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

[t.parker]

Sense is capable of getting good/acceptable readings even with a normal band, the one that comes with the watch. This is probably one of the reasons why Fitbit can't fix (or doesn't even try to fix) the issue. See session below (indoor spinning, steady-state activity but gradually increasing effort), red - chest strap PolarH10, blue - Fitbit Sense:

For a wrist sensor, this is actually not the worst. The last time I posted an analysis of my half-marathon run (a few pages of this thread back) and the HR was trashed. This one isn't exactly following PolarH10 100% and I'm pretty sure that PolarOH1 would be more accurate but it's just ok for general purpose (wouldn't use it for HR-based training but to burn some calories or AZM - should be good enough). Sometimes, I do have good readings doing absolutely nothing differently. There is nothing that indicates any factors that could improve readings. It happens randomly. Spending extra money on the different band (which I highly doubt is a factor making difference)? Nope, I'd rather use the extra money for a different device that actually works.

[m-umar]

@t.parker sense is ok when one is not pushing too hard, and is on the lower end of HR zone although still behind 10-15 bmp but it really struggles to register or keep up with burst of speed or even when you are at the at peak of your run (going flat out).

I went out yesterday with sense very tightly secured and sweat band for 5k run after a go ok d stretch and warm up. I pushed as hard as I could with a steady speed all the way and avg HR was 117 with occasional readings in 20s.  My Garmin was on the left wrist  consistently hovering around 138-144 bmp. I know my HR where it should be during my exercise bouts. 

[m-umar]

@MarkMM & @SunsetRunner let us not biker among each other. There is quite possible sense give woods some higher reading at that point but it doe not mean "right bmp readings".

It is problematic device on so many levels no doubt about it. 

[m-umar]

@Strikes it really hurts when blame is passed on to the customers. So many of us using it wrongly.  Really Fitbit that's the best you can do!

[t.parker]

@m-umar my experience with Sense shows that it can be same incorrect when I do low-aerobic or tempo steady-state activity as well as incorrect for HIIT interval when my heart shoots up to 178-180bpm. There is no rule. Sense sensor is equally bad and just sometimes it can be right. Early on, I tested it just walking and in that case Sense didn't do well either (the Sense HR was significantly higher than chest strap). I don't believe that Sense is good in one case and bad in another. For me, it is just bad with a few glimpses that it can do good wihout apparent reason.

[SunsetRunner]

Sense heart rate values are very much like a bad or stopped clock: we know it is right sometimes, but we don't know when.

---

We can try to learn its apparently temperamental behaviour, though. That has been much what we have been doing here.

[t.parker]

@m-umar blaming customers is just easier than addressing the problem. But let's assume for a while that customers indeed struggle with wearing the watch correctly. What would it say about Fitbit products? If I was about to buy my first Fitbit I would think "it must be really hard to use those watches if so many users clearly don't know how to wear them" and probably think twice before buying. I'd rather buy something easy to use than a product that so many users use incorrectly (according to Fitbit).

[SunsetRunner]

Reading so many posts about how to wear the Sense to get more accurate heart rate values, it seems clear to me that there are only general recommendations, but they work differently for each user and each activity.

Concerning the users, the fact that people's wrists can have many types of size and shape, it seems natural that some users will manage to find a way to wear Sense that works for them in some specific activities, while other users will never get it. That's how sensitive and unstable Sense heart rate readings are.

Apparently the same applies to different activities.

ADDED LATER:

And then there are those random times, as already mentioned in this forum, when we do everything the same way, but Sense decides to behave in a totally different way, showing totally wrong HR values, all over the place, that, when we began using Sense, would leave us either completely baffled and trying to understand what we thought were accurateish values, or we just freaked out, mainly those of us who have a heart condition.

[Irish57]

Well stated!

[LovelessSea]

In fact, I just had a lovely conversation with a Gerard in the customer service chat who said "Since this is not a known issue, the only option we can provide is a replacement. The replacements should work and track your data accurately."

They are completely ignoring this issue, claiming it's not even on their radar despite a sixteen-page thread on their own forums. 

[MSASTER]

I gave up. I got totally screwed on the luxe they never did bring all the
apps to it. And because it was after 45 days. Wouldnt return it. So
anything saying in the future wait till its there if it matters to you. My
sense is doing the same thing. I didnt even get someone that nice.
Customer Service obviously is lacking. Fitbit doesnt care just figures if
we get that dissatisfied we will buy an new one. And they wont have to fix
or talk about its issues lol



--
"Dogs are not our whole life, but they make our lives whole." - Roger Caras

[Irish57]

Absolutely, each and every workout, impacts all other data’

[SunsetRunner]

COMPARING HEART RATE READINGS BETWEEN FITBIT SENSE AND POLAR H10

The Polar H10 chest strap is considered the most accurate heart rate (HR) monitor fitness device in the market, with a error of +/-2 bpm or less most of the time, used by many reviewers as the standard against which all other fitness devices are compared to.

The 3 photos show a Fitbit Sense and a second watch paired by bluetooth with a Polar H10 (unfortunately, Fitbit watches do not pair with external HR sensors, like the H10). They show heart rate readings from both devices in 3 different moments during an easy walk on flat ground. The Fitbit Sense was weared in two different positions and a proper band tightness, all already tested many times as providing the most accurate HR values Sense can give. During the walk, sometimes (less than 50% of the time) Sense showed reasonably accurate HR values, but, for several times, it suddenly increased to absolute nonsense values, for no apparent reason. Some of these HR values are shown in the photos.

Photo 1:
Sense: 140 bpm
Polar H10: 74 bpm
Estimated real heart rate: 72 to 76 bpm.

Photo 2:
Sense: 129 bpm
Polar H10: 74 bpm
Estimated real heart rate: 72 to 76 bpm.

Photo 3:
Sense: 133 bpm
Polar H10: 78 bpm
Estimated real heart rate: 76 to 80 bpm.

This post is mainly for the new or prospective Fitbit Sense users, but also specially dedicated to those members of the Fitbit staff who still insist that "Sense heart rate accuracy is not a known issue". Most Sense users in this forum already know that for quite a while, at least those who have been following or participating in this or other similar threads/topics.

Photo 1Photo 2Photo 3

[Irish57]

It is interesting the the Sense registered higher whereas for me
particularly on the Elliptical the HR is far lower than the other device.
Thank you for the information!

[SunsetRunner]

@Irish57, reading many users posts about these topic, it became quite clear to me that Sense HR values are lower than the real values on high intensity workouts with high heart rates, but on the other end of exercise intensity, as is the case of an easy walk with low heart rate values, Sense HR values have this awkward behaviour I posted, quite the opposite of hard workouts. Unfortunately, none of them is satisfactory.

[SunsetRunner]

Just to make it clear: my post above (with the 3 photos) is about what happened in this walk and is similar to many other walks before. But sometimes Sense HR values are reasonably OK during the whole activity. Why? It is this apparent randomness of Sense HR behaviour that makes it so unreliable on HR for someone who wants at least accurateish heart rates the whole time.

[Drock76]

This happens to me too. The only reliable ways for me to get an HR above 105 is by cycling at a low resistance and jumping rope. Sometimes my HR will drop to 70 during cardio, while my heart is basically pounding through my chest.

Honestly, I expected more from a Google-owned company and am exploring non-Fitbit options bc they seem to be burying their head in the sand.

[S.a.maes]

I absolutely cannot stand my Fitbit sense. I’m breathless in my workout and my heart rate is reading 91! How in the heck is that possible? I clean it, I tighten it, I charge it, change wrists, I reset it, I sync it. Nothing seems to make it want to read accurately consistently. I fiddle with it for 20 minutes to get it to read correctly by that time I’ve wasted 20 minutes fiddling with the sense instead of working out. Very frustrating!!! It’s past my time to return and I would like my money back or my product replaced !!!

[S.a.maes]

Doesn’t work period. One of the worst purchases I’ve made in a really long time. I want this to work so much but I just doesn’t. A lot of money down the drain.

[MarkMM]

@S.a.maes I've been following up with support every week or so. The most recent support chat person offered a replacement. When I questioned in the follow up emails if a replacement would have the same issue, I was told yes. A replacement would not solve the heart rate issue. And they claim they're still working on it. So if you got them  to send you a replacement, after paying to ship it to them and waiting a few weeks, you'd likely have a refurb that does the same thing.