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HRV baselines seem out of whack

tbartman1
over 2 years ago

I have a 255 that I got in July. Long story short, it says my 7d HRV average is below my baseline almost every single day! How can my HRV be below "normal" for me 80% of the time? Doesn't that mean that the definition of "normal" is messed up? I'll attach screenshots and a spreadsheet here. These first 4 are the images since I got the watch 3+ months ago. The spreadsheet has the actual overnight HRV for each day, with some comments.

period 1     

hrv data.xlsx

You can see that right when I got the watch my HRV was a bit higher for the first few days, but then it came down a lot. At the end of 19 days, it gave me my first baseline of 47-67. But in the first 19 days, my AVERAGE was 50.5, and 7 of the 19 nights were below 47! Why would it calculate a baseline that barely covered my average and put nearly half of my points as "too low"?

As the weeks have gone by, it has been sneaking my baseline range down, but VERY little and VERY slowly. Today, my baseline is 39-55, but my average over the last 21 days is BELOW that at 38.4, and 15 of the last 21 days have been below 39. Just looking at that last image (which covers 4 weeks), don't you think the grey band should center on the long line of dots?

There have been periods in here where I have been on vacation, and taking multiple rest days, so I am CLEARLY not stressed this much. If anything, seeing a horrible HRV assessment every morning is adding to my stress!! Joy

How long will it take to re-equilibrate, or can I force it to start a new 21 day count from scratch?

  • 0 over 2 years ago

    The problem is that your HRV was quite high during the initial learning phase, and hence the baseline was set accordingly rather high too. Since that time your HRV continues to drop. The fact that the baseline adapts very slowly is completely intentional and needed. It would make no sense if it copied your averages, since it would then just always tell you that your HRV is within the optimal range, which is completely against the purpose of the whole thing.

    You can try the master reset of the watch to the defaults, if you are impatient. Or just wait a few weeks more.

    From HRV Status on Compatible Garmin Watches | Garmin Customer Support

    NOTE: Resetting a watch will require you to re-establish a new HRV Status by wearing your watch to bed for another three weeks.

  • 0 over 2 years ago

    Same for me, started high in August (work free month, less training cause of traveling), back in my work and training cycle it dropped and has been mostly right outside the "good zone" since then. 

  • 0 over 2 years ago in reply to trux

    I get that it doesn't want to move the range too fast or too much, but 10 initial days at an average of 54 doesn't seem to merit an initial range of 47-67. Again, during the 19-day learning phase, my single highest night was 66, and I had 7 days below 47! It clearly should have learned from the beginning that I was going to be below 47 a lot. And there have been over 80 readings since then, which seems like plenty to assume that I'm not stressed every single day. Just look at the last 1.5 photos - it's given me 6 points in 6 weeks that weren't orange or red.

    Reading more about the physiology of this (and I am a physician), it says that your parasympathetic nervous system (rest and digest) is always trying to slow your HR, and your sympathetic nervous system (fight or flight) is trying to raise your HR, and when these are balanced, that's what pulls your HR up and down by tens of milliseconds constantly, giving you a higher HRV. The assumption is that if your sympathetic system is ramped up from stress, your HRV will be lower because one system is dominant (and presumably, excess sympathetic tone would lead to a higher HR as well?)

    But, my resting HR is 43 and I drop to the high 30's at sleep! I wonder if it's possible that a low HRV could be because the systems aren't balanced, and it's the PARASYMPATHETIC system that's dominant?

  • 0 over 2 years ago in reply to tbartman1
    tbartman1 said:
    10 initial days at an average of 54 doesn't seem to merit an initial range of 47-67

    Well, if you know better than the authors of the algorithm (probably Firstbeat Analytics), just contact Garmin, and send them your proposal, and the theoretic papers backing your own algorithms.

    The problem is not how high or low your HRV (and/or your RHR) is, but the fact that it is continuously dropping since the beginning. Do not look at the absolute numbers, but at the trends. And the trend in your case is continuously decreasing HRV since July. Would it stay stable, you'd be in the 'green'.

  • 0 over 2 years ago in reply to trux

    No need to be snippy here. For some reason, I thought maybe Garmin folks would be on here and would be interested in my case, but we all know that Garmin created these forums so customers can support each other because actual Garmin customer support is non-existent (or useless when it is present).

    And even though I don't have my own, independent research, I don't think that means that the data I've provided is invalid. If YOU were Firstbeat, wouldn't YOU want to know that their algorithm over-weighted the first 7 days of my data and is using that to negate about 80 days of data after that? Do you think it is impossible that they have no room to improve? Or at least consider me a physiologic anomaly that is worthy of further consideration?

    I'm sorry if asking a question on here wasted all of your valuable time.

  • 0 over 2 years ago in reply to tbartman1

    I am afraid there is not much to do in cases like yours. If your HRV continuously drops since several months, then it is rather logical you are continuously dropping below the optimal range. I do not think that adapting the algorithm to any rate of HRV decrease, just to please the user, would make it better. However, feel free to send your recommendations for improvements to Garmin and to Firstbeat. For Garmin, you can use the form at Share Ideas | Garmin