HRV, low state for a long time

Sounds like that's the case. 

They might try to adjust their models with environmental temperature changes and/or other seasonal variables that affect HRV. Environmental temperature can be extracted from weather data for your location. 

Baseline adjustments should take that into account, and thus adjust faster. Because again, the training status stuck on Strained no-matter-what is going to be useless.

Same problem here since October low HRV and strained training condition

This problem does not seem to be new. See the thread in the link:

forums.garmin.com/.../hrv-drastically-lower-since-13-15-and-continues-with-latest-updates

P.S.: Interestingly, the problems appear from October onwards during the winter and disappear after a while. The winter period seems to be crucial.

Good find Thom@s! It looks like it all has to do with autumn-drops... After 6 weeks or so, I now see my HRV average crawling up, very slow, but up.

For me it took almost 3 months, but now it seems to be on track.

I honestly feel sorry for the people who have this bug ruining their race preparation and therefore have to rely on themselves instead of the data collected and evaluated by the watch or its software.

update: since 1 week my HRV average (nightly) is going up again, now I am in the green zone. But only because the baseline also dropped a bit further. At least the training readiness is on track again.

UPDATE:

So, I finally gave up my marathon training based on daily suggestions. I even skipped the event, because I am nowhere near the training level I should be.  Daily suggestions gave me base runs with a tempo of 6:15 km (slohooow, boooooring), for half an hour, for most of the time. Last two weeks even the long runs were skipped. I suspect there is a negative spiral here: HRV drop (why?) -> training status was strained all the time ->daily suggestions became less intense (because of low HRV status?)->stamina decreased ->HRV average stays low -> etc.

I deleted the event from my agenda, and put in a training plan for half a marathon in 4 months, based on heart rate. This evening, first training was in HR zone 2, which in my case means between 154 and 167 bpm. It cam with a tempo of 5:00. It was described as Easy Run. LOVE IT! Finally I felt I was doing something again.

Goodbye guides trainings of Garmin, they are no good to me. My stamina always decreases when I let Garmin decide what to run. Getting less fit instead of improving.

Funny thing is that "boring" and slow pace gives you a lot. 

What time you're planning for your marathon that 5/km is an easy run?

And what max HR you have that you z2 is 167 (what's your threshold?) 

Ps, everything above doesn't mean Garmin recommendation are fine. Never used ones, when I saw suggestions they looked wierd 

Goal of my marathon training was 3h40m. For half marathon plan (average level) I could not set a goal. So I wonder how I can train to the right tempo then.

Max HR is set to 194, LTHR is 177. LTHR pace is 4m58/km

Z2 154-167
Z3 168-178
Z4 179-190
Z5 190-max

Now here is the confusion. The Plan states I have an easy run of 35 minutes, Z2. So I kept the heart rate below 167, and ended up with an average tempo of 5m5s/km. Which is close to my LTHR tempo, so I think this should not be called Easy Run.

Today I had a scheduled Steady Run, which means Z3 for 40 minutes. Average HR is 173, tempo I could run in this zone for 40 minutes was 4m31/km.

You can imagine why 6m15/km is a very very slow pace, for only 30-40 minutes  per run. It brought me a lot: sure. My race prediction went in 10 weeks from 3h35 to 4h04 for the full marathon. Not the 3h40 I was aiming at.