New max HR detected absolute nonsense

You should be able to disable automatic Max HR detection

Settings -> Physiologic Metrics -> Auto Detection -> Max HR -> Off.

In my case, with autodetect on, everything from training effect to suggested workouts gets messed up. I left autodetect on as an experiment for a few weeks and it kept going up until it was completely unrealistic. Seems like FirstBeat missed a beat there, at least for folks in my demographic/fitness level.

Many thanks, I have just disabled it. And yes it was messing up everything I guess, from suggested workouts to recovery.

I raised a case on this and provided data to Garmin. At lease two phone calls. As you’ve done, feature off is best.

they replaced my 6X in April for a different fault and problem was on new one. I rang Garmin and they advised that case was closed because that watch returned. I asked them to transfer case to new 6X.

Had to disable all the detections as it is messing up my HR Zones which was providing false feedback to my coach. Zones on watch not syncing with those in connect at all. Made a total mess of several workouts. Should all be off by default.

Although Max HR auto detection is really rubbish, I would not say all the auto detections have to be disabled.

FTP auto detection works, and apart from some rare exceptions LT (HR, but not LT pace) auto detection is also sensible.

I guess the problem lies in the method itself. Measuring HR and HRV data gives you a real chance to estimate LT quite well, because the behaviour of HRV and reaching LT HR are really linked in real life, too.

While staying in a relatively low HR range says nothing about your individual max HR, because none of the measurable data in this  low HR range has meaningful correlation with your max HR.

Firstbeat must have used just some larger sample and tried to define some functions. Sorry, my English vocabulary is not good enough to explain what I mean exactly, but it is about to define functions where the average error/difference between the  individual values of the function and the real life data is minimized.

The only problem is that even if you do so, but you have no real link (=which can be explained logically) between arguments x,y,z etc and f(x,y,z,….) then it makes so little to do that drill.

I guess the pressure was there, it was so tough/exhausting/sometimes dangerous to do max HR tests, so we must give some solution to users. Especially because our physio data are heavily relied on a correct max HR value.

It's not a problem with the watch, it's with Garmin. Exactly the same thing happens to me and to a friend of mine who also has the Fénix 6 pro. The best thing is to disable it and have Garmin fix that problem that has been going on for a long time but does not provide a solution.

Big difference between models; after running with a Fenix 6 and a 7 for a couple of weeks, both on autodetect max HR, the Fenix 6 kept going up until a clearly way too high value. The Fenix 7 went up until it was slightly high, and then down to what seems completely reasonable. It changes 1 BPM sometimes, up or down. Other autodetect (LTHR, FTP) works exactly the same on both models (in my case). I think the Fenix 6 has an obvious bug in the max HR estimating algorithm, and it was not always that way. When I first had the 6, it worked well.

This bug got in there in an update (I don't recall which one). There are other bugs in the 6's software that have tickets created sometimes over two years ago, and are still waiting for a fix. Which is a shame because the 6 is still a totally adequate and capable device.

But yes, the best option is to set max HR on a fixed value on the 6. How to obtain that value, I'm not sure though.

Data said:

on autodetect max HR, the Fenix 6 kept going up until a clearly way too high value

My max HR is definitely has been at least 185 bpm, lreal measurements resulted in 188 bpm plus/minus 2 bpm.

My F6X gave me numbers like 158bpm, 164 bpm etc, just because in that period when max hr autodetect was switched on I had only low aerobic runs.

And again in the range of low aerobic hr zones there seems not to be any physiological processes which is linked to your max hr. So no proxy exists. It is so simple. You can use samples of people and can divide them into sub-groups to forecast max hr, but this will be only an estimation and not an auto detect. And it can  be accurate for person A, but totally rubbish for person B.

As a simile, if you push the  gas pedal of a car and you are allowed to use this car only in the speed range of 0-100 km/h, in the gears of 1-4, how accurately you can estimate its real max speed on flat terrain in windless situation? Provided that you have no additional information. You can listen to the engine, feel some vibration, feel its acceleration, but all these measures are distorted by the preferences of the car engineers.

At the same time detecting your LT is possible if you find a proxy, and it seems that HRV is a good one. Just because your real HR has been at least around your real LT during the runs.

But I accept that apart from the faulty approach there may be a bug, too, which ruins the estimation even for those lucky ones whose real max hr is close to the estimation of this model.