I can't pinpoint which update started this issue with HRV, but it's clearly wrong. It went from being in the 80-90 range to 50-60 range overnight, and has been steadily declining seemingly nightly for months. I'll have high sleep scores, with an avg HRV being in the 40s, which is ridiculous. At this point, I think my HRV would be higher while awake than it is during my sleep. Like many of the 955 issues, this feature is integral to how the rest of the data is utilized making the watch more of an inconvenience than anything else.
I've posted about this before and keep waiting for updates that explain or provide a fix to no avail. I bet more users are experiencing this than known as most people don't understand the data they're looking at in the first place. Beyond frustrating. I was happier with my 935.
EDIT: I commented this within the post, but figured I'd add an edit as well:
Ok, so, to anyone here having a similar problem and not just here to get off on telling people what they think HRV is (thanks for that btw), the factory reset seemed to work.
It is true: with the new update Physio True Up saves your HRV data and a factory reset won't erase this data, but it did seem to fix the problem. In the days after the reset, my HRV trended back to normal, above what has become my "baseline" due to months of incorrect numbers, and it now has a normal relationship to stress, HR, etc based on training. Again, nothing else about my training or daily life has changed - this was 100% an issue with a previous update.
If you're having this problem, or may think your HRV numbers don't accurately reflect what you're experiencing, try a factory reset. Hopefully that helps you out.
