Heart Rate/Calories Burned

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lisag0109
lisag0109 Posts: 18 Member
in Fitness and Exercise
Thought this info interesting and thought I'd share because this topic comes up so often and I'm a data/heart rate monitoring junkie!

Tried an elliptical interval experiment today to find out the difference in calories burned monitoring heart rate with a chest strap, my Garmin Vivosmart Hr (which monitors heart rate on wrist) and straight up calories burned on the elliptical.

I'm a 45yo female, so max heart rate is 175 based on age.
Moderate intervals keeping the machine between 150-170 strides per minute, varying speed and incline for one hour.

Elliptical readout:
615 calories burned

Chest strap info:
135 avg heart rate, 162 max heart rate
487 calories burned

Vivosmart HR info:
136 avg heart rate, 166 max heart rate
376 calories burned

Take it for what it's worth, but this is why so many people say eat back half your exercise calories and never believe what the exercise equipment tells you!


Replies

  • Rachelerik
    Rachelerik Posts: 262 Member
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    I use a garmin forerunner with chest strap and wondered about comparisons with wrist units... always thought the machine read outs were high. Thanks for posting.
  • robertw486
    robertw486 Posts: 2,390 Member
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    lisag0109 wrote: »
    Thought this info interesting and thought I'd share because this topic comes up so often and I'm a data/heart rate monitoring junkie!

    Tried an elliptical interval experiment today to find out the difference in calories burned monitoring heart rate with a chest strap, my Garmin Vivosmart Hr (which monitors heart rate on wrist) and straight up calories burned on the elliptical.

    I'm a 45yo female, so max heart rate is 175 based on age.
    Moderate intervals keeping the machine between 150-170 strides per minute, varying speed and incline for one hour.

    Elliptical readout:
    615 calories burned

    Chest strap info:
    135 avg heart rate, 162 max heart rate
    487 calories burned

    Vivosmart HR info:
    136 avg heart rate, 166 max heart rate
    376 calories burned

    Take it for what it's worth, but this is why so many people say eat back half your exercise calories and never believe what the exercise equipment tells you!


    What I'd be asking myself in that case is which if any numbers of the three or the most accurate, and why. HR monitors in general do not work well for other than steady state exercise, and doing intervals would easily skew the numbers. Even for steady state stuff, the HR monitor and software can only be as potentially accurate as the data inputs it receives.

    The same would apply to the machine. It might have different inputs, or available data. Depending on the type of machine, it could be inferior or superior data.

    And in the case of all three, you'd also have to account for which ones are giving you gross calorie burn, and which ones are giving you net calorie burn. That alone makes up some of the differences at times, and though not huge for most single events over time could mess with a persons maintenance/loss/gain goals.

    We have a machine with power measures. Power measures are absolute, though still subject to the flaws of calibration accuracy. But power is power, and more directly related to calorie burn than any other measure. HR would be a good indication if you could set the device up to scale with measured power in some way, as some of the new ones do. But without individual customization, HR alone really isn't all that great of a measure. Pumping efficiency, blood pressures, oxygen uptake, etc all factor in and as such HR at a given load isn't always the same person to person.

    And in all cases with any body weight supporting exercise, something as simple as a difference in weight inputs could grossly skew even an otherwise accurate device.
  • AllanMisner
    AllanMisner Posts: 4,140 Member
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    Further to your point, all of the calories in - calories out equation is estimated. It makes me shake my head when people think they’ve got this down to a definite number. Unless you’re in a sealed room having your carbon dioxide measured, it will always be an estimate (even with a heart rate monitor).

    On another note, calories in - calories out only works when your hormones are balanced, which means you need to be paying attention to a lot of other factors besides calories (sleep, proper nutrition, lifestyle, etc.). You should aim for a deficit, but if your insulin or cortisol is too high or your thyroid is whack, you’re not going to see the results the way you want.

    So, as for calories in - calories out, just plug a number you feel comfortable with and go. Stressing over it isn’t gong to help. If, after a few weeks, you’re not seeing the results you expected, tweak your estimates and keep charging forward.

    Allan Misner
    NASM Certified Personal Trainer (Corrective Exercise Specialist, Fitness Nutrition Specialist)
    Host of the 40+ Fitness Podcast

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