How accurate are the calorie displays on equipment?!

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  • jacksonpt
    jacksonpt Posts: 10,413 Member
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    Definitely get a heart rate monitor. Before I had one, I was going by the machines at the gym & MFP calories burned & both of those were WAY overestimating my calories burned. I have the polar ft4 with a chest strap. Definitely suggest one with a chest strap :)

    How do you know they were way over estimating? If you've got 3 methods of measuring, 2 give similar numbers and 1 gives you something very different, why would you believe the different one?
  • rainbowbow
    rainbowbow Posts: 7,490 Member
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    They overestimate about 30% for me.
  • Jul685
    Jul685 Posts: 81
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    Thank you to whoever posted about healthstatus.com, awesome site!
  • cynthiaj777
    cynthiaj777 Posts: 787 Member
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    Definitely get a heart rate monitor. Before I had one, I was going by the machines at the gym & MFP calories burned & both of those were WAY overestimating my calories burned. I have the polar ft4 with a chest strap. Definitely suggest one with a chest strap :)

    How do you know they were way over estimating? If you've got 3 methods of measuring, 2 give similar numbers and 1 gives you something very different, why would you believe the different one?

    Let explore why, shall we? HRMs use the user's height, weight, age and gender. It then in relation to the information tracks your HR and calculates an amount of calories burned. Machines just use a generic formula for someone who is 20, 5'6", 150 lbs and male....which obviously only those who are 20, 5'6", 150 lbs and male would this be accurate. That would be why multiple machines say the SAME thing (i.e. same formula), but when a HRM is used, it is different.

    Don't get it? Let me provide a real world example:

    Machine User 1:
    -23 years old
    -240 lbs
    -47% body fat
    -5'3"
    -runs 5 MPH for 10 minutes

    Machine calculates she burned 125 calories.

    Machine User 2:
    -26 years old
    -125 lbs
    -18% body fat
    -5'3"
    -runs 5 MPH for 10 minutes

    Machine calculates she burned 125 calories.

    Logic tells you that Machine User 1 burned far more than calories than Machine User 2 because of her body composition. The machine says the same thing no matter what, though.

    Now, put a HRM on each of them: Machine User 1 would say something like 175-200 calories. Machine User 2 would say something like 75-100 calories. Why is it different? Because it takes into account the actual person and tracks HR.
  • Showcase_Brodown
    Showcase_Brodown Posts: 919 Member
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    I would trust the calorie display on the machine about as far as I could throw the machine. As I am not a prime example of beastly might, I don't trust them.

    Even an HRM is going to give you a fairly wide margin of error.

    My solution, while not actually a solution, is to just not try to log exercise calories. Your weight over a month or two will tell you the story of how many calories you've been burning, given that you're tracking your eating.
  • jacksonpt
    jacksonpt Posts: 10,413 Member
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    Definitely get a heart rate monitor. Before I had one, I was going by the machines at the gym & MFP calories burned & both of those were WAY overestimating my calories burned. I have the polar ft4 with a chest strap. Definitely suggest one with a chest strap :)

    How do you know they were way over estimating? If you've got 3 methods of measuring, 2 give similar numbers and 1 gives you something very different, why would you believe the different one?

    Let explore why, shall we? HRMs use the user's height, weight, age and gender. It then in relation to the information tracks your HR and calculates an amount of calories burned. Machines just use a generic formula for someone who is 20, 5'6", 150 lbs and male....which obviously only those who are 20, 5'6", 150 lbs and male would this be accurate. That would be why multiple machines say the SAME thing (i.e. same formula), but when a HRM is used, it is different.

    Don't get it? Let me provide a real world example:

    Machine User 1:
    -23 years old
    -240 lbs
    -47% body fat
    -5'3"
    -runs 5 MPH for 10 minutes

    Machine calculates she burned 125 calories.

    Machine User 2:
    -26 years old
    -125 lbs
    -18% body fat
    -5'3"
    -runs 5 MPH for 10 minutes

    Machine calculates she burned 125 calories.

    Logic tells you that Machine User 1 burned far more than calories than Machine User 2 because of her body composition. The machine says the same thing no matter what, though.

    Now, put a HRM on each of them: Machine User 1 would say something like 175-200 calories. Machine User 2 would say something like 75-100 calories. Why is it different? Because it takes into account the actual person and tracks HR.

    In that case, yes... but you've picked the most extreme example possible to illustrate your point.

    What if you changed that scenario to include machines that allow you to enter age and weight? Then what?

    And you do realize that HR is only loosely tied to calorie burns, right? If I get startled, my HR increases. Am I burning more cals?

    Calories are a unit of energy. Energy is used to measure work. Work is calculated by multiplying force by distance. Force is determined by the amount of weight being moved and how it's being moved (activity, for our purpose).

    So if a 240lb man is running 3 miles, it doesn't matter how long it takes him, what his age is, or how fit/healthy he is. It still comes down to force X distance.

    So with all that said, who cares about things like HR, age, etc? If you're trying to be exact, no one does because those things don't matter (or matter very little). If you're trying to estimate, which is all any of these things do, then it can matter, but it really only matters if the device also knows your max HR. If it doesn't know that, then it's just another assumption that can lead to a wider margin of error.

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