Cardio machines' calories burned, based on age & weight
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Wakey618
Posts: 160 Member
I would never trust a cardio machine's estimate of calories burned if I just got on the machine and did my workout. But the Precor machines at my gym ask for my age & weight before my workout so I feel that it is giving me a more accurate number for calories burned.
Do you believe it's a reasonable assumption that the number would be more accurate since it asks for this information?
Do you think it's safe to count on this when balancing out my calories per day? I don't trust a HRM since there are too many variables, and I don't own a fitbit (and don't want one).
Do you believe it's a reasonable assumption that the number would be more accurate since it asks for this information?
Do you think it's safe to count on this when balancing out my calories per day? I don't trust a HRM since there are too many variables, and I don't own a fitbit (and don't want one).
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Replies
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It should be more accurate than machines that dont take any of this into account; however, it's impossible for it to be 100% correct. Most people only eat back 50-75% of machine estimates to be safe.
Ultimately, everything we are doing (mfp goal, exercise calories, logging as best you can) are really only a combination of best estimates. Time is the best test. Since you know this is a questionable area it would be the first place I look at for adjustment if you are getting unexpected results out of your journey in 4-6 weeks. Sorry I cant give you a more exact answer
~best wishes2 -
More accurate? Yes. Correct? Nobody can really know.2
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Because machines at the gym are RARELY calibrated on a consistent basis, I wouldn't have any client rely on the information on them. Many times the same exact machines have different readings even though the input of stats are the same.
A.C.E. Certified Personal and Group Fitness Trainer
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Been in fitness for 30 years and have studied kinesiology and nutrition
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You should actually trust these machines even less than you trust a HRM...4
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Age has nothing nothing to do with calorie burn. They ask that for context for your HR during exercise.
The problem with cardio machines, esp ellipticals, is not that don't accurately measure workload. They actually are highly accurate at it.
The inaccuracy comes from trying to translate that work output into a calorie burn. Developing these types of algorithms is time-consuming and expensive; for the most part, there is zero financial incentive for incurring the cost of making them more accurate.
They can be useful to compare results and track improvement over time, but should not be used as an accurate record for tracking purposes.1 -
Age has nothing nothing to do with calorie burn. They ask that for context for your HR during exercise.
The problem with cardio machines, esp ellipticals, is not that don't accurately measure workload. They actually are highly accurate at it.
The inaccuracy comes from trying to translate that work output into a calorie burn. Developing these types of algorithms is time-consuming and expensive; for the most part, there is zero financial incentive for incurring the cost of making them more accurate.
They can be useful to compare results and track improvement over time, but should not be used as an accurate record for tracking purposes.
If anything, there may be a financial incentive to provide the highest calorie burn estimate that's even remotely defensible. Most people would prefer to buy/use a machine that "burns up to 800 calories per hour!!!!" compared to one that "only" may burn 600.3 -
The inaccuracy comes from trying to translate that work output into a calorie burn. Developing these types of algorithms is time-consuming and expensive; for the most part, there is zero financial incentive for incurring the cost of making them more accurate.
As a software developer (in a different industry), I can say from experience that the product manager only cares that they used a common, accepted, defensible formula, not that it's an accurate one.2 -
I guess I'll just use it as a guide & adjust if needed. Thanks for all of the great input!1
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Age has nothing nothing to do with calorie burn. They ask that for context for your HR during exercise.
The problem with cardio machines, esp ellipticals, is not that don't accurately measure workload. They actually are highly accurate at it.
The inaccuracy comes from trying to translate that work output into a calorie burn. Developing these types of algorithms is time-consuming and expensive; for the most part, there is zero financial incentive for incurring the cost of making them more accurate.
They can be useful to compare results and track improvement over time, but should not be used as an accurate record for tracking purposes.
If anything, there may be a financial incentive to provide the highest calorie burn estimate that's even remotely defensible. Most people would prefer to buy/use a machine that "burns up to 800 calories per hour!!!!" compared to one that "only" may burn 600.
In the past that may have been true, but my experience in the the industry for 10 years is that it s more about manufacturing expediency than some conspiracy, at least among the major manufacturers.
At worst they might be using a 20 yr old algorithm that they paid some grad student at a community college to develop.
Most of the folks involved are fitness advocates themselves and take a lot of professional pride in what they do.
Now infomercial products--that's a different story. Distortion/lying are pretty much required.
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I've got a few studies I could dig up regarding energy expenditure actual vs machine measured. They were military studies used to use machines for a run substitute for people with certain injuries. Though many machines reported higher than actual, some also reported lower. Then again it's expected to some degree since any calculation of calories rather than energy is subject to error.
I wish they just reported actual energy use myself, and let us figure it out from there. Quite a few of the machines actually have very good generators and needed equipment to measure energy, the problem lies in the conversion to human calories.0 -
How would we go about figuring it out ourselves? Is there a general formula that I could use that may be more accurate than the algorithms built into the machines? Sorry if that sounds naïve, I don't really know much about all of this and a lot of good information has been presented here.robertw486 wrote: »I wish they just reported actual energy use myself, and let us figure it out from there.
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How would we go about figuring it out ourselves? Is there a general formula that I could use that may be more accurate than the algorithms built into the machines? Sorry if that sounds naïve, I don't really know much about all of this and a lot of good information has been presented here.robertw486 wrote: »I wish they just reported actual energy use myself, and let us figure it out from there.
I was suggesting they simply report wattage and kilojoules of of energy, which are absolutes. What takes place with most machines is they are often trying to calculate gross calorie burn (which would include your BMR/RMR estimate). If a machine reported only net absolute power use, it takes out one of the possible variables of the machine. But in any case, human efficiency is still an unknown without testing, so a machine using watts and kj would still not give an end user an absolute in human calories burned really.
I own a Precor elliptical, and have done some homework on them. They are designed to calculate METs from the machine outputs, and then calculate calories from that. Due to design, they are adding in your BMR/RMR. Having checked out studies and other calculator types, removing that from the calorie output it gives you should get you reasonable close on your calorie burn.
If you use the "Miles" output from a Precor elliptical, and compare it using the following calculator...
exrx.net/Calculators/WalkRunMETs.html
... you will find the numbers are usually fairly close. Both were designed using ACSM models. After using that calculator, regardless of using net or gross calculation, you will find that the numbers come up fairly close to studies.
One of the military studies on exercise machines. Keep in mind that these charts were only to assess what machines could be used for specific testing, and that the slopes and error shown may not be the same depending on exercise intensities, etc.
http://www.dtic.mil/get-tr-doc/pdf?AD=ADA590107
For what it's worth, when I was in my weight loss phase I logged 100 percent of my elliptical reported calories, even though I knew it was reporting gross calorie burn. It was easier than converting the estimate to net calorie burn, and that few hundred calories a week didn't hurt a thing for my loss goals. That might vary person to person based on metabolic efficiency, but really that is always a variable regardless of how you measure power and/or calories.0 -
As everyone else said, these machines will be more accurate than machines that don't ask your weight, but still not super accurate. None of the machines I've ever used have asked my height ... and if you think about it, the amount of cals burned for 150lbs is going to be very different if you are 5'10'' compared to 5'2''.
For this reason, most MFP-ers suggest only eating back 50-75% of exercise calories, just to have that margin of error.0
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