What does lactate threshold feel like?

Can you feel your legs starting to get heavy/build lactate? That's the feeling.

You want to feel like the first 20 minutes of a 60-minute race, which feels amazing. You don't want to feel like the last 20 minutes of a 60-minute race, which feels horrible. (I once ran a 15K off bad training in 1:00:04. At 10K the wheels fell off.) You shouldn't be feeling heavy legged or tasting acid or anything else like that. If you start getting that, you should back off the pace or split up the tempo run.

acid in your mouth? heavy legs?

You guys are not doing tempos.

It's a steady state run, and it is usually 1 minute slower than your 1 mile pace, so if you do the mile in 6 mins, your
tempo pace would be 7mins.

Your legs should not feel heavy. If that it is the case, you are generating too much lactate.

Comfortably hard. Think of it as the area between 10 and 20 pushups when you are doing 30 push ups . The first 10 push ups are easy as crap. The last 10 are hard as hell because your muscles have been contracting at a rapid pace for quite some time, so a lot of lactate has been generated, and your arms start burning . However, that middle 10 is comfortably hard. A little bit of lactate has built up, but not enough to cause pain or fatigue, so you can keep going.

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Scorpion_runner wrote:

acid in your mouth? heavy legs?

You guys are not doing tempos.

It's a steady state run, and it is usually 1 minute slower than your 1 mile pace, so if you do the mile in 6 mins, your
tempo pace would be 7mins.

Your legs should not feel heavy. If that it is the case, you are generating too much lactate.

Comfortably hard. Think of it as the area between 10 and 20 pushups when you are doing 30 push ups . The first 10 push ups are easy as crap. The last 10 are hard as hell because your muscles have been contracting at a rapid pace for quite some time, so a lot of lactate has been generated, and your arms start burning . However, that middle 10 is comfortably hard. A little bit of lactate has built up, but not enough to cause pain or fatigue, so you can keep going.

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Agree that scorpieon Runnwr has described it in a way that seems too slow to me.

Many tests you can use: 90% of maxnheart rate; about 20-25 seconds per mile slower than 5k pace, the way youva already described - a differently breathing rhythm than easy pace but not the same rhythm as race pace "comfortably hard" (agree this is too vague), and my personal favorite (the one I find most useful) - the pace at which you could get out a a full sentence in response to a question, but at which you are unable to comfortably maintain a conversation. So if, 10 minutes into the run, someone asks you how your feeling, you should be able to get out "this pretty much sucks" but you shouldn't be able to give a whole paragraph description of how it sucks.

Why all the freaking mystery? Use a calculator like Daniels to estimate your LT pace and use a watch to run at that pace and see. You don't have to do every tempo run at exactly that pace but this will tell you what it feels like. It's deceptively easy for the first half mile and pretty hard after that.

I see so many people have no idea what LT is on this board. Which is kinda sad, when it should be a huge part of the aerobic conditioning for the 800 all the way up to HM and M. MD and distance runners should be doing some form of this year round.

A fairly certain way of finding out what that pace is (besides getting a test) is doing 6-8x1k repeats with 1-1:30 rest. If you do those at a bit faster than "comfortably hard" and you're staying at a certain pace, usually within 3-5 seconds difference (for example: 3:25-3:20) over the whole workout, that is usually the LT for that athlete. You should never feel lactic during this as the LT is surpassed way before you actually feel it in your legs. The LT is between 3mmol and 4mmol and you usually start feeling "lactic" around 5-6mmol. The reason why I think 1k repeats is good is because its long enough that a FT runner can't rely on their speed too much to get through. 1k is also short enough that if you run too fast on one repeat you can dial it back down without it affecting the rest of the workout too much.

The times they average over the course of 8x1k usually corresponds with their 10k time later in the season, in my experience.

That is usually how I try to determine LT with the athletes I coach.

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Actual Coach wrote:

I see so many people have no idea what LT is on this board. Which is kinda sad, when it should be a huge part of the aerobic conditioning for the 800 all the way up to HM and M. MD and distance runners should be doing some form of this year round.

A fairly certain way of finding out what that pace is (besides getting a test) is doing 6-8x1k repeats with 1-1:30 rest. If you do those at a bit faster than "comfortably hard" and you're staying at a certain pace, usually within 3-5 seconds difference (for example: 3:25-3:20) over the whole workout, that is usually the LT for that athlete. You should never feel lactic during this as the LT is surpassed way before you actually feel it in your legs. The LT is between 3mmol and 4mmol and you usually start feeling "lactic" around 5-6mmol. The reason why I think 1k repeats is good is because its long enough that a FT runner can't rely on their speed too much to get through. 1k is also short enough that if you run too fast on one repeat you can dial it back down without it affecting the rest of the workout too much.

The times they average over the course of 8x1k usually corresponds with their 10k time later in the season, in my experience.

That is usually how I try to determine LT with the athletes I coach.

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Lactate threshold, unfortunately, does not have just one feel.

One thing is for certain: It's harder "comfortably hard." For most people it feels pretty close to flat out. It's true that the first 20 minutes of a 1-hour race feel good, but that's when you're actually in a race. If you're doing a workout in the middle of the week, that usually feels really tough. In fact, the most common test that cyclists and triathletes use is a 30-minute flat out effort where the average power/pace/heart rate for the last 20 minutes is your threshold. The assumption underlying the test is that without real competition helping you to push yourself, you can only hold your 1-hour pace for half the time. (I think experienced athletes are much tougher than that, but it at least suggests that the pace isn't really very comfortable.)

Another thing to keep in mind is that many of the descriptions you're reading are talking about a certain level of fatigue. But fatigue increases throughout your run, even if blood lactate levels are at a steady state. So LT feels one way at ten minutes, and it feels different at 20. This is one of the shortcomings of the oxygen-centered model of fatigue. It doesn't really explain why we slow down at LT or slower paces, where oxygen shouldn't be a limiting factor and fuel definitely isn't.

One of the other big problems with trying to hit your LT pace in workouts, however, is that LT changes all the time. If you actually have a lactate analyzer and testing strips, you'll see that the very same pace, from day to day and week to week, will produce very different blood lactate levels. It's every bit as variable as heart rate. So you might have a finely tuned sense of "LT pace," but one week that might be 3 mmol, and another week it might be 5 mmol. And while it's true that in a week where your blood lactate is lower, every pace is going to feel easier, it isn't going to feel so easy that you can run for an hour at whatever faster pace is necessary that week to get to 4 mmol (I'm assuming for convenience's sake that your true LT is 4 mmol, even though it varies a lot). That's because there's more than your blood lactate level making it difficult to hold a particular pace. And, unfortunately, we don't know what all of those things are.

So here's my advice. Despite all these caveats, training at one-hour race pace is a useful weapon in your arsenal. It's the most important thing for half marathoners, it's very important for marathoners and 10k runners, and it's good early in the season for middle distance runners. You can learn what one-hour pace feels like by paying attention to how quickly your legs are moving. A "skilled" runner (not necessarily a fast runner) is one who can run specific paces at will. He knows the difference between a 75 and a 77 without looking at his watch. Some days 77 might feel as hard as 75, and on those days he might choose to change his workout, but still he knows exactly how fast his legs are moving because he can feel it, entirely apart from the subjective sense of effort. That's your sense of absolute pacing. The other skill that's important to develop is your sense of relative pacing. In other words, if someone tells you to run as fast as possible for X distance or Y time, you can set off at a pace that's pretty close to the maximum average pace you're capable of for that distance. That's how you figure out your LT pace for training purposes. Don't stress about whether you're running at exactly your LT; nobody even knows what their LT is (very few people are tested, and for those who do, standard lab protocols for LT testing have a uselessly large margin of error).

Read the book Healthy Intelligent Training by Keith Livingstone. This book describes the Lydiard training methodology but he bases the effort levels off of HR, specifically based on Heart Rate Reserve (HRR, which is MaxHR minus RestHR).

Usually your Lactate Threshold (or Anaerobic Threshold) pace is your 1-hour race pace, or somewhere around 85% of your HRR. The formula would be:

Lactacte Threshold HR = RestHR + .85 x (MaxHR - RestHR)

For me, my RestHR is 42 and MaxHR is 192. So my HRR is 192 - 42 = 150. My LT HR would be 42 + (.85 x 150) = 169.5 BPM. Marathon Pace is well below this, and would be run somewhere between 75%-80% of HRR. These would be your steady state or "tempo" run HR, or "comfortably hard" runs. The point there is that you are NOT crossing over your LT. You're hovering just below it, teaching your body to clear lactate without inducing lactic acidosis (too much lactic acid buildup can cause overtraining because it erodes your aerobic fitness). A "threshold" run, as described in the book, is something that you don't do very often, should only be done for 20-30 minutes, and is very hard. Do that during your peaking/sharpening period, NOT during the base training period. This would be run at 85%-90% of your HRR. Personally, when I do my steady state / tempo / comfortably hard runs (1hr runs twice a week, as suggested in the book), I'm monitoring my HR and keeping it in check the whole way. Towards the end though when my HR has climbed close to that LT HR, I can really feel when I'm crossing over. I get the feeling that I'm working harder, starting to think more about how much longer I've got to keep going, beginning to struggle, cadence getting slower and breathing harder. When I keep my HR in check, there is none of that. It's truly a comfortably hard feeling where yes, you are working hard, but you feel like you can maintain that pace and that you could speed up if you wanted to.

Some above described aerobic threshold... In this book the aerobic threshold is described as the HR where you begin to produce lactic acid. That would be 60% of your HR reserve. This would be the lowest effort level to run at that would actually increase your fitness. Anything below that would be merely for recovery purposes.

Many people despise training based on HR. But if you are having a hard time figuring out what your paces should feel like, HR is great way to give you concrete data as to how hard you are working. This book also goes into great detail into how to use HR data to guide your training.

How about "a little slower than 10K race pace for that day"?

As I have described it: If you were to run a 10K today, think about that pace and back off just a bit (10-15 sec/mile).

This allows for weather (hotter weather, slow down).

I have used "comfortably hard" and some people get that (based on GPS data of the pace they actually ran and what I am estimating LT to be--again 10-15 sec/mile slower than 10K race pace).

I have also used "when breathing becomes noticeable and a bit labored".

It is important to note that you do not need to be all that precise. We are not that finely tuned.

It's always funny since I never knew about this board in JH or HS which I assume many posters are... I have a metabolic cart and BL analyzer in my lab so I just test. But to think of these concepts without ever seeing a test administered does make them seem very abstract. I just wonder what I'd think of these concepts if I'd never seen a lab or test.

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Actual Coach wrote:

I see so many people have no idea what LT is on this board. Which is kinda sad, when it should be a huge part of the aerobic conditioning for the 800 all the way up to HM and M. MD and distance runners should be doing some form of this year round.

A fairly certain way of finding out what that pace is (besides getting a test) is doing 6-8x1k repeats with 1-1:30 rest. If you do those at a bit faster than "comfortably hard" and you're staying at a certain pace, usually within 3-5 seconds difference (for example: 3:25-3:20) over the whole workout, that is usually the LT for that athlete. You should never feel lactic during this as the LT is surpassed way before you actually feel it in your legs. The LT is between 3mmol and 4mmol and you usually start feeling "lactic" around 5-6mmol. The reason why I think 1k repeats is good is because its long enough that a FT runner can't rely on their speed too much to get through. 1k is also short enough that if you run too fast on one repeat you can dial it back down without it affecting the rest of the workout too much.

The times they average over the course of 8x1k usually corresponds with their 10k time later in the season, in my experience.

That is usually how I try to determine LT with the athletes I coach.

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newrunner111 wrote:

Are there any good descriptions of what lactate threshold pace actually feels like? Comfortably hard is so vague and to me it sounds more like a high end aerobic run.

I've never raced an all out race of 60 minutes so I'd have no idea.

I usually use "heavy breathing. as a marker of when i'm around that level but whenever I hit that stage I'm uncertain if I can hold that for 1 hour- at which point I think i'm going anaerobic.

Some have described it as being able to taste the acid in your mouth?...I've never had that

Ugh, so confusing.

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The trouble I have with heart-rate based methods is that I've found that effective heart rate range varies quite a lot depending on level of fatigue.

Using the Livingstone formula with RHR = 45, MHR = 195, I get LTHR = 45 + 0.85 * (195-45) = 172.5

Last week I was at peak mileage in a marathon buildup that included a 10km race with no taper. My average HR for the race, excluding the first mile, was 168.5. So Livingstone would have me doing tempos at 4 bpm higher than 10km race pace (when fatigued)! My marathon HR when fully tapered is 165-166. So maybe ~172 bpm would be an OK LTHR for me when fully rested, but who knows in the middle of heavy training.

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HR training is unreliable wrote:

Using the Livingstone formula with RHR = 45, MHR = 195, I get LTHR = 45 + 0.85 * (195-45) = 172.5

Last week I was at peak mileage in a marathon buildup that included a 10km race with no taper. My average HR for the race, excluding the first mile, was 168.5. So Livingstone would have me doing tempos at 4 bpm higher than 10km race pace (when fatigued)!

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Y'all and your research and fancy formulas, unless I'm interpreting this incorrectly, isn't it lactic threshold?

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Actual Coach wrote:

I see so many people have no idea what LT is on this board. Which is kinda sad, when it should be a huge part of the aerobic conditioning for the 800 all the way up to HM and M. MD and distance runners should be doing some form of this year round.

A fairly certain way of finding out what that pace is (besides getting a test) is doing 6-8x1k repeats with 1-1:30 rest. If you do those at a bit faster than "comfortably hard" and you're staying at a certain pace, usually within 3-5 seconds difference (for example: 3:25-3:20) over the whole workout, that is usually the LT for that athlete. You should never feel lactic during this as the LT is surpassed way before you actually feel it in your legs. The LT is between 3mmol and 4mmol and you usually start feeling "lactic" around 5-6mmol. The reason why I think 1k repeats is good is because its long enough that a FT runner can't rely on their speed too much to get through. 1k is also short enough that if you run too fast on one repeat you can dial it back down without it affecting the rest of the workout too much.

The times they average over the course of 8x1k usually corresponds with their 10k time later in the season, in my experience.

That is usually how I try to determine LT with the athletes I coach.

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Good podcast by Steve Magness and Jonathan Marcus on threshold training

http://www.scienceofrunning.com/2018/02/episode-68-threshold-training-good-or-bad-and-what-in-the-world-is-it.html