Does the Charge 4 calculate HRV accurately?

[Seanseaton]

I have been recently playing with new hrv update and after some benchmarks, research from experts and manual calculations it appears that hrv measures are inaccurate in general across all advanced watches and bands.  Is this the case for you as well?

Moderator Edit: Clarified subject

[Notabetatester]

Any Fitbit support moderators care to weigh in on this topic? Clearly there are many people reporting inaccurate/low HRV reading, which can cause some anxiety given the potential health implications if data was to be accurate. No where in FitBit's FAQ does it suggest that "gross data inaccuracy" is a factor that can affect HRV values in the Fitbit device.

From the FAQs "WHAT FACTORS CAN AFFECT HEART-RATE VARIABILITY? Several factors can affect HRV, including age, sex, sleep quality, stress, and lifestyle choices, such as nutrition and exercise."

[PH6271]

Glad I found this discussion, been researching all night as my Charge 4 gave me a reading HRV of between 19 and 24 over the last 7 days which seems off as I run every day and have a resting HB of 57?

[QuinnF]

Feels low. HRV of 30 in my 30s. I’m fit. 

[AlejandraFitbit]

Hello guys, I hope you are doing fine.

I appreciate all the information provided and all the efforts in trying to fix this HRV issue. Fitbit uses the common formula called RMSSD to determine HRV from your recent heart-rate data. In the graph, your latest HRV measurement is from the longest sleep period over the past 24 hours. Only sleep periods greater than 3 hours are considered. Several factors can affect HRV, including age, sex, sleep quality, stress, and lifestyle choices, such as nutrition and exercise.

As with all heart-rate tracking technology, accuracy is affected by personal physiology, device location on your arm, and type of movement.

For a more accurate heart-rate reading:

• Wear your Fitbit device on top of your wrist, and make sure the back of the device is in contact with your skin.
• When you’re not exercising, wear your device a finger’s width above your wrist bone.
• During exercise, wear your device a bit tighter and higher for an improved fit. The band should be snug but not constricting (a tight band restricts blood flow, potentially affecting the heart-rate signal). Many exercises such as bike riding or weight lifting cause you to bend your wrist frequently, which could interfere with the heart-rate signal if the watch is lower on your wrist.

Have a good day!

[Kgou]

Thank-you for the update from fitbit. My readings however, have been
fairly consistent around the 15-25 range for months (app indicates it's my
personal range). I have tried different band settings.

Other readings including the sleep analysis seem to be fairly accurate. As
I and several other people seem to be stuck at the HRV 20 range, it seems
like maybe the readings are not good enough and 20 is a kind of lowest
reading that can be produced by the software.

Is there a way to get the raw data used for the analysis, or is the
computation done in the watch?

[AlejandraFitbit]

Thanks for getting back, @Kgou.

If the instructions provided were of no help, the best way to get help for this problem is to chat with us online or give us a call. Click here to get connected.

Keep the stepping up!

[QuinnF]

I’m sorry, but this is seems unhelpful to me.

You have 20-30 people in this room having the same issue. Sending us all to
customer service isn’t going to solve the problem of the tracker not
meeting its claim.

[Notabetatester]

I've received zero support on this matter from customer service. Here, support team just spits out their standard answers from FAQ, and completely ignore this issue, which seems to be blatant data inaccuracy. This is negligent behavior by FitBit, as HRV is meaningful health marker where accuracy is very important. If unable to accurately track HRV, then just remove the feature, instead of reporting erroneous data and getting users worried.

[Sondra123]

I’m new to sport watches. I’m in good shape. My HRV been mostly in the 20ies.

[Idunno]

In other words, it’s just a toy. Makes a nice watch though. 

[BobbyMcIdiot]

Another one here. Cardio fitness score of 50 (excellent), lowish resting HR of ~57, run 25k per week and walk another 25 on top of that. HRV of 19, pretty consistently. Never higher than 26, sometimes as low as 15. 

Reassuring to hear so many others have this issue, but disappointing that Fitbit don’t seem in any way interested in addressing the obvious: that this watch cannot measure HRV as advertised. It really makes me wonder if all the other metrics are screwy. Am I not as fit as I hoped? Is my resting HR accurate? Are my run times accurate (answer: no, because GPS is unreliable too). 

I’ve been a Fitbit customer for years and I’d hate to feel like all the data they’re feeding me is pure bull. But issues like this worry me that it might be. 

[PatrickUMB]

I think the basic metrics are good because they use palpable measurements. Their sleep score seems fairly accurate because I do remember the times I was dreaming and for the most part part the cycles seem to line up ok. I think their Cardio fitness score is hyper-sensitive and too reliant on RHR and not enough on daily activity. I dont use GPS so I cant speak to that.

[Goldblum57]

My Fitbit also shows my HRV hovering around the 20s or lower and has been ever since Fitbit added this display for nonpremium users. Not accurate. Makes you wonder what other information that it tells you, which cannot be easily independently tested, is inaccurate.

[Deirdre628]

Me too!! I just got a whoop to see if I’m recovering! Is it possible to overtrain in your late 40’s?! Lol. My whoop so far is higher than the Fitbit but I’ve only had it for 5 days... going to test the garmin also next week... cardiac issues in my family history so I’m hopeful maybe this is just an inaccurate reading... if so, Fitbit really shouldn’t be including it!!! 

[tjfairman]

I’m very pleased to find this thread. My HRV is freakishly (perhaps even impossibly) low on the Charge 4.  Given how many people are stressing  out about it I think the response from the Fitbit moderator is pathetic. I hope this issue gets some traction. If the metric is wildly inaccurate remove the function. Simple. 

[Nicola_grec]

I’m wearing my Fitbit every day , and when I wake up I look at HRV and I must say , if it is 28 , then I don’t feel so fit dat day , but I had days that it gives me 38/45 , and I feel good , I don’t know if the numbers are correct, but I feel the difference. 

-------------------------------

why you think its not acurate , maybe it is .

check your feeling when you wake up in the morning , and mesure you feeling against fitbit hrv . i think you wil be amazed.

[Kgou]

I always get a low reading. But I was sick a couple of days and HRV went
even lower and RHR an breath rate went up, as expected. The steady value
may be incorrect, but it does detect changes.

[ChrisB1966]

Hi, has anything been tweaked in the recent updates, if so and in general it would be good to have some release notes!

My HRV readings had been quite steady and in the 25-35 range and then suddenly they dropped to 14/15 for the night after HIIT exercise and then go back to my previous low reading as my 'new normal' on recovery days.   

While not great and contra to other health indicators, if the reading have just been turned down it would be good to know. I track my readings in a spreadsheet that shows trends and averages out the figures over a 7 day period, so they are mainly within a range again naturally - but know I don't know any true improvement if the goalposts have been moved.

[PatrickUMB]

I dont even put any stock in the measurements anymore aside from the steps and current HR. Im extremely active yet my fitness score is always low. I think the app's algorithm puts way too much on the resting heart rate for cardio-fitness. If I stay up a later than my designated resting times or have a few drinks, the resting heart rate sky rockets.  The HRV is so low that if it was accurate I would die any minute. The breaths per minute has this weird glitch that will sky rocket to 25 a minute for no reason, try breathing 25 times a minute, you'll pass out or at least feel really light headed.
I guess the moral of the story, take the readings with a grain of salt.

[YiannisP]

Indeed Chris, I noticed the same thing. There has definitely been an update, if anything it is obvious because now the HRV shows within a band/range in the app, that wasn't the case before. And yes, my average HRV reading has gone down as well after that band appeared, from averaging 70 to now 45. It would have been indeed a pretty obvious move to let people know about this so that they don't start worrying, but then it would be fitbit admitting they had it quite wrong in the first place... Not to say they don't have it very wrong still though, seeing that many people here are still getting crazy low readings and I guess now even lower than before. The sleep readings are also mixed at best, I have definitely noticed that it associates elevated heart rate with deep sleep! Should be the opposite one would assume. Whenever my HR is high when I go to sleep, it almost always registers a lot of deep sleep...and when I go all relaxed and HR 50, deep sleep is lower than average. My sleeping breathing rate is constanly 10, which Im not sure I believe either but I reserve judgement on that. All in all, not to take at face value, bit of a gimmick. Which we should all had guessed anyway if we weren't so keen on believing the marketing. I mean how can a little plastic thing replace several medical instrument of much larger size...