# LTHR Calculation **URL:** \ **Category:** Uncategorized\ **Created:** [13 November 2022 17:44 UTC](https://forum.intervals.icu/t/lthr-calculation/23734 "2022-11-13T17:44:22Z")\ **Posts on this page:** 16\ **Page:** 1
**Author:** ![Daniel\_Harris](https://forum.intervals.icu/user_avatar/forum.intervals.icu/daniel_harris/32/61348_2.png) [@Daniel\_Harris](https://forum.intervals.icu/u/Daniel_Harris)\ **Post date:** [13 November 2022 17:44 UTC](https://forum.intervals.icu/t/lthr-calculation/23734/1 "2022-11-13T17:44:23Z")
Hey y’all! I was wondering where I would find my calculated LTHR? I can’t see it and I’m sure o read something that suggests ICU calculates it!! ---
**Author:** ![MedTechCD](https://forum.intervals.icu/user_avatar/forum.intervals.icu/medtechcd/32/40383_2.png) [@MedTechCD](https://forum.intervals.icu/u/MedTechCD)\ **Post date:** [13 November 2022 20:35 UTC](https://forum.intervals.icu/t/lthr-calculation/23734/2 "2022-11-13T20:35:33Z")
It’s not exactly a calculation. It’s an estimation based on efforts done. So you will need efforts of 20min or longer for Intervals to estimate your LTHR. ---
**Author:** ![Daniel\_Harris](https://forum.intervals.icu/user_avatar/forum.intervals.icu/daniel_harris/32/61348_2.png) [@Daniel\_Harris](https://forum.intervals.icu/u/Daniel_Harris)\ **Post date:** [13 November 2022 20:56 UTC](https://forum.intervals.icu/t/lthr-calculation/23734/3 "2022-11-13T20:56:46Z")
Ah I see, so I need to do some longer efforts! Will it appear somewhere as a value? ---
**Author:** ![MedTechCD](https://forum.intervals.icu/user_avatar/forum.intervals.icu/medtechcd/32/40383_2.png) [@MedTechCD](https://forum.intervals.icu/u/MedTechCD)\ **Post date:** [13 November 2022 20:59 UTC](https://forum.intervals.icu/t/lthr-calculation/23734/4 "2022-11-13T20:59:52Z")
You will get notified if a higher value is detected in the same way you see FTP improvements. ---
**Author:** ![Daniel\_Harris](https://forum.intervals.icu/user_avatar/forum.intervals.icu/daniel_harris/32/61348_2.png) [@Daniel\_Harris](https://forum.intervals.icu/u/Daniel_Harris)\ **Post date:** [13 November 2022 21:14 UTC](https://forum.intervals.icu/t/lthr-calculation/23734/5 "2022-11-13T21:14:27Z")
I see, thanks! Time to do some hard efforts!! ---
**Author:** ![david](https://forum.intervals.icu/user_avatar/forum.intervals.icu/david/32/30189_2.png) [@david](https://forum.intervals.icu/u/david)\ **Post date:** [14 November 2022 04:17 UTC](https://forum.intervals.icu/t/lthr-calculation/23734/6 "2022-11-14T04:17:34Z")
Intervals.icu will notify you if it thinks your LTHR might be higher that what you have captured. It uses 98% of your highest 20m average HR. ---
**Author:** ![Daniel\_Harris](https://forum.intervals.icu/user_avatar/forum.intervals.icu/daniel_harris/32/61348_2.png) [@Daniel\_Harris](https://forum.intervals.icu/u/Daniel_Harris)\ **Post date:** [14 November 2022 05:04 UTC](https://forum.intervals.icu/t/lthr-calculation/23734/7 "2022-11-14T05:04:12Z")
Thanks @david - it’s just not displayed anywhere, unlike eftp? So when I get the email I’ll have to update the setting.would be cool if there was anyway to display LTHR somewhere! ---
**Author:** ![Gerald](https://forum.intervals.icu/user_avatar/forum.intervals.icu/gerald/32/28423_2.png) [@Gerald](https://forum.intervals.icu/u/Gerald)\ **Post date:** [14 November 2022 06:25 UTC](https://forum.intervals.icu/t/lthr-calculation/23734/8 "2022-11-14T06:25:50Z")
Your threshold HR is displayed in Settings. There are two options: - Threshold HR - Max HR A third option is the HRRc HR, which is the minimum value used before it will show the recovery after a hard effort. ---
**Author:** ![Daniel\_Harris](https://forum.intervals.icu/user_avatar/forum.intervals.icu/daniel_harris/32/61348_2.png) [@Daniel\_Harris](https://forum.intervals.icu/u/Daniel_Harris)\ **Post date:** [14 November 2022 09:53 UTC](https://forum.intervals.icu/t/lthr-calculation/23734/9 "2022-11-14T09:53:32Z")
> [@Gerald](#): > > - Threshold HR > - Max HR Understood - thank you! ---
**Author:** ![david](https://forum.intervals.icu/user_avatar/forum.intervals.icu/david/32/30189_2.png) [@david](https://forum.intervals.icu/u/david)\ **Post date:** [14 November 2022 18:06 UTC](https://forum.intervals.icu/t/lthr-calculation/23734/10 "2022-11-14T18:06:05Z")
It is displayed like “FTP Up” but your LTHR is not automatically updated. It is easy to run a high HR if you get thirsty or it is very hot etc. so you need to decide if the new value is valid or not. ![Screen Shot 2022-11-14 at 20.07.09](https://forum.intervals.icu/uploads/default/original/2X/1/1b3a51b51de689108e4bb6b766af77c3a5ccc8d1.png) ---
**Author:** ![Daniel\_Harris](https://forum.intervals.icu/user_avatar/forum.intervals.icu/daniel_harris/32/61348_2.png) [@Daniel\_Harris](https://forum.intervals.icu/u/Daniel_Harris)\ **Post date:** [15 November 2022 05:24 UTC](https://forum.intervals.icu/t/lthr-calculation/23734/11 "2022-11-15T05:24:34Z")
My comment about it being shown was more about it being displayed at the top of activities similar to eftp etc. But this all makes sense! Appreciate your reply ---
**Author:** ![stevexyz](https://forum.intervals.icu/user_avatar/forum.intervals.icu/stevexyz/32/25896_2.png) [@stevexyz](https://forum.intervals.icu/u/stevexyz)\ **Post date:** [16 November 2022 05:56 UTC](https://forum.intervals.icu/t/lthr-calculation/23734/12 "2022-11-16T05:56:13Z")
I’m curious how this compares to TrainingPeaks. For example based on the same ride intervals.icu computed 171 and TrainingPeaks 166. Do we know how TrainingPeaks does this, and what the pros/cons of the different methods are? ---
**Author:** ![stevexyz](https://forum.intervals.icu/user_avatar/forum.intervals.icu/stevexyz/32/25896_2.png) [@stevexyz](https://forum.intervals.icu/u/stevexyz)\ **Post date:** [16 November 2022 19:14 UTC](https://forum.intervals.icu/t/lthr-calculation/23734/13 "2022-11-16T19:14:23Z")
So based on Friel’s _Training Bible_, 5th ed. p. 50, the threshold heart rate is 95% of a 20min effort, or 100% of a 30min effort. That would explain the discrepancy since intervals.icu is using 98% of 20min effort and those numbers roughly check out for 20min@174bpm. However during the same ride I also had a 30min+ window at 173bpm. Which according to Friel at least would seem to imply a 173 threshold. Obviously this isn’t a support forum for TrainingPeaks, but I am curious why intervals.icu chose to use a 20min@174bpm vs a 30min@173bpm interval to flag the threshold heart rate. ---
**Author:** ![david](https://forum.intervals.icu/user_avatar/forum.intervals.icu/david/32/30189_2.png) [@david](https://forum.intervals.icu/u/david)\ **Post date:** [17 November 2022 15:53 UTC](https://forum.intervals.icu/t/lthr-calculation/23734/14 "2022-11-17T15:53:23Z")
Intervals.icu will use 1 hour if this gives a higher number than 20m but it doesn’t try and interpolate in between. I initially used 95% of 20m but after some discussion on this forum bumped it to 98%. ---
**Author:** ![az100](https://forum.intervals.icu/user_avatar/forum.intervals.icu/az100/32/25896_2.png) [@az100](https://forum.intervals.icu/u/az100)\ **Post date:** [18 November 2022 11:32 UTC](https://forum.intervals.icu/t/lthr-calculation/23734/15 "2022-11-18T11:32:02Z")
Can you please add the LTHR pace when LTHR HR is detected? ---
**Author:** ![Marco\_Ciampi](https://forum.intervals.icu/user_avatar/forum.intervals.icu/marco_ciampi/32/26802_2.png) [@Marco\_Ciampi](https://forum.intervals.icu/u/Marco_Ciampi)\ **Post date:** [24 November 2022 15:39 UTC](https://forum.intervals.icu/t/lthr-calculation/23734/16 "2022-11-24T15:39:33Z")
In my opinion, it would be interesting to receive the notification of the new threshold even when this is below the value set in the settings. As with the passing seasons our cardic capacity tends to decrease and consequently the threshold to lower.