Stanford study finds Apple Watch top-notch heart rate monitor, mediocre calorie counter

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  • Reply 21 of 26
    wigginwiggin Posts: 2,265member
    maestro64 said:
    It has been a while since I had chemistry and doing calorie measurements and calculation if I remember correctly it is the amount of energy require to raise I centliter of water one degree Celsius. Bases on this there is no direct way to determine how many calories the human body uses. All method today use indirect methods. They are all estimating so I'm not sure how anyone could say one device is better or worse than the other. Even the high cost machines are just making an estimate since the machine can not determine each person's efficiency, some people burn calories faster than others.

    At best they are all making a guess.

    Also if remember correctly Apple did testing and calibration on thousands of people not just 60. I would say Apple is probably a little better than most since they have more data. Face it even Apple with all its data is just triangulating onto a calorie number and sometimes it does a better job than others.
    Well, chemically speaking, we know how much energy is released when a hydrocarbon atom breaks it's bonds and creates energy for your body to use. Those carbon atoms then leave your body when they combine with oxygen and are exhaled (fun fact...when you lose fat it leaves your body via your lungs ). So by measuring the ratio oxygen and CO2 entering and leaving your lungs you can determine how many carbon atoms are leaving your body and thus how many bonds were broken and how much energy was released. You then have a pretty accurate, if not perfectly direct, method of measuring the calories you are burning.

    This is the method the study used as their "gold standard" for calories burned. But like everything it's still subject to imperfect and/or limitations in the testing methodology.
    GeorgeBMac
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  • Reply 22 of 26
    GeorgeBMacgeorgebmac Posts: 11,421member
    badmonk said:
    Having an accurate heart rate will lead to better calorie estimations because calorie consumption involves the consumption and delivery of oxygen of which heart rate is an important component.  Apple is doing involved VO2 measurements with their employees in exercise.  Apple will improve faster than others.
    Heart rate is an indication of how hard your heart is working -- not your body.  And its your body (including the brain) that burns the calories...   True, you can estimate calorie burn better by looking at heart rate -- but still, it's a guess.
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  • Reply 23 of 26
    maestro64maestro64 Posts: 5,043member
    wiggin said:
    maestro64 said:
    It has been a while since I had chemistry and doing calorie measurements and calculation if I remember correctly it is the amount of energy require to raise I centliter of water one degree Celsius. Bases on this there is no direct way to determine how many calories the human body uses. All method today use indirect methods. They are all estimating so I'm not sure how anyone could say one device is better or worse than the other. Even the high cost machines are just making an estimate since the machine can not determine each person's efficiency, some people burn calories faster than others.

    At best they are all making a guess.

    Also if remember correctly Apple did testing and calibration on thousands of people not just 60. I would say Apple is probably a little better than most since they have more data. Face it even Apple with all its data is just triangulating onto a calorie number and sometimes it does a better job than others.
    Well, chemically speaking, we know how much energy is released when a hydrocarbon atom breaks it's bonds and creates energy for your body to use. Those carbon atoms then leave your body when they combine with oxygen and are exhaled (fun fact...when you lose fat it leaves your body via your lungs ). So by measuring the ratio oxygen and CO2 entering and leaving your lungs you can determine how many carbon atoms are leaving your body and thus how many bonds were broken and how much energy was released. You then have a pretty accurate, if not perfectly direct, method of measuring the calories you are burning.

    This is the method the study used as their "gold standard" for calories burned. But like everything it's still subject to imperfect and/or limitations in the testing methodology.


    One problem, you also sweat and radiate heat so this the other source or energy consumption/loss. The breathing method only captures one way energy is used. I know some systems out there actually measure heat loss as well, they put the person in a seal chamber and they are able to measure the change in air temp.

    For something like the apple watch or any calorie tracker it repeatability. I have not used other device so I have no frame of reference. I do have the apple watch, and I do the same walk every day with my dog in the morning. and I measure my pace so I have a very good idea how fast I am going from day to day. I do look at what the watch shows as my energy usage, and it fairly consistent for my walk each day it usually only a calorie or two difference for the same pace. This I would say is more important than did is calculate the exact calorie. I also know that it took a good month or so of doing the same thing before it was repeatable. Apple said the watch did learn over time. Did the researcher take this into consideration, did the use do the same activity day after day for a period of time before they ran their tests. I suspect not, it sound like they gave 60 people different devices and hook them up to the Calorimeter and then measure and this could be the reason the devices were all over the place with their readings. 

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  • Reply 24 of 26
    jbdragonjbdragon Posts: 2,315member
    I never did expect the calorie count to be accurate. But I think it's going to read a normal value for each person. It may be completely off, but pretty close in readings for that user. As in it may read off, but it still know you're burning more calorie's one day then another day. One day you're sitting arund and the next jogging. Zero set point for you may be off 100, or 500, and go from there. It's still getting a number I didn't really get my Apple Watch for Fitness. I like that It tells me to stand up every hour, though it really needs to smarten up in that area. If I'm going 20+ MPH, I'm not jogging or running, I'm in a car and it's kind of hard to stand up right then. The other thing, I've already been up doing something and then a couple minutes later it tells me to stand up. I was just up!!! It's great to know the heart rate sensor works really good. Being able to look at your heat rate over the month or year and see if there's some issue is good. But it's really nice to just be able with a quick glance being able to see the time/date, my next appointment, Temp, my rings and sunset and sunrise on my display. Then get all my important Notifications without having to pull out my phone. I don't think people realize how well and what All the Apple Watch can do. For example, it's my own personal so called ECHO. Except I think it's better. It works every room I go to and even outside and away from home. At any time without touching the watch I can go Hey Siri and issue a command. I can set a Timer, a Reminder, a Appointment, send a message. call someone. Tell me a joke. Tell me when the giants play next. Turn on/off lights, adjust the temp. Shortly I'll be able to open and close my garage door. I can do it now with a app on my watch, but being able to go Hey Siri Open garage door and it opens, try that with a Echo. If you put your Echo next to a open Window and then YELL really loud out of the car window, maybe it'll hear you?!?! That's the normal way I get in/out of my house. Not having to keep a Remote in my truck, all the better security wise. Siri works really well on the Apple Watch. Even my Original. It's not FAST but it works pretty good. Apple needs to get some more basic things working. I should be able to say Hey Siri, Give me directions to my next appointment, and it should see my next appointment, see the address listed, load up Apple Map's and the directions to where I need to go. Siri can't seem to do that. Siri needs a lot more work on some things. But it does work surprisingly good. Talk clear and a little slower then you would a real person and it's generally perfect at what I'm saying. I see zero reason to get a Amazon Echo or a Google Home. I really don't the point of a SIRI Speaker. To me it seems like older tech. Something stuck in a single room plugged into power. Though I could see something like a Kinnect for the Apple TV4 and newer that plugs into the USB C port. That gives you always on Siri and Facetime support right there on your TV. A optional thing if you want to add it to your AppleTV. If they could add a few things like Room Temp, Air quality. Just to give it a little something more, all the better. I get tired of hearing how Apple is falling behind in this area when Apple had been in it for 2 years now. It's called the Apple Watch!!! Keep hearing how the Echo is doing so sell. It sold 10 million in the 2 years it's been around. That's doing great? The Apple Watch sold 12 million last year alone, not counting the first year. But all I hear is how the Apple Watch is a failure. Really? Because if that's the Apple Watch, the Echo must really be a disaster. Can't have it both ways. eeeeeTheeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee
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  • Reply 25 of 26
    wiggin said:
    Curious why they didn't include any devices from athletic watch makers such as Garmin and Suunto. I'd be curious how they stack up. I doubt they would beat Apple's HR accuracy, but they also have additional configuration options which may (or may not) lead to more accurate calorie counting.

    They used "commonly used" devices, the ones that most casual exercisers use.  The purpose of the study seems to be an attempt to find out if the devices most people are using are actually going to be beneficial, or if they're a waste of money, or even worse, show erroneous data that leads to poor health decisions, e.g. "My heart monitor shows that my heartbeat only goes up a few beats per second when I'm running, so I must be in pretty good shape.  I guess I can that cake after all."

    The higher end devices are, from reports I've seen, still more accurate, but they're used by a smaller subset of the people who are actually exercising, so don't have the same impact on heath decisions as do the cheaper devices.

    edited May 2017
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  • Reply 26 of 26
    macguimacgui Posts: 2,649member
    macsimcon said:
    You're really going to use words like "mediocre" and "failure" when the Apple Watch was more accurate at counting calories than any of the other devices?

    The Apple Watch was only off by two percent! I'd hardly call that mediocre or a failure, I would say it's close to perfect.
    Apples and oranges.  The 2% refers to heart rate accuracy, the mediocre refers to calorie counting.

    And  25% isn't something to be proud of. "We're not not the best, but we're not as bad as most of the others!' isn't going to sell anything.

    None of the devices actually measure energy expenditure as much as calculating an approximation, more of an If / Then situation so I'm not surprised that none of them come close. And 25% isn't close in my book.

    Still, regarding 'making life decisions' based on the mentioned devices, how bad could that be? You buy a fitness device and work on getting healthier based on the information it provides. Assuming the heart rate is fairly to relatively accurate, how does the lack of accuracy of energy expenditure (counting calories 'burned') negatively affect you? You know if you're losing weight or not, if you're losing inches (usually fat) or not. I'm not sure how using a fitness device and getting fatter or less heal thing would be the fault of the device, unless it was horrifically and somehow negligently less accurate.

    The varying accuracies make it difficult to impossible to compare data among different devices, but most any device that encourages a more active life style is should be applauded.

    I wish there had been more information about using 'gold standard' devices and how they work. It was only one data point, but on an episode of MacBreak Weekly, Laporte compared the first iteration of the Apple Watch to an audience member's hospital-issued heart rate monitor and they both had the same results. Based on what I've read elsewhere, the Watch has always been accurate at measuring heart rate.

    As long as it or any devices' inaccuracy are consistent, they should serve well enough to provide most of us the motivation needed for an improved life style. Apple is veering it's advertising to fitness, but for me it's as much the utility of it's other features as well that make it my choice over a Garmin or Fitbit, etc.
    GeorgeBMac
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