Lactate Threshold

rickj2903 I don't have a 5X but have a 935 which I suspect is similar. I have had my watch for about 8 months and have no LHR measurement - I think that's because I haven't run the Lactate threshold test or entered values manually in the watch settings - see excerpt from 925 manual below

"If you already know your lactate threshold heart rate value, you can enter it in your user profile settings (Setting Your Heart Rate Zones)."

Hi JSRUNNER,

Thanks for your response, I had already set up the HR zones and have been getting LTR data up to about 3 weeks ago and as far as I know I haven't changed anything in either user settings or device settings, however on checking the HR zones the max HR has gone up to 172 when it should be 161. I don't know if this is a factor or not, I have just spoken to Garmin support and they didn't really suggest anything.

rickj2903 Interesting - I have had HR zones set up since day one but never had Lactate Threshold info

I have fixed my HR Zones and max HR based upon race experience and beep test

Are you certain your MHR is 161 - that sounds quite low how did you determine it?

How's your strap working? Are you getting "odd" readings (e.g. double-rate counting some of the time)?

I ask because right when 8.x firmware hit my older HRM-RUN (black, button-style with the dude on it) started returning garbage results only on the heart rate on a frequent basis. All the other run dynamics remained fine, but I got two bad (very bad, and obviously wrong!) lactate threshold updates and then haven't seen one since -- over a month ago. Optical HR reporting works fine for me, even during hard workouts -- no dropouts and no bad data. The strap is now to the point that I can put it on in my house, shirt off, and it'll almost-immediately start double-counting (e.g. showing a 140 heart rate with me walking around the house); take it off and the Fenix reverts to the OHR and the true rate immediately reappears.

I finally gave up on the strap and just yesterday hard-reset the watch (which, interestingly enough, did NOT clear all my loaded maps -- I had expected it to!) -- last night I got a valid VO2Max reading from a hard training run on optical HR that's right where I expected it to be given the pace of the run and how I subjectively felt during it. I don't expect to get a lactate on that since from what I understand you need a chest strap to get one, but I'm going to try a new HRM-RUN and see if the screwy data disappears and my lactate threshold reporting starts working again as well.

PS: If the OP is 59 years old then 161 is the correct "default" for max HR (220 - age) that Connect will "offer up". I use a slightly different formula -- I'm 54 and can exceed the alleged "calculated" value, so I go with one of the alternatives that comes up with pretty-much what I can achieve during an "all out" effort on a 5k race.

rickj2903

Are you certain your MHR is 161 - that sounds quite low how did you determine it?

Hi,

I used the 220-age (59)

Hi JSRUNNER,

Thanks for your response, I had already set up the HR zones and have been getting LTR data up to about 3 weeks ago and as far as I know I haven't changed anything in either user settings or device settings, however on checking the HR zones the max HR has gone up to 172 when it should be 161. I don't know if this is a factor or not, I have just spoken to Garmin support and they didn't really suggest anything.

The 220 minus age formula is OK for the average of the population as a whole, but is rubbish at predicting any one individual's MaxHR. One possible cause of the increase is the MHR autodetect feature finding you are exceeding the formula prediction.

Aha..... You said:

Thanks for your response, I had already set up the HR zones and have been getting LTR data up to about 3 weeks ago and as far as I know I haven't changed anything in either user settings or device settings, however on checking the HR zones the max HR has gone up to 172 when it should be 161. I don't know if this is a factor or not, I have just spoken to Garmin support and they didn't really suggest anything.

Your strap is probably screwing you -- this is the exact pattern I saw several times before mine went all wonky on me.

Either Connect or the watch will "helpfully" reset your MHR (and all the zones!) if it gets what it believes is a "good' reading that is materially beyond your 100% rate. This WILL screw up the lactate threshold computations and once it happens even if you put it back it will take a fair while before things start working again, IF they do without a hard reset.

This sounds like exactly the same thing I have run into -- I've got a new strap on order and we'll see if that corrects the problem. If it doesn't then something in the 8.x firmware release porked the strap heart-rate reporting as the problem appeared on my F5x exactly when that update hit and has continued since, including with the current beta code. I did send in a report on it to the beta address but got no response.

If the strap is borked then it's not a big deal but if it's the watch code that's a much bigger issue for all the obvious reasons. I did hard reset the watch so when the new strap shows up it'll have "clean" data to work with. We'll see in a few days when it gets here and then I have enough runs on it for it to integrate and start reporting (probably about a week from now.)

The 220 minus age formula is OK for the average of the population as a whole, but is rubbish at predicting any one individual's MaxHR. One possible cause of the increase is the MHR autodetect feature finding you are exceeding the formula prediction.

Hi McAlista

If I exceeded the 161 and the watch amended the Max HR and zones accordingly surely I would still get a lactate threshold reading? Or would I have to reach a higher HR?

LT is typically around 86-92% of MaxHR (although there are outliers). I don't know the extent to which the LT detection algorithm rejects inflection points in the HRV curve outside the expected range. If Connect is saying there isn't eligible data, this may be the case.

I've gone back through each activity working out what the Max HR setting is at that time using the HR % given against the activity i.e. 158bpm = 98% of max = max calculates to 161. It looks like the Max HR hasn't changed up to me amending the setting for the HR Zone calculation to use % of Max HR rather than the "Lactate Threshold BPM" which I did last night after my run. Therefore I am at a loss to explain why I am not still getting a lactate threshold readout. I don't remember amending the HR zone calculation to use LT BPM as a base. Unless it's a faulty chest strap as Tickerguy suggests.