Is Apple Watch reliable to measure calories burned during workout?

vickygalo
vickygalo Posts: 41 Member
edited January 2019 in Health and Weight Loss
Hello MFP Gods!!!

I am posting a whole bunch but you have been so absolutely helpful!
I have an Apple 4 watch. My daily calorie intake is 1350 but I walk on the treadmill at a fast pace and my watch tracks between 450-650 calories. I just want to know, in your experience, how accurate this is as I will be eating back all those delicious calories and I obviously don’t want to go over.

Thank you!!!! ❤️💪

Replies

  • emmylootwo
    emmylootwo Posts: 172 Member
    edited January 2019
    In my experience the HR monitor on the Apple Watch and similar fitbits are pretty accurate in terms of actual BPM tracked. Problem is that I don't know what formulas they use to calculate calories burned from increases in HR and if those formulas are accurate in their own right. I believe I read that HR isn't a great way to estimate exertion and calories burned. Hopefully someone can chime in on that... I could be wrong! Lol Plus, I'd be worried that the calories burned are gross and not net calories (aka includes calories that you would have burned just living).

    The only thing you can really do -- since everything is an estimate -- is to just try it out for a few weeks. Eat back all or a percentage of your exercise calories and stick to it. Re-evaluate after seeing if you've lost the amount you expected over the course of a month or two. I got a Fitbit recently but for now I've chosen to ignore its calorie estimates in favor of this website's calculator for treadmill walking: https://www.exrx.net/Calculators/WalkRunMETs The values there seem really reasonable to me.
  • vickygalo
    vickygalo Posts: 41 Member
    emmylootwo wrote: »
    In my experience the HR monitor on the Apple Watch and similar fitbits are pretty accurate in terms of actual BPM tracked. Problem is that I don't know what formulas they use to calculate calories burned from increases in HR and if those formulas are accurate in their own right. I believe I read that HR isn't a great way to estimate exertion and calories burned. Hopefully someone can chime in on that... I could be wrong! Lol Plus, I'd be worried that the calories burned are gross and not net calories (aka includes calories that you would have burned just living).

    The only thing you can really do -- since everything is an estimate -- is to just try it out for a few weeks. Eat back all or a percentage of your exercise calories and stick to it. Re-evaluate after seeing if you've lost the amount you expected over the course of a month or two. I got a Fitbit recently but for now I've chosen to ignore its calorie estimates in favor of this website's calculator for treadmill walking: https://www.exrx.net/Calculators/WalkRunMETs The values there seem really reasonable to me.

    ohh I understand. that sucks though, because I hit 1650 calories today and then went to walk and it calculated 450. I don't want to go over but I also want to eat back my calories because I LOVE FOOD lol
  • wenrob
    wenrob Posts: 125 Member
    edited January 2019
    I’ve been a FitBit user for years and I’m fairly new to the Apple Watch. It seems it’s taken about a week and a half to “know” me. I trusted my FitBits after the break in period and the Apple Watch seems on par with them so far, maybe a little more conservative. Right now the Health App shows my “resting energy” as 1,161 cals and my “active energy” as 476 cals. I will eat the 476 cals with no worries. I have years of experience with my calorie intake though so I know that’s about right if not a little under for today.

    MFP is designed to eat some if not all of your exercise calories back. As mentioned above you have to kind of play with it and monitor it and decide from there how accurate it is for you.
  • vickygalo
    vickygalo Posts: 41 Member
    wenrob wrote: »
    I’ve been a FitBit user for years and I’m fairly new to the Apple Watch. It seems it’s taken about a week and a half to “know” me. I trusted my FitBits after the break in period and the Apple Watch seems on par with them so far, maybe a little more conservative. Right now the Health App shows my “resting energy” as 1,161 cals and my “active energy” as 476 cals. I will eat the 476 cals with no worries. I have years of experience with my calorie intake though so I know that’s about right if not a little under for today.

    MFP is designed to eat some if not all of your exercise calories back. As mentioned above you have to kind of play with it and monitor it and decide from there how accurate it is for you.

    I absolutely want to eat my calories back, but I also don't want to over indulge. How does everyone on here track their calories burned in order to eat them back?

    I just checked my health app, it shows 1132 active energy kcal (I don't know what this means) and 2140 resting energy (also don't know what that means!).
  • vickygalo
    vickygalo Posts: 41 Member
    just googled both active and resting :) now I understand. so resting us 2140, meaning if I lay in bed all day and did nothing, I would burn 2140?
  • wenrob
    wenrob Posts: 125 Member
    vickygalo wrote: »
    just googled both active and resting :) now I understand. so resting us 2140, meaning if I lay in bed all day and did nothing, I would burn 2140?
    Yes, your BMR. How much do you weigh? Did you put all your stats into the Health app? 1350 seems low if your resting energy is 2140.
  • vickygalo
    vickygalo Posts: 41 Member
    wenrob wrote: »
    vickygalo wrote: »
    just googled both active and resting :) now I understand. so resting us 2140, meaning if I lay in bed all day and did nothing, I would burn 2140?
    Yes, your BMR. How much do you weigh? Did you put all your stats into the Health app? 1350 seems low if your resting energy is 2140.

    I'm 178 cm, 239.6 lbs, and listed myself as sedentary so it recalculated from 1650 calories to 1350 a day. I walk on the treadmill daily for an hour and burn quite a bit of calories, so I want to make sure its accurate so that I can eat them back!
  • vickygalo
    vickygalo Posts: 41 Member
    I also chose lose 2 lbs/week.
  • wenrob
    wenrob Posts: 125 Member
    vickygalo wrote: »
    wenrob wrote: »
    vickygalo wrote: »
    just googled both active and resting :) now I understand. so resting us 2140, meaning if I lay in bed all day and did nothing, I would burn 2140?
    Yes, your BMR. How much do you weigh? Did you put all your stats into the Health app? 1350 seems low if your resting energy is 2140.

    I'm 178 cm, 239.6 lbs, and listed myself as sedentary so it recalculated from 1650 calories to 1350 a day. I walk on the treadmill daily for an hour and burn quite a bit of calories, so I want to make sure its accurate so that I can eat them back!
    Well FWIW, I think you could easily eat half your exercise calories and still lose 2+pounds a week. One of the biggest problems with fast weight loss is getting too hungry and then binging. Like I said in my previous post the way MFP is set up you are meant to eat your exercise calories. I would at least eat some. If you are truly burning 1,000+ calories in exercise and are only eating 1350 you are setting yourself up for that starving/binge cycle. Try adding some back for a bit and see how it goes.

  • vickygalo
    vickygalo Posts: 41 Member
    wenrob wrote: »
    vickygalo wrote: »
    wenrob wrote: »
    vickygalo wrote: »
    just googled both active and resting :) now I understand. so resting us 2140, meaning if I lay in bed all day and did nothing, I would burn 2140?
    Yes, your BMR. How much do you weigh? Did you put all your stats into the Health app? 1350 seems low if your resting energy is 2140.

    I'm 178 cm, 239.6 lbs, and listed myself as sedentary so it recalculated from 1650 calories to 1350 a day. I walk on the treadmill daily for an hour and burn quite a bit of calories, so I want to make sure its accurate so that I can eat them back!
    Well FWIW, I think you could easily eat half your exercise calories and still lose 2+pounds a week. One of the biggest problems with fast weight loss is getting too hungry and then binging. Like I said in my previous post the way MFP is set up you are meant to eat your exercise calories. I would at least eat some. If you are truly burning 1,000+ calories in exercise and are only eating 1350 you are setting yourself up for that starving/binge cycle. Try adding some back for a bit and see how it goes.

    I would love to eat baxk my calories but my exercise calories as tracked by my watch during my walks is 450-600 calories!
  • sijomial
    sijomial Posts: 19,809 Member
    A rough guide to net calories burned during normal speed walking is bodyweight in pounds X distance in miles X efficiency ratio of 0.3

    At 239lb you would be looking at around 72cals per mile walked.
    Your estimate sounds badly inflated, beware it may also be an estimate for gross calories not net calories (gross includes the calories you would have burned anyway in that hour whether you exercised or not).

    HR isn't a good estimator of calories for exercise/activity outside moderate intensity cardio. It can also be really poor for people with an unusual exercise HR.
  • vickygalo
    vickygalo Posts: 41 Member

    sijomial wrote: »
    A rough guide to net calories burned during normal speed walking is bodyweight in pounds X distance in miles X efficiency ratio of 0.3

    At 239lb you would be looking at around 72cals per mile walked.
    Your estimate sounds badly inflated, beware it may also be an estimate for gross calories not net calories (gross includes the calories you would have burned anyway in that hour whether you exercised or not).

    HR isn't a good estimator of calories for exercise/activity outside moderate intensity cardio. It can also be really poor for people with an unusual exercise HR.

    Wow it came out to 243 based on that math, meanwhile my watch calculates 400-600. That’s crazy. Why such a drastic difference?
  • LadySaton
    LadySaton Posts: 500 Member
    I find mine overestimates. I eat back half of my calories for most exercise, but for running I eat 100 calories per mile and for walking, 50 calories per mile. This has led to fairly predictable results for me (167lbs, 5’6”), but it took some trial and error to figure it out.
  • sijomial
    sijomial Posts: 19,809 Member
    vickygalo wrote: »
    sijomial wrote: »
    A rough guide to net calories burned during normal speed walking is bodyweight in pounds X distance in miles X efficiency ratio of 0.3

    At 239lb you would be looking at around 72cals per mile walked.
    Your estimate sounds badly inflated, beware it may also be an estimate for gross calories not net calories (gross includes the calories you would have burned anyway in that hour whether you exercised or not).

    HR isn't a good estimator of calories for exercise/activity outside moderate intensity cardio. It can also be really poor for people with an unusual exercise HR.

    Wow it came out to 243 based on that math, meanwhile my watch calculates 400-600. That’s crazy. Why such a drastic difference?

    Inappropriate use of a heart rate monitor I would guess, they just count heartbeats and cannot count energy.
  • yirara
    yirara Posts: 9,941 Member
    vickygalo wrote: »
    sijomial wrote: »
    A rough guide to net calories burned during normal speed walking is bodyweight in pounds X distance in miles X efficiency ratio of 0.3

    At 239lb you would be looking at around 72cals per mile walked.
    Your estimate sounds badly inflated, beware it may also be an estimate for gross calories not net calories (gross includes the calories you would have burned anyway in that hour whether you exercised or not).

    HR isn't a good estimator of calories for exercise/activity outside moderate intensity cardio. It can also be really poor for people with an unusual exercise HR.

    Wow it came out to 243 based on that math, meanwhile my watch calculates 400-600. That’s crazy. Why such a drastic difference?

    Possibly because your heartrate is higher than average (that's not a bad thing, but genetics!) and the watch inflates calorie burn based on that. Hey, I get crazy burns with my fitbit if I just walk through a supermarket.
  • lucy3425
    lucy3425 Posts: 5 Member
    I’ve got an Apple Watch (3, not 4) and I’ve found that eating back roughly half the calories burnt (during ‘workouts’) is about right? I sometimes go over, but seem to get away with it :-)
  • missiontofitness
    missiontofitness Posts: 4,059 Member
    emmylootwo wrote: »
    Problem is that I don't know what formulas they use to calculate calories burned from increases in HR and if those formulas are accurate in their own right. I believe I read that HR isn't a great way to estimate exertion and calories burned.

    As an example, I have a heart arrhythmia; my fitbit does pick up on my heart rate during an episode that isn't accurate to the activity I'm doing, which definitely doesn't accurately represent the calories burned. For the most part, I've found that the burns it estimates while I don't have an episode are accurate to multiple different estimates on different sites.

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