Calorie Discrapancy Help me understand this, Please!

oeagleo
oeagleo Posts: 70 Member
in Fitness and Exercise
I have recently began including a bicycle ride in my exercise routine, and have a Garmin Edge 705 bike computer to assist in tracking my development. However, I have noticed a major difference in the calorie burn between the calculation that the Fitbit website uses to calculate calories, and what the Edge says that I burned. For instance, for today's ride:
I rode 9.3 Miles, in an Hour and 9 minutes. Actual Moving time was 59 Minutes, 4 seconds. Average cadence was 47 RPM, heartrate varied between 140 and 160, average speed including stops was 8.0, average moving speed was 9.5 Mph. Variations in elevation, gain was 743 feet over the 9.3 miles. Given this scenario, Fitbit calculates the calories burned at 341, while the Edge computes the calorie burn at 756.

I realize that any calculation is merely an estimate, to be used as such, and simply as an indication, or relative picture of how I'm doing, but I do not understand the major difference in these calculations. Can anyone help me understand which is a more close representation of what I've done, and why?
Thanks

Replies

  • EatClenTrenHard
    EatClenTrenHard Posts: 339 Member
    lol 150 heart rate. 8 miles per hour on bike with almost 1k feet elevation and 341 calorie burned? u get that walking with dog.
    Fitbit sucks. thanks for giving honest review of that crap product.

    2nd number seems close to realistic.
  • EmmaM2211
    EmmaM2211 Posts: 536 Member
    Isnt a fitbit based on steps taken? So would be wildly inaccurate for cycling? I'd go with somewhere in the middle probably. Your best bet is to invest in a HRM x

    ETA - Oh sorry just realised you know your HR - I'd go with the EDGE in that case!
  • SheilaN1976
    SheilaN1976 Posts: 266 Member
    i would go with what your Edge says since its specifically for bike riding....fitbit is for steps not so much as biking and etc. or you could just do half of what edge says
  • LaurenAOK
    LaurenAOK Posts: 2,475 Member
    What does MFP say? I'd put in an hour of cycling at 8 mph on here and see what it tells you... people say MFP is inaccurate, but I've found it to be spot on with what my HRM tells me. I agree that the fitbit count seems wayyy too low though. The Edge is probably more accurate.
  • oeagleo
    oeagleo Posts: 70 Member
    @Emma, the Edge has a heart rate monitor that comes with it, that way I get a pretty complete picture of the biking.. I tend to agree that the fitbit is a little light on the calories. Any other opinions?
  • alison2429
    alison2429 Posts: 236 Member
    Does the Fitbit have a chest strap? How does it measure your burn? I don't know how either of these devices work but I do know that unless you have a chest strap then everything is an average and not tailored to you. Looking at your info about the bike ride I would think somewhere in between would be about right but I don't know your stats.
    Not sure if that is any help at all........I'm no expert!!

    Hope you get some more informed replies.

    A
  • justlistening
    justlistening Posts: 249 Member
    I thought a fitbit makes estimates according to the steps you take. If you are on a bike it probably is totally off.
  • DebbieLyn63
    DebbieLyn63 Posts: 2,654 Member
    My husband who is a competitive cyclist says to go with the Edge.
  • jtkwood
    jtkwood Posts: 24 Member
    I'd go with the Garmin. HR monitor is always more accurate. Fitbit has no idea it's up hill or anything, which will be harder, so it burns more calories.... The Garmin is going to have a much better idea how much work you are actually doing since it's monitoring your activity. I live in the mountains and had to get something with a HR monitor so I'd know exactly how many calories are burned and the estimates on MFP were way off because of it. But they were pretty close if I went to a park and walked where it was flat.
  • ewl6850
    ewl6850 Posts: 158 Member
    I'm in the same boat.

    I usually do an hours on the bike, covering 18.5-19.5 miles. RPMs 78-81.

    The bike says 400-420 usually, while MFP wants to tell me like 1000+ calories burned...
  • JLand918
    JLand918 Posts: 156
    What does MFP say? I'd put in an hour of cycling at 8 mph on here and see what it tells you... people say MFP is inaccurate, but I've found it to be spot on with what my HRM tells me. I agree that the fitbit count seems wayyy too low though. The Edge is probably more accurate.

    For me the MFP calc. for calories burned is way off not sure what your looking at. for example I can walk at 2.5mph pace for 10 min treadmill no incline it burns 25-30 calories. But same info put into MFP will tell you like almost 6x that. So how is that remotely accurate?
  • cordianet
    cordianet Posts: 534 Member
    Most heart rate monitors are going to be more accurate than something that is using a table to calculate the results. While not 100% accurate (+-10% can be expected), there is a very strong correlation between how hard your heart is working and actual calories burned. It's most accurate when doing full body or leg based aerobic work (walking, running, cycling), and less accurate when doing anaerobic work, especially such work focused on the upper body only or primarily.
  • SJCon
    SJCon Posts: 224
    I have both a fitbit and HRM, I consider the FB to be valid for general activity but it does not take into account effort where the HRM does.The calories burned between FB and HRM for 10 flights of stairs is significant. I input HRM results when exercising and let FB do its thing to get a rough TDEE. I get mixed comparison on MFP tables sometimes close sometimes not, depends on activity.
  • gpstrucker
    gpstrucker Posts: 930 Member
    While the Fitbit is a great product for daily activity monitoring, it is designed for STEPS. It is not designed for cycling, swimming, etc.

    Your HRM will be much better for cycling, strength training, swimming, etc.

    The right tool for the job.
  • rebelq
    rebelq Posts: 64 Member
    I'm glad to see this discussion, I was thinking about asking for a fitbit for my birthday.
  • mockchoc
    mockchoc Posts: 6,573 Member
    While the Fitbit is a great product for daily activity monitoring, it is designed for STEPS. It is not designed for cycling, swimming, etc.

    Your HRM will be much better for cycling, strength training, swimming, etc.

    The right tool for the job.

    Correct! It's a pedometer type of device for measuring steps not bike riding etc. It's not crap by the way tons of people are loosing heaps of weight using it. I have one and I'm loosing very well with it.
  • Cyclink
    Cyclink Posts: 517 Member
    9 mph on a bike is generating a pretty low power output, probably 100 to 120 watts. At that intensity level, 340 calories per hour sounds about right to me. If you're not getting above 15 mph, cycling does not burn a lot of calories.
  • gpstrucker
    gpstrucker Posts: 930 Member
    9 mph on a bike is generating a pretty low power output, probably 100 to 120 watts. At that intensity level, 340 calories per hour sounds about right to me. If you're not getting above 15 mph, cycling does not burn a lot of calories.

    That's true for the most part, but it also depends a great deal on the physical condition of the person. An out of shape (or heavier) person will burn a lot more calories at that speed than someone who is lighter and more physically fit. Exactly why an HRM is needed to measure exertion levels via heart rate.
  • EatClenTrenHard
    EatClenTrenHard Posts: 339 Member
    9 mph on a bike is generating a pretty low power output, probably 100 to 120 watts. At that intensity level, 340 calories per hour sounds about right to me. If you're not getting above 15 mph, cycling does not burn a lot of calories.

    he was going uphill
  • gregsonevans
    gregsonevans Posts: 232 Member
    I use the Garmin 705 and I find it pretty good but slightly generous, on your settings knock off a few pounds on the device and you will get more accurate numbers, Looking at the bpm can we assume that you are new to cycling and this was a hard ride for you? I weigh about 230lbs and ride about a 14mph average on a 35lb bike and my average bpm comes in at around 120-125 even when I do hillier rides so yours was very high for that speed and that will boost the calorie burn
  • gregsonevans
    gregsonevans Posts: 232 Member
    p.s. if your bpm are exceeding 160 then you need to keep a close eye on them, safe limit for a man is 220 take away your age, good luck with the rides :smile:
  • junipearl
    junipearl Posts: 326 Member
    9 mph on a bike is generating a pretty low power output, probably 100 to 120 watts. At that intensity level, 340 calories per hour sounds about right to me. If you're not getting above 15 mph, cycling does not burn a lot of calories.
    yah this totally depends on the person. if his HR was at 150 it is pretty safe to say that he is burning more than the experienced biker at that speed.

    I burn about 340 cals on a 40 min bike ride averaging about 13mph.
    So for a 70 min bike ride where your heart rate was up that high, 2nd number would definitely be closer.
  • Cyclink
    Cyclink Posts: 517 Member
    9 mph on a bike is generating a pretty low power output, probably 100 to 120 watts. At that intensity level, 340 calories per hour sounds about right to me. If you're not getting above 15 mph, cycling does not burn a lot of calories.

    That's true for the most part, but it also depends a great deal on the physical condition of the person. An out of shape (or heavier) person will burn a lot more calories at that speed than someone who is lighter and more physically fit. Exactly why an HRM is needed to measure exertion levels via heart rate.

    If he was really killing himself, the difference in efficiency does make a difference (up to 25% more), but it's going to more than double his calorie output.

    It's one of the harsh truths that I had to learn from training with a power meter is that there the only way to really burn a lot of calories from cycling was to go faster, and people who ride really slowly, regardless of their efficiency levels and heart rate, don't burn many calories.

    It all goes back to the fundamental problem with heart rate based calories: the heart monitor can't tell the difference between a heart rate of 150 BPM from being really anxious (which does not burn many calories) and a heart rate of 130 BPM cross-country skiing, which burns calories like crazy. A higher heart rate just means that you are working harder, not that you are burning more calories.
    yah this totally depends on the person. if his HR was at 150 it is pretty safe to say that he is burning more than the experienced biker at that speed.

    It's actually quite the opposite. An experienced cyclist will be putting out far more power at 150 BPM than an inexperienced one, thereby burning more calories.
    he was going uphill

    Not the whole time. If it was 9 miles out and back, with 743 feet of climbing, that also means he was descending (probably coasting) for 743 feet as well. You burn very few calories while coasting.
    I burn about 340 cals on a 40 min bike ride averaging about 13mph.

    If you ever get a chance, try a power meter or a cycling ergometer (some higher end bike shops offer weekend classes that let you ride on one, the most common brand is CompuTrainer...and yes, I own one). You'd be stunned to find that calorie number is very high unless it involves a lot of climbing.
  • kramalicious
    kramalicious Posts: 143
    I think what you meant to say is that it is NOT very high unless you are doing a lot of climbing. And I totally agree, generally you need a much higher cadence than that to be burning significant calories. Right now I am rehabbing on a recumbent bike at the gym, and I need a really high RPM and resistance to be able to get a minimal burn. People beside me read a book and don't even break a sweat. Is better than lying in bed and reading but not by much.

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