How to setup auto detect heartrate and lactate treshold?

It is partially solved with 15.19. It will detect lactate threshold, but there are still issues with it transferring to Garmin Connect.

Yes, you need a chest strap (I use a Polar H9, but Garmin and others make them as well)

You may or may not need to lower your max heart rate setting depending on how close you are to reality.

Yes, switch the auto-detect on for max heart rate and lactate threshold.

A guided test is one option, the other is to just wear the strap for multiple runs and eventually it will trigger the calculation (hard runs are most likely to trigger it - Zone 4 for longer durations or sometimes Anaerobic or Sprint workouts).

When it works, your watch will alert you right after the activity that a new Lactate Threshold heart rate and pace have been detected. It will give you the option to accept it or decline. Once Garmin fixes the issue transferring it from the watch to Garmin Connect you will be able to change your heart rate zones so they are based on Lactate Threshold instead of Max heart rate or Heart rate reserve. For now, you can take the LT result and manually enter it into the watch for updated zones.

I use Ant+ for my chest strap, but others have stated that Bluetooth is better - I haven't had any issues myself though. I have tried it both ways and haven't noticed a difference - and I think my bluetooth headphones worked fine regardless of Ant+ or BT.

You don't have to run with it forever, but yes if you're going for regular updates to your LT numbers wearing it on more difficult runs would be the minimum. Probably not necessary to wear it on easy runs or recovery runs. You won't get updates without the chest strap though - it needs the HRV info during the activity that your watch can't provide.

Thx for your complete response! I think you made a mistake though (or I did not get it :-). LT is not transferring to GC. You suggest to take the LT result and put in manually into the watch. I think you mean into GC, while the zones are determined in GC and not the watch. Right?

And about the lowering of the max heart rate. I think it is pretty close to reality now, but measured on my wrist. So it could be a bit off. Will max heart rate also be lowered if it is never reached in training?

I am asking because I manually set it to 196 (which is way of the general rule 220-age, I am 50 years old ). Last week I got to 192 in the final sprint of a half marathon. So seems in line. But maybe wrist based is recording to high HR compared to HRM.

You are correct - take the LT #'s from the watch and enter them into Garmin Connect. Good catch!

It's not completely clear how Garmin (Firstbeat analytics) calculates your actual max heart rate, but during a threshold run in the past when my heart rate was in the mid 160's for quite some time it came up with an autodetected max HR of 187 for me. So it must be extrapolating from the data that it gets to make an educated guess. Supposedly Firstbeat starts with 210 – (0.65 x age) = maxHR until it has enough data to calculate something different, then it makes adjustments.

Seems like it would be safe for you to start with 210-(.65x50)= Max HR of 178 (rounded up) and then let the watch determine the max hr and LT. Will be interesting to see if the numbers it suggests are close to what you think they should be.

DaKo said:

Will max heart rate also be lowered if it is never reached in training?

Apparently, it can only get higher.

"If a heart rate higher than your currently set maximum is identified and passes a reliability threshold, your personal maximum heart rate is updated on the device or in the Garmin Connect app. "

https://www.garmin.com/en-US/garmin-technology/health-science/heart-rate-monitoring/

If you really want to optimize your metrics and training, you need an accurate HR Max value. The only way to get it is to run a field or lab HR Max test, if your doctor lets you. These tests are really really hard.

Formulas like 220-age all come with a significant standard deviation (12bpm for this formula). This means that  68% of people will have their actual HR Max within -12bpm to +12bpm. Quite a range!

https://www.builtlean.com/how-to-calculate-your-max-heart-rate/

DaKo said:

Last week I got to 192 in the final sprint of a half marathon. So seems in line

Could be. Most athletes often reach 90% of HR Max during races, but rarely more than 95%. Lab or field HR Max are optimized to elevate your HR while keeping in check fatigue and lactate as much as possible...

Undertaking a Max HR test is really worth your while is you can. The error will be much lower than a formula. With regards to Garmin's auto-detection, it is too sensitive to abnormal HR sensor data (wrist in particular, but strap as well): this has been my experience at least.

Same thing with the threshold auto-detect. The built in test is working well but the auto-detect will always give me an under estimated set of values during supra-threshold interval workouts. It works OK if your run looks like a real threshold effort (steady maximum effort for at least 20-30mn).

DaKo said:

Do I need to run with the strap forever? Or just to do the test, and the intensive trainings like treshold runs? And if I do run without strap, but with wrist based HR, how does that interfere with the automatic update

Again, if you care about your metrics, like VO2 max, training status, readiness, etc., you really want to use a chest strap. While it is required for threshold detection, it is definitely optional, but the accuracy of your HR data can be affected a lot. The metrics are already hard to get right with a chest strap....

DaKo said:

- Switch auto heart rate detection and auto Lactate treshold detection to 'on'

So, no. Turn these off. Do a HR Max test. Do the built in threshold test or a field threshold test (after warm up, run or bike at maximum steady effort for 30mn, take 95% of your HR, pace or power values for the last 20mn). Operative words here are "maximum" and "steady" :-)

ShawnPDX said:

Will be interesting to see if the numbers it suggests are close to what you think they should be.

With Garmin it is interesting every day

Etupes25 Interesting thoughts. Put things in another perspective (...again). 

If FR955 still has "built in threshold test"?
My FR935 has it, but I could not find it in FR955.
Or where to find it?

Run - Training - Lactate Treshold Guided testt

Thanks kbf.
Will try LT Guided Test recently.

So, I bought a HRM and lowered my max heart rate to 178 (from 196) manually in GC. Today I had an easy run, and at the end the watch told me a new max heart rate was registered. The new rate was determined at 194. Pretty close to my own manual max rate I used before. That part seems to work, also transferred to GC-app. Next week I will try a threshold test and figure out if and how that works.