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

[Windman]

It was wise of you to do so.

I switched from Ionic to Sense because fitbit promissed that the sense would offer ecg and a more accurate hr sensor, and because the Ionic never lasted longer than a year. What I got was a watch that is less accurate than any other puls watch I own. The Sense is absolutly useless for sports tracking, and I haven't got ecg functionality yet. In addition as all the apps of the Sense that I use where made for the Ionic and are less readable on the Sense, its a poor smartwatch. The Ionic was also quite inaccurate when introduced to the market, but it improved with updates to an almost acceptable level, and I hoped that that the Sense would improve, but it has not improved so far, well except that I can use it to answer calls. Today I use a Garmin to measure pulse, and to get ECG I probably have to buy a Withings (recommended by my doctor). I still hope that Fitbit will improve pulse accuracy  and deliver ecg, if that does not happen soon I will probably give up Sense and Fibit. Meanwhile there other alternatives that are accurate and deliver quality.

[Beezy1978]

Yeah, sometimes my heart rate is accurate during exercise and sometimes it is wildly inaccurate.

it seems like the colder that the temperature is in my surroundings? The less accurate my sense is.

i have had it since pre-order, and I’ve been let down in SO MANY WAYS.

[SunsetRunner]

This has not been the case for me. My Fitbit Sense is within 1-2 BPM of my Samsung Galaxy Watch and old Fitbit Versa 2. Maybe this is just a bad batch?

[SleepyxEquus]

That would be a whole lot of bad batched watches than 😂. Because all of Amazon and Fitbit board has been complaining about it. I mean I wish mine had been 1-2 BPM off, as it was a nicely made watch look and feel wise..mine just never kept me anywhere above 100 BPM. 

[Windman]

I belive that most opitcal smartwatches have accuracy issues, but the Sense is extreamly innacurate To compare a Sense with an other Fitbit og Galaxy watch will not give reliable refrence data. I only trust pulse belts. Such comparisons tells me that the Sense have a 15 to 20 minutes lag, and that when it catches uo it may be up to 50 bpm lower, and at always a zone lower. My Fitbit was one of the first batches. Maybe the extreme deviation is due to batch HW issues. If there are more user out there experiencing accurate results pls tell us. 

[simon87]

So am I, I've had the sense for a year now and from the very beginning it's been inaccurate, especially since the last update, makes me wonder if the charge 5 has something to do with it, I've had a fitbit blaze, fitbit charge 4 and the sense, fitbit don't care about their loyal customers, just the new gulable ones

[SleepyxEquus]

Yes! I just got the Versa 3. I wanted to see if it’s the same issue as the Sense. As others are saying it doesn’t, but then those posting on the forum are saying that it does. I figure I have 15 days to use and test it, before it needs returned. So far the regular sitting and doing nothing HRM is accurate and it’s hit or miss with the stairs. 

[MSASTER]

No they don't care. I bought a luxe thinking it was going to get the spo2
which it still doesn't have and they won't return it even when it was 1 day
late and I had called numerous times. So that's a waste of money because I
will never use it. Charge 5 doesn't have the EKG either it's a we plan on
getting it someday. Lol

[SunsetRunner]

I totally agree that Sense HR inaccuracies are just appaling.

I recently bought a Polar H10 chest strap, considered the most accurate sport HR monitoring in the market at the moment. Comparing the values from both devices and checking them also with a third, a pulse oximeter, I realized:

• Sense HR innacuracies are sometimes even worse than I thought.
• H10 strap is indeed very accurate, always +/- 1 or 2 bpm from the pulse oximeter and my real HR (confirmed by checking with my fingers and a watch), just with a few seconds time lag.

Besides, I want to share with all of you that, as due to some health problems I can no longer run or do hard exercises, I use Sense just for calm walks (3-4 km/h) and everyday tasks HR monitoring. On this other end of the spectrum, concerning most users' exercise intensity, the HR errors I get very often are:

• Sense showing me HR values that can stay between 120 and 140 for 15 minutes or more, while my real HR is always in the 60 to 90 range during that time. It is this bad.

One year having passed since Fitbit launched Sense, I no longer believe they will ever fix it. Maybe in some next watch that Fitbit, or Google, may release on the next months, who knows... Not for me, probably.

[pjruggeri]

When my Sense dies which I’m sure it soon will….Im gone. Been a Fitbit fan for years but these last two products have been absolutely awful. 

[VB278]

Same problem but also even when sitting where the sense is almost always 10-12 beats higher than my actual rate as measured by a finger tip device.  But as reported it is to low when exercising.  This is NOT what was advertised when I bought at AND tech support didn't care.  Can't trust fitbit.

[SunsetRunner]

That is disappointing. I periodically check this site to see if they have fixed it. I guess not. I too have a heart condition so, I depend on the accuracy of the device. Its too bad that they cannot make something that is consistently reliable. 

[SunsetRunner]

To fellow Sense users with a heart condition too, to whom Heart Rate (HR) accuracy is really important during most of the day, inside and outside physical exercises:

• I have been using a Polar chest strap for the past 10 days to monitor my HR and comparing it with both Sense and a medical pulse oximeter. The result is that I am really happy with this chest strap. It's really very accurate all the time and puts Sense HR to shame, mainly when there is movement involved, which is most of the time.
• The point now is to have a watch to easily monitor the strap HR, because doing it on a phone app is just not that practical.
• Apparently, Fitbit still has no plans to allow pairing its watches with an external HR sensor. And apparently they also have no plans to produce a chest strap of their own, as far as I could find searching this Community forum and the Community Suggestions.
• Other brands are already doing it: Garmin, Polar, maybe Samsung, Apple and other brands too.
• Reading other users older posts from several threads, we see that Sense HR big inaccuracies are a problem since the beginning, about a year ago, and Fitbit is still unable to solve it.
• Having all this into account, it is only a matter of time (and money) that I abandon my Sense and move away to another brand. Much to my regret, because otherwise I love my Sense and used to love Fitbit, but all Sense and Fitbit flaws and shortcomings are just crossing that red line and going down to an unacceptable low quality level, as far as HR is concerned, not to mention other features not so important to me. I'm so sorry and disappointed, but Fitbit has just not been up to the task.

NOTE: chest straps heart rate readings are usually known for being more accurate than any watch, due to using a different technology (electrical measurements, similar to the ones used by ECGs, instead of the optical sensors used by watches). Besides, they are not affected by hand and arm movements that have an impact on watch HR accuracy. Chest straps can be more unconfortable to wear, though. I'm fine using my H10, but some people may not like it.

[VB278]

I fully agree with you and am actively seeking an alternative. I have used
Fitbit for more than 5 years but the marketing behind Sense vs. reality is
simply unacceptable and given the misrepresentation on Sense leaves me not
trusting Fitbit. It was much better before Google.

[SleepyxEquus]

100% Versa 3 is exactly like Sense with the same issues. I did pre order the charge 5, as I am a glutton for punishment I guess. As I like trying out the latest watches and make my own decisions on it. I see a ton of times, the very first products out with a pre order are fine and then start to go down hill from there…so we will put that to the test. If it’s the same as Sense and Versa, I am done with Fitbit going forward..sucks as I really love their app set up.

[VB278]

Let us know what you think of the charge 5 as I am searching.

[Toons114]

I made a strange discover regarding this issue. the problem for me is the sense is always way to high ... from simple rest (+10 bpm) to activity (+15 to +25 and more at least). When I make this comparison, it is with garmin venu, and two oxymeters. For info, oximeters and venu are the same +/- 1 bpm

As I was running i used a sense on my left wrist, the garmin venu on my right wrist and took the two oximeters with me.

Over one mile I compare the sense which made already alerts with 156bpm and more, the venu was at 129, the I tried to use one of the two oximeters while running ... and guess what ... the oximeter indicated almost the same result of the sense ... which I found very strange and when i looked to the sinusoidal signal on the oximeter, it was very parasitized.... as it was very distorted by the movement of running... I then stopped and walked, and in 3 second the signal on the oximeter was good and the heart rate was the same as the venu... 

It sounds like the sw treatment and correction or maybe the hardware is false regarding the simple treatment of heart bit while moving ... from regular moves ... to activities .... I will then try to use the warrantly but I'm not sure my unit is consider as faulty by fitbit ... what A SHAME

[SunsetRunner]

Thanks for sharing your experience, @Toons114 .

Concerning the pulse oximeter readings while running or otherwise moving your arm a lot, I also tried that before and concluded that I need to keep the oximeter "glued" to the finger in order to keep having accurate readings. Either by pressing it with two other fingers, or just using tight adhesive tape. But it doesn't always work very well. I tried to do the same with my Sense but did not succeed on getting better results.  

At the moment, for accurate heart rate readings in any daily activity, including exercising, I'm more and more into a chest strap, which has always given me accurate readings for the past two weeks or so. @SunsetRunner  has also reported good results with an armband, in another thread. The main issue with these straps or bands is that Sense doesn't pair with them, either by bluetooth or ANT+, you have to read the HR on the phone.

[SunsetRunner]

@Toons114, you wrote "sense which made already alerts with 156bpm".

Do you get these high heart rate alerts on Sense? How do you do it while running or walking?

The only way I get this kind of alerts on Sense is by using a non-Fitbit app called AlertMe with a very basic interface. But as Sense HR is too often so far away from the real HR (higher most of the time), AlertMe kept giving me false alerts.

[Irish57]

I agree with inaccurate heart rate information. At one time months ago I felt it was pretty good but now I don’t believe close!