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Calorie calculators on bike riding differ dramatically

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kateharp2112
kateharp2112 Posts: 8
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I'm a newbie so forgive me if this has been asked before: I've searched the web for various bike calorie calculators per mile based on my weight/height/speed etc...and they are dramatically different. Even Mapmyride app is double what the others are. I just want a basic estimate so that I know how much MORE I should eat (to replenish health/energy sustainability) when I ride for 15 miles. I'm 155, female, 5'4" and ride about 8 MPH on flat land. I don't work well with "timing" my rides since I run a lot of errands, but I do have a great mileage tracking. Any clue how much I should estimate for "calories burned" per mile?

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  • cyclist_44060
    cyclist_44060 Posts: 86 Member
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    Calorie burn is primarily a factor of age, weight, heart rate and M/F. I struggled with getting a more accurate calorie burn number. The best way to get that is to use a heat rate monitor while you are riding. I did and it is worth the investment!
  • Archon2
    Archon2 Posts: 462 Member
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    There are ways to get a more accurate number. Using a heart rate monitor and factoring in your weight, speed, and other variables. A power meter is another (expensive) option that will really help. Keep in mind, you will never have the exact count no matter what.

    I recently started using a HRM and uploading my ride data to Strava. I use that calorie number, and usually eat back 1/2 to 2/3 of that number just for insurance.

    You might also want to look at TBY's thread here:
    http://www.myfitnesspal.com/topics/show/1120751-strava-calorie-calculations

    If you like numbers and analysis like I do that is :)

    If not, just use the figure you get some place like Strava or MFP and just use that as a baseline and eat back some percentage.
  • allaboutthecake
    allaboutthecake Posts: 1,533 Member
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    With just a little bit of information, you can go to Livestrong.com and plug in your numbers and see what your extra calorie burn is. 8mp is light bike ride comparison say to 14-15mph, so do factor in your speed. (Not saying you're slower, don't read it like that!). Figure about 38cal per mile.

    You didn't say what/how much you are/have lost, but in mho I think, if I were you, I would maintain your calories and eat your calories that you normally would "without" factoring in your activity. If you find that after 3 weeks you are dropping weight too fast, then add in another 100kCal per day until you are losing weight at a safe speed.
  • kateharp2112
    kateharp2112 Posts: 8
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    What a great group. Thanks for speedy response and advice/resources.
  • jacksonpt
    jacksonpt Posts: 10,413 Member
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    A slightly different take...

    Try not to go chasing numbers or accuracy or perfection. Everything you do regarding calorie counting/weight loss is an estimate. You estimate the cals you eat. You estimate the cals you burn. You estimate the cals you need to lose weight. etc.

    When eating, try to get your portions dialed in. When exercising, do the best you can with duration and/or intensity.

    IMO, trying to be perfect will drive you crazy. And there is sooo much freedom that comes with the realization that your results will be as good or better if you are consistently close than if you're sporadically perfect.


    But more to your question...

    Yes, there are a lot of factors that impact calorie burn which is why estimates can be all over the board (as you've seen). It's very reasonable to estimate your calorie burn based on your perceived effort. Take a look at the chart below. I find the ability to speak an excellent way to estimate effort. Think about your workout and your average effort (RPE). If it was a moderate effort, then multiply 5 (moderate RPE is 4-6) by the number of minutes you exercised. If it was a very hard workout (intervals, perhaps), then multiply 9 by the number of minutes exercised.

    So as an example, a fairly flat bike ride might result in an average RPE of 7 for me. So 7 x 75 minutes of exercise = 525 calories burned.

    It's far from exact, but it's probably as reasonable a starting point as any other estimate.

    rpe_chart.jpg
  • scrittrice
    scrittrice Posts: 345 Member
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    This was a useful thread:

    http://www.myfitnesspal.com/topics/show/1317695-question-about-calories-burned

    Also, your cat and my cat are long-lost twins...

    I agree with jackson, though, that you could make yourself crazy trying to be exact and that it's more important to be consistent than it is to get an exact number (as gratifying as that can be). Pick one calculator/method, use those numbers for a few weeks, see how it goes, and reevaluate.
  • rileysowner
    rileysowner Posts: 8,226 Member
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    Just a comment on Mapmyride. I found the calorie burn the app gave was really high. Then I went to the mapmyride web page and had it recalculate the calories using the same information. I didn't change anything, and the website gave a recalculated number of about half the one the app gave. I don't know why that was the case, but it was because of that I switched to endomondo. Now I have a bluetooth HRM which Endomondo works with. When I upgrade my phone and HRM I will likely switch to a different app as Endomondo has some GPS issues that make the distances it calculates somewhat inaccurate.
  • kcjchang
    kcjchang Posts: 709 Member
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    The most accurate you can get outside of a lab is to use a power meter. It is still subject to errors due to the device's sensitivity and each person's efficiency in converting energy expended to work. Echoing others' post, use the calculator value as a "measuring stick". Monitor your results and adjust as necessary. If you are not losing weight, cut back as needed to match with your "measuring stick". I would recommend making adjustments based on % rather than absolute numbers. See http://www.bodyrecomposition.com/fat-loss/adjusting-the-diet.html. For woman, water balance tends to fluctuates so set your monitoring horizon away from a weekly cycle to a "monthly" cycle. Here is how power meters calculate calories expended.

    http://www.bikeforums.net/training-nutrition/153865-wattage-output-directly-linked-calories-burned.html

    "Power calculations are a better indicator of energy expenditure than HR monitor because energy output and HR are not linearly correlated. Here is how to calculate energy expenditure using power :

    Energy = power output x time.

    Power is measured in watts (W) and time in seconds, which gives an answer in joules (j). 1cal = 4.19 j,

    Example : 500 kj would be 119 kcal. however, the body is about 20 - 25% efficient, which means that you expend 4 - 5 times the energy, i.e., ~ 500 kcal. So basically in the end to get the number of calories spent in one hour, just take your average wattage for an hour and multiply by 3600(seconds in one hour) then divide by 1000 (to get the number in kilo calories). "
  • bsexton3
    bsexton3 Posts: 472 Member
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    I have found the calculator on MFP is about 50% higher than my heart rate monitor. If MFP states I burned 1,500 calories, my heart rate monitor is around 1,000. That has been fairly consistent.

    Also, I don't eat all my exercise calories. In fact, many a day I don't eat any of them.

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