Inaccurate Calories Burned on Elliptical?

PugBug20
PugBug20 Posts: 55
in Fitness and Exercise
Hi, all. I do cardio almost daily (I do strength training, too, but I warm up with cardio on my strength training days) and I almost always use the elliptical machine (just a personal preference). The elliptical machines at my gym calculate the number of calories you burn based on your weight (which you enter at the beginning of your workout), your number of strides per minute, and your incline and resistance. I had assumed that it was a reliable system, but I did some research online today and was surprised to learn that most machines make inaccurate calculations. Is this true? If it is true, where are the inaccuracies coming from? Should I rely on my machine's calculations or the calculations of a calculator like this: http://www.glamour.com/health-fitness/activity/calculators/elliptical_trainer/result?switchMeasurement=US&calculators=/health-fitness/activity/calculators/elliptical_trainer&met=7.7&weightPounds=&duration=&activity=? Thanks.

Replies

  • onefortyone
    onefortyone Posts: 531 Member
    Most machines/estimates are known to be inaccurate because they cannot factor in effort. I might be giving it 100% and going the exact same speed as someone next to me who's giving it 50% because they've been doing that exercise for a few months and they're used to it. So my heart rate would be 160+ and theirs might be 130-140. But the machine doesn't know that (a lot of them have heart rate handholds, but you can't keep hold of them the whole time).

    The link you posted may be slightly better because you can choose between intensity levels. But the best calculator is a heart rate strap that you wear during your cardio workout (though that is also an estimation). But if in doubt, use multiple calculators and pick the lowest estimate. Or, some people prefer to log what the machine says and only ever eat 50-75% of those calories back.
  • PugBug20
    PugBug20 Posts: 55
    So, basically, if you were to do the same incline, resistance, speed, etc., each time you used the machine (I don't, but hypothetically), it wouldn't burn as many calories as it would if you were to increase all of the above because your body would get used to it? I mean, I usually don't eat back the calories I burn, anyway, but I'm just curious.
  • SimaN2014
    SimaN2014 Posts: 23 Member
    So, basically, if you were to do the same incline, resistance, speed, etc., each time you used the machine (I don't, but hypothetically), it wouldn't burn as many calories as it would if you were to increase all of the above because your body would get used to it? I mean, I usually don't eat back the calories I burn, anyway, but I'm just curious.

    Yup, pretty much this. It took me a while to get this but basically it's physics. If you are going at the same incline, resistance, speed, etc. it takes a certain amount of energy to make the machine move like that. But, your body is not very efficient (I forget the percentage) in burning energy... so you burn energy and some of it goes to moving the machine, and some of it goes to heat and some of it goes who knows where. The amount of energy you actually use (i.e. the calories that you care about) is measured in relation to the amount of oxygen (VO2) you are using up, which is in proportion to your heart rate. The first time you do a certain exercise, your body is less efficient at it than the 20th time. The 20th time, you need less oxygen to make that machine go at those settings, your heart rate is lower and you are burning fewer calories. So, yes, to get the same calories used, you need to progressively up the settings on the machine over time. Your body gets more efficient. That also means your are more fit, which is the upside of it all.
  • PugBug20
    PugBug20 Posts: 55
    How often should you increase your incline, resistance, speed, etc. to burn the most calories? When you current workout becomes easy?
  • sijomial
    sijomial Posts: 19,809 Member
    So, basically, if you were to do the same incline, resistance, speed, etc., each time you used the machine (I don't, but hypothetically), it wouldn't burn as many calories as it would if you were to increase all of the above because your body would get used to it? I mean, I usually don't eat back the calories I burn, anyway, but I'm just curious.
    Calories burned are nothing to do with how "used to it" you are. Weight, power produced, time - these are factors that are important.
    Your calories burned will increase if you increase speed, incline, resistance or time.

    A 200lb unfit, fat person walking up a flight of stairs will burn the same number of calories as a super fit 200lb bundle of muscle walking up a flight of stairs - just because it's hard for one and easy for the other doesn't mean you burn more/less calories to raise 200lbs up the height of a flight of stairs.

    The big difference will be that the fit person will be able to walk up many flights of stairs. :smile:

    Perceived effort and heart rate are not measures of calories. Calories are a unit of energy remember.
  • SimaN2014
    SimaN2014 Posts: 23 Member
    I use a heart rate monitor and just make sure I'm keeping my HR at a reasonable rate. I alternate between steady state cardio on some days and HIIT on others (where I really go for gold -- i.e. very high HR -- on the intervals).

    Over time, I have just progressively put up the speed and incline. (I usually use an AMT, so similar to the elliptical, but I prefer it.)

    If you don't have a HRM, then just keep challenging yourself. Use a metric you can get on the machine (e.g. calories per minute or watts, or total calories over your workout time), and just set a goal that's hard. When it becomes less hard, up the goal to something harder.

    As much as I love being outdoors and hiking and biking, the great thing about the machines in the gym is you really can up the difficulty and keep your workout to the same amount of time. I imagine there is a limit, but I haven't hit it yet (and I'm about 18 months in on my regular gym routine).
  • runner359
    runner359 Posts: 90 Member
    So, basically, if you were to do the same incline, resistance, speed, etc., each time you used the machine (I don't, but hypothetically), it wouldn't burn as many calories as it would if you were to increase all of the above because your body would get used to it? I mean, I usually don't eat back the calories I burn, anyway, but I'm just curious.
    Calories burned are nothing to do with how "used to it" you are. Weight, power produced, time - these are factors that are important.
    Your calories burned will increase if you increase speed, incline, resistance or time.

    A 200lb unfit, fat person walking up a flight of stairs will burn the same number of calories as a super fit 200lb bundle of muscle walking up a flight of stairs - just because it's hard for one and easy for the other doesn't mean you burn more/less calories to raise 200lbs up the height of a flight of stairs.

    The big difference will be that the fit person will be able to walk up many flights of stairs. :smile:

    Perceived effort and heart rate are not measures of calories. Calories are a unit of energy remember.

    This exactly. I'm surprised how many folks don't get this.
  • onefortyone
    onefortyone Posts: 531 Member
    Maybe I'm mistaking something - because I still reckon the fat 200lb person's heart rate would be higher going up those stairs than the muscle-bound fitter 200lb person. Sure they're both moving the same weight, but cardiovascularly, they're in different leagues.

    So if they both tracked their calories on a stairmaster, wouldn't the consistently higher heart rate coincide with more calories burned? It's not perceived effort, it's effort!

    I'm ready to be enlightened!
  • sheiladay
    sheiladay Posts: 1
    I've wondered why my calories burned from the elliptical machine at Planet Fitness is always lower than the calories on my Fitness Pal. I always change it to the lower number. I'm guessing the calories on the machine with my age, weight, time, and effort calculated in is the more accurate measure?
  • sijomial
    sijomial Posts: 19,809 Member
    Maybe I'm mistaking something - because I still reckon the fat 200lb person's heart rate would be higher going up those stairs than the muscle-bound fitter 200lb person. Sure they're both moving the same weight, but cardiovascularly, they're in different leagues.

    So if they both tracked their calories on a stairmaster, wouldn't the consistently higher heart rate coincide with more calories burned? It's not perceived effort, it's effort!

    I'm ready to be enlightened!
    You have been taken in by the myths around HRMs!! Very common on MFP.....:smile:

    You cannot actually measure calories in heartbeats. Calories are energy, you would have to measure then in terms of power or heat. There is a relationship between oxygen uptake and calories (in cardio exercise) but you would have to wear a gas analyser to measure that (like they do in sports science labs). Not very practical for everyday use....
    There is a general relationship between heart rate and oxygen uptake - but it's very general and is an average. That's what HRMs use.

    As an example - a couple of years ago my resting HR was 65, now it's 48 as I'm much fitter. I also have to push much, much harder to raise my HR during exercise. I can create more power, for longer with a lower HR - which completely throws out HRM calculations. My real calorie burn is higher (more power produced) but my HRM would tell me I've burned less calories (less heart beats).

    HRMs are not an exact science, just a general estimate for an average person.

    If the same person did two Stairmaster workouts then the HRM would tell them which workout burned more calories.

    If two different people with same weight did a Stairmaster workout them it's a complete lottery which person actually burns more calories. If the Stairmaster records power (commonly in watts) then that would show who produced more energy (calories) but heart rate has too many variable factors.
  • onefortyone
    onefortyone Posts: 531 Member
    Ah I see! TY for the info :) I knew it was a correlation, not exact causation, but I didn't know much behind it.
  • WorknProgress202
    WorknProgress202 Posts: 3 Member
    Hi,

    I wear a heart rate monitor when I do the elliptical at my gym to compare. My Dr. says going by a heart rate monitor is more accurate then what the gym machine say.. I wear a Polar HRM and compare it to the machine when I'm working out and the HR is accurate, but according to my HRM I'm burning more calores then it says on the machine. Go figure!

    Good luck!
  • acpgee
    acpgee Posts: 7,995 Member
    My typical workout is 65 minutes on the elliptical targetting a heart rate of 140. My HRM says I burn just over 500. The machine (which knows my weight) says around 750 and MFP database says 897.

    I've been told that manufacturers of machines tend to choose to display upper end of calories burned, rather than median, for marketing purposes.

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