LTHR Calculation

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!!

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.

Ah I see, so I need to do some longer efforts! Will it appear somewhere as a value?

You will get notified if a higher value is detected in the same way you see FTP improvements.

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I see, thanks! Time to do some hard efforts!!

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.

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!

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.

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Understood - thank you!

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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

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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

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?

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.

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%.

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Can you please add the LTHR pace when LTHR HR is detected?

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.