F6X - lactate threshold cannot be detected

Hello.
F6X owner here.
Since some time I have a problem with lactate threshold detection. It just doesn't work, either auto-detection, nor during a guided test (I am just getting message, that threshold was not detected at the end of test).
I was trying to solve it with Garmin support. I even got watch and also HRM replacement. Nothing helps.
Actually I am using Stryd for running metrics, I also set watch to read pace from it, and I wonder if it can be causing this situation (some bug in software)?
Unfortunately, I am following a training plan for race and I don't have possibility to insert such test within next few weeks.
Question: does anyone use Stryd and observe that a watch cannot detect LT because of that? I am curious if it's worth to try, or it will be just a waste of time to go for another attempt.
Any other ideas, how to fix this issue?
Here two of my runs, where I followed a guided test, maybe you can spot that I did something wrong:

connect.garmin.com/.../5610859667
connect.garmin.com/.../6411977846
  • I remember reading somewhere that the watch would have a trouble completing the test if max HR wasn't set correctly. If max HR is too low the test may never push you far enough for the HR curve to plateau. The idea of lactate threshold is that from that point the HR curve changes the pattern. Before the threshold it goes up steadily proportionally to the effort, but from LTHR, adding an extra effort makes it much harder to further increase the HR and sustain it.

    Try setting your max HR higher.

  • "TIP: The device requires a few runs with a chest heart rate monitor to get an accurate maximum heart rate value and VO2 max. estimate. If you are having trouble getting a lactate threshold estimate, try manually lowering your maximum heart rate value."

  • Thanks for that tip, but its not the case. My HR is set correctly. I measured 186 bpm last year (this is valie set in GC) and having runs when it was as high as 185 bpm since then.

  • Have you tried leaving the auto lactate threshold detection and just going for a tempo/threshold pace 5k+ run? Mine never fails to detect it( with HRM on obv)

  • I have regular tempo runs at +/- lactate HR.

    Actually I even don't need lactate HR measurement itself, but knowing my estimated pace at LT could help to adjust training paces when there are no races due to pandemic. There is a field test protocol, but it is much more fatiguing than Garmin guided test.

  • Question: does anyone use Stryd and observe that a watch cannot detect LT because of that? I am curious if it's worth to try, or it will be just a waste of time to go for another attempt.

    Possibly, especially if you have your Footpod settings have Speed from Footpod set to Always. The LTHR test requires GPS pace, and I'm not sure whether Stryd pace invalidates this. Either turn this setting off for the LTHR test, or just leave the Stryd at home that day.

  • Still problems with that. Week ago over weekend I was doing incremental tests because I had possibility to test my LT using blood measurements. Also I was doing a fartlek and hills session during last week. On all 3 of those workouts I certainly hit LTHR, but Garmin didn't detect it. And all 3 were with Stryd pace and distance set to off, for fartlek run I even disconnected Stryd from the watch.

  • I run with a 6 Pro not a F6X but I assume the software is identical

    I've heard Stryd not working with various metrics before but your last update says you had turned it off.

    I've had my Lsctate Threshold auto-detected within the last few days, running 15.71 beta firmware on a 10k run, I wasn't doing any particular training (I don't train) just a normal easy-ish run.