Heartrate tracking and removal detection broken

[ArtOfCode]

I already commented about this in the recent firmware thread here: https://community.fitbit.com/t5/Sense/Sense-OS-update-5-2-1/m-p/4944965/highlight/true#M31901

Essentially, lately I've noticed at times that when I'm exercising and tracking it, my tracker seems to become somewhat to very inaccurate with my heart rate.

The example today was that after my gym session when my heartrate was still high I went to stop the exercise and my heartrate was showing somewhere in the 80bpm. I quickly felt my pulse and could tell that was way off. After stopping the exercise and going back to the home screen it showed the heart rate was 144bpm which seemed about right.

Sometimes when I take it off and wipe the back it seemed to fix it but not always.

Also, in regards to taking it off, it doesn't always seem to detect it's been removed, if I don't put it on the charger. Usually I just notice because it doesn't ask for my pin when I pick it up/put it back on, but I noticed one day recently that during the time I'd left it at home when I'd gone out it had measured a high heart rate during the period it was sitting on the shelf.

I posted in the firmware thread because I thought it might be related but then when I think about it I think this problem might have been here for a while, maybe since it was replaced under warranty.

[Guy_]

The Sense heart rate is known to be absurdly inaccurate when moving, or take a long time to get the correct reading.

However if you are still for a few minutes it will probably give you a good reading.

This issue appears never to have been addressed.

[Giampi71]

In other words Sense/Versa 3 heart rate sensor is useless when exercising/running/hiking and so on, quite a let down for the top of the line products of one the biggest fitness devices company out there and that makes the mentioned product totally not fit for use.

You can watch the following videos on youtube for an evidence of the issues

- From the Quantified Scientist (very scientific and accurate)

- From Wearable Whisperer (closer to personal use)

I can anticipate moderators comments "we are aware of the issue but we are unable to offer a solution at ths time".

[SunsetRunner]

I've been comparing HR readings between the Sense and Scoche's Rhythm 24 armband HR monitor during jogging.

Armband monitor connected to Runkeeper app and the app is set to provide HR readings from armband monitor every one minute. Sense and armband monitor have been consistently within +/- 2 to 3 bpm within one another. 

There were a few times during the beginning of the run wherein the Sense HR would spike to a high reading for a few seconds, then stabilize after. The Sense is worn about 2 finger widths from the wrist bone. 

Is this acceptable? I guess it would depend on the user. It would be great if the spikes were alleviated. 

I'm ok with it for now, we'll see how the rest of 2021 goes since I now rely on Runkeeper for jogging and use the fitbit as secondary dataset.

[ArtOfCode]

Maybe it's something wrong with my device, because there's a big difference between 80something bpm and 144bpm

[Guy_]

@ArtOfCode 

It's easy to check. If your watch says 144 and it should say 80, put the display timeout to 60 seconds.

Then when you have this situation, keep still and watch the heart rate come to the correct value.

You will see it changing way faster than the body can. Which proves it was showing the wrong value.

It's probably like this for all watches on the same firmware level, as there may be slight differences between versions, though it might be the same for all versions.

[ArtOfCode · Accepted solution]

I was able to solve the heart rate thing by wearing it higher on my wrist during exercise after feedback from the other thread. I'm still not sure about the removal detection though.

[ksattler]

I am having the same heart rate issue with my Fitbit Sense that you posted about. Wearing it higher up my arm did not resolve my issue. Sometimes, wiping it off helps, but not much. Sometimes wearing it lower seems to help but not for long. It is very frustrating because it isn't doing the job I bought it to do. It is typically 20-40 BMP off when doing exercise other than walking. There was an update to it shortly after I bought it that helped, temporarily. I'm looking for a solution so it isn't just an overpriced watch.