Sense heart rate monitor is not accurate

[blenderbender]

I've been feeling the heart rate monitor is way off on my Sense and just proved it today pitting it against my Polar chest strap monitor. It's way off (low) over 15% on the way up and though the difference is less on the way down it's still significant. Is this usual and is it anything that can be addressed? I should have known, paying more for all the silly bells and whistles and the most important feature isn't even close to being accurate. Who gives a flying ____ about nighttime skin temperature.

Moderator edit: updated subject for clarity.

[John1D]

Sole chest strap for elliptical said 130 bpm. Sense said 84. Adjusted Sense to make sure it was in place and it said 103. Gave me 2 fat burn zone minutes for a 30 minute exhausting workout. The only things that the Sense does well is tell time and the alarm works. 

[reydernation]

I totally agree with the HR inaccuracy. How is it when I'm "cooling down" after a bike ride, low rpm and low resistance, and yet my heart rate is going up to 140 - 155 bpm? And when worn side by side with a more reliable exercise HR monitor (and no not even "medical" quality) it shows my cooling down HR at 80 - 85 bpm. This has happen dozens of time, it's not just an isolated result.

Bottom-line is my Sense is a nice way to find my phone, and occasionally look at the time. I don't trust any of the HR numbers. For what we paid for the Sense we should expect more. I mainly brought this watch because of the heart rate feature. Very disappointing! Time to look around for something different.

[IgorR11]

I recommend returning

I'm a sense 1 user and for 1 year I've been waiting for a fix for this problem and no fix

[ScottIowa]

I tried returning or getting my money back. They said a fix was coming or take it back to where you bought it. Mine was a gift and the store had a 90 day return policy on electronic products and really it was not the store that was as fault. After all the run around I got with Fitbit CS I gave up and bought an apple watch. I am very happy with it, it does what I need and more. The sense is sitting in a drawer. I see they have a new version I hope they fixed the problem. It would have been nice for Fitbit to give a truthful response to the issue over the long period of time that complaints were posted on this site.

[MarkMM]

I went with the Versa 2. Don't know what I'll do next if the Versa 2 is taken down. Reports seem to show the newest products likely have the same heart rate technology as the Versa 3 and Sense, which would seem odd since they were telling us it's a known issue they're working on?

[t.parker]

@MarkMM they just tell us what we want to hear.

[IgorR11]

Friends, it's been more than 1 year since they promised and nothing is done, it's a complete failure! Sense 1, sense 2, Versa 3 and versa 4. They are saying what we want to hear, but nothing is done, they are obsolete watches that keep generating defect and not even the main function is not fulfilled.

I did a cardio workout and was getting an average of 90/130 bpm when I was almost 200 bpm. I do not recommend fitbit watches to anyone!

[RDG1973]

I don’t know if anyone ever resolved this? I having the same issue, whilst exercising I have impossible swings in my HR. During a spin class it fell  from 168 to 70 in a couple of seconds then stayed around 100 for a few minutes then shot back up to 160! I had a Polar chest strap on and it had my rate consistent at an average of 158 but whilst the sense averaged 126! I was on to fitbitsupport and was told HR can be affected by temperature, the exercises im doing etc and cannot be compared with a chest strap because they use different technologies! Absolute nonsense they are recording the same function.  Anyhow fitibit help totally useless, why are the advertising this as fitness watch when it plainly it doesn't work whilst exercising? The HR data is consistent during resting walking etc but is absolutely useless when you need it to be accurate. Also the GPS and is way off and battery life all over the place. Really dissapointed, after owning several fitbits over the years this was supposed to be the premium model and it's utter rubbish! Fitbit won't offer a replacemnt or refund so buyer beware. I'll never buy a fitbit again!

[hflip]

Did restart, cleaned sensors and still way off.

[Topmatriarch]

It's funny you said that because I'm actually looking for my Versa 2 right now it was great it kept my heart rate right this sense 2 that I have drives me nuts I work out and the pulse ox monitor says I'm at like 150 to 155 and my sense 2 is sitting over here at 99 if that I'm really regretting the money I paid for this thing almost 300 bucks that's insane

[MichelleAllen68]

I am having this heart rate drop during exercise with my Sense,  very frustrating. I hope they are working on fixes

Yes I am not happy with the sense HR monitor either. It kept jumping up from 80 to 120 while I was just sitting. Then during a bike ride it went from 126 to 68???? Ugg so frustrating 

[grtoro]

I have a question for Fitbit and for other Sense 1 users: I frequently see HR spikes in the Sense daily records and I want to know if they are real. The graph below is from a fairly sedentary day, with a few trips up and down the stairs and short walks within the house. When I go cycling, I see spikes like these on the Sense but I don't see them with a Polar arm band (I don't use the polar at home). I don't care about systematic errors of up to (say) 10 bpm, but I worry about whether these spikes are real because I have had problems with atrial fibrillation.

I would like to know if other Sense users have seen (possibly bogus) spikes like these in their HR data. Could this have to do with the vintage of the watches (mine is from February 2022)?

Thanks. 

[SoDumb]

I originated this post as rmms but found I had to create a new username for some reason so I did.   Anyway,  after having the sense for the last year I think a lot of the HR problems are tied into how much you are moving your arm when you are doing the activity you are trying to monitor.   It does seem to swing wildly from one heart beat to the next, but, I wore my Fitbit Inspire and noticed that it wasn't off by much from that much compared to the sense.   Of course you mentioned that you are seeing it while cycling so I wouldn't think that your arms would be moving much....  Do you do a reset of the sense at least once a month?  I think that is a good thing to do.  Have you upgrade to the latest firmware on the Sense?  They rolled an update out a few months back.  Anyway, I am pretty happy with it over all.. You may want to try just switching the arm that you are wearing the sense, it may make a difference.  It seems to do a better job of sleep tracking then my inspire and seems to be working better for me.  But I do still see a lot of heart rate spikes that don't seem right at times. 

[Sparky72]

The Sense has been the worst model in my experience. I bought mine in June 2021 and it has been inaccurate with HR since day one. I contacted support a couple of times and just got the standard response to reboot, factory reset, update, etc. And nothing has ever helped it improves. It just keeps getting progressively worse. 

This is my fourth FitBit and likely my last. Not only has the HR been an issue, it often doesn't give an Oxygen value, and all the metrics seem to act up from time to time. As of the last few days all the measurements under the health metrics heading in the app have been blank. It doesn't show a resting heart rate, skin temp, oxygen, nothing. I think this **ahem** watch is on it's last leg and I'm looking at sw I thing to Garmin or Polar. I bought a Polar chest strap around four years ago just for when I'm working out for more reliable tracking of my excercise. I have been very happy with that, so I may go with Polar for a fitness watch as well, but Garmin has a lot more impressive looking trackers than Polar and supposedly can pair up with my Polar chest strap. Looks like Fitbit needs to improve both their equipment and customer service.