How accurate are our fitness devices? Published study.

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  • AnnPT77
    AnnPT77 Posts: 32,277 Member
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    earlnabby wrote: »
    PAV8888 wrote: »
    earlnabby wrote: »
    I noticed one odd thing in the abstract: why would darker skin tone cause the wearable to be less accurate? (Not that I am concerned, I have the typical pink white skin tone of my Scottish and Irish ancestors)

    Earlier led sensors had more trouble "seeing" through darker skin (or when the hand is cold).

    This has been remediated to varying extents by the various sensor manufacturers (extra and different color LEDs, better mechanical contact, improved processing, and what have you).

    The watch models in the study are less than current cutting edge. And valid criticisms (including the lack of more accurate alternatives) have been raised.

    No one on MFP has ever said that you should take watch burns as Gospel and avoid comparing your expected results to your actual results over 4 to 6 weeks so that you can adjust.

    Utlimately it really does not matter how accurately your watch or your logs estimate you calories in and out.

    What does matter is that the calculations are *consistent* (not all over the place) giving you an opportunity to adjust based on how the perceived caloric balances are affecting your weight trend.

    I have been using a wearable for about 5 years (first a Fitbit Flex, then a Garmin Vivofit2) and have found them to be accurate enough for my purposes, and they got more accurate the longer I had them and there was more data to parse.

    And mine is howlingly inaccurate . . . though only after about 5 months to "learn" me. It's just another statistically-based estimating method, not a "measurement".

    (It's a Garmin Vivoactive 3, being compared with nearly 4 years of logging experience, and found to significantly underestimate TDEE, just as most calculators do, and by about the same factor.)

    Wearables will be accurate for some (most) people, less so for others (a minority). Statistics.
  • NorthCascades
    NorthCascades Posts: 10,970 Member
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    Calories are only one of a bazillion features in these things. My Garmin is way too generous with walking calories, but that's not why I bought it, and I know to take those numbers with a heaping spoonful of salt. Some days I wish I could take them with butter.
  • Johnd2000
    Johnd2000 Posts: 198 Member
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    The thing is, it doesn’t really matter.

    In use, if you’re tracking calories in and out, you soon get a feel for the margin of error. It took me no more than a few weeks to see that I gain weight if I eat more than about 40% of the extra calories (above my base MFP figure) that Fitbit “gives” me. Once I worked that out, it quickly became easy to leave a margin for error.

    None of the data we use to manage our weight is exact. CI, CO, weight and even tape measurements are all subject to a margin of error.





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