Heart rate inaccurate on Fitbit Sense

[Cameronoates]

Hey 

is anyone else experiencing huge heart rate inaccuracy during exercise with the sense? 

During exercise with the sense it won’t ever get above 120bpm for me 

but if I use my charge 4 during the EXACT same exercise my heart rate is between 145-170bpm in the cardio zone 

It’s extremely disappointing and I don’t want to have to switch to my charge 4 everytime I exercise to ensure accurate heart rate 

defeats the purpose of having the sense 

seriously one of the most frustrating experiences I have ever had.

Moderator Edit: Clarified subject

[Abhi2879]

Spot on Mateo. I am in dialogue with fitbit support right now. I noticed
the same thing with cardio, it's off but not as extreme as weightlifting.
I'm going to try something today, where I won't turn on the "exercise"
weightlifting and see what the heart rate readings are.
I love the sense, but for me I spend more time with training than cardio so
if it can't track my primary activity well, it's a beautiful accessory
albeit useless.

[Mateos]

Hi Abhi, I also do weight training and then the differences are even more off. Curious to know what support says. I have contacted them some while ago, but they came back with the general support sheets on how the weat the Sense.

[Abhi2879]

So far that's exactly where the conversation is going.. not to tight, not
too loose, wear it snug, don't compare with other heart rate trackers.....
I love the depth of information fitbit provides both on workouts and
sleep/HRV/RHR but I might end up switching to a combination of a Garmin
chest strap for workouts and an Oura for HRV/RHR/sleep.
Ordered the sizing kit for Oura today.

[Mateos]

I find the advice to not compare it to other trackers a bit annoying. I can fully understand that there is a difference in the exact results between trackers (depending on placement, left or right arm, etc). This morning I was in the gym doing an hour of exercise. Same program that I have been following for a while now. Ionic gave double the Active Zone Minutes for that workout as the Sense.  So this morning I did that workout again. This time with a Charge 4 that I bought this weekend (as I got fed up with having both the Sense and a Polar strap) and it again gives me AZM and minutes spent in HR zones that are comparable to the Ionic. Why should I not compare these devices and accept that I have to do double the effort to get to the same AZM? Especially as the Charge 4 coincides pretty much on a consistent basis with the Polar strap and the Sense does not. Does this advice mean that measuring your health status depends more on the device than your actual health and physical condition? Since replacing the Sense for the Charge 4, my heart condition in the dasboard has gone from "very good to excellent (41-45)" to " Excellent (47). I am sorry, but Fitbit needs to come with a formal statement regarding all the reported HR issues and tell if they are working on a fix or not. I love the Sense and want nothing else than the device to come up with sensible data. That is why I am keeping both the Sense and the Charge 4 for the moment, but I am running a bit out of patience with Fitbit's response to this matter. 

[t.parker]

@Mateos I find it annoying too and for me, it's a sign of being uncertain of the tech. I agree that comparing the results of interpretation of data makes not much sense (comparing calories, AZM etc. especially between different brands) as it will usually give different results. However, Fitbit very often says not to compare things like heartrate readings (because PurePulse is right and everyone else is wrong). We have only one heart, a beat is a beat no matter which device we use to monitor it. The device is either right or wrong. Heart rate is fully measurable. Comparing HR between devices of same or different manufacturers makes a lot of sense and as users we should be doing it to find the one that gives most accurate results. Giving the tech a cool sounding name ("PurePulse") doesn't make it automatically right 🙂

[Abhi2879]

I had the same feedback to the support tech. Finally asked point blank if
they intend to help or is the purpose of support to just defend what the
device does. They have created a case, I'll see where it goes from there.

[eilermcr]

@Abhi2879 I used “workout” today instead of “weightlifting” and got much closer to accurate than before.  At least showing my effort in higher zones.  Not a fix but at least closer to correct than before.  When I canceled “weightlifting” I was at 103 and when I started “workout” a second later I was at 145

[Abhi2879]

Thanks! I figured as much. I'll report to the case agent and see if they have anything they can share about this discrepancy in behavior!

[DangerDorsey]

This is a KNOWN issue in the community, but it is something that Fitbit has turned a blind eye to. I have researched this extensively and the problem is with the Sense and what happens is that your heart rate will not track properly until about 20-25 minutes into the exercise. The only caveat is if you stop exercising, rest for 10-20 seconds, and then resume, it will *sometimes* start to track properly. However, it will drop off again and stop tracking the proper heart rate. This is consistent with every time I exercise. Because Fitbit never acknowledged the problem (only says, we will improve), I was forced to buy an Apple Watch and abandon Fitbit after 10 years. It is disappointing. 

[DangerDorsey]

Here is another example. The thing that annoys me is that Fitbit has access to this data. You can clearly see that there is an issue. Many users are reporting this and yet Fitbit will not acknowledge that there is an issue. 

[TraciK1]

I have been a long time Fitbit user and recently changed from the Versa to the Sense.  In tracking my workouts it grossly under reports my heart rate.  I can be in a medium to high intensity workout and the heart rate zone shows I am "below zone" the entire workout.  It does this for any type of workout; cardio, yoga or strength training.  My Versa never had this issue and easily moved between Fat Burn, Cardio and Peak as it should.  This is happening across the majority, if not all, Sense devices so it isn't an individual issue, it's a software issue.  

Please Fitbit, please acknowledge this is issue and fix the software problem.  The Sense has the ability to be an awesome device with so much amazing technology, but the workout portion of the smartwatch is just as important.  I hope you will do what is right and fix this software issue.  This device is expensive and the customer should be able to use the watch as marketed.  I appreciate your time.

[flamelily48]

thanks for your response!

[Angeash]

Exactly the same here. I do intense cardio workouts and the heart rate tracking from Versa clearly corresponded to the changes in the workout intensity. Sense on the other hand has an annoying habit of suddenly dipping into resting HR mid-workout. There's no way I can go to resting heart rate in the middle of those workouts, minutes after being in peak - I'm not that fit! Please fix this!

[JWaddell95]

For as expensive as the Sense is, I would expect better accuracy on the heart rate. I recently upgraded from a charge 2 and am extremely disappointed. I have changed how I wear it (loose, tight, lower and higher in my wrist) with no accuracy improvement. During a workout the sense read 120 bpm. When I took it manually I was at 189 way over my max. My charge 2 was usually dead on. What other aspects are not accurate? SPO2? Sleep? ECG? Someone please tell me why I spent 300$ on this? 

[Onehourloves]

Right? Mine was $421AUD ON SALE. who votes that when Fitbit actually comes up with a decent watch they give us all one for free to make up for this absolute waste. I’m about ready to march down there and demand a refund. The steps tracker is way off too. Over it.

[Mannbrad]

I have deemed the sense as a heart rate monitor is USELES!!

[Brendån]

Same as radzieus, for me, the last few workouts.

Preeeeeeetty annoyed. I was hopeful it would be more accurate than my charge.

[YuliiaS]

I really like my Fitbit Sense but extremely disappointed and frustrated after each workout. That's an average difference between Polar and Sense. What the hell, really? 

[Angeash]

Frankly, if I didn't get Sense as a gift, I'd have returned it. I don't find the new features very useful, and the existing features don't work as well as on the good old Versa. 

[flamelily48]

me too!   paid an extra £100 pound too!  instead of versa 3