Calories adjusted for low resting heart rate?

[Kmove]

I cannot seem to find this answer anywhere- but if my resting heart rate is 43 (it is), wouldn't my zones -- fat burning, cardio, etc -- be different than someone who has a resting heart rate of 100? For me, a heart rate of 90 is twice my resting rate. Shouldn't I be showing higher calorie burn? Otherwise, would this mean that a low heart rate suggests a low metabolism as well? 

No amount of googling tells me anything about this, besides that the internet believes that any resting heart rate under 50 must be a very young marathon runner which is not the case. 

[shipo]

@Kmove I seriously doubt there is a correlation between the two.  My RHR is, and has always been pretty low as well (I just checked my recent stats, over the last 4 weeks my lowest daily RHR was 37 and my highest was 41) and I've never noticed any significant disconnect between what my Fitbit tracker reported vis-à-vis calorie burn compared to friends in similar condition as me but with higher RHRs.  Yes, I realize this isn't quite what you asked, but I'll take it a step further; regardless of whether it was me, or one of the folks in my circle, when our Fitbits reported we'd burned an excess of 3,500 calories in a week, we all pretty much lost a pound of weight.  Yeah, there were variances either way, but on the whole, the numbers proved out.

As for having to be a young marathon runner to have a low RHR, yeah, no; I'm 64, 30 pounds overweight, and only run the distance of a marathon (plus a little) per week.

[t.parker]

Lower RHR means that you need less energy to sustain your bodily functions in rest. It may (but doesn't have to) mean also that you need to work harder to burn more calories. The more fit you are the more effort you need to make if you want to burn more calories (which makes sense because your body becomes more efficient due to improved cardiovascular system). I don't use Fitbit zones because 1) they are too simplified, 2) they are not based on lactate threshold. My zones (my RHR is 39-40bpm) look like this:

Zone 2 is something like "fat burn" in Fitbit (more or less) and it's over 3x my RHR. I don't think RHR contributes to my zone ranges at all. Low RHR means (kind of, I greatly simplify it) only that I need more effort to get my body using more energy. The fitter you are the harder to burn more calories. In other words, if you expect your zones to be changed due to improving fitness level (with assumption that RHR is result of such improvement, not just genetics) then they would rather be shifted to higher numbers than lowered.

[Heybales]

Your sources for what a low resting HR means are aged.

More research has shown that not only the variability in HRmax, but also in restingHR - means that some people are just low, and just a little bit of fitness they go lower.

Perhaps these are the ones that could be genetically gifted in sport if they went that direction.

Studies have shown the HR-flex point where aerobic exercise starts - is about 90 in vast majority of population, no matter the HRmax or RHR.

A high or low HRmax merely means the range is wider or shorter for the different HRzones.

A high or low RHR doesn't mean as much, except likely decent fitness, therefore used in the Karvonen method formula for HR zones.

But most HR zones based purely on HRmax (and 220-age is terrible estimate for majority), or based on a tested Anaerobic/Lactate Threshold figure (very good method if cardio sport is your goal).

The very few calories actually required for the heart to beat is immaterial compared to the most metabolically active organs actually using up calories as part of your base metabolism (BMR). So a difference in resting HR is not meaningful as part of that.

Heat is the effect of your metabolism - plenty of people with low HR generate a lot of heat, plenty with elevated don't.

It is interesting though when people start a diet, generally HR will lower a tad, as generally does the higher metabolism functions that generate heat. BMR generally doesn't lower quick unless you are doing an extreme diet and keeping it up.

[SunsetRunner]

Thank you @Heybales , I've learned a lot from your replies to various questions. The depth of your knowledge and the willingness to share it really help, also @shipo . Just as an affirmation to an earlier discussion, I went to a sporting goods store and bought a pair of Brook's Trace running shoes. I read you guys suggestion to go to a store with knowledgeable sales people rather then just buying a pair of sneakers from the internet. I went to a sporting goods store and was helped by someone trained in footwear and feet. Turns out my right foot is a size 9.50 with supination and my left foot is a 10 with pronation. They also determined what kind of arches I have and suggested different sneakers for me to try. What a huge difference in my daily walk, much better. Take care.

[shipo]

Yeah @SunsetRunner, it makes a huge difference when you have the proper footwear.  

[Kmove]

Are you saying that 45 rhr s not a low heart rate? That is outdated info? I'm a little confused about the rest as it pertains to my question. Are you saying that my max heart rate is the same as someone with a 100 rhr? That my rhr doesn't matter to my burned calories or "zones"? 

[Odyssey13]

Hi @Kmove  you posted in the community forums and we're just users of the Fitbit, not health care professionals who can offer the same advice as your own doctor. The Fitbit is a tool, but not a medical precision instrument. If you're concerned, you should be talking to your heath care team and not searching Google for answers.

[Kmove]

I'm not concerned. Just curious. 

[Heybales]

---

@Kmove wrote:

Are you saying that 45 rhr s not a low heart rate? That is outdated info? I'm a little confused about the rest as it pertains to my question. Are you saying that my max heart rate is the same as someone with a 100 rhr? That my rhr doesn't matter to my burned calories or "zones"? 

---

No, it is low. 

I'm saying the source that says that is only possible being a young marathon runner is outdated.

Just as HRmax is very variable, so also what a low RHR is, and how much exercise is needed to drop it low.

There are some young marathon runners that have RHR in the 60's - they just don't genetically have real low one.

You may.

Your HRmax has no bearing from your RHR - HRmax is genetic.

Yes - your HRmax could be exactly the same as someone unfit that has a RHR of 100.

Both calculated HRmax, and an actual test of HRmax.

Do realize there is a difference between calculated and actual.

Just as that sticker on a new car may say 25 mpg city/40 mpg highway - but you actually get 20 city and 35 highway.

And in the Fitbit world, and many other formulas that give HRzones - resting HR has no bearing on those zones. I gave 1 formula above that does use RHR.

As to Fitbit calculated calories burned, your exercise HR as a % of your calculated HRmax (220-age which is considered very outdated too) is what is used in the formula for calories burned.

RHR has nothing to do with it.

If you had a Fitbit HRmax figure of say 200 - which is going to burn more calories?

If your exercise averages 140 (70%), or 180 (90%) for 1 hr?

Now, a low RHR may likely mean you are pretty fit - so it may be easier to hit 180 for an hour, compared to someone unfit that has trouble doing 140 for 1 hr.

But you both could have an estimated HRmax of 200 because you are both 20.

And that's why that's such a bad formula.

Sorry about any confusion, but if you want to understand it - there it is.

As to your questions in the original post - No, No, and No.

Questions in your new post - No, No, Possible (especially with 220-age), No.

But for some reason I figured that might not be enough - perhaps it is.

[shipo]

@Kmove, just one data point here, my RHR rarely gets up to 40 these days (typically when I'm sick, have just had a vaccine, I've had 6 this year already, or injured), however, I can get my HRmax well above the long discredited 220-Age formula used by Fitbit.  In my case, per the formula my HRmax should be 156, however, just this last Saturday I went for a 10-mile run and for the last 3-miles I maintained an average 9:00 per mile pace, and wouldn't you know it, my heart rate, which averaged 128 for the full run, hovered right about 160 for those final 3-miles.  Not too bad for a self described "fat old man".  😛

[SunsetRunner]

Hey @shipo , I wanted to ask you since we're both about the same age (I'm 67) and another "fat old man", I was thinking about jogging some. I've lost over 40 lbs. could stand to lose another 40. I'm 5'9" 218 lbs. I'm afraid to blow out my knees, they sometimes get sore from walking especially when I pick up the pace. It's hilly where I live and I walk on asphalt. Have you had any problems with your knees? I did read about going from the couch to a 5k that's where I'm going to start, thanks.

[Kmove]

@Heybales - thanks! This has been something irritating me, as if the lower resting heart rate folks are just not really considered for the other heart rate data and I could not seem to find the info in the short, broad info articles and posts. This all makes sense to me the way you explain it.

[shipo]

Wow, @SunsetRunner, a kindred spirit!  🙂

SImilar to you, I'm 5' 8" (maybe 5' 8.5" on a good day); when I started running again mid-December 2020 my weight was roughly 250 (it was more but I was too afraid to get on a scale), and of late I've been hovering a pound or two either side of 220.  Also like you, here in New Hampshire, it is hilly; my typical 6-8 mile trail run courses have between 400' and 600' of elevation gain (and loss), and the 10-miler road course around a local lake has over 1,000' of elevation gain/loss, so yeah, knees take a bit of a beating when dealing with such hills, especially downhill.

Regarding your situation, a C25K program is one of the very best places to start; your fitness background and how much running you've done in the past will determine how quickly you can/should get through the program; in many cases, folks with very little running in their background should repeat weeks, once, twice, heck, three, or four times before moving on to the next week; your body will tell you when it is safe to step up to the next week of the program.  To me, getting into running, or even back into running if you've done it in the past, is a very good thing, however, it should be done with an abundance of caution.  Why?  As you may or may not have seen me write elsewhere, various systems in your body develop at different speeds; your cardio, pulmonary, and muscular systems develop fairly rapidly, however, your skeletal, joint, and connective tissue systems come along at a MUCH slower pace, and at our age, these systems tend to develop even slower.

With the above cautionary comments out of the way, once you've completed the C25K program and can run a full 5K non-stop, your body will be ready to step things up a bit.  Many of those I've coached are anxious to start dialing up speed the day after they finish their C25K programs; this is something I ALWAYS discourage; dialing up the speed is a sure-fire way to get injured.  What should you do once you finish your program?  My advice is to do some research on LSD (Long Slow Distance), and then start extending the length of your runs; a classic metric is no more than a 10% extension per week.  Keep things as slow as possible until you're regularly able to run 6-miles or 10-kilometers at a crack, and then start dialing up the speed at the end of the run; this is where you'll safely be able to develop both your endurance and your speed.

To illustrate what I'm talking about here, as previously mentioned, I started running again last December after a 3.5 year layoff due to a series of health issues (pneumonia, and COVID), and injuries (broken bones and such); prior to that point I had been rather physically fit quite literally until the week when I turned 60 (which is when I got the pneumonia).  Even with my background of running and fitness, I started running again with "an abundance of caution", logging my first runs of about a mile in length in about 16 minutes, yeah, slower than my typical fast walking pace; and I gradually built from there, doing my utmost to keep my average pace no faster than 13 minutes per mile.

Speaking of my "fast walking pace", this brings me back to another point you made, you said, "I'm afraid to blow out my knees, they sometimes get sore from walking especially when I pick up the pace."  I hear you on that; last year I was just starting to jog again after a broken leg in early 2019 when I got my first of two COVID infections, and that ended any attempts to try running again.  I ended up hiking and fast walking for the next 10 months, and wow did my knees get sore, I mean like, so sore I couldn't sleep as the throbbing would keep me awake for hours on end and no amount of NSAIDs would help.  I have been diagnosed with "tricompartmental osteoarthritis" in both knees, not at all unusual for folks in our age rage, and this may, or may not be why my knees blew up last year when I was walking and hiking, and why your knees are so sore after a fast walk as well.  This brings me to my final point; when I flipped from walking or hiking an average of 25-miles per week to slow-jogging ("Slogging"?) maybe 8-miles per week, my knee pain went away almost immediately.  By February this year I was back up to the 25-mile per week level and whaddya know, no knee pain!  I have since completed several 50+ mile weeks, all on uneven dirt trails, and am happy to say, other than being a little stiff in the mornings, my knees feel great!

If you want to carry out your plan and start running, feel free to start a new thread and ask advice as questions and observations come up, I will of course be happy to offer helpful comments, and I can all but guarantee @Heybales will do the same.

[SunsetRunner]

 Hey @shipo , lol, I'm guessing I've lost a little over 40 or 45 lbs. because I refused to get on a scale at my heaviest. After I started walking and eating better, losing weight did I have the guts to weigh myself and I was 260 lbs. OUCH!!! Thank you so much for the info. That's interesting about jogging and your knees feeling better. Slogging, I like it, that probably describes what I'll do. Thanks again, take care.