Is there such thing as ‘Lactate Threshold Heartrate”

TTE test. Heart rate decoupling, and cardiac drift occurring at all points along the effort.


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You’re not wrong.

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Note: Not a sports scientist but am other, real, scientist.

I argue that this is more a matter of terminology, In physiological terms, for long efforts around FTP, you are slowly building lactate (through the test itself) and straining your body and heart further and further as you push it towards failure. You would absolutely expect your HR to rise as your body struggles to feed more oxygenated blood toward the muscle.

However, this is NOT the same as what you would do in a real world scenario. In many endurance races or hard events, I find myself hovering right around what feels like my ‘limit’. The closest approximation to these events for myself is that they are sort of like over-unders. You can feel when you go into the red, and also when you are just right on the cusp of staying sustainable. In this case, my heart rate tends to hover around an exact number, and I consider that my ‘threshold’ heart rate, as anything above that very quickly ends up leading to a lot of pain from lactate. e.g. i try to rarely cross that threshold in a race.

I would say that in the first paragraph, that sort of heartrate in the training environment is different from what I consider finding in a real world environment. Which is why I consider this a terminology difference.

there are any number of different reasons your HR could have drifted in this test. Hydration, cooling, nutrition, or you were just over FTP. Tough to say without more details.

Here is a long test of mine with the last 20 minutes of said test. Pretty stable and bang on what my in-season LTHR has been for literally years (which is about 181-182)

If you don’t think it exists and you don’t use it for anything training wise, just don’t sweat it.

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From the above graphs, I’m not sure what you are arguing. Your power is increasing, so why wouldn’t you expect your heart rate to also increase?

This! When truly fit and riding/running at/near threshold, my HR is also very steady. However, this also requires proper hydration, nutrition, and good temps. Even if all of these factors are good, if I’m not “fit”, the duration at/near threshold before drift occurs is short or non-existent. Example, early season, maybe 20min threshold and HR increases from start to finish, not to mention 20min sucks. After 3mo, threshold up, TTE up, and HR basically jumps up w/10min and stays relatively flat for the duration which is now over an hour. Again, I see the same when riding and running. While I don’t try by HR in either sport, I do record and look at it as a sanity check.

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Was going to post the same. With rare exceptions (usually really hot days) my LTHR on long efforts has been the same.

I have done other 30+ min steady state efforts and have experienced cardiac drift. Regarding this effort, you’re right, power was increasing, but only in the final 10 minutes. The previous 15 minutes were at a set wattage, and HR increased over 5 BPM within that time frame.

I could be wrong, but I could be right.


It’s something I’ve always used to gauge effort against wattage, but I don’t know if it ever actually dictated anything. More or less just a benchmark metric.

I think there’s for sure a HR that you can feel the tipping point. It’s not always exactly the same and there’s a bunch of factors that effect it up or down.

But I think what you’re suggesting is that there’s not one single HR number that at which you switch off and on from being able to clear everything. To that I say you’re right.

Interestingly (to me) my HR at which I can feel the tipping point (considered a number, but really a range about 3-4bpm) has definitely gone up this year. I’ve also increased markedly the max HR I tend to see and tolerate during harder stuff.

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True. But as others have said, the problem with heart rate on any given day is that it is affected by external factors: hydration and cooling being the two biggest.

Do you always see this pattern for steady efforts?

That doesn’t strike me as odd or inconsistent……I would expect to see some minor HR drift after 15 min at a relatively high intensity.

There is a reason why power meters became popular. Gauging anything above AeT/LT1 with heart rate alone is tricky. It works but it takes a good understanding of how one’s body responds to certain effort levels. You can see a lot from HR dynamics, other sports w/o powermeters do it all the time.

I don’t know what is meant with “Lactate Threshold HR”, probably LT2. For many an effort at this level will cause a significant drift. This is not unusual.

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Recognise that test - nice!

Indoors my HR always looks like that, it never goes steady. However during cross races, my HR will sit at what I think is my threshold HR, with minor fluctuations depending on the course. I don’t race with power, so power might be trending down, but lap times are usually steady. (There can be many reasons for that so its not the main point I want to make).


I usually do these after a 15-20 minute warmup, and never with a ramp. So that would be Progression 3 in The Physiology of FTP and New Testing Protocols blog post.

Here is one down 9 days after a 20 minute estimate, done outside and by feel. Highlighting the last 20 minutes like Steve did above:

and an overpaced 29 minute solo time trial with 9% decoupling (power dropped 44W and HR increased 4bpm):

That was after an hour hammerfest on a group ride, when I peeled off toward home and did the solo TT effort.

Personally I find it easier to do a TT effort (progression 3) rather than KM’s progressions that involve a ramp.

Does this in part come down to how trained you are, and what your FTP is ‘built’ from. I use the ramp test and think I have a strong VO2 or anaerobic contribution. I have to put in a lot more effort to drag threshold style intervals out towards 10-20 mins but enjoy a good VO2 workout! Not the same way around that many report, my HR almost constantly creeps in threshold efforts, even long SS. I’m not sure if this is another draw back of HR vs power or what, I just follow the training plan and do my surveys!!