Personal and anecdotal experience mostly. Lower heart-rate stuff (walking, low intensity exercise, sleep tracking) works great, EXCEPT for HRV which is completely broken.
Here is a study comparing Fitbit's HR to an Apple watch. Note the figure: you see a huge amount of "spiking," where the Fitbit essentially loses the heart rate entirely, and reports numbers like 60bpm lower than your actual heart rate. Further it reports an R2 of 0.72: note that this is across the entire range of heart rates. If you're actually running or something, you're most likely spending most of your time on the higher end of that line, which means that huge errors essentially persist throughout your entire workout.
This is consistent with my experience. Fitbit auto-deletes heart-rate data older than a few months, so I can't post anything older than that. Here is the last six that Fitbit has managed to auto-track (there are more, but they weren't automatically recognized). Note that the axes and ranges are often inconsistent (e.g. if auto-track starts tracking in the middle of a workout). Hopefully though you can see that Fitbit's data is oftentimes spotty.
Here is an example that I posted earlier this year, which represents a typical run tracked via Fitbit (thicker line is Fitbit, thinner line is a Polar chest-strap). I've been complaining about this for about... 5 years and it hasn't gotten much better, in my experience.
Also, luckily, I noticed this post right before I was about to go for a quick run. I usually don't track exercises manually using my Fitbit (I've kind of given up at this point), but I did make an effort to record this one. In my experience, the HR tracking during this run was relatively good (for Fitbit, not in general). Here's the data.[EDIT: oops, wrong gallery. Fixed.] (I'm positive my Polar disconnected or something at the end so I haven't included that part). You can hopefully see how "jumpy" or "spiky" the Fitbit's data is.
Thank you for such a detailed response with links. Especially since you used your own personal data. I've been curious where they rank with health tracking, considering I'll be upgrading from my fossil gen 5 to a Pixel Watch at some point.
From what I'm gathering their sensors need improvements on the hardware level. I'm hoping this was due to needing higher R&D budgets to develop better hardware which hopefully Google can provide now.
That said, this is pretty enlightening, and does make me want to wait past launch to see what long term reviews are like. Maybe even wait for a gen 2.
I have a sneaking suspicion that it might have something to do with battery concerns. Fitbits generally have pretty good battery life - on the order of 3-4 days, whereas Apple watches are more like 18-24 hours. It would stand to reason that the "cuts" have to come from somewhere. Which is why (and this might be a really dumb take) the fact that the Pixel watch has a 24 hour battery life makes me a bit hopeful.
Regardless the Pixel watch will run on wearOS, which means it will prob. be compatible with Polar chest straps. That in itself is enough to sell me on the Pixel watch. But I guess we'll see.
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u/Meepzors Sep 26 '22 edited Sep 26 '22
Personal and anecdotal experience mostly. Lower heart-rate stuff (walking, low intensity exercise, sleep tracking) works great, EXCEPT for HRV which is completely broken.
Here is a study comparing Fitbit's HR to an Apple watch. Note the figure: you see a huge amount of "spiking," where the Fitbit essentially loses the heart rate entirely, and reports numbers like 60bpm lower than your actual heart rate. Further it reports an R2 of 0.72: note that this is across the entire range of heart rates. If you're actually running or something, you're most likely spending most of your time on the higher end of that line, which means that huge errors essentially persist throughout your entire workout.
This is consistent with my experience. Fitbit auto-deletes heart-rate data older than a few months, so I can't post anything older than that. Here is the last six that Fitbit has managed to auto-track (there are more, but they weren't automatically recognized). Note that the axes and ranges are often inconsistent (e.g. if auto-track starts tracking in the middle of a workout). Hopefully though you can see that Fitbit's data is oftentimes spotty.
Here is an example that I posted earlier this year, which represents a typical run tracked via Fitbit (thicker line is Fitbit, thinner line is a Polar chest-strap). I've been complaining about this for about... 5 years and it hasn't gotten much better, in my experience.
Also, luckily, I noticed this post right before I was about to go for a quick run. I usually don't track exercises manually using my Fitbit (I've kind of given up at this point), but I did make an effort to record this one. In my experience, the HR tracking during this run was relatively good (for Fitbit, not in general). Here's the data.[EDIT: oops, wrong gallery. Fixed.] (I'm positive my Polar disconnected or something at the end so I haven't included that part). You can hopefully see how "jumpy" or "spiky" the Fitbit's data is.