Surge Heart Rate Monitor Inaccurate

[Jac0209]

I have seen quite a few posts about the heart rate monitor being very inaccurate.

My FitBit Surge is brand new, it was kindly replaced by FitBit when the band on the previous one broke.  I did not really have a heart rate monitor issue with the old one.

Since I have had the new one, I have found that the heart rate tracker is astoundingly inaccurate, partly at higher heart rates, and during selected "Exercise" activities.  For example, today I completed a workout at the gym, which included both weights and cardio.  The gym machines recorded my average heart rate for 30 minutes on the stationary cycle at 179 bpm.  The FitBit recorded my average for the exact same time at 115 bpm!  That is quite a difference.

Also, at a specific time, the gym cycle recorded my heart rate at 192 bpm, while the FitBit at that exact time, told me my heart rate was 125 bpm!  I actually measured my own heart beat with my fingers and it was almost exactly what it was on the gym heart rate monitor at the same time, while the FitBIt was around 50 bpm lower (than my fingers).

I have also noticed that my heart rate is say, around 100bpm on the FitBit, and then I will select an exercise, and as soon as I do, the heart rate on the FitBit instantly drops to around 80bmp and does not increase as I start the exercise, and often actually drops!  And it does not match even remotely, to what the gym machine heart rate monitor is telling me, and recently, what my own fingers on my carotid are telling me.  This happens regardless of what exercise I am doing, be it cardio or weights.

Interestingly, the calorie count is very different too.  The gym machines calculate my calorie burn estimate based on my weight, age etc, as well as my heart rate and it will give me a vastly different calorie count than my FitBit, for the exact same exercise and the exact same age, weight, etc.  Over an hour of exercise, FitBit will tell me my average heart rate is over 50bmp lower, and my calorie count more than 200 calories less (often far greater difference than that!), compared the gym machine heart rate monitor.  I have also used many different gym machines and brands and they all show me roughly the same info, but always vastly different to the FitBit.

Often times, the FitBit will show a sudden increase from say, 115 bpm, to 170 bpm, for about 2 seconds and then return to what it was.  Just randomly.

I have changed the positioning of the band, as suggested, I have also loosened it, turned it on and off a few times and nothing has changed.  I try and keep it sweat free (although really, a fitness device should really be able to deal with sweat, one would think - it is kinda like selling a beach towel with the instruction of "for best results, keep the towel away from sand and water").

Unfortunately it seems that this is a very common problem, across many of the FitBit products, not just the Surge!  And there seems to be no actual fix from what I have been able to see.

On a side, note, I also have the Aria scale.  It gives me a body fat percentage that is consistently 10% to 15% higher than the results I have gotten from numerous, rather expensive body composition analyses from a medical specialist!

I understand that the FitBit is not a medical device as such, and I do not expect 100% accuracy.  But I would at least expect it to be accurate enough to be useful, especially for the Surge which is one of the most expensive of the range.  For the money I paid, I would expect it to not be completely inaccurate, at least!

When a device consistently shows a heart rate at 50 bpm or more below the actual during activity, and body fat percentage 10-15% higher than actual, then I do not consider this to be useful at all.  How can one measure their progress and alter training and activity in response to data, when the data is wildly inaccurate?  It just means the devices are not worth having at all!

Unless these issues can be fixed, then I think I shall be searching for another brand, and writing off the nearly $600 I have spent on FitBit products.  Customer service is awesome, but the technology is not.

[YojanaFitbit]

Hi @Jac0209 It's great to have you here in the Forums! Thanks a million for your overall feedback, it's really appreciated! 

After reading your post I can tell that you have had some time to test your replacement and I'm starting to think that you might have to let our team know about the way it is behaving. You can try to restart it a couple of times to see if this helps. You can also turn off the HR and sync it, and later on put it on Auto and sync again. But as you mentioned you didn't have HR issues with your old one so you can recognize that something is not right with this one. Please try to do so, and if you don't have the option get in touch with support I can request a new case for you!

Thanks for the feedback about Aria scale, you can read more information how accurate is my Aria in our website. If you need more details feel free to post your question in the Aria Board to get help from an specialist.

I'll be around! 

[MonteC]

Just curious...with your max heart rate being 220 - your age in order to be at 192 like your gym's machine tell you then you must be at or near your maximum cardiac output.  Is it possible that these machines are not accurate?

Being at or close to your maximum is very difficult to maintain for any period of time.  If this was just normal exercise for you then you should not be anywhere near your max.  The Fitbit bpm's look more normal to me.

Hope this helps

[Jac0209]

Hi MonteC, thanks for your reply.

As I mentioned in my original post, I also measured my heart rate myself, with my fingers on the carotid, and the count was exactly the same as the gym machine that I was on at the time.  I have noticed this on many different gym machines when compared to the FitBit, and the FitBit is WAY off no matter what I compare it to.

Re my heart rate, I have been training for over 2 years and I am pretty familiar with what it is when I am doing particular things, and I have a medical background too.  I am 46 years old, so 220 - 46 is 174.  This is the theoretical 100% heart rate for my age, and yes, based on those calculations, I was operating at around 110% of capacity. However, it is important to bear in mind that these are estimations only and that every person is different.  In reality my true maximum cardiac output may be significantly different to another female my age, or a male my age for a load of reasons.  My resting heart rate is also 57bpm, which also may be very different to others at my age, due to differences in people.

It is also worth noting that the maximum heart rate general calculations do not really factor in particular kinds of exercise, such as HIIT where the heart rate can be quite elevated, temporarily.   And I was actually doing HIIT cycling at the time I was measuring this, and many other times.  There are plenty of other similar examples of the discrepancy between the FitBit and my own count/machine measurements when I am doing regular cardio and non HIIT.  My own heart rate is at about 80-90% during regular cardio sessions, and is still at least 50bpm higher than the FitBit shows.

Generally I perform regular cardio at between 80-90% of my theoretical max, which is actually how cardio should be done, and this is well above what my FitBit shows.  If you are doing cardio at 120 when your theoretical max is 174, then you are not getting your heart rate high enough to do any good, as it is only 68% of max.  And given that my true max is a lot higher than theoretical max, then 120bpm is way too low.

If you are, however, 70 years of age, your max is then 150bpm, which would put your 80% at 120bpm, which would be entirely reasonable.  I am however, not 70 years old. Interestingly though, my Dad is 75, and when he does cardio exercise, his heart rate is well above his theoretical max (145bpm) regularly and he is fine.

Thanks for your reply and concern though, I appreciate it!  Cheers 🙂 

[Jac0209]

Hi YojanaFitBit, thank you for your reply.

Since posting this, I have tried as you suggested, again, as I had tried these before, and nothing has changed. I also went back over my old data, and found that with my old FitBit, there were certainly circumstances where the HR was way too low when compared with the actual, but it just did not happen quite as often as with this one.

I have also done quite a bit of reading and have found that this is an exceedingly common problem with all FitBits, not just the Surge, and there seems to be no explanation for this at all, and no real fix.  It does seem as thought the technology itself is questionable, however.  

I am looking into other brands at the moment, as I require reliable technology and if this issue cannot be at least identified, if not fixed, then I have no use for it, and it is in fact dangerous.  It is not fit for the purpose that it was purchased for.

But thank you again for your reply.

[AsadCapeTOwn]

I have the surge. The heart rate reading is far from accurate. In rest mode it works fine, but when starting a working out and heart elevates over 80 bpm, I notice it is out by 20% displaying a lower rate when checking manually.

The only reason I still wear the device is the sleep tracking works great, best on the market undoubtedly.

I did raise this with Fitbit via email, together with my battery issues not lasting as claimed, recharge every 4 days with evidence of tracking it providing reports. Response recieved was negative,

"Unable to repair or replace."

I hope I just had an isolated bad experience as the brand seems well and devices are motivated  to make an impact on our health.

Kind regards.

Surge user