Newbie. Exercise app accuracy question

Discussion in 'Apple Watch Fitness and Health' started by sgtsnake, Mar 8, 2016.

  1. sgtsnake

    sgtsnake New Member

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    Ok so tonight I exercised and I used both my Apple Watch and my fitness from the iPhone to measure what I did. I set the Apple Watch to outdoor walk and the my fitness was set to run. I walked a pretty fast walk then occasionally would do a good steady jog as far as could...did this off and on. Here are the end results. I'm curious which is more accurate and what should I rely on when counting calories and exercise for dieting.

    Apple Watch
    Time 31.56
    Distance 2.26 miles
    Active calories 219
    Total calories 284

    Apple Watch only syncs the 219 calories to my fitness...why?

    My fitness app
    Time 32.16
    Distance 2.31miles
    Calories 373

    Which is more accurate and better to use?

    Thanks
     
  2. twerppoet

    twerppoet Well-Known Member

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    With apps like this both the sensors and the calculations/approximations made by the apps vary; and frankly neither are terribley accurate. And they don't need to be. What they need to be is conssistant. They are meant to show progress, and you'll usually find a disclaimer somewhere in the small print along those lines.

    The most accurate measure of walking/running is a known course, and a stopwatch.

    You can approximate a known course somewhat with a GPS, but you'll still get some variation due to the sampling rate and inherrent inaccuracy of the GPS.

    An app that simply counts steps is always a rough approximation. How rough depends on the calibration, and wether you maintain a consistant stride length and pace. The AppleWatch self calibrates, as long as you are carrying the iPhone (GPS); so it can be somewhat accurate if used alone after being used with the iPhone for a while (minding the other factors).

    I don't know what the myfitness app (or device ) does, but the Apple Watch may or may not being using a GPS, depending on the app you are using and whether you have you iPhone with you. I've walked the exact same course a few times (with the phone) and had as much as a 1/10th mile difference. That's not great, but it is still close enough that I can track goals met, and whether I am doing better or worse over time.

    So the unanswer to your question is that unless you are in a competition, or are trying for an accurate mesure of distances, it doesn't matter. Pick the one you like best and use it consistantly. Or, like the man with two watches, you'll never be sure what time it is.

    BTW, I've used Runmeter with the iPhone and AppleWatch. I belive it does better in overall accuracy, but that is because it has a high sampling rate mode. I use it mostly for bicycling, where distance and mapping are important to me. The down side is that by making heavy use of the GPS it also drains the iPhones battery faster than the AppleWatch's native Workout app.

    Note: Runmeter, Walkmeter, and Cyclemeter are bascially the same app. They just have different defaults.
     
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