Heart Rate Has Become Inaccurate/Incorrect

[VTHockey11]

I've had my Fitbit Charge 2 for about 10-11 months. No major issues with it, and have had an amazing time losing weight and getting great exercise!

However, lately I've noticed that my heart rate monitoring appears to be functioning incorrectly. 

Up until about 1 week ago my runs were showing my heart rate at ~60% cardio zone, 40% fat burn. Over the past week my runs, even 7-8 mile runs, are showing I'm in fat burn zone 100% of the time. This seems like a very sudden change!

For comparison, my Apple Watch shows my runs are coming in with heart rates that are notably higher - in the cardio zone.

Additionally, my resting heart rate has slowly dropped over the past 10-11 months from about 52 to 48. However, over the last week I'm consistently coming in even lower - 46 now. My resting heart rate, per my Apple Watch, is ~48. 

It just seems like the heart rate sensor is measuring my heart rate as lower than it should be. 

Has anyone else come across this with heart rate becoming inaccurate over time?

Thanks!

[greyfox1938]

I have the opposite problem, my heart rate is exceptionally high. I have used the Fitbit since February and in the last 2 month the high readings started and continue.

[Ashym]

I have the same problem. When I check my HR its sometimes off by 20- 30BPM. 

[augerin]

 My Heart Rate was accurate when I first got the Charge 2 about 2 months ago, but now its off 15-20 beats comparing it to a chest strap. It seems to have gotten worse after the latest update. The only time its accurate is at resting

[Faatima]

Mine has not been accurate at all since the last update. Off by 20-30 even when resting, and especially sleeping. Last night it showed that I had a HR of 103 during deep sleep! I know HR goes up during REM, but my chart is showing my lowest HR at night is 70. I’ve had my charge 2 since July and my HR while sleeping usually goes down to 52. Please fix, Fitbit!!

[Bibbie]

It's happening again.  I have been having a similar issue with my Charge 2 since the update to Version 22.55.2.  I have had my Charge 2 for a little over a year, with a typical RHR calculation in the low- to mid-60's.  Now after this latest update, RHR has steadily risen to over 70, although there has been no change in my activity level or health, and my manual readings throughout the day still indicate my RHR is between 62-68 bpms.

Something is definitely wrong with the current Fitbit RHR calculation.

[Ashym]

I am also having this problem still. I have reset the device and do so each time I charge it in hopes that it rectifies the problem, but never any luck. I have gone from a reading of a HR in the 60s, which is where my manual HR is, to a measured HR of in the 80s or 90s sitting still. Something is very wrong.

[DRun86]

Same issue. Shows fat burn zone even when I'm sprinting 100% for 2 laps around track. I've had to send it back for new replacement for same issue but not helping. Tried reseting fit bit and trying different areas on my wrist bit no luck. Kind of questioning my trust in fit bit. May pick apple watch? 

[SunsetRunner]

Mine has gone up too since the last update. I was in the mid 50's and now struggle to get into the mid 60's even though I sleep in the low/mid 50's. Last night I was sitting there and saw it go to 49 while awake, but it doesn't get logged.

[Cad_man]

I know this is a relatively old post I'm replying to, but having a very similar problem where my Fitbit is understating my heart rate during exercise.  Anyone have any tips?

[Dann213]

I just found out that  my fit bit charge 2 is “defective”  and that one day out of the one-year warranty I was offered 25% discount to buy a new one from them, which is higher than Amazon or other sellers.  The way this works is after one year you cannot get it repaired and you might as well throw it away. I am trying to think of another product, computer car washing machine television set up that after the warranty runs out you can’t get it repaired and you have to trash it. I also noticed that if You live in Europe you get a 2 year warrenty. NO REPARS! Bad company!  Buy Apple Watch after warranty runs out you can still get it repaired instead of trashing out and throwing it away. Comments please

[Zaaz]

Mine too it was fine until yesterday. Now my resting heart rate is at 122! I am burning 5000 calories watching a movie! 

[Vickytom9]

I had this problem too; the heart rate would sit at 150 bpm when the tracker wasn’t being worn! As I wanted a GPS tracker, I upgraded to an ionic. This was after about 20 months of having the charge 2 and wearing it all the time. Now, reading about the problems with Ionics failing, if this happens and I’ve no reason to doubt that the product will fail, I will not be purchasing another Fitbit model until the product is robustly tested, provides what Fitbit promises and has a customer service base which actually pays more than lip service to its PAYING  customers. 

[VenaF]

I got my charge 3 less than a month ago and it’s already giving me a hard time. I was literally just laying down and my monitor went from 78 -135 and than down to 60. I even moved it to my fiancé’s arm and it read the same on her. Almost like it’s picking up other people’s numbers or just glitching out 

[Nopasswdworks]

I have the same problem, heart rate way too high on checking against the HR on a blood pressure monitor.  I have had 3 Fitbits now and have had different problems with each one.  It's very frustrating!