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Full Video Transcript

Introduction to Lactate Threshold

Let’s talk about the lactate threshold. What is it? Can we improve it? What is this zone 3 all about?

Is it junk? Should we avoid it like some say? Or does it matter? We’re going to break it all down, including the science.

We’re going to look at lactate curves. But don’t worry, we’re going to pull out of that and look at the training to improve the lactate threshold as well in when it matters. So, I want to start with breaking down some of the science. Okay.

So, first off, lactate gets a really bad

Understanding Lactate: Myths and Facts

rap. And that’s mainly because of some mistakes throughout history. You look way back in the day looking at animals, they realized that lactate increased because it was one of the few things that they could measure at the same time as we’ll call it fatigue. And from there, lactate got this bad rap, this bad name where we thought, “Oh my gosh, lactic acid is increasing.

This causes fatigue. This causes us to tire. It is the enemy. More recent work, as we’ve going to uncover, actually it’s not even recent anymore.

It’s literally been the past 40 years. Led by people like George Brooks has shown that lactate is a fuel. It is not the enemy and it does not cause fatigue. But why do we measure it?

First off, it’s because it’s easy to relatively. You take a blood prick of your finger and you can use a portable lactate monitoring device and get a relatively decent appraisal of what the lactate level is. So it’s easy to measure. And second of all, it correlates or appears at about the same rate at about the same time as fatigue or as things like hydrogen ions, acidosis, other things that cause or contribute to fatigue.

So the way I like to look at it is lactate is a surrogate marker that doesn’t cause fatigue itself, but gives us some valuable information as long as we realize that. So let’s break things down. Generally, when you see a lactate curve, which we’re going to talk about a lot, is it

Lactate Curves and Thresholds

looks something like this. It’s nice and neat and pretty, starts out pretty level, and then you see this gradual increase, we get what we call the lactate threshold. When we go from a very small increase to starting to go up to a rapid increase, that’s what we call the lactate threshold. Sounds great, right?

We can look at this curve and say hey we can see that we’re lactate is exceeding our capacity to utilize it essentially or clear it. We’ve gone over lactate threshold in zone model parlance which I’m not a huge fan of but I’ll talk about it anyways. five zone model it’s zone three which is generally between LT1 and LT2 which basically means when there’s the first start of gradual arising very early on and then LT2 is that very rapid increase. Okay, here’s the problem though.

When we look in the real world, it often doesn’t look

Real-World Applications and Testing

like this nice neat little graph. Sometimes we have lactate thresholds or rises that are clear. Sometimes they’re not clear whatsoever. Sometimes if we look at how do we even classify it and look at the research on the lactate threshold, there are literally a dozen plus different methods to find and determine where your lactate threshold is.

Now, we can get lost in the science here, but the point is if we don’t even have a really good scientific measurement for exactly precisely where the lactate threshold is. Should we obsess over it? We’re going to dive into that. I’m going to give you the answer.

But here’s what I think is important right now is first off, you often hear lactate threshold occurs at 4 millm moles. That’s something we thought in the 80s as a very rough like hey this is where it generally occurs. What we know now is that’s not actually the case. So lactate threshold can occur as low as 2 point something and as high as six, seven, maybe even 8 millm moles.

Because what we’re really after is what researchers call max, which is maximum lactate steady state, which if you were to measure this in the lab, you’d essentially go to the lab, you’d run for extended period of time, depends on the test, but 20, 30, 40 minutes at a pace, and you say, “Hey, is your lactate increasing at 6 minute pace during this?” No, it’s steady. Okay, then we’re going to take a break, a long break, or come back the next day and we’re going to increase the speed and go from 6 minutes to 550. Is lactate still steady? Okay, great.

We’re going to do this again. Next time, 540. And eventually, you get to a point where during that 20, 30, or 40 minutes, depending on the test, that lactate stops being steady and it starts going up a little bit. And you say, “Okay, my maximum lactate steady state is at 540 pace.” Now obviously that takes a hell of a lot of testing and you bring in fatigue if you guess wrong and have to do this test too many times etc.

So it’s not very practical to do that. But that’s kind of what we’re after for the fastest pace where we can sustain lactate where it’s not getting that that significant. Okay. And if we were to look at that, as I said in the research and in athletes, sometimes you see a very high lactate levels for that.

Sometimes you see it low. For instance, one group of studies in cyclist, they looked at blood lactate during a 60-minute trial. That was essentially their max last where they could keep it relatively steady. And as you can see in this chart, sometimes that occurred at 2 millm mole.

Sometimes that occurred up to seven mill mo. Now it’s rare to have it up to 7 mill mole. That’s really rare. And you can see it does cluster somewhere in the 3 to four range for most people.

But this is really important because often when we talk about lactate, we think, okay, it’s at this precise at 3 and a half mill or 3.9 or 4 mill mo. Most of it’s Let’s just be honest because it varies so much at the individual level and most of it’s BS because it varies based on a lot of factors from a day-to-day basis. So everything from the weather, the humidity, the heat can affect it because that will shift fatigue. It’ll shift your sweat rate and all other types of things.

Everything from that to carbs beforehand or not to caffeine beforehand or not to if you’re depleted going into it. All of those things can impact lactate levels on an individual level. So that’s why I’m not a huge fan of precision on like we need to train at this exact lactate level, but more of a ballpark which individually that determines. Now, okay, we’ve gone

Training to Improve Lactate Threshold

through the lactate curve. We’re going to talk about a little bit more, but for right now, I want to simplify and again I’m going to emphasize simplify. Well, how do we end up with lactate in the muscles and then in then the blood? And again emphasizing simplified.

There are a whole hell of a lot of steps that go from essentially glycolysis down to lactate. Totally acknowledge that for you exercise science nerds. If you want to read all that, go check out my first book, Science of Running. Go into it.

But I’m going to simplify it because we’re trying to get to practicality here. Here’s here it is. You have

Simplifying Lactate Production

glycolysis. You go through a crapload of steps. You end up generally having pyuvate. Again, there’s some variation here, so don’t yell at me.

Which then we either go towards lactate by a lactate dehydrogenous enzyme or acetyl coa acid COA by a PDH pyuvate dehydrogenous. Okay, we have this little split in the road. Again, it’s not always this simple. Sometimes we have a step before we get to pyuvate where we can go to lactate as well.

Again, the model is complex. Depends on what you look at, but I’m simplifying here. Okay, when we get to that pyuvate, okay, here’s how I like to think of it is we can either go into, okay, produce some muscle lactate, some lactate in the muscle, or we go off to the KB cycle, aerobic energy going into the mitochondria. Okay, it’s great.

We go that way, no problem. We go towards the muscle lactate side. Then what happens is in that muscle we can either convert it to pyuvate and shuttle it to adjacent fibers or into the like space between the interstitial space. So utilizing it as fuel locally or right next door.

Think of it like that. Or we can have that muscle lactate then get thrown into the blood which then is shuttled around and sent to the other muscles or livers or other organs by what George Brooks called the lactate shuttle. Again simplifying a little bit but the idea is once we have lactate in the muscle can either be utilized shifted cleared to adjacent spaces or sent into the bloodstream. Okay.

to then almost be like a transport system. Here’s how I like to think of it. It’s we have a factory. In that factory, we produce some lactate and we say, “Hey, can we utilize this here?” And most of the time it’s no, we need to send it elsewhere.

Well, can we send it to the store next door? No. Okay, we better load it up into a truck and send it out onto the freeway system. And where it goes depends a little bit on where it’s utilized.

So lactate in general is a fuel transport system among some other things. It also has a role kind of acting like a hormone, kind of acting as an immune system regulator or adjuster a little bit, but that’s not here or there. We used to think as well that lactate was only produced in quote unquote anorobic hypoxic without oxygen situations. But that is not true.

Okay. There was some research study called tic and systemic postprenatal lactate shuttle phases and dietary carbohydrate carbon flow in humans that looked at this and they said and I’ll quote from it. The present study challenges the notion that lactate production is the result of hypoxia in skeletal muscles. Our work indicates that glycolysis proceeds to lactate in fully aerobic tissues.

Okay. So it doesn’t have to be anorobic to get there. It’s not caused by the oxygen deficit hypoxia. Modern research basically shows that it’s combination of a couple things.

Faster rate of glycolysis, meaning we’re going through glycolysis faster, more activation of fast twitch muscle fibers because we generally in our muscles, we have fibers, muscle fibers that are really good at producing lactate, generally fast twitch fibers, and fibers that are better at clearing or utilizing that. often slow twitch fibers. So it depends on how many muscle fibers of each type are activated that influences the lactate. The other thing that influences lactate production, accumulation, all that stuff is if our glycolysis is occurring at a faster rate than we can essentially utilize it.

So the way I like to think of it is we have this balancing act between production and clearance or utilization or transport. And that balance is reflected in our blood lactate levels. And that’s why we see that nice rise as we increase intensities because glycolysis is taking up more of the load and energy production and we’re recruiting more fast rich fibers which means we’ve got more producers, less consumers and we’re stuck accumulating things. Now it’s interesting.

So when we look at the lactate threshold testing which I want to come back to before we get into training. So lactate threshold testing

Advanced Training Techniques

traditionally we just do a standard test meaning you do five by five minutes with each 5 minutes getting a little bit faster short rest in between. We measure lactate after everyone and we see that nice curve right. Well, Yan Alrech back in the ‘9s and early 2000s developed a model where he said, “Yeah, yeah, that that makes some sense, but it doesn’t really help us all that much because other factors are contributing to the lactate curve.” Meaning, it’s not just seen in this one little bubble. Simplifying, said essentially that our anorobic ability or power matters as well.

And here’s how I’m going to simplify this. If we look at it through a muscle fiber lens, if I’m someone who has better anorobic ability, meaning I have more fast twitch fibers, then I have more lactate producing muscles that at every speed I’m going to produce a little bit more than someone with entirely slow twitch fibers because my max capacity and the amount of fibers that I’m calling upon on that are fast twitch is going to be higher at every level. So another way to think of this is if my max anorobic ability my max ability to produce lactate or as Alrech suggested the maximum lactate that we get after a like 400 or 600 meter all out which gives us an indicator of this. What it tells us is if that max level is higher, generally we’re going to have higher lactate levels at just about every speed because our glycolysis going back to what we said earlier, our glycolysis rate is generally higher at every step.

Okay, so what does this mean? If we were to look at that lactate curve, right, what we can do is realize that it’s not just a reflection of our quote unquote aerobic ability, but it’s that anorobic ability as well influences it. So, let me simplify. If in addition to our five by five minute test where we get a little bit faster, if we then take full recovery, get lactate levels back down and then do a allout 400 and then check to see what is our peak lactate afterwards, that gives us a better interpretation of the curve for a simple reason.

Because think of it like this. If I do all this endurance work, okay, no speed whatsoever, no speed maintenance, no anorobic maintenance, my lactate threshold probably gets better, right? I produce less lactate as we get faster along every pace. But part of that might be due to the fact that when I go run that all out 400, instead of running a 50, I run a 53.

and instead of producing 16 millm moles of lactate, I only produce 12. What that means is I’ve suppressed my anorobic system. Okay? And because of that suppression, I should see lower lactate levels.

And to a degree, I don’t see lower lactate levels. My curve doesn’t shift towards what we generally consider positive because I improve my aerobic system a whole hell of a ton. I just train my body to say, “Hey, forget that speed stuff. Forget that producing anorobic power.

Let’s just dampen it down.” Or to put it in a another way, if we took our fire hose of lactate, meaning glycolysis coming down, if we shrunk that fire hose because we’ve decreased the the ability or the power behind it, we shrunk that fire hose, it’s going to look like, “Hey, Steve’s got moss lactate in his blood. he’s better aerobically, but it could be because I just neglected that speed component. Okay, so it’s this interaction that matters. It’s the interaction between lactate production both for the pace and our maximum amount, right?

and our aerobic ability or lactate clearance, utilization, disposal. They have slightly different meanings, but for our case, we’re just going to lump them all together. How well can you utilize and clear this stuff out as we increase intensities? Both of those matter.

So when it comes to lactate curves, what we need is both figures because we can roughly guesstimate, hey, if my my curve shifted, meaning as I got faster, I’m now producing less lactate. Let’s say at 5 minute pace it used to be 4 1/2 mill mole and now I’m at 3 mill mole. If that max lactate during that 400 test stays about the same, meaning during both tests it was, let’s say we ran it in 51 and produced about 15 millm moles, then we can say, hey, we maintained the size of that fire hose, but we’re producing less at 5 minute pace. So this was a real aerobic boost, aerobic benefit.

And what this comes to when we look at training is generally we do see some shifts in our quote unquote anorobic ability that 400 right early on that drains a little bit when we focus purely on aerobic stuff. That’s fine as long as it drains just enough so that we can bring that back when we start adding the specific or competitive work or emphasizing that a little bit more. Well, we’re maintaining that aerobic side. It’s just the balance.

Okay, so hopefully this makes sense. Let’s get into Okay, great. Steve, you just threw a bunch of science at me training. Okay, so here’s how I like to look at improving the lactate threshold.

You can either push or pull it up. Okay, generally we traditionally pull it up. Meaning, we work right below it or a little bit below it and we say, “Hey, body, we’re working at a high rate. Improve it.” And in fact, there was some recent research that found that the maximum clearance rate in trained, I think it was cyclists occurred not right at lactate threshold, but a little bit below threshold.

This is why you see athletes or elite athletes like Mary’s Backan or Yakab Inger Britson and the Inger Britson’s emphasize often not training right at that lactate threshold because it’s really hard a to find. Um but B because our clearance rates are generally high or a little bit lower, not a ton, right? So if your lactate threshold occurs at four mill moles, maybe it occurs between three and three and a half. Again, rough estimates.

Or another way to think of it is maybe 5 to 10 seconds per mile slower depending on the athlete. Fitter athlete, shorter gap, not as fit, bigger gap. But that is often why they train at that pace. So let’s look at pushing the curve up.

So first off, before we get into this zone three lactate threshold, you got to set the stage. So a lot of the lactate clearance ability depends on mitochondria, mitochondria transporters, a whole slew, think of it as building the freeways and then the capacity to offload from the trucks, building bigger trucks, offloading from the trucks and transporting it in and then utilizing it in different muscles. So what s sets the stage? Lots of easy training.

I’ve talked about it a ton. easy. Zone one, zone two, it doesn’t matter too much. Just lots of easy.

Eventually, you want to transition that from easy to adding in some what we’d call steady or moderate to marathon pace work. So, in zone parlance, high zone 2 into the low zone 3. Why? It just challenges clearance a little bit differently and it activates more of those intermediate or mixed fibers that we often don’t train too much when we go easy.

So, it activates them, gets them used to a training and then also increases their capacity for utilizing. Go to what I’d call level one, which is just threshold runs that are a little bit below threshold. And the goal here is to gradually increase the time spent at around this pace, which again could be from five to 15 seconds per mile, slower than lactate threshold, give or take. And the goal is to very gradually increase.

So generally from for noviceses, it’s starting at around 10 minutes at this pace or effort and then increasing to 20 or 15 20 25 minutes. For more advanced runners, you’re looking at increasing to 30, 35 minutes, maybe even a little bit longer. You can do this in a variety of ways. Generally, when we look at we used to do just straight threshold runs, meaning run 30 minutes at threshold, ride in the line.

It’s a little riskier because you have to find that line and ride it. It’s a little safer to do what I’d call just split threshold runs, which is just split it up. In actuality, I like telling athletes, “Hey, we’re going to spend 30 minutes at a little bit slower than threshold today.” Split it up however you want. When you start feeling like you’re going over the edge, take a short break.

The key here is a short break because it maintains the aerobic system and doesn’t let anorobic recover as much. So, we can stay on that threshold. You can also do things like cruise intervals or medium length repeats, K repeats with really short rest. You could even also do it 400 meter repeats with really short rest.

But the key is around that thing. The next step, level two of this is what I call threshold runs with something extra. Meaning where you’re you’re dipping into a little bit of throwing stuff into the system. Okay, what do I mean by this?

Instead of running your threshold runs on the track or on a flat trail, you add some hills which will naturally spike lactate just a little bit and then you come back down and get used to utilizing this. You could also do throw in some light surges in the middle of a threshold run. Again, the idea is very gradually get used to throw something in it. Not for a very long again, not huge hills, not straight uphill for a long time, but throwing a little bit of lactate more production in there and then coming back underneath it.

Okay, so that’s the second level. The third level is we’re starting to get to where we’re pulling the curve up. Okay, third level is runs or intervals that are slightly faster than threshold. So, you’re looking at mile repeats at 5 to 10 seconds faster.

Again, still with relatively short rest. You’re looking at 2k repeats. You’re looking at maybe shorter intervals with short rest that are faster than threshold. 400s at 15k pace, 800s at 15k pace, maybe even some 400s at 10k pace with 20, 30 seconds rest, maybe longer between sets, but you’re looking at just faster.

So you’re activating a little bit more fast twitch fibers, but because of the short recovery and the shorter rep length, we’re still staying largely aerobic in some sort of balance of gradual accumulation, but we’re still pressing that clearance and utilization and lactate shuttle. The last part that I think is pulling the curve up is what I’d call alternations or Kenova would call alternations or flux training, which essentially here is you’re going to alternate just faster than threshold, maybe at 15k pace or 10k pace or for those who don’t like distances, a pace you could sustain for 45, 50 minutes down to maybe 30 minutes. And you’re doing it where you’re going 800 on and then 800 off or 600 on 1,000 off or 400 on 400 off. You get to modulate the thing.

But the key here is on these alternations the off isn’t jogging or walking is still keeping it relatively steady because you’re trying to push. Think of it like this. You produce a little bit more. You go over that lactate threshold.

You spike lactate for that 800 on. And then during the off, you want basically the highest aerobic ability you can sustain while sustaining the workout. So maybe around marathon pace or that steady effort or maybe slightly faster. And what you’re doing is you’re teaching or training your slow twitch fibers to then be able to deal with and then take up and clear some of that work.

So here again, increasing the volume slightly. You might start with three miles of alternating 400 on off at 15k pace and marathon pace. You might lengthen that out where we go 400 on off to then 600 on maybe 600 off 800 on 800 off or any variation of that, right? And then we’re increasing the volume too.

So, we might start with three miles worth of work, then three and a half, four, get up to five, six miles of work for most people who are experienced runners, and you’re in a good spot. Okay, that’s how you train. That’s it. Okay, I’ve thrown a lot at you.

The last

Practical Tips for Identifying Lactate Threshold

thing I’m going to throw at you is identifying the lactate threshold without using blood lactate. Here, I think it’s really important to teach the feeling. Okay? Some people love heart rate.

I’m not a big heart rate guy. Assuming I live in Houston, Texas, where it becomes useless in the humidity. So, I like to teach the feeling of what it feels like in watching athletes when you’re under control. You’re working hard, but you’re under control.

You can say a few short sentences. So, my go-to, and I tested this with with Lactate, is I could say, “I feel good. I feel great. I want to communicate.” And basically during communicate, I should start to have this sensation of, oh, I should have another breath.

Take another breath here. If it’s occurring earlier, I’m too fast. Now, there’s going to be some variation in that, but that’s what I like to look at. You can also use a pace, right?

A pace or effort that you could sustain for about an hour at the elite level. About a half marathon is generally where our lactate threshold occurs. And then the last thing I look at is the splits during the workout. So if you’re doing six by mile at, you know, just below lactate threshold with a minute rest, if I start seeing the pace dip or the effort increase a ton during rep five and six to maintain threshold or just below threshold, I know I’m in trouble.

I know I went a little bit too fast. So it’s about finding that line to ride. And again, sometimes you’re going to want to be really close to it. Often you’re going to want to be just far enough away from it where you feel pretty good about it.

Where does lactate threshold training

Periodization and Race-Specific Training

fall? Well, it depends on the race that you’re doing. Generally, lactate threshold falls between impurization, between the base phase, meaning mostly easy, some smooth and fast stuff. It’s that next level of what I call high-end aerobic development where you mix in some marathon pace, some steady stuff, some threshold stuff, which then sets the stage for your 10k, 5k, or even mile development because you develop the aerobic system so well.

Now the key thing here is remember back to that seessaw balance between lactate threshold or aerobic side and max production is generally when we emphasize the threshold a lot it decreases our max production. So we’ve just got to do things like hill sprints maybe some 200s on the track to maintain that kind of quote unquote anorobic side even if that term is not practical. Now where this changes is if you’re training for the half marathon obviously lactate threshold is specific. If you’re training for the marathon, generally in periodization, what we see is we need to boost our threshold up before then going to the marathon specific of, hey, we’re trying to then extend our ability to run at a pace that is slightly slower, a little bit slower, but we now have that gap between our kind of lactate threshold and our marathon pace, which makes marathon pace a little bit easier and gives us more room for improvement.

All right, today was a long one. Thanks so much for checking it out. If you like

Conclusion and Final Thoughts

this, like it. Comment if I missed anything. I went deep into the science today. Normally I don’t quite go as deep, but you know, that’s what we’re here for, to inform you.

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