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  1. #1
    Senior Member DOOM_NX's Avatar
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    Do I really burn 1640 calories in a workout?

    Hello guys!

    Ever since I started cycling on my new bike, I seem to not lose any weight. I must be building muscle or something. Today I went ahead and dropped a visit to a dietitian so that she can provide me with an eating plan. I told her I ride 5-6 times a week for about 1 hour. I hope she gets the counting right.

    Well, my last workout went like this:

    Code:
    Cycle Computer                HRM
    
    Trip Distance: 14.17 miles   Total Time: 1:25:00
    Moving Time: 1:20:58         Calories: 1640
    Avg Speed: 10.50 mph         HRavg: 147 bpm
    Max Speed: 14.18 mph      
    Avg Cadence: 69 rpm
    Did I burn anything close to 1600 calories? I've set the HRM right (it's a Sigma Onyx Classic with a chestband), but is it counting right? I weigh 260 lbs.

    What do you guys think? How should I estimate my calorie expenditure during my workout?
    Last edited by DOOM_NX; 07-14-11 at 10:46 AM.
    DOOM_NX

  2. #2
    Senior Member ill.clyde's Avatar
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    That seems high to me ...

  3. #3
    runnin' down a dream edbikebabe's Avatar
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    I'd say divide that number by two & it will be closer to accurate. They say "vigorous" cycling burns around 700 kcal per hour. You might burn more than that based on your weight, but I doubt it's that high. It's better to underestimate calories burned than over estimate.

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    Quote Originally Posted by edbikebabe View Post
    I'd say divide that number by two & it will be closer to accurate. They say "vigorous" cycling burns around 700 kcal per hour.
    I'm around 185lbs at the moment. My power meter suggests I burn 500-550 calories an hour. That's at an average pace of 17mph, which means that I'm seeing mostly 19-20mph on the speedometer except when I slow down to 12-14mph to climb hills or stop completely for traffic. A significantly heavier rider would probably burn slightly more calories.

    HRMs, cardio machines at the gym, and websites are notoriously inaccurate ways to estimate the number of calories burned. Numbers from a power meter are more accurate, though I'd take even those with a grain of salt!

  5. #5
    Senior Member ill.clyde's Avatar
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    Quote Originally Posted by sstorkel View Post
    I'm around 185lbs at the moment. My power meter suggests I burn 500-550 calories an hour. That's at an average pace of 17mph, which means that I'm seeing mostly 19-20mph on the speedometer except when I slow down to 12-14mph to climb hills or stop completely for traffic. A significantly heavier rider would probably burn slightly more calories.

    HRMs, cardio machines at the gym, and websites are notoriously inaccurate ways to estimate the number of calories burned. Numbers from a power meter are more accurate, though I'd take even those with a grain of salt!
    The OP is averaging around 10 mph ... so it's quite a bit less I'd say.

  6. #6
    Gears? CliftonGK1's Avatar
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    Quote Originally Posted by sstorkel View Post
    HRMs, cardio machines at the gym, and websites are notoriously inaccurate ways to estimate the number of calories burned. Numbers from a power meter are more accurate, though I'd take even those with a grain of salt!
    Especially the gym machines; never trust one. Take it from an industry insider (I work for an equipment manufacturer).
    All equipment calculates caloric expenditure on the same formula, and that formula is based on user input of AGE and WEIGHT, plus the variable input of HEART RATE. The key element in the formula is POWER at a given speed and resistance level, which is estimated. Cycles and ellipticals are the worst because there is variability in resistance levels (most are electromagnetically controlled) not only between manufacturers, but from unit to unit of the same company. The voltage tolerances on these things aren't that tight, and the mfg tolerance of flywheel to magnet distance will also vary the resistance level at the same voltage potential.
    So, that power calculation carries an initial slop factor. Compound that with every company using a different multiplier for "mechanical inefficiency" from 20 - 25% and you've got some companies saying that Resistance Level 5 for a 35yo, 170lb user = 250cal/hr, and another telling you it's 380cal/hr.
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  7. #7
    Senior Member Mithrandir's Avatar
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    My Garmin edge 500 (no power input) says I burned 971 for a 1:25 commute this morning, 19 miles @ 13.5mph. I weigh 362.

    I was concerned *that* sounded too high. You're more than likely not burning 1600 calories in the same amount of time, especially at 10mph.

  8. #8
    Senior Member DOOM_NX's Avatar
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    Sorry guys, I used the metric system. I corrected the original post to show values in imperial system. I weigh 260 lbs.

    Regarding the power meters, don't they just cound the watts spent on the bicycle? And then converting to calories spent on it? I think they don't consider your overall energy spent, but only the energy spent on the bike.
    DOOM_NX

  9. #9
    Retired C.O. RandoneeRider's Avatar
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    I may not know any better.... perhaps ignorance IS bliss.
    - BUT -
    I have chosen to disregard amount of calories used... as claimed by my pedometer.
    I ignore the various scales that claim to know what thirty minutes of any particular exercise will burn.
    I'm not sure, but I think my bicycle computer may even claim to know how many calories I've burned as well.
    Each of them can vary by a rather significant amount, and though I know "calories burned" may be an academic assertion based on a mathematical formula, I can't help but think that it may be information no more applicable to one person as it is the next. Bodies and their metabolic rates differ, and some bodies are VERY good at finding a way to do exercise while expending as little energy as possible.

    I've only recently taken an interest in calories that I might eat, but I don't put much stock into indicated calories burned.

  10. #10
    The Fat Guy In The Back Tundra_Man's Avatar
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    I weigh 224. Yesterday morning I ran 8.19 miles in 122 minutes. By my calculations, I burned 1153 calories during that time. To estimate my running calorie expenditure I use the following formula which I got off of some running site several years ago: weight * distance * .63

    Comparing that with a person cycling at an easy pace for roughly the same amount of time, I too think that 1640 calorie count is quite inaccurate (on the high side.)
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  11. #11
    Senior Member goldfinch's Avatar
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    Too high. Way too high. They almost are always too high. At my size I would have burned about 300 or a bit more calories per hour at that speed. At your weight maybe you'd burn close to 700 calories for one hour at 10 to 12 mph.

  12. #12
    Senior Member DOOM_NX's Avatar
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    It was 1640 cal for almost an hour and a half guys... So how can I estimate and be in the safe side? I need to calculate the calories I burn. Only with lab testing?
    DOOM_NX

  13. #13
    Senior Member mwchandler21's Avatar
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    30+/- cal/mile is usually reasonable.

  14. #14
    Gears? CliftonGK1's Avatar
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    A question for everyone out there who is interested in all these numbers:

    What's with the recent push in the fitness world for all the picky analytic data? Just in the past month I've had to explain the concept of caloric calculation to a dozen customers, and in the prior 8 or 9 months no one could care.

    Additional question:

    By what provocation does someone see a Watts measurement on their equipment, a Calories measurement on their equipment, and then complain to my service department that "you're wrong, because when I put X Watts to calories into Google it told me this super low amount, not what your bike tells me" (ignorant of the fact that the direct calculation of Watts to calories per the mathematics they've provided accounts for a 100% efficient system).
    Then they have the gall to refute the maths I provide to them, because the infallible almighty Google told them otherwise.


    Sorry, just ranting really. Being in the fitness industry I deal with this crap all day long. I start wondering when "if your pants are tight, eat less and exercise more" stopped being good enough, and people who have difficulty remembering how to tie their shoes* decided that they need PhD thesis grade quantitative data about every bit of their food and exercise.

    *Not a reference to anyone here on BF. Reference to customers on our support line, who likely couldn't figure out how to operate a computer and join this forum in the first place.
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  15. #15
    Senior Member DOOM_NX's Avatar
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    Soooo... Are these way off? Why would they include such measurements if they're so off? I mean every other measurement in these devices is fairly accurate. Why would they include such a faulty feature?
    DOOM_NX

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    [QUOTE=CliftonGK1;12927665]What's with the recent push in the fitness world for all the picky analytic data? Just in the past month I've had to explain the concept of caloric calculation to a dozen customers, and in the prior 8 or 9 months no one could care.QUOTE]

    Blame it on Dr. Oz.

  17. #17
    Senior Member mwchandler21's Avatar
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    Quote Originally Posted by DOOM_NX View Post
    Soooo... Are these way off? Why would they include such measurements if they're so off? I mean every other measurement in these devices is fairly accurate. Why would they include such a faulty feature?
    The numbers are probably very accurate under a certain set of assumptions. Say 150 lb person, exercising at an even effort, etc. We just don't know what assumptions each manufacturer is using in their formula and if you are not matching those assumptions then the formula fails, often badly. Also for exercise equipment I'm sure there is some juicing the Cal burned count because it makes customers feel good and maybe buy more equipment.

  18. #18
    2 Fat 2 Furious contango's Avatar
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    14 miles @ 1640 calories means more than 110 calories per mile. If you were going up the side of a mountain, perhaps. If you weighed double what you do, even then I'd say it's a bit high unless you did some serious climbing.

    I'm around 250 and reckon on around 40-50 calories per mile on average as a very rough-and-ready figure, which would give you a guesstimate figure of more like 600 calories. If you're taking on calories assuming 1600 then you're potentially miscalculating by 1000 calories per day. Over a week that could total 7000 calories, equivalent to two pounds of fat.

    Personally I'd rather estimate low and lose a bit more weight than expected than estimate high and struggle.

  19. #19
    Senior Member squirtdad's Avatar
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    Quote Originally Posted by CliftonGK1 View Post
    A question for everyone out there who is interested in all these numbers:

    What's with the recent push in the fitness world for all the picky analytic data? Just in the past month I've had to explain the concept of caloric calculation to a dozen customers, and in the prior 8 or 9 months no one could care.

    .
    My guess/theory is that morre people are seeing these numbers and then see the high number and wonder why they are not losing more weight. Examples the ellipticals as my club....show calories....and yes this has been arouund for a while, but my new HRM (a very basic Timex) shows calories, my old one did not. The mapmyride android app shows calories....and it doesnt even have my weight age. and so on.
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  20. #20
    Gears? CliftonGK1's Avatar
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    Quote Originally Posted by DOOM_NX View Post
    Soooo... Are these way off? Why would they include such measurements if they're so off? I mean every other measurement in these devices is fairly accurate. Why would they include such a faulty feature?
    I don't know who started it, but let's say it was Precor who first came out with a feature like calorie count. Shortly after the IHRSA show where it gets revealed, Landice, StarTrac and SportsArt will all have their versions of it. It doesn't matter if it's correct, it matters that it's there, using a similar algorithm and comparable within X% of the competition's results... Maybe fudge the numbers with a 1.05 multiplier so people think they're getting a better workout on your equipment instead of the other guy's stuff. (Yes, it's just like tire manufacturers calling a 23 a 25 to claim theirs is lighter than the competition.)
    Now it's become so common, people expect it to be there. Even if you were the dead-set-honest company that advertised "We don't have calorie count because the Wattage estimation is crap!", people would buy the competitor's stuff because it has more doodads. (The recent doodad is integrated televisions, because treadmills are so boring you need to watch TV when you could just go outside and enjoy the RealLife-3D experience.)
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  21. #21
    Senior Member Mithrandir's Avatar
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    Quote Originally Posted by DOOM_NX View Post
    Soooo... Are these way off? Why would they include such measurements if they're so off? I mean every other measurement in these devices is fairly accurate. Why would they include such a faulty feature?
    It makes people feel good about having bought the product. It's basically marketing.

  22. #22
    Senior Member DOOM_NX's Avatar
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    Quote Originally Posted by mwchandler21 View Post
    The numbers are probably very accurate under a certain set of assumptions. Say 150 lb person, exercising at an even effort, etc. We just don't know what assumptions each manufacturer is using in their formula and if you are not matching those assumptions then the formula fails, often badly. Also for exercise equipment I'm sure there is some juicing the Cal burned count because it makes customers feel good and maybe buy more equipment.
    The input to the HRM were: my age, my sex, my weight and whether I'm fat or fit. I chose fat obviously. Then I tried to keep my HR constant for all the time during the exercise.
    DOOM_NX

  23. #23
    Gears? CliftonGK1's Avatar
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    Quote Originally Posted by mwchandler21 View Post
    We just don't know what assumptions each manufacturer is using in their formula and if you are not matching those assumptions then the formula fails, often badly.
    You can find out easily what the assumptions are. When you enter "user data" for a program mode on the equipment, what are the default weight and age values? Typically between 150 and 175 pounds, and 35 to 38 years of age.
    You can see why the "assumptive" formula in something like a Quick Start mode where you enter no user data would fail horribly if you're 47 years old and weigh 265 pounds.
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  24. #24
    Senior Member mwchandler21's Avatar
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    Quote Originally Posted by DOOM_NX View Post
    The input to the HRM were: my age, my sex, my weight and whether I'm fat or fit. I chose fat obviously. Then I tried to keep my HR constant for all the time during the exercise.
    What I am saying though is that the company's formula is a model that probably only works on a very narrow range of data. You can enter all the variables you like but more than likely the model they are using fails outside of the range they used to calibrate it.

    Lets say for the calibration test they accurately measured a runner or cyclist used 100 calories in 15 mins, and say they weighed him at 150 lbs and his average heart rate was 130 bpm, so they do the test a bunch of times get a scatter plot and try and fit a formula to the data. Basically they end up with something like A(15mins)+B(150lbs)+C(130 bpm)+ D(age)+ etc = 100 Cal. But most likely the scatter plot didn't come close to looking like a function at all but just a random placing of points. So the Constants (A,B,C,D....) are of questionable accuracy.

  25. #25
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    I have a cheap Bell computer. Today I rode 59 miles with a 12.5 average speed.
    It shows I burned 3362 calories.

    I am 65 years old and the computer thinks I weigh 220, lost some since is was set.
    On a scale of one to five for fitness, I entered 3.

    That is 56 calories per mile.

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