Heart rate not tracking correctly, therefore readiness, resting heart rate, etc all incorrect

[Shao3000]

The Charge 5 seems to randomly make drastic miscalculations for heart rate during exercise, and I'm losing all faith that it is able to measure heart rate at any time with any degree of consistency or accuracy.

The drops are usually to about a half or a third of the actual rate.

It will sometimes be accurate within 1-2% for a while, and then just completely drops the ball, and nothing seems to get it reading again, not adjusting straps, not rebooting.  And I've been watching it while comparing to an actual on-chest heart monitor, and when the fitbit does pick accuracy back up again, it seems to be without any external changes.. no adjusting position or restarting or anything, it's just suddenly accurate again.

( Here I tried to insert an image of the charge 5 data overlaid with real tracker data, but my post got marked as spam, so I've removed it )

I've been trying so hard to get this to device to work for me and help improve my lifestyle, but I'm really not happy.  I'm seeing a lot of people saying that other devices weren't as bad, but this is my first Fitbit device, so I've got nothing to compare it too (well, except for a selection of other heart monitors which all show similar figures to each other, but completely different numbers from the Charge 5).

Some days it seems better than other, perhaps after a fresh charge?  I'm not sure whether there's an pattern to these issues or it's just an outright hardware design failure, or bad software implementation, but then it's not my product to investigate, I'm just reporting that it categorically IS a major issue.

Apart from this issues, one of the reason chose a device listed in the Google store was because I wanted to use it with Google Fit, and it fails even on that front.  And how does an app from a Google owned company in 2022 not support dark mode without hacking around in developer menus?

What I'd like to see is some kind of any official statement acknowledging on these problems and that they are being actively investigated (and not just the same copy paste "have you tried turning it off and on responses).  

In a way, under reporting exercise might is better than over-reporting, but it's frustrating knowing that a workout worth 61 zone minutes in Google fit only counts for 20 zone minutes in the Fitbit app. And that the Fitbit app might be recommending me to do 50-90 minutes of exercise, when I should be doing active recovery.

The heart rate tracking during exercise not working correctly would also be more tolerable if the Fitbit app was able to sync the REAL workout data from Google Fit and overwrite the bad data from the Charge 5, so perhaps that's something for Fitbit to work on too?

[Dane02]

I am having this exact same problem, it worked well for the first two weeks but then it completely tanked. 

[AntonieFountain]

  

Just did a bike ride. The Polar chest strap averaged my heart rate at 153, where my new Charge 5 stated my maximum was 147. This is just a bizarre difference. 

[SunsetRunner]

I'm having similar problems. While rowing it's usually hit or miss if I get correct readings or not. Sometimes it's the opposite problem when I am lying i my sofa and the clock starts vibrating telling me I have reached my target. According to Charge 5 I'm apparently participating in an intense training session while I'm lying there resting... Even had my Charge 5 exchanged to a new one, but it made no difference.

[iceddante]

I started getting the same issue yesterday after about a month of use (and accurate readings). I work out on an exercise bike that tracks heart rate and saw that Charge5 reported my HR within 1-3 beats of what the bike reported. However, yesterday I started seeing numbers that were almost half of what the bike stated.

When my HR was about 140Bpm, the Charge 5 was reporting numbers in the 80s/90s/100s. Or it would report no beat at all. I tried moving it to the other wrist and got the same result. I tried wiping my arm dry but that did not have an affect.

Periodically the numbers would shoot up back into accurate territory! only to drop down again soon after.

That was a low intensity cardio session. Today I did some high intensity interval training and got really whacky numbers that were much lower than my actual rate, though again, they would periodically correct themselves.

I can take more diligent notes about the behavior if it would help.

It would be great to know if the Fitbit team is aware of this issue and has any idea if a fix is possible. thanks!

[iceddante]

Can we get a follow up from you all on this issue? It has never gone away and I'd like to know if anyone is aware or if this has been investigated at all.

[AntonieFountain]

I still have this problem, although I've found that putting the strap on
super tight helps a bit.
But basically I've stopped using it as a heart rate monitor, as I have
dedicated Polar gizmo on a strap on my chest when I'm cycling anyway. Big
disappointment.

[Shao3000]

I've found that I get accurate tracking if (and only if) I manually start an exercise activity on the device at the start of a work out, rather than just relying on auto-detection to categorise things afterwards.

Would be interested to find out if this improves things for anyone else.

[OhThatTodd]

This my seconded Fitbit. Fitbit is not remotely accurate for heart rate and never has been. Especially if you are doing something not steady-state like interval training. 

I did intervals on the bike. It claimed my heart rate was 91bpm. Pulse oximeter showed 130 bpm. When I was done Fitbit showed majority of workout was not even in training zone. These are not for any serious training.

Frankly I’d like my money back.  

[mmazzini1]

I have to admit that Charge 5 is quite erratic in measuring heart rate.  In my case most of the time overstates my heart beats, especially when i am at rest.  Also during exercise, ups and downs are just too much…

i believe the power of the led is just too low vs Charge 4 or 2…to save an already poor power reserve, heart rate accuracy has been sacrificed 

[ncoolong]

Thank you for writing this. Of the several posts on this exact topic (hint hint, devs, and yes, I've tightened the strap, and resetting the device is a daily activity) this one matches my experience the closest. 

I do interval training on an elliptical machine, and when my heart rate reaches 160+ (usually around the 3rd circuit) it will plummet suddenly. I've become accustomed to trying to dry off my wrist between circuits and that typically sets it to "--" for a little bit. Sometimes it will return to a heart rate that's more reflective of where I really am, but sometimes it'll fall even further, sometimes down to the 110 range. 

I've never had an interval workout where this does not happen. Sometimes it corrects itself, but I'm always left with a massive sawtooth showing a heart rate that went from 165 to 110 during the time I ramped up my pace. 

While I understand the goal is the workout itself and heart rates on wrist-worn devices shouldn't be used for serious tracking, the entire zone minute concept for which Fitbit markets its product depends on heart rate measurements. Because it continuously tracks measurements as much as 50 bps off for minutes at a time, I end up anywhere from 10-25 zone minutes off, which cannot be manually adjusted, and that plays into the app's recommendation of me being more active the next day by virtue of a "readiness score" that's largely connected to a garbage zone minute score from the previous day. 

This says nothing of the fact it's a massive distraction from my workout, and really seems defeating of the point. 

I've heard every tip and recommendation, nothing works, so I'm just posting in case someone in the market for one of these is reading. Buyer beware. Great concept, the product just doesn't work as designed. 

[Shao3000]

I was exactly at that point and close to giving up on it completely, but one thing support never suggested to me was adding Elliptical to the manual exercise types stored on the device, and at the start of the workout I now manually start the Elliptical activity on the tracker itself and since then it's been tracking with more or less equal accuracy to my chest strap monitor.  Have you definitely tried that?

Although I'm still not happy that we can't manually add minutes or edit time ranges on the heart rate history, as I do Kung Fu classes, and there are often periods of 10-15 minutes where I have to remove the device for it's own safety.   

[Madssch]

I'm seeing strange behavior for the heart rate tacking on my Charge 5 as well.

When exercising it shows 80 BPM when my heart is just pumping much faster.

At other times when biking nice and easy is shows 110 BPM.

How can you trust it then?

Has anyone gotten a good reply from Fitbit on this matter?