of your miles should be easy miles. But what does most mean in that situation? Then I'd hear the 8020 rule and think, okay, is that like a hard and fast rule? How am I actually supposed to apply that when I don't have a lot of time to train? Nobody was answering those specific questions. So today I want to have the zone two conversation that I actually needed someone to have with me when I was starting out. We're going to talk about what it actually is, why your watch is probably getting it wrong, how to know if you're actually in zone two without any fancy equipment, and what nine weeks of real zone two training did to my pace. But before we dive in, I want to be upfront about something. I am not a doctor, I am not a coach, and I don't have any credentials in exercise science. I'm just a guy who knows how to read and has access to the internet. Everything I'm going to share today is either something that I found in my own research or something that I experienced personally. I am not here to tell you what to do. I am just here to show you what I found and share my own experience. Hopefully it's helpful, but please don't take anything that I say as medical or professional advice. All right, with that out of the way, let's start from the beginning. Let me back up a little bit and tell you how I even got here. I got back into running not too long ago. I had taken some time off, and when I came back, I decided that I was going to train for a half marathon. There's actually a lot more to how and why I got back into running, but I'm going to try to save that for another episode. The short version is this. I was putting in the miles, I was making progress, but I was mostly just running by feel and assumption. I didn't really have a structured plan around intensity. I was running as hard as I could for as long as I could every time I went out for a run. It wasn't until I started reading some books and researching a little bit that I realized I should have been building an aerobic base from the start by running a lot more zone two miles. And once I understood that, I decided to take a step back and do it right. But then came the execution problem I mentioned. What is zone two exactly? How do I actually know if I'm in it? Most watches, whether it be a Garmin, an Apple Watch, a Koros, a Samsung, whatever you use, they all use what's called a five zone model, where zone one is the easiest, zone five is an all-out sprint, and zone two is on the easier end of the running spectrum, roughly 60 to 70% of your max heart rate. That sounds simple enough, except there's a problem. That calculation starts with your maximum heart rate, and your watch almost certainly doesn't know what your actual maximum heart rate is. Most watches use a formula called 220 minus your age to estimate your maximum heart rate. So if you're 35 years old, your watch takes 220, it subtracts your age of 35, and assumes that your max heart rate is 185 beats per minute. The problem is that that formula has a standard error of plus or minus 12 beats per minute, which means your watch could be off by 12 beats per minute in either direction. And for older runners, it can be off by as much as 40 beats per minute. That's right, 40 beats. That's not a rounding error. That is a completely different zone. And here's the thing: every single zone on your watch is calculated off of that one number. So if your estimated heart max heart rate is wrong, your zone two range is wrong, your zone three range is wrong, all of it is wrong. Now, I'm not telling you to go throw your watch in the trash. I use my my Garmin 4Runner here on every single run, and I love it. But I am saying that you shouldn't treat those numbers like they're the gospel because they're built on an estimate. And as we'll get into in a few minutes, there's actually a much more reliable way to know if you're in zone two. And it doesn't require any watch at all. And honestly, it's not really your watch's fault. It's just trying to use an estimate that works for the whole population. But heart rates are wildly different from person to person. For instance, my resting heart rate sits around 54 beats per minute. My wife's resting heart rate is around 78 beats per minute. Same house, same diet, same lifestyle, completely different heart rates. So not only is your watch working off of an estimate, but even if it wasn't, you still couldn't compare your heart rate numbers to anyone else's. Your zones are yours alone, and nobody else's numbers mean anything for you. And by the way, it's not like your zones are hard line set in concrete like a running watch might make it look. Your body doesn't even know what your zones are. So if your watch is telling you that your zone three starts at 130 beats per minute, it's not like your body hits 130 and says, oh, I'm in zone three now, I have to stop making aerobic adaptations. Those adaptations taper off as your heart rate increases. You're gonna get more of them when you're in zone two, and you'll get less of them the further and further away from it you go, but they taper off gradually and all the zones overlap with one another. It's not a strict on and off switch. Now, before we get into how to actually know if you're in zone two, I want to take a step back and explain what's actually going on in your body and why so many coaches and runners swear by zone two. Zone two training is essentially training your body to become more efficient at using oxygen and fat as fuel. When you run at low enough intensity, your body relies primarily on your aerobic energy system, meaning that it uses oxygen to burn fat for fuel. And the more you train in that zone, the better your body gets at doing that. The main adaptations you're chasing here are mitochondrial development and capillarization. Mitochondria are basically the little powerhouses of your cells. They're responsible for producing energy. Zone two training causes your body to produce more of them and make the ones that you already have more efficient. At the same time, your body is also growing more capillaries, which are the tiny blood vessels that deliver oxygen-rich blood to your muscles, which means oxygen can be delivered more efficiently. So more mitochondria plus better oxygen delivery equals more capacity to produce energy aerobically. And for us runners, that means you can run faster at a lower effort. Now there's a specific physiological marker that sits right at the high end of where your body performs those aerobic adaptations. It's called the first ventilatory threshold, or VT1. That's the point where your breathing starts to shift, specifically because your body starts producing more CO2 relative to the oxygen it's consuming, which triggers your brain to increase your breathing rate to compensate. And when that happens, it becomes noticeably harder to speak comfortably. Below that threshold, you're maximizing those aerobic adaptations. Above it, you've crossed into higher intensity work. I'm going to come back to that in a minute because it's actually the key to the most reliable way you can know if you're in zone two. And one more thing that I want you to know about zone two is that it is a long game play. These adaptations don't happen in a week or two. Research shows that it takes about eight to twelve weeks to see noticeable gains. And the real compounding benefits happen over months and years of consistent training. This isn't a quick fix, it's a foundation. And the runners who take the time to build this foundation are the ones who keep getting better and better long after everyone else has plateaued. So now that we know what zone two is doing for your body, the next question is how do you actually know if you're in it? And that starts with understanding why your watch is probably getting it wrong. So I promised you a more reliable way to know if you're in zone two without relying on your watch's zone calculations. And it is called the talk test. Now, you've probably heard the phrase conversational pace thrown around a lot when people are talking about zone two. And when I first heard that, I thought, okay, conversational. Like I can just chat normally when I'm running. So I'd go out for a run and I could say a short sentence or something like that, but I couldn't just talk without stopping the way I would in a normal conversation. So I wasn't sure if I was actually in zone two, even though the pace felt pretty easy. Because saying a short sentence here and there is not the same as having a conversation. And that confusion is actually really common because conversational pace is kind of misleading. Truly conversational, like sitting on your couch talking to someone, is actually too easy. You're probably not even in zone two at that point. But the research shows that the point where speech first becomes difficult is right at VT1, that threshold we just talked about. So the real target is somewhere in between. Effortful, but not labored. So here's the actual test. Can you speak one full sentence without stopping mid-sentence to take a breath? If yes, you're in zone two. But if you can talk completely freely with no effort, you're probably going too easy and you're in zone one. And if you can't even get through that full sentence without stopping for air, then you're above zone two. Which brings us back to where I started. I asked myself in my head if I could speak a sentence. So I answered myself out loud. Yes, I can speak a nice little sentence without having to take a breath. I got through that whole sentence, and then I needed a few breaths to catch up before I was able to talk cleanly again. And from what I understand, that's exactly where you want to be. It's effortful, but it's not so labored that you can't make it through the sentence. So between the talk test and understanding that your zones aren't that exact, you've actually got really everything you need to start running zone two the right way. But knowing what it is and actually putting it into practice are two different things. And when I started doing that, I ran into a whole bunch of questions. Some of these questions I had personally, and some of them are questions that I saw other people asking in places like Reddit or Facebook. The first one is the most obvious. What pace should I be running in zone two? And the fact is, there is no universal zone two pace, because zone two is not a pace. It's an effort level. Your zone two pace depends on your current fitness level, the terrain you're running on, the weather, how well you slept, how much stress you're carrying that day, how you've eaten, how hydrated you are. All of that affects your heart rate and your effort level. That's exactly why the talk test is more useful than a target pace or your watch, because your pace will change constantly, but your body's response to the effort stays consistent. What I can tell you is that when I first started doing real zone two training, I had to slow my pace way down into the 14 minute mile pace on a treadmill. And if I had started doing zone two training at the beginning of my journey back into running, like I should have done, I probably would have had to do some run walks just to stay in zone two. I don't think I could have just run straight. And honestly, I'm not embarrassed to say that, because that's just where my fitness and my aerobic base actually was. I wasn't as fit as I thought I was. I was just really good at suffering through hard efforts. And it turns out that those are not the same thing. The next question I had was how much zone two should I actually be doing per week? And this is where the 80-20 rule comes in. You've probably heard of it. 80% of your miles should be easy, 20% should be hard. And on the surface, that sounds simple enough. But here's the thing I didn't come across when I first heard about it. That rule was built for people who are running a lot. And I mean like a lot, a lot. We're talking elite runners who are putting in 15 to 20 hours of training per week and maybe more. When you're running that much volume, doing 80% of it easy makes total sense. Your body needs that recovery, and you're still getting plenty of hard work done in that remaining 20% because the total volume is so high. But most of us are not running 15 to 20 hours per week. If you're running four or five hours a week, that's pretty normal for a recreational runner. Applying the 80-20 rule really strictly means you're only doing about 45 to 60 minutes of hard work per week. And that might just not be enough intensity to keep making progress. So here's a rough framework that I think might be more useful. If you're running 15 or more hours a week, then 80% zone two makes perfect sense. If you're running five to 10 hours a week, something closer to 60% zone two is probably more appropriate. And if you're under five hours a week, you might be looking at closer to a 50-50 split. But I do want to be clear, these are not hard and fast rules. They're rough guidelines that I myself put together based on the underlying principles I found in the research. They're not specific numbers from any one study. The point that I'm trying to make here is to be thoughtful and intentional about how you're structuring your training so that it fits your life and it still gives you the progression that you're looking for. So don't just go apply these percentages that I'm throwing out blindly. Pay attention to how your body is responding and make adjustments based on how you're feeling and how you need your training to fit your life. Another question that I want to address is why does your heart rate spike when you're going uphill? And does that mean that you're out of zone two? And the answer goes back to what we've already established. Zone two is an effort level, not a pace, and hills require more effort at the same speed. Your heart rate is going to spike on a hill because your muscles are working harder to push you up the hill. That's just basic physics. So what do you do about it? You slow down. Or if you need to, you even walk. And I know that can feel really defeating, especially if you're in the middle of a really good run and you're at a great pace that you're proud of and you're excited for your friends to see it on Strava, and then you hit a hill and you end up having to walk, and now you're embarrassed for your friends to see your pace on Strava because it went way down just because of this stupid hill. But here's the thing: walking uphill to keep your effort in zone two is not cheating and it's not a failure. And even I still have to tell myself this all the time when it happens. You're still training, you're still moving, and you're still getting the adaptations that you're out here to get. Because let's be honest, it can be a bit of a bummer, but we have to keep the goals in mind and the adaptations that we're training for in mind. So here's another thing about hills that can be very frustrating as well. Even on an out and back run, when you go up and down the exact same hill, your overall pace is still going to be slower than if you'd run on some the same distance on flat ground. Because the effort that you lose going uphill is greater than the effort you gain coming back down. Downhill doesn't cancel out the uphill. When you're running downhill, even though it feels a lot easier, and it is easier than running on flats or uphill, it still puts quite a lot of eccentric loading on your legs, especially your quads. Now, eccentric loading is when your muscle is lengthening under load. So every footstep, your quads are lengthening while they're still working because they're basically acting like a brake to slow you down against gravity. And that braking action actually uses more energy than you'd expect. So even though running downhill feels easier, you're not getting the heart rate recovery that you might think or that you might want. That's why downhill never fully repays the effort for uphill. So if you're in zone two on flat ground and you're running around a 12-minute mile, don't be surprised if a hilly route pushes that closer to 13 or 14 minutes. And that doesn't mean it's a bad run. That's just hills and they suck. All right. Next question is how long until I actually see results from zone two training? This is the one that I was the most impatient about when I started. And the fact is, it takes longer than you want it to. Research shows that it takes about eight to twelve weeks to see noticeable gains in untrained runners. And I know that sounds like a long time, especially when you're out there grinding through slow, easy miles day after day, and you're wondering if any of this is even working. But here's my personal proof that it does work. After my half marathon, I committed to this nine weeks of real structured zone two training. I followed a pretty simple formula that I found on a YouTube video. You do one long run per week, one speed workout per week, and easy zone two miles for every other run during the week. I was running six to seven days a week and I built my mileage from around 18 to 20 miles a week up to 30 miles per week over that nine-week period. I was trying to keep the time on feet consistent and not worry about the distance I was covering, just the amount of time spent in the correct zone. I started out at 40 minutes and I worked my way up to about 60 minutes. My first zone two run was on a treadmill at a very memorable 14 minutes 14 seconds per mile pace. But at the end of nine weeks, I was able to run 11 minutes 45 seconds per mile at the same heart rate. That's almost two and a half minutes per mile faster at the same effort level in just nine weeks. Slow, patient, humble miles did that for me. And there were so many times throughout that training block when I felt like I wasn't doing anything. There were weeks where I felt like I wasn't making any progress at all. And it wasn't until I looked back at my earlier runs and compared numbers that I realized how much progress I had made. So even if it doesn't feel like this is working or like you're not getting any benefit from it, you probably are. Like I said, it takes time. So give it the full eight to twelve weeks before you decide that it isn't working. Is zone two overrated? I've seen this question everywhere lately. And my answer is it depends on how you're rating it. If someone is telling you that zone two is the only thing you should ever do and that all of your miles should be easy all of the time, then yes, that's overrated. Zone two is foundational, but it's not magical. You still need intensity, you still need a complete balanced training program. But on the flip side, writing zone two off completely is just as big of a mistake. The aerobic adaptations that we talked about earlier, the mitochondrial development, the capillarization, those compound over time. And we're not just talking weeks here, we're talking months and years of consistent training. The runners who build and maintain a strong aerobic base are the ones who keep getting faster long after everyone else has plateaued. It's the difference between running for a season and running for a decade. So is it overrated? No. But it's also not a magic bullet. It's one important piece of a well-structured, well-planned training program. And if you treat it that way, you'll get exactly what it's designed for. Slow, steady progress throughout your entire running career. Now, one cautionary note from my own personal experience here. Your cardiovascular system and your muscles adapt faster than your structural components do. And nobody warned me about that. And what I mean by this is that your heart, your lungs, and your muscles are going to get stronger and more efficient relatively quickly. And that's actually part of the problem here. Because with all of those improvements happening at once, it can feel like you should be able to keep pushing harder and harder and faster and faster. But your tendons, your ligaments, your joints, those take a lot longer to catch up. So my zone two block lasted nine weeks, and by the end of my pace was improving, my mileage was building, and cardiovascularly, I was feeling really good. But my Achilles tendon started to break down and I developed Achilles tendinopathy. And on top of that, an old knee injury I've dealt with ever since college started flaring up more and more often. So I made the decision to take a break from my zone two block and shift into a strengthening phase for the month of June. Right now I'm running four days a week, all of it's easy, and then I'm doing strength training the other three days, with specific exercises built in to support the muscles around my knee and strengthen my tendons. So build your mileage gradually and take your rest days seriously and dedicate some of your training time. I know it might be limited, but dedicate some of it to strength work so that your tendons and your joints can keep up with your cardiovascular fitness. Because if you do, you won't have to stop building your mileage completely like I did. You can just build it more intentionally. The aerobic fitness will come, but it won't do you any good if you're sitting on the couch with an injury. So we've covered a lot of ground today. We've talked about what zone two actually is and what it's doing for your body, why your watches probably isn't as accurate as you think or hope, how to use the talk test to find your zone without any gadgets at all, and some of the real questions that come up when you actually try to use zone two in your training. That's everything I've learned so far from my experience and from the research I've done. But before you go, let me boil it all down to the most important points that you can actually put into practice. First thing, zone two is an effort level, not a pace. Use the talk test, not your watch's zone calculations to know if you're actually in zone two. Second, your watch zones are probably off. The formula your watch uses to estimate your max heart rate has a standard error of plus or minus 12 beats per minute, but don't treat those numbers like they're the gospel. Third, the 80-20 rule was built for high volume elite runners. If you're running under five to ten hours a week, you probably need more intensity in the mix than 80-20 allows for. Be thoughtful and intentional about how you structure your training. Fourth, hills are effort, not pace. Slow down or walk if you need to. You're still training. Fifth, zone two results take time. We're talking eight to twelve weeks. So stick with it for the long haul before you decide whether it's working or not. And sixth, build your structural fitness alongside your aerobic fitness. Don't let your cardiovascular system outpace your tendons and your joints. Add strength work to your training before your body forces you to. And the next time you're out on a zone two run and you're not sure if you're actually in zone two, ask yourself and then answer out loud, yes, I can speak a nice little sentence without having to stop for breath. If you got through it, you're right where you want to be. Zone two training has genuinely changed the way I run, and my hope is that this episode gives you some actionable information that you can use to change the way you run too. If it gave you some value, could you do me a huge favor and hit the follow or subscribe button wherever you're listening or viewing right now? I'll be putting out more educational and inspirational content every other Friday, and I don't want you to miss out on it. Until next time, just keep running.