Resting heart rate wildly inaccurate.

[OUGrad05]

Well to make a long story short, misplaced my fitbit, finally found it again a few weeks ago.  Hadn't worn it in several months (November).  Put it on and updated it and it appears the already inaccurate resting heart rate calc is now worse?  

For example, my RHR for today is listed as 65bpm, yet this morning, even according to FitBit's own data from 7:51am to 8:50am I was in my office and my heart rate never exceeded 64 that was briefly when I received a phone call.  For the huge majority of the hour it bounced around between 52 and 58, and yet my RHR is 65???

Granted the fitbit devices have always (at least in my experience) been pretty inaccurate on RHR, previously it would show 58-62 depending on the day, despite frequent dips down into the low 50s much like this morning.  

I really don't understand why Fitbit is making it so difficult to come up with RHR, AHA lays it out pretty plainly, why reinvent the wheel?  Any settings that anyone is aware of that I can change to fix this?

Moderator edit: Updated subject for clarity.

[YojanaFitbit]

Nice to see that you're digging into the Forums @OUGrad05, let me give you a warm Welcome to our Community.

It's good to know that you're using your Fitbit again, just let's take a look of some details regarding to the HR readings you're getting. I'd like to clarify that our PurePulse heart rate tracking offers automatic, continuous wrist based tracking for all-day health insights and workout intensity. Remember that resting heart rate refers to the heart rate measured when you’re awake, calm, comfortable, and have not recently exerted yourself. We use your heart rate data from when you’re awake and asleep to estimate your resting heart rate, but for best accuracy, wear your device to sleep. 

Your resting heart rate is usually higher than your heart rate while you are asleep, so don’t be surprised if your resting heart rate is higher than the lowest number that you see in your heart rate graphs. Since you stop wearing your tracker, it might also calibrating the information using your most recent readings. It'd be a good idea to restart your Fitbit just in case it is having hardware issue too. 

Your heart rate may be affected by any a number of factors at any given moment throughout the day. Movement, temperature, humidity, stress level, physical body position, caffeine intake, and medication use are just a few things that can affect your heart rate. Different medical conditions and medications can impact your heart rate that's why it's important to consult your doctor before starting an exercise routine.

A good thing to mention is that according to the National Institute of Health, a normal resting heart rate for adults ranges from 60 to 100 beats a minute. Generally, a lower heart rate at rest implies more efficient heart function and better cardiovascular fitness. 

For example, a well-trained athlete might have a normal resting heart rate closer to 40 - 60  beats a minute. You can check your HR with an expert and let him know more details about your training though, since Fitbit trackers are not medical devices, they were created to support your training and motivate you towards your goals!

Hope this helps! 

[OUGrad05]

Generic response, clearly didn't read my post.  I'm going to assume the device is using some proprietary number to come up with RHR since it's not uncommon for me to have extended periods of 52-58bpm while awake and in the 40s while asleep.

[YojanaFitbit]

Thanks for getting back @OUGrad05, sorry for the misunderstanding. Did you restart it? Your Fitbit will take your overall resting HR from the history of you data. When did you start using it?

See you around.