Garmin HRM (bike) calorie accuracy?

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djdube525
djdube525 Posts: 69 Member
I have one of the Garmin 500 Edge cycle computers, with the premium heart rate monitor straps. I was wondering how accurate they tend to be.

Today, I did a fairly easy paced 30 miles (15mph)... Garmin calculated 820 calories burned... MFP was suggesting 1900 (way way too high).

I also stumbled across this article: http://www.dcrainmaker.com/2010/11/how-calorie-measurement-works-on-garmin.html

And was wondering if anyone has tried the new leaf VO2 test profile method... Which you can supposedly put the test data back into our Garmin (newer models) and it'll give you the most accurate results (scoring o the article).

Thoughts?

-DD

Replies

  • snowbike
    snowbike Posts: 153 Member
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    Mine (not garmin) shows much less cals than MFP quotes for cycling.
    Flat out (speed I cant do more than the hour), I seem to do about 650 an hour on the HRM and MFP says this should be nearer 800 -900 !!

    With some tweaking the the V02 settting , My HRM now seems to now match up with the long term gains or losses in weight.
    I have retrospectively worked out my v02 max is around 55 for my HRM to tie with my cals in and out over time.

    If you find yourself drifting weight wise in and unexpected way over time and your intake is accurate then it may be your v02.
  • djdube525
    djdube525 Posts: 69 Member
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    How did you get your VO2? Did you go to a testing lab, or did you use some calculation?
  • snowbike
    snowbike Posts: 153 Member
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    How did you get your VO2? Did you go to a testing lab, or did you use some calculation?

    Not had it tested. Just adjusted the hrm monitor over the last 6 months to match my gains and losses as I keep cals in accurate.

    This site has a few calculators ...

    http://www.shapesense.com/fitness-exercise/calculators/vo2max-calculator.aspx

    The resting one seems to match me.

    Not tried the others
  • Cyclink
    Cyclink Posts: 517 Member
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    With a power meter, the Garmin gets you within about +/- 10% of your actual calorie burn (usually reading 10% low when you are deeply anaerobic and 10% high when you are gong really easy).

    Using just heart rate, it's closer to 20%. You might be able to get it calibrated more along the 7 to 10% accuracy he lists for a single workout, but that ignores the multiple variables that cause your heart rate to run higher or lower than normal, completely throwing out the calibration values.

    A power meter also gives you a good way to calculate your VO2 max from a 5-minute max test. I don't test specifically for it. I just take my 5-minute best from WKO each month to check it.

    Your absolute VO2 (total liters per minute) has a lot more to do with how much power you can put out while your relative VO2 (ml/kg/minute) is based a lot more on your weight.

    I've done the crash-cart-and-mask VO2max tests before. The numbers from my power meter were close enough that it was not worth the money to do them anymore (the same thing goes for lactate threshold tests)
  • dirtybadgermtb
    dirtybadgermtb Posts: 140 Member
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    I have an older Garmin 305 and I never actually look at the calorie read on the device. However, I do upload the ride data to both Strava and Garmin Connect. There are typically huge differences in the calorie count. It is not unusual for the count between the 2 websites to be 20-30% different. I think that part of the reason for the big difference is because Strava dismisses stop time on rides while Garmin Connect does not. For instance, if you take a 10 minute pee break on the ride or hit a bunch of traffic lights, Garm Conn keeps clicking off calories whereas Strava doesn't. I don' think that this is the only reason for the difference though. They must both use a different algorithm. Strava calorie counts are always a lot less than Garm Conn.

    My goal is to shed body fat so I always try to remember the old dieting axiom that people overestimate activity and underestimate how much they eat. Because of this, when logging my burned calories into MFP, I go by the lower Strava count. I just play with the different cycling speeds in the MFP data base that fits the Strava calorie count. For instance, I may have been on a 16-17 pace ride for 60 minutes but the calorie count on Strava is more in line with a 14-15 pace ride for 60 minutes. I just pick the speed that best allows the total minutes of riding to match Strava. I hope that doesn't sound too confusing.
  • jkrobertson1998
    jkrobertson1998 Posts: 30 Member
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    I use Endomomdo and then upload my file to Strava. I have noticed a big difference in the calories. For instance:

    Endomondo: 40.1 miles at 16.4mph 1789 calories

    Strava: 40.10 miles at 16.4mph 1130 calories.

    http://www.shapesense.com/fitness-exercise/calculators/activity-based-calorie-burn-calculator.aspx