HRM sampling frequency *while asleep* has decreased dramatically [firmware 4.2 & 2.6]

I am observing the exact same sampling patterns. (See attached image). I am also noticing breaks in the graph at times which you can also see in the image. Nothing too serious but there all the same.
I really can't see the point of reducing the overnight sampling to that extreme? At least there should be 4 points per hour and preferably more. No wonder Fitbit HR users have such a shock when they switch! The Fitbit sampling is extremely granular even while asleep.

I'm not sure of the impact on RHR. The 235 not seems to be picking up slightly abnormally low readings, but GC seems to be smoothing these out. I.e. my RHR on GC is lower compared to the watch. However these have never matched ever since I have had the watch so who knows what is correct?
On a positive note the higher day sampling is much improved and seems to be reflected in the calorie burn for the day. I.e. move around a bit and the elevated HR is captured and calorie burn incremented accordingly. Before I'm not sure this was happening.

Oh, and if someone can tell me how I can actually attach a jpg image please let me know. I just get an undefined error.

Thanks Paul. Good to see i'm not going crazy :)

I'm wondering actually if the reverse is true; that the improvements are so significant that they've now removed the HR cityscape we'd previously been used to even while asleep. After all, i'd expect my HR to be fairly steady during these hours. Before with the low sampling, an incorrect jump would stick around and be noticeable. Now perhaps, such visible jumps are diminished because higher sampling means a more accurate HR (which isn't actually changing much if at all while asleep). Or maybe it's just smarter sampling that can now tell the difference.

You can see on my watch face above that many samples are actually being taken, but that the variation is pretty small. Perhaps they're too small for the smoothing algorithm on GC, and hence we just get a steady line there. A line that is in fact representative of your actual HR during those hours of being immobile ...?

Can anyone easily dump out the .fit file and have a look at what's actually being recorded?

IOh, and if someone can tell me how I can actually attach a jpg image please let me know. I just get an undefined error.

I put my image in dropbox then copy the public link. Then add an image when posting using "from URL". I leave "Retrieve remote file and reference locally" unchecked as i've found the pic doesn't display automatically then, just an attachment to click on (which is not what i want).

Thanks Paul. Good to see i'm not going crazy :)

I'm wondering actually if the reverse is true; that the improvements are so significant that they've now removed the HR cityscape we'd previously been used to even while asleep. After all, i'd expect my HR to be fairly steady during these hours. Before with the low sampling, an incorrect jump would stick around and be noticeable. Now perhaps, such visible jumps are diminished because higher sampling means a more accurate HR (which isn't actually changing much if at all while asleep). Or maybe it's just smarter sampling that can now tell the difference.

You can see on my watch face above that many samples are actually being taken, but that the variation is pretty small. Perhaps they're too small for the smoothing algorithm on GC, and hence we just get a steady line there. A line that is in fact representative of your actual HR during those hours of being immobile ...?

Can anyone easily dump out the .fit file and have a look at what's actually being recorded?

I attempted to and it seems there is a polling interval of 15 minutes while asleep (sometimes disturbed by movement or big increase in measured hr or something?).

What I mean by that (and the following I see a few times):

I see a number of readings measured 15 minutes apart, they are in the 50-50-49-51-51 range. Then suddenly 12mins later there is a 57 reading, 1 minute after that a new measurement of 52 and then 15 minutes later a 50 again... (and then agian 15 min intervals of 50bpm).

So I guess there is some smoothing or averaging in the graph in garmin connect.

While awake this seems to be somewhere between 1 and 5 minutes (more often 1 and around that then 5) and every now and then above that (I've seen a few 8 and 9 min intervals as well).

When looking up RHR definition it's hard to find a clear answer whether sleep is considered the proper state to measure this in (complete resting state is mentioned, usually adviced to measure it about 5 mins after waking up while lying down and being at complete rest).

Anyway... this is what I have been able to figure out I think, as far as I understand the fit file format ;)

And about the smart vs 1s polling, that's only for activities and will not influence 24/7 monitoring as far as I know...

I attempted to and it seems there is a polling interval of 15 minutes while asleep (sometimes disturbed by movement or big increase in measured hr or something?).

What I mean by that (and the following I see a few times):

I see a number of readings measured 15 minutes apart, they are in the 50-50-49-51-51 range. Then suddenly 12mins later there is a 57 reading, 1 minute after that a new measurement of 52 and then 15 minutes later a 50 again... (and then agian 15 min intervals of 50bpm).

So I guess there is some smoothing or averaging in the graph in garmin connect.

While awake this seems to be somewhere between 1 and 5 minutes (more often 1 and around that then 5) and every now and then above that (I've seen a few 8 and 9 min intervals as well).

When looking up RHR definition it's hard to find a clear answer whether sleep is considered the proper state to measure this in (complete resting state is mentioned, usually adviced to measure it about 5 mins after waking up while lying down and being at complete rest).

Anyway... this is what I have been able to figure out I think, as far as I understand the fit file format ;)

And about the smart vs 1s polling, that's only for activities and will not influence 24/7 monitoring as far as I know...

This is exactly what I found viewing my files. The watch is sampling every 15 mins (unless there's a significant change, increase/decrease of around 5 bpm). It doesn't explain the straight line graphs while sleeping though. I'm wondering if the line is the average during sleep?

GC seems to have flatlined my HR even more!

While the image attached to my previous post at least showed two small HR changes, they now seem to have been "flattened"! (See attached)