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

[SunsetRunner]

@SunsetRunner 

Am still getting similar readings from my armband monitor and the Sense when exercising in Run mode. Both the Sense and armband HR monitor are mostly +/- 1 or 2 BPMs with each other. I read somewhere that when the Sense is in one of the exercise modes, the HR reading intervals are increased, this might explain the almost matching HR readings between the arm band and the Sense. While at rest, compared to my oximeter, the Sense is about +/- 2 to 3 BPMs whenever I take morning readings with the oximeter. 

Anyway, thought I'd share my experience with the Sense and fitbit has always mentioned that the Sense is not a medical device, as a caveat to everything that the Sense is capable of. Suppose any sensible company would place that language in their products in the realm of wearables. 

[VB278]

Same experience

-----------------------------

I have come to same conclusion...a chest band is only way to get accuracy
but then I have to give up fitbit

[SunsetRunner]

Thanks for your feedback, @SunsetRunner .

I'm glad you nailed it for your running exercises.

I thought I had nailed it for my walkings until this year's May/June firmware update. Since then, I lost it. And it's not just a matter of Sense not being a medical device. When I'm wearing my Sense correctly but still have unexpected spikes lasting several minutes with heart rate values 1.5 to 2.0 times higher than the real HR... it's just unacceptable.

The resting HR values are also quite accurate with me.

As for the rest of the day... it depends, the HR can range from accurate to wildly inaccurate. Which makes HR dependent values, like Calories or Active Zone Minutes, quite pointless.

My conclusions:

• Heart rate accuracy may vary a lot from one user to another, and from one kind of activity to another.
• Fitbit still has a lot of work to do concerning HR accuracy.

[Toons114]

i will also had that at this stage it creates STRESSFUL, ANXIETY-INDUCING in almost ALL situation of life !!!!!

Even when you rest IT IS TEN OVER, how can fitbit pretend to care of our health ? 

Most of the indicators are based ON the heartbeat.... !!!! even sleep !

And not talking also while exercising !!!! +30 over !!!! 

What as shame!

Shame for not assuming 

Shame for not beeing transparent assuming that THERE IS AN ISSUE

Shame for nor saying if it is HW or SW

Shame for not giving a SCHEDULE .... 

IT IS LIKE THE FLOOR COUNTING .... NO TRANSPARENCY !!!! 

[Irish57]

I agree, my resting heart rate has been increasing without apparent cause!
I don’t understand as you said with the repeated number of people with
concerns why this is not being addressed!

[VB278]

Man I wish I could answer the why question? I have called technical
support but they essentially blew me off. As I said things seem to have
been better before Google took over BUT of course I can't prove that.

[VB278]

One thing I can say with certainty is that the EKG function DOES provide
100% accurate heart rate information but the standard heart rate function
does not.

The difference is that the EKG function is based on fingertip values like
most heart rate/oxygen devices whereas the standard heart rate function is
based on "wrist readings" which are not as accurate. The difference can be
considerable. I have had more than 10 beats per minute differences.

I know this because I have a slow heart rate.

Thanks

[SunsetRunner]

An improvement on Sense heart rate accuracy - my recent experience:

For the past days, I wore my Sense with its band a bit tighter than before (one notch more) and the heart accuracy improved significantly. The odd spikes in the middle have not reappeared so far. At the same time, I was wearing a H10 chest strap to compare HR results.

Cons:

• Wearing Sense this bit tighter, its band probably won't last as long as it should. But it's still early to say.
• Also, after finishing wearing it like this for an hour or so (my daily walk) I definitely have to take the Sense off for a while and rub that wrist place, because the band shape is clearly marked on my skin, band holes and all. Not that confortable, I would say.

Some thoughts:

• Maybe the watch band gets streched after using Sense for several months and then we will need to tighten it one more notch?
• People's forearm and wrist are not all equal, some are thinner, some fatter, others more bony, etc. So, probably the right band tightness on Sense will not be equally confortable for everyone. Assuming there is a "right band tightness".

Hope this helps at least some of you.

---

More:

• There is definitely a significant time lag between our real heart rate and the HR displayed by Sense. I have not carefully measured it, but I estimate it can be up to 10 seconds maybe. For some people and situations this can be important. Anyone with other experiences on this?

[Irish57]

I have tried this before but not in quite some time. For sure my leather
band has stretched. Will have to put an additional hole though as my wrist
is thin. Great advice and will try or simply replace the band.
May I ask what impact was on your resting heart rate?
Thank you

[Strikes]

Here we are a year in... still no solution. Definitely not purchasing a fitbit again in the future nor will I recommend them anymore. Such a disappointment. Support is useless and gives you the run around... This is a problem with the device and or it's firmware.

[SunsetRunner]

Hi @Irish57 ,

I have used the Sense band this tight only during exercises. I don't think that will have any impact on my resting heart rate.

Anyway, I read also your previous post on this and checked my resting HR for the past months. I couldn't take any conclusion. Its values keep fluctuating as always did, I didn't notice any recent change on that.

[SunsetRunner]

@Irish57 , I only thought: could it be that your resting heart rate is getting higher because it's getting more cold now? Assuming you also live on the northern hemisphere. But I don't know much about that subject anyway.

[IgorR11]

Hi everyone, I hope you guys are alright.
So, lately I've been very active here on the fitbit forum in order to find a solution to these problems with the accuracy of fitbit sense/versa 3 sensors.
I use my free time to observe and test the watch functions and after some reports I participated in here on the forum, and incredibly this last Monday, the watch seems more accurate!
I use the watch on a short walk of almost 10 minutes daily and I have never exceeded 150 bpm (the watch seems to be buggy in this beat margin), so using as I do daily I put it in "walk" mode and reach a margin of "162 BPM" and an average of "140 BPM", I was curious and thought it was some miracle. Later the same day I managed to hit "72 minutes of AZM". For those who use sense, you know what I'm talking about and getting this average is very difficult, I've used running and haven't reached even half of it, that is, I felt a slight improvement in relation to these data.
I have a bachelor's degree in pharmacy and I'm addicted to health data, so I used tools to verify the veracity of these sensors, in the tests I used a finger oximeter and an arterial pressure cuff, I also used a garmin 6x pro solar and amazingly the results were the best . I hope fitbit solves this problem for us users and see that it is more important to keep customers happy than just launching models every semester.

[MarkMM]

@IgorR11 That seems pretty amazing. There hasn't been an update release, so why would it suddenly be more accurate? 

My Versa 3 has been shut off for a couple weeks now, and I'm enjoying more motivational results being back with the Versa 1. I couldn't even hit 90 BPM walking hard for two miles on the Versa 3. Regardless how tight/loose, low/high I wore it. Fitbit has me at 100BPM for fat burn, so I get 0 results walking hard. Meanwhile rinsing vegetables in the sink will be fat burn. 

[Irish57]

Thank you

[IgorR11]

@MarkMM I really don't know what to tell you, I don't know the real reason. I'll keep an eye out to see if it was a fluke, I need a few more weeks or even a month to make sure if it's more accurate or was something occasional

[SunsetRunner]

@MarkMM , according to Sense, rinsing vegetables in the sink is indeed an excellent and easy way to burn fat. As well as washing hands or dishes

😂  Wish it was true....

[SleepyxEquus]

I went back to my Ionic and sent the Versa 3 back. It was the same as Sense and I have the Charge 5 on pre order to see what it does. Probably same BS..but we will see. 

[t.parker]

@IgorR11 in my tests, I noticed the readings could get very accurate (aligning with chest strap data most of the time) but then 9 out of 10 tests the readings were just rubbish. It just shows that Sense can be accurate when it wants but there is nothing telling why sometimes it is quite accurate (I didn't do anything different, was wearing the watch the same way, ran the same trails, etc.). It's not much help when 9 out of 10 times it fails. I stopped using Sense a long time ago (I think it's somewhere dead in my car :D). Fitbit's focus is on releasing new devices rather than supporting and fixing those which are already in the market.

[MarkMM]

@SleepyxEquus Does the charge 5 use pure pulse 2? The Sense and Versa 3 both had the new pure pulse 2 technology and have issues.. I haven't seen what Firbit is doing going forward.