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ann121212
ann121212 Posts: 290 Member
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Has anyone worked out the formula for the way vivofit calculate the calories? Or even a close guesstimate?

Replies

  • numsquat
    numsquat Posts: 133
    I have no idea. I've looked at my running data using the Vivofit with my HRM strap along with my Timex data and my own formulas in my spreadsheet for calculating calories burned and none of the three are close for the same run. My Timex I have always felt was high, hence the reason I use a separate formula, and that formula has worked well in the past. The Vivofit tends to have lower calories burned than my formula but then will have a higher number now and then that's much higher.

    I will say the Garmin BMR is very close to my calculated RMR number, pretty much within 20 calories difference.
  • fyoung1111
    fyoung1111 Posts: 109 Member
    First, The calorie and steps GC shows for Vivofit HRM linked "Activities" are seriously messed up and have been since the get go. As one great example, I did a 10 mile, nearly all down hill bike ride yesterday afternoon. GC reported an impossibly high 1,593 calories. Net calories read directly from the Vivofit for this same activity were a much more believable 462. The band is always "right". GC is correct on a whole day basis but only right occasionally and accidentally for individual activities. As another example of both of these points, GC awarded me with 3,729 combined calories for yesterday's three Activities but only 3,799 (1,848 BMR + 1951 Active) for the whole day.

    Second, all Garmin devices do not calculate calories the same and Garmin pretty much refuse to disclose how they do what they do. For example, I wore an HRM1G connected to an Edge 705, a Forerunner 410, and a VivoFit for my uphill bike ride yesterday. These three devices reported 1,219, 832, and 1,131 calories burned respectively (VF calories netted directly fro the band). They are all estimates and it takes a lot of calories to make a difference. Generally speaking, I have found the VF estimates to be 10%-20% less (more conservative) than other devices and manual methods like METS and HR calorie consumption calculators.

    Hope this helps.
  • ann121212
    ann121212 Posts: 290 Member
    Yes it does help thanks.

    Originally I thought there was something wrong with the equipment - only reading intermittently or something. Then I thought I had fitted it wrong - too high/low on the chest, not enough moisture to make a good connection (its my first hrm, I had NO idea).

    Eventually I gave up trying to understand everything and concentrated on just what appeared right. I am now venturing back into some grey areas trying to find out more detail.
  • fyoung1111
    fyoung1111 Posts: 109 Member
    Which HRM do you have? HRM1 has a big plastic piece that covers the whole front of your chest. HRM3 is all fabric with a transmitter that snaps on.

    I find that if you wet either of them before you put them on they work well. The 3 starts to do strange things when the battery gets low. It's more comfortable but not worth the irritation. My third HRM3 is in the mail from Garmin right now.

    In general, they are not very sensitive to placement. You can get a heartbeat just by placing a thumb on either side. Strap just snug enough to keep it in contact with your skin. Vertical placement--anywhere on your rib cage where it won't slide down to your naval.

    Finally leave your VF in the HEARt display and keep an eye on it. It should not be erratic. With time and practice you will know what it should be reading. In the interim, if you are panting with exhaustion and it is reading 80, trust your body and not the stupid device.
  • ann121212
    ann121212 Posts: 290 Member
    Thanks again fyoung - you are a welcome font of wisdom :drinker:

    I have the HRM1. My first confusion was taking my resting heart rate with hubby's blood pressure machine - it gave a reading of 62 (which I thought was a bit low for an unfit, slightly overweight, middle age, short female [thank heavens I am not blonde or left handed or I would really be done for lol]).

    The numbers and zones just seemed odd - until I did some studying of what is applicable to my age/gender group (back in the olden days I used to push to and hold at 220 - we had no zones, just worked to excess).

    The more I use the hrm and vivofit the more things are falling into place. I am definitely getting benefits from it.

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