Resting heart rate changed drastically

auntstephie321

I can't figure out what is going on with my charge hr. my resting hr used to be around 78 pretty consistently, now everyday its lower and lower today it's 63. Also I used to always be at least 4 or more hours in fat burning zone, now it'll be like 30-60 minutes a day. I don't understand why its registering so much lower. has anyone else noticed a change recently?

NancyN795

Mine has dropped a bit in the last week or so, which I didn't expect. I had been on blood pressure meds and the doctor decided I should try a trial off of them (I've lost a lot of weight and gotten more fit and was having pretty low readings sometimes). When I went off the meds, my RHR dropped from around 55 to around 50. The doctor said that was probably because the BP meds had a diuretic, which can raise the heart rate a little. However, it turned out I still needed BP medication (which didn't surprise me), just a lower dose, so I went back on and expected to see a rise in my RHR again. It went up a bit, which is what I expected, but now it's back down to <50.

I can't tell if there is any appreciable difference in my time in the various heart rate zones. It might be a little lower, but I'd have to analyze my activities over those days to see if that is reasonable.

heybales

Despite Fitbit calling it restingHR - it's not the traditional meaning of the term.

Normally that means first thing in morning after waking, and settling down after alarm freak out.

Fitbit seems to measure your lows and average them.

Still a good result though no matter.

Possible reasons for lowering -
Body is making some improvements from exercise that had never really been done prior, and those are always bigger at the start.
Something in your diet changed that was elevating it beyond what body really needed, now it's lowering more to where it's needed.
Accuracy of reading HR is improving or getting worse, so it was wrong and is now more right, or vice-versa. You ever felt pulse and measured to compare at sitting, standing, moving a little, ect to confirm Fitbit is reading correctly?

The getting fit seems to fit in better with being in lower HR zones though, but all three could cause range changes like that too.
But when you get fit that is what happens - heart doesn't need to beat as much to provided needed oxygen for a certain level of effort.
So your daily activity is burning the same calories if moving the same mass in the same way - it's just more fat calorie now then carb calories because you are providing enough oxygen with less heart beats.

Probably should notice the same thing with exercise, harder to push the HR as high as it once was.
So the muscles will still get the same workout, except for the muscle of the heart.

And in fact that is the problem with walking as only form of exercise - you reach a certain fitness level - and then it's no longer a stress on the body to improve, unless you walk faster, or hills, or with extra weight.
And if you lose weight and don't do one of those things - it actually becomes easier for your body and you'll lose fitness level moving around less mass.

So keep it up - but now to keep working out your heard - you'll need to step it up too.

Then your restingHR will probably keep on moving down.

Oh, it sounds like the vast amount of that time was in the "fat-burning" zone in daily activity. Well, most your daily activity has major fuel source as fat anyway (except right after meals), so even though HR isn't getting that high - you are burning more fat now, less carbs, with that effort of time.

natethegreat80

I think thats a good thing...lower heart rate means you are in better health!

auntstephie321

I agree I am just surprised by the change, I keep double checking my hr to what my fitbit says and its correct every time. it just seems like a major change over a short time

NancyN795

I do wonder if there hasn't been an algorithm change. When I first got my Charge HR (January 2015) the RHR it came up with was definitely high. I'd been measuring it at around 50 or below first thing in the morning, and Fitbit had it over 60. Then, at some point, the Fitbit number came down a bit, to the upper 50s, but my independent measurement hadn't changed. Now, Fitbit has it in the upper 40s, which is reasonably close to where I've been seeing it all along.

This is all a huge improvement over what it was before I started exercising (over 3 years ago), when my RHR was probably in the 70s.

heybales

Ah, so perhaps they decided they can figure out what the before wakeup HR is, and is correctly using that. I think they already had it and used it for the HRM calorie burn estimate.

It still might be useful to then base a daily average low HR on that though.

I could see that useful to inform you how much higher your daily HR is compared to restingHR - perhaps give a clue if you have stress issues, or perhaps caffeine issues, ect, that keeps you elevated all day.

laura935

My resting heart rate is in the low 60's so that sounds normal to me, but would depend on your age and level of fitness. As for the hours in the fat burning zone it would depend on your level of activity. I pretty much only get in the "fat burning zone" when I'm actually working out, or maybe running a lot of errands or cleaning the house.