How much of this health/fitness data is because of my Apple Watch?

I notice that in the regular iPhone Health app, and also in the Fitness app, that even if I’m not running “Workouts” per se on my Apple Watch during the day during my current U.S. trip, that all the following get updated nicely:

  • Move calories
  • Steps walked
  • Distance walked

So I was wondering:

(1) How much of this data is because I’m wearing the Apple Watch? If I wasn’t wearing the Watch, what would get recorded?

(2) Whether there is any real point in running the Workout app on my Watch, which is a big power drainer, if I have all this info anyway.



Energy levels (both active and resting), steps/distance walked, and flights climbed are automatically recorded by the iPhone. I don’t have an Apple Watch, but these are still recorded in Apple Health on my iPhone. I’m not aware of any way to turn off the recording of this data, but you can restrict Health’s use of location data and allow/deny other apps access to Health data in Settings.

  1. I think the iPhone itself is capable of counting “steps” using its accelerometer. I can’t be sure, since I’ve been wearing an Apple Watch daily since they came out. But I remember Apple making a big deal about it for one of the iPhone releases.

  2. To record workouts, of course. The AW (currently an Ultra) is far too primitive for me to use (I use Garmin devices), but Workout will record actual GPS distance (as opposed to “step” distance), speed, HR, GPS track, etc. during an activity (I think; as I said, it’s far too primitive for me to use). It’ll be much more accurate than mere “step” counting (there are no “steps” in cycling or cross country skiing or a lot of other activities that you might want to record, anyway). Every ride I do is recorded on a Garmin Edge 1040 and the results uploaded to Garmin Connect and Strava. The AW in principle could do part of the same job.

The WorkOutDoors AW app is a much better bet than Apple’s Workout (but it still isn’t good enough for me).

Just to clarify, I don’t want to turn off the recording of this data. I just want to know what, if anything, the Apple Watch is adding that the iPhone doesn’t already do. The total Active Calories count maybe?



Simple is ok for me. I just want to know where the data shown - particularly the active calories (since I track calories) is coming from. Would it should up without the Apple Watch?

When I wake up in the morning and put on my Apple Watch and start doing morning housework and stretching exercises, for example, I notice that the Active/Move calories start incrementing. And of course they also increment during exercise walks - even if I don’t use the Workout app.

So can I assume that the calories are because of the Watch but the other values are because of the iPhone (steps, etc.?)



It could be, but I doubt it. I think calories is simply steps x (calories/step), with the calories/step number pulled off some ratty table somewhere. Maybe other motions recorded on the watch might also count, but if you took the watch off and recorded on your iPhone alone you’d probably still get calories. “Steps” is a primitive, and pretty useless, measure of activity, and as I said, lots of activities with significant calorie burn don’t involve “steps”. Personally I ignore calorie numbers, since they’re pretty poor estimates and not real measurements. (The one exception is if they’re computed from the data provided by a cycling power meter, but I don’t have one on most of my bikes.)

I’ve found the calorie tracking useful for years now. I don’t know how accurate they are, but I’ve lost 140 lb and am down to 144 lb now and for the past few years it’s the first time in my adult life not to be obese. :slight_smile:

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Good for you!
Comparative values are what it is useful to observe and track. Repeatable measurements are more important than accuracy.

I only use workouts when I am literally working out. Just going out and about, never.

I find it valuable that the Watch collects this data.

It’s more sophisticated than that. The Watch is able to estimate effort based on how much your arm is swinging as you move. If you start jogging it will notice the difference and estimate a higher number of calories than if you are just walking around the house. The same if you are climbing stairs, as the Watch can determine the elevation change as you walk. But, of course, age, gender, and weight also factor in to the calories as you move. (Also you will gain a lot of calories while shoveling snow or gardening while you are not taking any steps.)

My understanding is that the watch is more accurate at these calculations than the phone, simply because of placement. A phone in a pocket can’t really tell how much you’re moving as well as a device on the wrist.


I guess that is what I was getting at. Plus one thing is if I’m doing housework and chores around the house I may not even have my phone on me at the time.

During my trip to the U.S… I’ve also been doing things like taking very long walks to and from Boston Common from my sister’s place in Brookline. But I have intentionally not used the Workout app because it’s a power drainer. Without using the Workout app my Watch Series 2 (yes I still have not upgraded) easily lasts all day.

I used to use the Fitness app on the iPhone to see how many move calories I had burned. And also see the Workout results, which are also interesting, because they show real distance and workout maps.

But I noticed that even without using Workout that both the Health app and Fitness app showed the same numbers for move calories, steps, and walking/running distance, so I was curious what they would both show if I simply didn’t use a Watch. Or if I used the Workout app when concentrating on a long walk and not just doing extra stuff, like housework.

The workout app will give you a better estimate of calories burned while you are actually working out, because it takes continuous heart rate samples and uses location services / GPS to see exactly how far you’ve gone. GPS and heart rate are not used when you are not using the workout app.

See Get the most accurate measurements using your Apple Watch - Apple Support for more info.

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I can see that for sure. I’m curious though how my total Fitness app and Health app stats might differ under these situations:

  • No Apple Watch - just an iPhone.
  • Apple Watch but not using Workout.
  • Apple Watch with workout.

There is a way to find out. Do a few walking laps on a track doing each of those separately and see how the data changes from before you started until you finish. (In other words, record all of the data in Health just before you start and just after you finish.)

I’ve looked at it, and everything is recorded by the iPhone. It is all recorded from when you started using the iPhone, and when you upgrade it is all copied across to the new phone. It seems to use accelerometer data rather than GPS, and I think mine is overestimating the distance, maybe because I’m mainly carrying my iPhone in a pocket on my upper leg. In Fitness the results are only shown from when you first open Fitness but the data is still there. If you want to see the data, open the health app, then tap on the icon on the top right and at the bottom of the page there is “Export All Health Data”. This will export as an XML file. I use R to turn that into a data frame and analyse that way. Because each type of data is a separate XML element it requires some manipulation to turn it into a nice spreadsheet style file. I have to do some more work on that as Apple has added extra fields and also there seems to be bugs at times, so there are duplicate records. Obviously, for heart rate data you need to have an Apple Watch.

An iPhone should also be able to determine if you are jogging or walking, as it will observe the amount of motion both forward and up and down. I expect that arm movement would vary a lot between people.