How does Fitbit calculate Resting Heart Rate?

[BigHaole]

I'm finding this very frustrating to be sitting at my desk, and see my HR showing as 74, but my Resting HR being 80.  Clearly Fitbit is not using the conventional definition (from Wikipedia):

"The basal or resting heart rate (HRrest) is defined as the heart rate when a person is awake, in a neutrally temperate environment, and has not undergone any recent exertion or stimulation, such as stress or surprise."

This definition would lead me to expect my reported resting heart rate to be the low value reached in the early morning, or at least the low value I reach, during the day.  Instead, it's above both of these.  I would like to know how it is being calculated, so I can know if my Fitbit is reporting anything useful when this number goes up or down.  Over the recent new years holiday, I got more sleep and more exercise, with less stress, so I was expecting this to go down, but it has gone up and I do not understand why.

[electronicmagic]

A simple question. Can't see what starving kids in Africa have to do with anything. I want to know and want to know if the fitbit is a chocolate teapot.Is resting heart rate accurate? Starving kids in Africa i'm already supporting.


Sent from my Samsung Galaxy smartphone.

[RogerSCcB]

What I don’t understand is how my Fitbit can show a resting heart rate in the morning when I haven’t even been wearing the device and it changes day to day even when not wearing it! I have an ionic now and this gives higher values than my surge by about 10bpm. I wore both to check this!

[Kagakusha]

Frankly it’s clear that Fitbit’s calculation of resting heart rate is a mess.
They really should sort this out and publish the algorithm.
In my view about the only thing you can use it for is - with some doubts about its validity still - to track changes in your own resting heart rate measured on one device you wear.
You can’t compare it to *ANYTHING* else in a meaningful way. Not to other people, other devices, or text book/web values, or your own measures in others ways.
So you might discern trends over long periods; that’s it.

Moderator edit: personal info removed

[Babinator]

By "higher value" do you mean more accurate by 10bpm?

Sent from my iPhone

[RogerSCcB]

I have no idea which if either of the trackers is more accurate

[MaginB]

Hi to all it's great to see you around! 

Thanks for providing all your feedback. I understand you have inquiries about the resting heart rate, as you mentioned the resting hear rate takes into consideration the hear rate data during your sleep and this is why we always advise to wear your tracker to bed for better sleep tracking accuracy. I know most of you are already aware of this info but I'd like to share here a few tips to improve accuracy and information about what can impact hear rate readings. 

It also wouldn't harm to perform a restart to your tracker if you haven't done so already. 

Hope you find this helpful! 

[silverhooligan]

My heart rate when I’m sleeping averages 52-56. Test when I wake up and look at FitBit and the hr says 58 the app and dashboard says the resting rate for the day is 60. During the night I never went above 60. 

[MaginB]

Hi there @silverhooligan! 

Let me help you to clarity this. Keep in mind that to calculate resting heart rate it will take the information from all day long and not only while you're sleep because sometimes when you're awake you take resting periods. 

Catch you later! 

[Kagakusha]

The whole thing is VERY poorly defined.
NO other standard definition of 'resting heart rate' uses data whilst asleep.
How long a 'resting period' should it take into account.....
The result is near meaningless *except* to monitor your own trends.
Useless for comparison to anything else.

[gateswood]

---

@Kagakusha wrote:
The whole thing is VERY poorly defined.
NO other standard definition of 'resting heart rate' uses data whilst asleep.
How long a 'resting period' should it take into account.....
The result is near meaningless *except* to monitor your own trends.
Useless for comparison to anything else.

---

What good are the trends when the monthly graph looks like a saw blade or mountain range with eight point swings between the high points and the low points?

[Kagakusha]

That's a common problem with biological data & not really Fitbit's fault.
Inevitably there are day to day variations, its affected by meals, going to the gym, a drink or two.....

Looking at it however over substantial periods - at least a month - you can discern trends.

Personally I'd calculate means (averages) & standard deviations over different periods & then do a statistical test of significance; or maybe fit it to a smooth curve (most simply, do a correlation, linear fit) but such calculations are not to everyone's taste 🙂
The mark one eyeball does a reasonable job; if it's clearly now fluctuating about a higher/lower mean than it was a month ago, that's probably a real change.
If it's just bouncing around over the same range, nothing changed.

Don't over-interpret the data.

[silverhooligan]

Thank you, I do understand that, but during the day my resting heart rate is in the 50’s too.

It rarely tracks exercise accurately either. It’s great for runners I would guess, but not much help for cyclists. Ex: I rode for an hour in cardio, and 40 minutes just a few beats below cardio. It didn’t kick in to record an activity.

Sent from my iPad

[MaginB]

Hey there @silverhooligan @Kagakusha @gateswood! 

Thanks for all the feedback, Fitbit continuously works to improve the quality of products and services, and all this information is useful to our team of developers. Thanks again for taking the time to share your experience. 

Catch you later! 

[ainsley31415926]

This morning my overnight heartrate went from 61 to 74, that is a maximum of 74. But it claimed my resting heart rate was 75. This was when I got up this morning. I reiterate there was no reading above 74,  but the resting rate was 75. Impossible!

[krishnaj]

I gotta say your complaining is getting old. Kids in Africa do not even
have food or water and you're sitting here upset because your resting heart
rate jumped a beat? Pathetic, please re-evaluate yourself and your peculiar
train of thought!!! :)))

[MaginB]

Welcome to the Forums @ainsley31415926! 

Thanks for sharing your inquiry please make sure to follow the steps that were shared on my previous post. If you need further info assistance feel free to post here so I can further assist you. 

Keep me posted! 

[Dr-Mike]

You can’t over-interpret something that has no verifiable meaning.

i am a few months from cometing my 8-years I’d training to earn the title “Medical Doctor” which means I know how the American Heart Association. and  resting heart rate is defined by The American College of cardiology. This is not how Fitbit defines it. AND without having access to your Fitbit’s raw data, it would be difficult to guess how they have chosen to calculate it.

without knowing how it’s calculated, it becomes nearly impossible to understand all of the factors that would cause variation, and what the implications are for individual health.

the “resting heart rate” data on your Fitbit has absolutely zero medical use, at this time.... sorry to let you down!

Moderator Edit: Format

[Kagakusha]

I would agree entirely it has no medical use, and that the absence of details of how it calculates ‘resting heart rate’ is highly unsatisfactory.

Equally, the conventional definitions also suffer from a considerable lack of clarity in how they should be measured, limiting their utility.

Probably the only good thing about the Fitbit resting heart rate is that it is calculated by an algorithm and hence is not subjective. It may have limited utility in tracking long term trends for a single individual. But thinking ‘it increased by one yesterday’ is nonsense.

Comparison to others, or to literature values, is pretty much invalid. I have seen evidence from my own use (hence a single case and anecdotal, far from convincing evidence!) that it does tend to drop as I get fitter as judged in other ways (PB times etc.)

[Johnc61]

I measure my resting rate each morning before I get up, my rhr is between 58 & 62 however fit says my rate is 73, while writing this message my rate is currently showing 72, I don’t se how the Fitbit can measure it accurately. 

[rachelowlglass]

I've been in the doctor's office multiple times with the heart rate monitor on my finger ... with the instant heart rate on my Ionic listed as 10 BPM higher than what my doctor's equipment says

I'm gonna trust medical equipment over Ionic

I only look at it as a baseline for change over time ... I take off 10 bpm