# Lactate Treshold, Aerobic Treshold and 80/20 Zone Calculator

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• #15807
Jeff
Participant

My lactate threshold = 168
My aerobic threshold = 138

(The difference of 30 bpm between these two is more common than strange.)

However when I use LTHR = 168 the HR zones calculated by the 80/20 calculated are completely different as when I use talk test = 138.

Which of the calculated zones should I use? Am I missing something?

#15818

Hi Jeff,

Using our 80/20 calculator I see that the talk test gives you a LTHR of 153 vs the 168 you got from a HR threshold test – a difference of 15bpm.
My first question would be, which test did you use to get your LTHR of 168 did you do it in similar conditions and terrain as the talk test? HR can be impacted by external factors such as race excitability, heat and terrain so the difference could be due to that? I personally like to err on the side of the talk test result for training zones, particularly for longer endurance events and it’s easy to repeat and change during your training cycle without impacting your training intensity balance.

Leyla

#15823
Jeff
Participant

Hi Leyla,

Thanks for coming back to me. Indeed, I derived my LTHR basically from a race (Half Marathon) event. So race excitability might have been a factor. But then again, as your already observed,15 bpm is a huge difference and it is rather unlikely that my LTHR would be lower than my Half Marathon HR.

The solution I found is to go with the lower HR, based on the talk test, for the training runs in zone 1 and 2 and to go with higher paces, based on the LTHR, for the training in the higher zones.

#15830
Jeff
Participant

I guess the question would be that, if as a rule of thumb there is usually a difference of 30 bpm between the Lactic Threshold HR (LTHR) and the Aerobic Treshold HR (ATHR), why then is the ATHR so high with your calculator and the difference between LTHR and the ATHR so small (only 17 bpm)?

#15831
David Warden
Keymaster

Jeff, a few thoughts first:

– A HM is too long for a threshold test. If you can average 168 bpm for 1.5+ hours, your LTHR (which is the intensity you can maintain between 30 and 60 minutes) is probably much higher than 168. This actually makes the talk test delta worse! Maybe you can clarify how you extracted LTHR from your HM result.

– The talk test does not identify ATHR. The talk test is an alternate to the more brutal formal 20-minute protocol. Instead of testing with a 20-minute time-trial every rest week, the talk test can be done on any given day to validate zones.

– The most accurate method to determine LTHR is our 20-minu field test. Use that test, then use the talk test to check in periodically.

– Finally, don’t use HR, use Pace or Power. HR has way too many drawbacks and inconsistencies. Most of these issue will melt away with Pace or Power (if you scour this forum, you’ll find that 90% of zone issue are HR related, and very little issues when athletes use Pace or Power).

Regarding your last question on LTHR and ATHR in calculator, I can’t find a reference to ATHR in our calculator nor in our documentation. OK, wait…just read Leyla’s response and now it makes sense. The top of Zone 2 is not ATHR in the 80/20 system. it’s just the top of Zone 2. Your real question is, “why do I get such different zone results when using the talk test and my estimated LTHR from a HM?”

My answer is that extracting LTHR from a HM is unreliable, and that the talk test using HR is somewhat unreliable. Do a formal LTHR test with Pace or Power and your training will be more effective.

However, your LTHR is never lower than your best result. Even if the LTHR from the HM is unreliable, it can’t be lower than 168 (assuming you averaged 168 for the HM, maybe you are using another measure, like the peak 20 bpm of your HM, which is still inaccurate). A formal 20-minute test or two will make this clear.

David

#15903
Jeff
Participant

Hi David and Leyla,

First of all, let me say that I’m rather impressed with the amount of high quality feedback I receive on my questions and it is great to see how directly and personally involved you are with your product. Didn’t expect that when buying the plan or the book, so that is a big extra.

Now to come back on your first point. I completely agree with what you state. I suppose, I just have to clarify that, although my LTHR is derived from my last HM (averaging a HR of 162 bpm), my definition for the LTHR is with 168 bpm higher than the average HM HR. And although I didn’t do a lab-test, I have more reasons to believe that the definition of my LTHR at 168 bpm, is rather accurate. (Probably beyond the scope of this forum issue, so I won’t go into details.)

“The talk test does not identify ATHR. The talk test is an alternate to the more brutal formal 20-minute protocol. Instead of testing with a 20-minute time-trial every rest week, the talk test can be done on any given day to validate zones.”

Ok. Here might be the crucial point. What I understood from the literature and my own experience is that the ATHR, in theory and more or less, usually coincides with your MAF-pace and with the point on which it starts to be difficult to maintain a conversation without breathing difficulties.
You are explaining here that the result from the 80/20 talk test is not related to the ATHR. I didn’t know that. So now I understand that the top of the 80/20 zone 2 could be well above the rate of the ATHR.
On the other hand with a LTHR of 168, the top of zone 2/ bottom of zone X would be at 151 bpm, according to the calculator. I can guarantee you that at HR 151 I’m unable to squeeze out anything else than short word compilations.

“The most accurate method to determine LTHR is our 20-minute field test. Use that test, then use the talk test to check in periodically.”

Thanks for pointing that out. At one point I definitely will dive into the field test. However at this moment I am rather confident in the estimation that my LTHR is about 168 bpm.

“Finally, don’t use HR, use Pace or Power. HR has way too many drawbacks and inconsistencies. Most of these issue will melt away with Pace or Power (if you scour this forum, you’ll find that 90% of zone issue are HR related, and very little issues when athletes use Pace or Power).”

Interesting, I must say that when the calculator sets the paces per zone, based on the LT-pace or on the recent HM-time, the result seems to be spot on. (On the contrary, that calculated 151 bpm HR at the top of zone 2 seems far too high. For reference: If I pick the top of the zone 2, using pace instead of HR, then I can confirm that I use to have a HR of 140 or lower, instead of 151, at that pace.)

“Regarding your last question on LTHR and ATHR in calculator, I can’t find a reference to ATHR in our calculator nor in our documentation.“

Agreed. I supposed that this relation would exist (see above), but, as you pointed out, there is not such a relation. (In your view, the result from the talk test corresponds to the top of zone 2, but not directly with the ATHR.)

“OK, wait…just read Leyla’s response and now it makes sense.”

You probably refer to our parallel discussion on this forum. Indeed Leyla seemed to somehow share my view that the values obtained with a talk test will probably be similar to those obtained from the MAF-formula. (In my case these are nearly equal indeed.)

“The top of Zone 2 is not ATHR in the 80/20 system. it’s just the top of Zone 2.”

Fair enough (see above).

“Your real question is, “why do I get such different zone results when using the talk test and my estimated LTHR from a HM?”

Knowing what I know now, after you clarifying that (see above), this would indeed possibly have been my next question. Thanks for helping me out!

“My answer is that extracting LTHR from a HM is unreliable,…”

Okay.
But we seem to agree that the LTHR (168 bpm, in my case) should be higher than the average HMHR (162 bpm, in my case.), isn’t it? Well, then the problem still exists that even if we would pick a LTHR only slightly higher than my average HMHR, let’s say 163 bpm, for example (although this estimation of the LTHR would probably be too low), then the calculated “top zone 2 HR” of 147 bpm would still be far too high, in my opinion.

“ …and that the talk test using HR is somewhat unreliable.”

Okay. Good to know.

“Do a formal LTHR test with Pace or Power and your training will be more effective.”

Thanks. At one point in time I definitely will have a look at Power meters. (Pace and HR, each in their own way, seem to be more subject to circumstantial circumstances, of course, than Power. So Power, in theory, would be the way to go but although I also heard that, in practice, it still has technical issues.)

“However, your LTHR is never lower than your best result.”

Agreed. We are lined up with this one!

“Even if the LTHR from the HM is unreliable, it can’t be lower than 168 (assuming you averaged 168 for the HM, …

Yeah well, there was a misunderstanding here that I tried to clear up before. But anyway, I averaged 162 bpm an we, indeed, completely agree that my LTHR should be higher than that. A LTHT of 168 bpm is not strange in that context IMO.

“…maybe you are using another measure, like the peak 20 bpm of your HM, which is still inaccurate)”

I didn’t and, as said before, I am quite confident that a LTHR of 168 comes rather close to the real value.

“…A formal 20-minute test or two will make this clear.”

Thanks. for pointing that out, even though, at this moment in time, I am confident in the reliability of the calculation that my LTHR = 168 bpm.

My conclusion of all this is, that indeed it might be a better option for me, at this moment, to go with a paced based training program rather than keep using my current HR based training program, due to the rather high value that the HR zone calculation determines for the top of zone 2.

Should I additionally purchase the paced based program? Or can I easily continue with the HR based program that I bought before and that I am currently using, considering that I could use the zones it indicates, using them as pace-zones instead of HR-zones? I can then simply use the paces per zone, which can be calculated with the online 80/20 calculator?

#15931
David Warden
Keymaster

Jeff, thank you for the thorough answer. We never require you to purchase the same plan twice, and the switch of a plan from HR to Pace is covered under our Level Guarantee (assuming you purchased the plan originally). You can submit that request at https://www.8020endurance.com/contact/

David

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