Tracking AF with a Fitbit/heart monitor - AF Association

AF Association

20,244 members24,777 posts

Tracking AF with a Fitbit/heart monitor


I've recently purchased a Fitbit to monitor my general health trends (how much exercise, sleep etc.) and I was wondering if anyone else has used one to monitor episodes of PAF. I was hoping to use the heart rate function to spot when I am going into AF, particularly at night. The thing is, I don't know how the Fitbit responds, does it track a massive increase in heart rate, or does it simply stop recording? The heart rate monitor has stopped recording for about an hour for the last two nights and I can't work out whether this is AF or something else. Is anyone else using a Fitbit with a heart rate function with their AF? How does it respond to AF?

24 Replies

Hi, a Fitbit can only record a regular sinus pulse. It doesn't work if you're in AF so won't record it. If you have a gap in your recordings you could then assume that you were having an AF episode but it is only an assumption it could be the position you were lying in meant it wasn't recording. Things that might suggest it was AF is that it was a long gap or when the recordings start again you're heart rate is lot higher and then slowly drops over the next couple of hours (that is the case for me). You will spot the patterns more when you have AF when awake and you can see what your Fitbit is recording. If you want to record AF a Kardia is a mobile ECG device but this records on demand not constantly so wouldn't record when you are asleep. One word of warning about a Fitbit / Kardia is don't let it become a habitat and constantly check it throughout the day as it can drive anxiety.

Pikaia in reply to Richard75

Yes, I wondered if the pre- and succeeding heart rates might indicate AF. I know the fitbit won't catch everything, and I'm thinking of spotting AF as an added bonus, but it would be good to be able to spot episodes that I'm not aware of, such as at night. You're right about not getting obsessed with it. I've started only downloading data from it first thing in the morning and then again in the evening, otherwise I'll spend all day checking my stats!

Which model do you have? I got a Charge 2 for Christmas so have just completed 1 month. I am in permanent AF (apparently) but rate controlled. Apart from the odd run of ectopics, I am unaware of being in AF.

My overall impression is that it is a good general rate guide only in my case as I am rate controlled and unaware of rhythm. The graphs show that my resting heart rate during January was 63, varying from 61-68. The overall rate varied from 56-114. Unfortunately my main exercise activity is swimming which I can't monitor because the model I have isn't waterproof.

I can't comment on whether it should record a massive increase in heart rate but my model has the capacity to record much higher numbers. It is of course possible to be in AF even at a low/normal rate as some of us are. I don't think Fitbit is sold as an AF detector as such.

Mine has stopped recording briefly at times. The help information recommends moving the position of the watch on your wrist and/or adjusting the fit of the strap to find where the pulse is strongest, so I suggest you look at the information for your model.

I hope this helps.


Pikaia in reply to Mrspat

Hi Pat, I also have a charge 2. It seems pretty good. It has spotted when I was about to have an episode, as I could watch my heart rate steadily increasing and I managed to stop it in time. Mine has stopped recording for about 1 hour the last two nights and I'm trying to work out why. It's been fine the other 30-odd nights, so I'm wondering if I'm suddenly sleeping differently or if I've had two episodes of AF in my sleep. Anyway, I guess I have to catch a full blown episode before I know exactly how the fitbit responds.

Mrspat in reply to Pikaia

Presumably you are using a PIP to stop it?

I have found that the Fitbit is not always an accurate step-counter when measured against actual performance.

Pikaia in reply to Mrspat

Not yet. I'm just on diltiazem. If I catch AF just as it's starting I can sometimes stop it with a few coughs or a bottle of water. The Fitbit isn't too accurate, I can record steps just by moving my arm, but as a general trend monitor, I think it works quite well.

RexH in reply to Pikaia

I have a garman vivosmart HR .

Have found it quite good, and water proof.

Never stops reading as well.

But agree danger of always monitoring what's happening can fuel anxiety. But also found it can give assurance as well.

Teresakelley in reply to RexH

I have used one as well it helps me to relax and monitor when I need to stop and sit down

Samazeuilh in reply to RexH

Will this device pick up an irregular heart rate and wake you up with an alarm if it is detected? I thought only the new Apple 4 watch would do that. If it doesn’t , does anyone know of a device which trigger an alarm which is a bit less expensive than the Apple 4? I don’t expect it to be 100% reliable.

The Fitbit Charge 2 won't reliably detect AF and won't wake you up if a particular threshold is broken. Sorry but it is not the device you are looking for.

I have a Fitbit and it does not read the skip beat

I used the fitbit hr to prove I was having SVT and what the trends are etc. it also caught episodes I wasn't aware of when sleeping. The fitbit takes an average reading over an interval, I had it on my wrist in a and e and it matched the hospital monitor, but what it couldn't recognise was sharp spikes in my heart rate the screen would show two lines. But when I synced later it kept a reading but it was at an average rate so didn't show my over 200 measurements but recored at 199 instead. I think it does a reasonable job at showing the overall picture and it has helped me and I managed to gather evidence to get my ablation last week, so i'm happy :)

Pikaia in reply to Ekheath

Excellent. That's just the response I was hoping for. Hope your ablation sticks!


I have the fitbit charge and only have had 3 very symptomatic a fib episodes in 13 mo. When Im in hard a fib my fitbit goes blank. It is only useful re heart rate when Im in sinus rhythm. Interesting sidebar, Dr put me on Mobic( nonsteriodal anti inflammatory drug) for my painful knee. After a couple weeks of taking it, I saw my average resting heart rate went from 60 to 80, gained 6 lb( fluid retention) and blood pressure up 20 points so decided knee pain was better than taking drug thats jacking with my heart rate.

I like my fitbit to use when Im exercising, ok with my heart rate going up to 120 but I slow down if it gets higher.

Like Mrspat I'm in permanent AF and I'm totally unaware of my condition. My resting heart rate over recent weeks has been in the range of 59 - 62. If i check my daily range it does show me as hitting peaks of around 170-190 but these seem to be at the times I take my daily exercise (most days!) of an 8km/5ml brisk walk. As for night times according to my Fitbit records my heart rate has stayed very constant in the high 50's

Hi I don't have AF I have bradycardia with occasional high peaks. My Fitbit is very accurate but I have read on the internet that the result are less accurate the higher the heart rate. I had a 24 hour ECG that confirmed the

Slow heart rate and my beta blockers have been reduced. I was on them for HBP

The Fitbit monitor is not heart rate monitor. It is a pulse rate monitor. With normal sinus rhytm the two rate is equal. During arrhytmias the pulse rate might be lover that leads to wrong conclusion. In the if Fitbit this might be an issue. If you search on the net with "fitbit" and "lawsuit" combination you can read about the risks using Fitbit.

Pikaia in reply to Mercurius

Good point about the distinction between heart and pulse. Thanks.

Hi Pikaia, my Fitbit type monitor was how I found out I had Strange heart rhythms. I was seeing spikes while asleep or sitting quietly up around 140 and higher beats per minute. Doctor put me onto ECG and the diagnosis was AF. Even on medication I have some high spikes, but less often. So yes, I would say it can show you some spikes. I like to wear my monitor but don't watch it constantly, feels like I can see how I am going, and gives me some comfort when I don't see spikes :)

Pikaia in reply to Sydneyside

Thanks. How high were your spikes when sleeping? I often have spikes, but only to about 60-65bpm from ~50bpm, so I don't know if that indicates AF or that I'm dreaming of something exciting.

Sydneyside in reply to Pikaia

I have similar daily ups and downs (+60-65) which are very different to my friends heart rates via Fitbit, but both my cardiologists have said those could be normal rhythm..

Bit of an update. After just under 2 years I've had another two, short (~30 minute) episodes of AF. I noticed them, but my fitbit had no idea and just kept recording a steady pulse in the 90s (granted, higher than normal but nothing to be excited about). So currently, for me at least, the FitBit Charge 2 doesn't catch AF.

I have a fitbit and it records the heart rate and is quite useful in that it tells me to slow down at whatever I am doing. I compare the fitbit with my blood pressure monitor and the pulse is always higher, I thought they would have been the same, so all the fitbit tells me is to slow down. I know this is not very helpful but maybe interesting to you.

My personal opinion: those Fitbit’s are a waste of money. They give you false information, when compared to more professional equipment and monitors that are available to the public. Why use something that doesn’t give accurate info, surely the stress from that is not a good thing, thus giving you worry about what’s right or wrong. You get a sweaty wrist (I don’t wear a watch) perhaps not good for accuracy of the Fitbit’s sensors. Perhaps more of a fashion accessory than a helpful medical planning tool/device!

You may also like...