Charge 6 - AFib alert

[Jbondfl]

Has anyone else successfully use d the AFIB feature on this device where it actually notified you of AFIB event? I've had two high events, one last night. I was 170 BPM Resting heart rate and the device never noted it or recognized it. I had a previous event that my heart rate went up to 149 BPM and again, no alert or notification of that event. I don't get it. Any help would be welcome  

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[RiekoC]

Hello @Jbondfl 

This help page explains how Fitbits detects AFib and how the notifications work (<-- click link). 

Basically, Fitbit can only analyze your heart rhythm data for AFib when you’re still. If I remember correctly, the device is monitoring for high heart rate when you're still for at least 10 minutes. 

[LZeeW · Accepted solution]

@Jbondfl   I participated in the Fitbit Heart Study that developed this feature.  Fitbit published the results in the journal Circulation. Your Fitbit must detect an irregular rhythm for a minimum of 30 minutes in order to generate an alert.

[Earther]

I'm pretty sure that Charge 6 reports my heart rate when I'm moving or have just moved, not only when I'm still.

[Earther]

That can't be true, because most aFib incidents don't last 30 minutes. Results of the study that you participated in were published in Circulation on 23 September 2022. I'm responding in August 2025, so surely they've improved that feature by now, and it is different from what you describe, as far as I can tell. 

I've had recent aFib alerts on my relatively new Charge 6. They state the time but not the duration (screenshot follows), so it could be true but it would be quite surprising if so. Notice that I didn't get the notification until 12 hours later, after the incidents were "analyzed." I have an implanted heart monitor (just a monitor, not a pacemaker). I had fluttering that morning but not at that time. So I'm concerned about 2 things:

• Does it differentiate between aFib and tachycardia? I have short instances of tachycardia sometimes, and I'm betting that's what these really were, not aFib. I didn't get this notice until hours later, but I ran an EKG then, and results showed "Normal sinus rhythm."
  
  
• The disparity between the HR irregularity and the Fitbit transmittal of the alert make it not nearly as useful as I had expected and not useful for any true emergency.
  
  

[Earther]

CORRECTION: No option to delete my reply saying "I'm pretty sure that Charge 6 reports my heart rate when I'm moving or have just moved, not only when I'm still." in response to RiekoC's post: 

"Fitbit can only analyze your heart rhythm data for AFib when you’re still. If I remember correctly, the device is monitoring for high heart rate when you're still for at least 10 minutes."

Both are true, but I misunderstood and meant that Fitbit tracks HR data when we're moving, not just still. But it's true that it monitors for aFib only when we're still for at least 10 minutes, plus it doesn't send notifications of any incidents until the data has been analyzed, which can be many hours later.

[Samareno]

I used it like that too.  I used to get congrats on my zone level.  Since I knew I was only walking or watching TV, I knew I was probably in afib.  Now I don’t get those.  I never get low/high heartrate either.   Fitbit stopped being useful.  Since heartrate is so basic feature, not thinking will bother to upgrade.  Last week afib was so much I could feel it but Fitbit said was <70 beats.  I checked my old AppleWatch6 and pulse was >134 and all kinds of weird beats.  There is 0% use for average/resting heartrate when bradycardia/tachycardia/afib might be an issue.  Like I said, not working like intended but that worked for me until now Fitbit broke it all. Contacted support and do not even have notification setting!  Sure, registers a pulse but what use if not accurate and not alerting me?  I know I have bradycardia and afib and have been thinking all is good when all is BROKEN. :(. Very sad because having info helped when these things happened.  I am searching for replacement.  AppleWatch doesn’t track all the time like Fitbit but gives liw/high warnings or afib.  Fitbit no longer does anything, It really showed <70 BPM when I can take manually and tell it’s crazy fast? in the past,  sometimes would show lower then higher when irregular, but last week nothing was off while I was in afib!  What use is that?  Would be more worried about BPM  being accurate if I was actually using it to make sure I was not too high to give myself a heart attack while exercising!

[Earther]

I also have bradycardia and AFib, along with intermittent brief PACs and SVTs and other heart problems. Obviously high risk for stroke and even sudden death, so the main reason I bought another Fitbit is, like you, for the heart rate monitoring and alerts. As I said in a previous post (with screenshot), it did report prolonged incidents of AFib back in July or August but nothing since. Not even when my heart rate dipped to 29 while asleep! I know about that because I now have an implanted heart monitor, aka loop recorder. The Fitbit EKG feature syncs nearly perfectly with the implanted monitor, though. 

I'm still hoping they release a Fitbit Charge 7. I'm never switching to a watch (tried one, hated it). I'm also not forking out money for anything from Apple, which wouldn't be compatible with either my $ constraints or my phone or laptop computer. So if no Charge 7 this year, next year I'll probably buy Garmin or just give up on all of it. 

If you find something that gives instant alerts for drastically low or sudden heart rate drop, increase, or erratic beats, please tell us what you chose and why.

Related: People here seem to constantly complain about the sleep reports. Mine are nearly always accurate, but I use the Sensitive setting.

Judith in Port Angeles, WA, USA

[Earther]

PS: My implanted heart monitor does not alert me, and it takes several days or weeks before the staff at the hospital reads the reports that it sends. It has confirmed a couple of things, but it's not likely to help save my life in an emergency. Even so, I'm glad I have it and am now on $$$ per month Eliquis (blood thinner to prevent a stroke caused by a blood clot, theoretically). Anyone who has AFib should find out whether they should be taking a blood thinner, too, if they aren't already. Answer is likely to be Yes.