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Lactate Threshold way off

I've had this issue for a couple of months but it never bothered me much, but now I'd like to know if it's only me or do others have issues with automatic LT estimation as well?
Mine is way off, as seen on the attached screenshot, and in our national garmin fb group others report the same with various devices.
Note that I've installed all FW updates up until 9.72 where I rolled back (with a complete reset) to 9.10 which I still use, so it seems to be FW independent.
I know, this LTHR is nothing which you could base your training on, but still, some people might be completely misguided by this.
Does anybody have accurate LTHR estimates when comparing to a real lab measurement? ciq.forums.garmin.com/.../1406309.jpg
  • Does anybody have accurate LTHR estimates when comparing to a real lab measurement?


    I have not done any lab measurements and have previously been running with watches without the LTHR feature, but after upgrading to F5+ I find the LTHR estimate very consistent with what I previously have experienced in terms of perceived exhaustion rate vs. heart rate/intensity during real life running.
  • For most people, LTHR is around 86-92% of maxHR. If it is much outside this range, you should reject it.

    LTHR works by picking the inflection point in the HRV curve typically associated with LT. However, it can sometimes pick up inflection points elsewhere in the HR curve - from your graph, this appears to be the case at least some of the time.

    The best way to deal with this is to give the watch better data to work with through taking the specific LTHR guided test that can be found on the watch. This will give the watch enough HR data in the relevant ranges (ie. a bit below, and a bit above LT).
  • For most people, LTHR is around 86-92% of maxHR. If it is much outside this range, you should reject it.


    I usually do, but it appears that I might have accepted it some time ago - could that influence later estimates? Is there a check to see if the rolling average is in the same ballpark as the one measured in the latest activity? Because for months I haven't had a proper reading - which should be around 170 - it always puts it in between 80 and 110bpm.

    LTHR works by picking the inflection point in the HRV curve typically associated with LT. However, it can sometimes pick up inflection points elsewhere in the HR curve - from your graph, this appears to be the case at least some of the time.


    yes, I know how it should work, but I thought it'd be a bit more precise.

    The best way to deal with this is to give the watch better data to work with through taking the specific LTHR guided test that can be found on the watch. This will give the watch enough HR data in the relevant ranges (ie. a bit below, and a bit above LT).


    I could do a guided LT test, but it doesn't bother me that much, as I don't use it at all as input, just thought I'd share this phenomenon.
    Though I regularly go above LTHR in my training, especially during intervals, so the watch should have plenty of data.

  • I guess another way around the problem could be to open the Running activity, but only press Start once your heart rate is above 110. Losing a couple of minutes off your run shouldn't distort Training Load, etc data too much.
  • Mines been pretty consistent (albeit pretty bad because I've been having a bad year)
  • I guess another way around the problem could be to open the Running activity, but only press Start once your heart rate is above 110. Losing a couple of minutes off your run shouldn't distort Training Load, etc data too much.


    Not really an option for structured workouts unfortunately.

    Mines been pretty consistent (albeit pretty bad because I've been having a bad year)


    depends, what I see is that your LTHR went down and the LT pace went up, that's looks pretty good to me.
  • I don't see why this is not an option for structured workouts. Extending the warmup by 2 minutes is not likely to alter the nature of a structured workout. Or you could just edit the length of the prescribed warmup, knowing that you will be doing the full warmup anyway.
  • depends, what I see is that your LTHR went down and the LT pace went up, that's looks pretty good to me.


    Most runners will not look that positively at it if their pace in minutes/km goes up.
  • perhaps you can pause activity during warm-up, get your hear-rate up during pause and then resume.