Heart Rate and Calories Burned

ani_terzyan
ani_terzyan Posts: 35 Member
in Fitness and Exercise
I have a fitbit which calculates my calories burned based on my heart rate throughout the day. I've been using it for the past few months and never really questioned it until last week I had burned 2,500 calories (my average is 2,100) even though I spent most of the day in bed fighting a cold. My heart rate was high enough to be in the fat burning zone all day, I'm guessing because my body was working hard trying to fight the cold. So, my question is - does my body actually burn more calories every time my heart rate is raised? I'm thinking about like when it rises due to stress, anxiety or pretty much anything not exercise related. Thanks!

Replies

  • callsitlikeiseeit
    callsitlikeiseeit Posts: 8,626 Member
    it makes sense that it WOULD, though not in the way that you can eat back those calories ;) its normal metabolic calorie burn (is that the right term? it seems like it should be, if its not LOL)

    my concern with the fitbit (and similar) and all the people that have one, is that people think they can eat back all those calories. i see a LOT of people eating back a LOT of calories and wondering why they aren't losing LOL i know thats not really your question but i went off on a tangent LOL
  • ani_terzyan
    ani_terzyan Posts: 35 Member
    lol thanks for the tangent, i totally agree! I definitely didn't eat back those calories because I didn't even notice until the next day! I was so surprised that I find it really hard to trust those numbers now - which is why I'm asking :smile:
  • brianpperkins
    brianpperkins Posts: 6,124 Member
    HRMs are designed and programmed to estimate calories only for steady state cardio. A 150 heart rate watching a scary movie does not produce the same caloric burn as a 150 heart rate in the middle of distance running.

    HRMs work by using heart rate as a proxy for effort then plugging that into a formula based on a narrow range of steady state cardio activities.
  • mwyvr
    mwyvr Posts: 1,883 Member
    Where can I catch that cold? Is the virus for sale on Amazon?
  • AJ_G
    AJ_G Posts: 4,158 Member
    brianpperkins wrote: »
    HRMs are designed and programmed to estimate calories only for steady state cardio. A 150 heart rate watching a scary movie does not produce the same caloric burn as a 150 heart rate in the middle of distance running.

    HRMs work by using heart rate as a proxy for effort then plugging that into a formula based on a narrow range of steady state cardio activities.

    /thread
  • ani_terzyan
    ani_terzyan Posts: 35 Member
    edited May 2015
    @brianpperkins So basically, I shouldn't put too much weight on the estimate unless I know I've actually done some physical activity - is that right?

    @mwyvr Ha, I would be more than willing to sell it to ya for $50 on eBay - can't make any calorie burning guarantees though! :wink:
  • SnuggleSmacks
    SnuggleSmacks Posts: 3,731 Member
    brianpperkins wrote: »

    HRMs work by using heart rate as a proxy for effort then plugging that into a formula based on a narrow range of steady state cardio activities.

    This. And this is why other fitness monitors such as the BodyMedia work with fair accuracy by measuring things other than heart rate...like skin temperature and ambient temperature changes. It's another measurement of effort.

    While fighting off a cold, I imagine, burns a few more calories than laying around not fighting a cold, the effect is very minimal and certainly in no way makes up for the activity you've missed (which would have required actual effort and burned significant calories.) Of greater concern is that your heart rate is elevated enough to register as "fat burning"...either your Fitbit is not calibrated well for you, or else you might want to consider a doctor's appointment. That's not normal, even while sick.
  • brianpperkins
    brianpperkins Posts: 6,124 Member
    Exactly.
  • ani_terzyan
    ani_terzyan Posts: 35 Member
    edited May 2015
    @SnuggleSmacks Thanks for the information, it was very helpful! According to the fitbit app, 98-137 bmp is considered the fat burning zone and I was a bit over 100 for most of the day. My resting hr ranges between 68-78, mostly on the lower end. Is that still something to be concerned about? I have a history of heart disease in my family so maybe I should start paying more attention to this stuff...
  • Mr_Knight
    Mr_Knight Posts: 9,532 Member
    ani_terzyan wrote: »
    So, my question is - does my body actually burn more calories every time my heart rate is raised?

    No.
  • jaqcan
    jaqcan Posts: 498 Member
    Gonna jump on with a question of my own, if you don't mind. Would it be beneficial to just wear a fitbit during exercise, such as a bike ride? Or do you need to wear it all the time so it knows your resting heart rate?
  • shadow2soul
    shadow2soul Posts: 7,692 Member
    jaqcan wrote: »
    Gonna jump on with a question of my own, if you don't mind. Would it be beneficial to just wear a fitbit during exercise, such as a bike ride? Or do you need to wear it all the time so it knows your resting heart rate?
    @jaqcan

    The problem with that is your whole calorie would be off for the day. You would only be getting your BMR + exercise calories and not get credit for your daily activity. If your a fairly active person this would make your calorie intake calculation off.

    An example:
    I would have gotten a total daily burn yesterday of 1850 if I had only worn it during my runs. The runs only counted for 7157 steps of 12,254. That leaves the calories for 5097 steps unaccounted for. It would also mean that even if I had MFP set to Sedentary, I would lose calories with a negative adjustment (MFP estimates 1900 for me at Sedentary).

    Which one do you have? I know with the Surge at least, I can turn the HR on and off. So if your worried about getting to many calories for day to day stuff, you could turn off the HR and only turn it on for workouts.
  • MeanderingMammal
    MeanderingMammal Posts: 7,866 Member
    ani_terzyan wrote: »
    ... does my body actually burn more calories every time my heart rate is raised?

    No

    Which is why HR is such a poor indicator of calorie expenditure
  • MeanderingMammal
    MeanderingMammal Posts: 7,866 Member
    ani_terzyan wrote: »
    My resting hr ranges between 68-78, mostly on the lower end. Is that still something to be concerned about?

    The delta seems significant, so would be worth a GP visit.

    Notwithstanding that, your RHR appears high, inasmuch as that's higher than mine was when I was at my heaviest and least fit. That's probably a function of your fitness, so getting some decent quality CV work in should help improve it.
  • ninerbuff
    ninerbuff Posts: 48,915 Member
    I have a Fitbit. I DON'T use it to count calories. I use it to remind me if I've done enough moving around for the day.
    As for the question, it's been covered. A raised heart rate DOESN'T always mean higher calorie burn.

    A.C.E. Certified Personal and Group Fitness Trainer
    IDEA Fitness member
    Kickboxing Certified Instructor
    Been in fitness for 30 years and have studied kinesiology and nutrition
    9285851.png
  • Sued0nim
    Sued0nim Posts: 17,456 Member
    ani_terzyan wrote: »
    I have a fitbit which calculates my calories burned based on my heart rate throughout the day. I've been using it for the past few months and never really questioned it until last week I had burned 2,500 calories (my average is 2,100) even though I spent most of the day in bed fighting a cold. My heart rate was high enough to be in the fat burning zone all day, I'm guessing because my body was working hard trying to fight the cold. So, my question is - does my body actually burn more calories every time my heart rate is raised? I'm thinking about like when it rises due to stress, anxiety or pretty much anything not exercise related. Thanks!

    No it doesn't

    An HRM is only good for steady-state cardio

    Elevated HR does not equate to the same calorie burn across every activity / exercise
  • Sued0nim
    Sued0nim Posts: 17,456 Member
    edited May 2015
    callsitlikeiseeit wrote: »
    it makes sense that it WOULD, though not in the way that you can eat back those calories ;) its normal metabolic calorie burn (is that the right term? it seems like it should be, if its not LOL)

    my concern with the fitbit (and similar) and all the people that have one, is that people think they can eat back all those calories. i see a LOT of people eating back a LOT of calories and wondering why they aren't losing LOL i know thats not really your question but i went off on a tangent LOL

    Now a basic fitbit (non-HRM version) is basically a funky pedometer and tracks your acitivity level

    Over time, for me, judging by weight against calorie intake it has proved extremely accurate but my activity level on here is set to sedentary with negative calories enabled .. if anything my TDEE is higher than I would see from the numbers

    So yes I eat back every last calorie from my fitbit burns which for 10K steps based on my settings equates to approximately 400 calories per day

    this is equivalent to a 45 minute gym workout incorporating 30 mins hard cardio burn for me (as measured on my separate HRM)

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