Average RHR dropped to lowest ever

[Lkcamp85]

Hi, I've been wearing my fit bit all day and night for months now. I use it mostly to track my cycle for TTC reasons. I don't work out at all and I'm certainly not fit or getting fit. Over the past few days my RHR has dropped from my usual 57/58bpm around this time of my cycle to 54bpm. It was actually 53bmp yesterday but changed to 54 later on in the evening, the lowest it's ever been before was 56 and that was when I first started wearing it. The weather is very hot right now so i'd expect it to be slightly higher than usual, not lower. Everything I've read about heart rate declining has said it's due to getting fitter but what could be the cause if fitness isn't a factor? 

[Dominique]

Welcome to the community, @Lkcamp85!

First of all, how did you establish your fitness level is unchanged since you’ve been tracking your RHR? Has your average step count remained the same? What about your cardio fitness score (if you have a Fitbit that can estimate it)? The bad thing with cardio fitness score is Fitbit doesn’t store historical values, so you have to make a mental note of what it was at a particular time, or write it down somewhere. My point is you may in fact be fitter, even if you don’t realize it.

RHR can fluctuate for other reasons than fitness. For instance, it tends to elevate for me with stress. I’d assume sleep and sleep quality would have an impact too.

At any rate, a 4-5 bpm variation is very small. In the three years my Fitbits have been tracking RHR, I’ve seen it fluctuate within a 15 bpm range (= between 50 and 65). I think very few people would see a straight line (same RHR within ± 1-2 bpm) for months on end.

[Lkcamp85]

Thank you for replying.

I'm not an active person, my daily steps can range from 4000 to about 9000 depending on what I'm doing and I'm rarely in the cardio burn range. I don't keep a note of it but I do notice when I go into it as it's so rare. My diet also hasn't changed. 

But I'm glad that you don't think it's significant enough to be a concern.

[skneck]

On the topic of Heart Rate .. I am 74 yo, slim, fit, walk an avg of 4.5 mi per day, also do Zumba weekly and sometimes row a single scull.  My RHR is 58-62.  For some months, I've been seeing heart rate spikes of up to 172 when I walk, but it doesn't always happen.  The walking course is always the same, and the weather has been similar each day.  I was concerned enough about the spikes that my doctor ordered an ECG (normal) and a 24-hr Holter monitor (normal).  The docs are saying the heart rate spikes are an anomaly of the Fitbit Charge 2, as another heart rate monitor (Android Heart Rate app) at the same time of the spike reflects a heart rate of 110-115.   Note:  the Fitbit Charge 2 and the Android Heart Rate app show the same value when I am sitting. 

Has anyone experienced such heart rate spikes with a Charge 2?   

[emili]

I echo Dominique. If it reduced by 20 points consistently with no effort on your part, I would think there is something to call your doctor about. But a few beats is nothing. You may be feeling more relaxed or sleeping better or breathing more deeply. Whatever it is, it is a good thing.