Heart Rate Monitor Question about my kcal burn

Training2Tri
Training2Tri Posts: 28 Member
in Fitness and Exercise
I own a Timex Digital Heart Rate Monitor watch, its the kind with the waist strap you wear to measure your heart rate. I went through my maual and watched a YouTube video and did the whole HR set up thing recently. I set my current weight (131 lbs) and set my Max heart rate (185). I'm a 34 year old female. I calculated my Max Heart Rate by taking :

200(max) -35(my age) =185 to get to my max HR. It is totally possible that my weight is a little off - I may be a little heavier than the 131.

Today I worked out at the gym for 2 hours. I did a warm up of 10 minutes on a cardio machine and then I went to a crazy intense weight-lifting class for 50 minutes. After the weight-lifting class, I stuck around and did this insane cardio kickboxing class that had my face beet red after class.

My total kcal the watch is reporting for my 2:00 of working out was 1085. This seems very high to me. Can anyone confirm this calorie burn is accurate, or tell me that I have something wrong with my watch? I'm fairly active (but really out of shape right now) as I'm training for an Olympic distance Triathlon this July (as my username suggests).

I really greatly appreciate the comments as I would love to get an accurate reading of my calorie burn. I feel that this is totally overstated.

Thank you!!

Replies

  • Training2Tri
    Training2Tri Posts: 28 Member
    * and by waist strap I mean chest strap.
  • libby555
    libby555 Posts: 43 Member
    I take the same two classes sometimes (we call them BodyPump and Body Combat) and I get around the same thing. I didn't believe it at first either but after checking around on here as well as the Les Mills website it was about right. It's a great workout!
  • jacksonpt
    jacksonpt Posts: 10,413 Member
    What was the lifting class like? If it was high intensity/high reps/little rest, then yes... that class combined with the other cardio definitely makes a high burn possible/likely. If it was heavy weights/low reps/rest between sets, then I'd be a bit more skeptical about the high burn. Most traditional "classes" aren't like that though... most boot-camp type classes are high reps/high HR which could definitely give you a high calorie burn.
  • Reptileszz
    Reptileszz Posts: 47 Member
    Hi, intense working out like that should net you at least 500-600 cals per hour even at your weight so yeah, sounds about right to me!
  • megs2003
    megs2003 Posts: 90
    For a 2 hour workout that sounds more than reasonable to me.

    I also have a Timex and it gives me some very high ratings sometimes too (360 cal for a 25 min workout). Sometimes they don't even feel that intense... but because I am in such bad shape right now, my heart rate gets high very fast, which is likely why the calorie burn is so high. I suspect it is the same for you. Do you have a review option where it shows you average heart rate and min and max heart rate? I always log this information in my Exercise notes so that I can keep track and as you get fitter the max heart rate should go down (and the calorie burn will go down too as my body gets more efficient).
  • penroseg
    penroseg Posts: 53 Member
    Sounds right to me.
  • Colbyandsage
    Colbyandsage Posts: 751 Member
    I agree with everyone above. You calculated ur Max HR correctly. I don't have the brand you do, put i have a Polar FT4. I burnt almost 500 calories yesterday walking/jogging outside. I kept my HR up.
  • Training2Tri
    Training2Tri Posts: 28 Member
    Thank you so much for your comments and feedback. I really appreciate it.

    The weightlifting class was intense. I had moments of "wow, I'm so out of shape" and I had moments where I felt that I was struggling to keep up with the rest of the class.

    It blows my mind that I could burn 1,000 calories in 2 hours of working out. I'm excited to do more intense workouts now. Thank you for the suggestion to log the min-max average HR as well. I do look at that info when I review my workout metrics at the end of my classes.
  • Azdak
    Azdak Posts: 8,281 Member
    The overall number is not unreasonable (it's about a 9 MET sustained intensity for your weight), but the calories are likely being overestimated for the strength class. HRMs always overestimate those because heart rate increases while oxygen uptake does not.

    So while hypothetically that number is not out of the ballpark, it is probably somewhat overestimated for the particular workout you describe (again, at 60kg, your numbers are always going to be a little lower than others since you weigh less).

    It's not a big deal unless you eat all the calories back, which I would never recommend--some, but not all.
  • jacksonpt
    jacksonpt Posts: 10,413 Member
    HRMs always overestimate those because heart rate increases while oxygen uptake does not.

    Can you explain this a bit more? I know I don't have a good grasp on it, and with the 1000s of HRM threads around here I'm sure the mass public doesn't either.

    Increases in HR is fairly obvious. So is an increase in effort or intensity. But since HRMs are based largely on oxygen intake, can you talk a bit about how/when that increases?
  • Azdak
    Azdak Posts: 8,281 Member
    HRMs always overestimate those because heart rate increases while oxygen uptake does not.

    Can you explain this a bit more? I know I don't have a good grasp on it, and with the 1000s of HRM threads around here I'm sure the mass public doesn't either.

    Increases in HR is fairly obvious. So is an increase in effort or intensity. But since HRMs are based largely on oxygen intake, can you talk a bit about how/when that increases?

    I am going to have to ask you to do a little work on this one:

    http://www.myfitnesspal.com/blog/Azdak/view/hrms-cannot-count-calories-during-strength-training-17698

    But I think this should at least explain the strength part.
  • jacksonpt
    jacksonpt Posts: 10,413 Member
    HRMs always overestimate those because heart rate increases while oxygen uptake does not.

    Can you explain this a bit more? I know I don't have a good grasp on it, and with the 1000s of HRM threads around here I'm sure the mass public doesn't either.

    Increases in HR is fairly obvious. So is an increase in effort or intensity. But since HRMs are based largely on oxygen intake, can you talk a bit about how/when that increases?

    I am going to have to ask you to do a little work on this one:

    http://www.myfitnesspal.com/blog/Azdak/view/hrms-cannot-count-calories-during-strength-training-17698

    But I think this should at least explain the strength part.

    Thank you. I'm more than happy to do the reading on my own if the info already exists (as it does here). I'm not sure I'm 100% clear on the volume vs pressure, but I'm going to mull it over a bit and reread tomorrow.

    Thanks. I always find your posts informative.
  • jonilynn70
    jonilynn70 Posts: 145 Member
    Yep sounds right to me! Awesome burn - great job!

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