How does the Apple Watch determine whether I am exercising (Aside from using fitness app)

[j-a-x]

I'm sorry if this is a duplicate topic. I've seen several topics on this subject but I've never seen an answer I am satisfied with.

What I Would like to know is how does the Apple Watch know whether I am exercising aside from using the fitness app. On Monday I didn't go to the gym or do an actual "workout" but I went on a 30 minute walk with my girlfriend and figured I'd get some "fitness" minutes to close my yellow ring. I already had 20 minutes of exercise throughout the day from just doing random things (mostly walking from my car to my office and back). So I figured an actual 30 minute walk should at least give me 10 more minutes. I manually loaded the heart rate app a few times on the walk to log more heart rate measurements than would normally happen in the background but I did not start the workout app. My heart rate during that walk was maybe in the 90 bpm range. I got zero workout minutes.

Then as a test I tried walking up and down my stairs (again no fitness app) to try to get workout minutes, and I got a few but not as many minutes as I was walking. Again I used the heart rate app but not the fitness app. My heart rate then was in the 110-120 bpm range.

After about an hour of trying to do things to give me workout minutes, I only logged 5 minutes.

Finally I had to open the workout app to log my last 5 minutes.

So my question is: what specifically triggers workout minutes when not using the workout app? Is it heart rate, GPS, gyro/accelerometer wrist movements or something else? Is it the same for all users or does it depend on an individual's level of fitness (which might change week to week)? Does anybody know specifically how this works?

 

[Julien]

https://support.apple.com/en-us/HT207941

 

[j-a-x]

https://support.apple.com/en-us/HT207941

Thank you for the link.

This was particularly useful:

To make sure that you earn Exercise credit during walks, allow the arm with your Apple Watch to swing naturally. For example, while walking your pet, let the arm with your watch swing freely while the other holds the leash.

If you need both hands while walking, for example to push a stroller, you can still earn Exercise credit with the Workout app. Open the app on your Apple Watch and tap Outdoor Walk. The Activity app relies on arm motion and an accelerometer to track movement, but the Workout app can use the accelerometer, the heart rate sensor, and GPS.

 

[Julien]

Also you must meet your metrics threshold of "...a brisk walk..." to get Exercise ring credit. For instance casual walking will add to the Move (calories) ring but won't count to the Exercise ring.

 

[BlueMoon63]

Looks like when you walk by yourself, you walk faster than when with your girlfriend or even holding hands and the hand with the watch?

Seriously, I walk about 4mph and get 1:1 minutes of exercise or very close. Walk with my wife and I get 5 minutes :/)

 

[j-a-x]

That might be it. I assumed that maybe my heart rate (even with the periodic background measurements) would contribute to exercise minutes not just the accelerometer but maybe holding hands or just walking differently was part of the reason I didn’t get any minutes.

When it was trying to get minute at home by going up and down the stairs maybe I was looking at my watch too much to view my heart rate and not swinging my arms normally.

If I activate the workout app, does it automatically assign me more calories towards my “move goal” than it would if doing the same activity without the workout app on (say a modest walk with my girlfriend)? Or would it have the same “move goal” impact but just more “exercise goal” minutes?

 

[BlueMoon63]

Yes. If you turn on the workout app,
You get active calories and it tracks your heart rate as you know.

Walking without a workout doesn’t measure heart rate because you are moving. It waits for you to stop moving to start tracking again.

 

[j-a-x]

Yes. If you turn on the workout app,
You get active calories and it tracks your heart rate as you know.

Walking without a workout doesn’t measure heart rate because you are moving. It waits for you to stop moving to start tracking again.

If I look at my heart rate data in the health app I do see heart rates while I’m walking though. Every 3-5 mi minute just like usual. You can tell when I’m walking because when I’m resting their 50-60 and when walking 90-100.

Is that abnormal that my watch is recording my heart rate while walking?
[doublepost=1531944590][/doublepost]

Yes. If you turn on the workout app,
You get active calories and it tracks your heart rate as you know.

Walking without a workout doesn’t measure heart rate because you are moving. It waits for you to stop moving to start tracking again.

From Apple:
"In addition, Apple Watch measures your heart rate throughout the day when you’re still, and periodically when you’re walking (Apple Watch Series 1 or later)."

So aside from the old school Apple Watch which I never owned, these watches DO measure your heart rate while walking.

Interesting though that Apple says "The Activity app relies on arm motion and an accelerometer to track movement, but the Workout app can use the accelerometer, the heart rate sensor, and GPS.". That implies that even though your heart rate is being measured while walking, the activity app does not use that heart rate towards your move goal.

 

[BlueMoon63]

Good catch on the periodic. Forgot that changed. The whole point for me or at least from Apple’s point of view is that if you aren’t walking fast enough and swinging your arms, they don’t count that as working out.

I shoot hoops for 15 minutes with the basketball workout and get about 150 calories and avg heart rate around 115.

I shoot hoops for 15 minutes without the workout and get about 3 minutes of exercise and half the calories.

I’m such a poor shot, I am running all over chasing down my misses.

Thanks for posting that info. Half I didn’t know or remember.

 

[j-a-x]

Good catch on the periodic. Forgot that changed. The whole point for me or at least from Apple’s point of view is that if you aren’t walking fast enough and swinging your arms, they don’t count that as working out.

I shoot hoops for 15 minutes with the basketball workout and get about 150 calories and avg heart rate around 115.

I shoot hoops for 15 minutes without the workout and get about 3 minutes of exercise and half the calories.

I’m such a poor shot, I am running all over chasing down my misses.

Thanks for posting that info. Half I didn’t know or remember.

No problem. It’s interesting to try to figure it out.

I can think of time when I have minimal arm swing and it doesn’t pick up my activity as exercise but my heart rate is definitely elevated such as climbing a bunch of stairs. Usually if I don’t have time to go into full exercise mode but I want to know what my heart rate is doing, I load the heart rate app. If measured my heart rate more often than usual but I’m still not sure if it uses that data when calculating my exercise minutes.

Interesting that you get more calories when tracking an exercise versus not. I wonder if I keep the heart rate app open for a 5 min walk (to ensure it’s regularly measuring my heart rate) vs. running the walk workout for 5 min would be any different.

 

[j-a-x]

Just for fun I tried an experiment.

I walked to lunch (15 min or so) without looking at my Watch much or running the heart rate app. If only measured my heart rate a few times in that walk. I measured about 50 calories.

Then walking back I tried to trigger the heart rate measurements a bunch of time using the heart rate app. I also
Measured about 50 calories. Neither time I used the exercise mode.

What that tells me is it is truly not using my heart rate during the times it measures exercise outside the exercise app. Calories must be based only on steps taken or distance.

Tomorrow I’m going to try using the exercise mode on the same walk so it uses my heart rate. I’d expect it to again be about 50 again but it will be interesting to see how the likely more accurate measurement using heart rate will compare.

 

[ftaok]

Just for fun I tried an experiment.

I walked to lunch (15 min or so) without looking at my Watch much or running the heart rate app. If only measured my heart rate a few times in that walk. I measured about 50 calories.

Then walking back I tried to trigger the heart rate measurements a bunch of time using the heart rate app. Neither time I used the exercise mode.

What that tells me is it is truly not using my heart rate during the times it measures exercise outside the exercise app. Calories must be based only on steps taken or distance.

Tomorrow I’m going to try using the exercise mode on the same walk so it uses my heart rate. I’d expect it to again be about 50 again but it will be interesting to see how the likely more accurate measurement using heart rate will compare.

I would bet dollars to donuts that you'll register more calories when you use the exercise app.

Here's my theory as to how this all works.

The AW uses whatever data/sensor I available to determine calorie burn for the Move Ring.

If you walk a mile at a 3.5 mph pace without selecting a workout, you'll occasionally get some HR readings. The AW doesn't know that you're working out, so it calculates calorie burn by tracking your movements and the vigorousness of your arm swings.

If you walk that same mile but select a workout, the AW has access to continuous HR reading and will likely use a different algorithm to calculate calorie burn. I'm certain that this algorithm is more aggressive in counting calories and will result is more Move Ring credit.

 

[j-a-x]

I would bet dollars to donuts that you'll register more calories when you use the exercise app.

Here's my theory as to how this all works.

The AW uses whatever data/sensor I available to determine calorie burn for the Move Ring.

If you walk a mile at a 3.5 mph pace without selecting a workout, you'll occasionally get some HR readings. The AW doesn't know that you're working out, so it calculates calorie burn by tracking your movements and the vigorousness of your arm swings.

If you walk that same mile but select a workout, the AW has access to continuous HR reading and will likely use a different algorithm to calculate calorie burn. I'm certain that this algorithm is more aggressive in counting calories and will result is more Move Ring credit.

Could be.

One thing I noticed is if I start a workout and then don’t actually start working out right away, it starts counting more calories than if I hadn’t started the workout.

For example let’s say I went to the gym, started strength training workout, then bumped into a friend and talked for 15 min. On those 15 min I just burned 50 calories according to my watch but otherwise that would have been nearly zero.

I read somewhere that the algorithm takes the greatest calorie value between a brisk walk (roughly 50 caps per 15 min) or heart rate and uses that. So if my heart rate stays low it still assumes I’m doing something that’s burning calories just not getting my heart rate up yet and that could be why it assigns me calories. Interesting.

 

[j-a-x]

Another question:
Let’s say I’m walking up and down stairs. My series three can see the elevation changes but supposedly it relies on and movements mot heart rate to compute my calories towards my move goal. Does it also take into account elevation changes or at least flights of stairs climbed? I know stair climbs show up in the activity all but does the move goal algorithm use them?

 

[j-a-x]

Another question:
Let’s say I’m walking up and down stairs. My series three can see the elevation changes but supposedly it relies on and movements mot heart rate to compute my calories towards my move goal. Does it also take into account elevation changes or at least flights of stairs climbed? I know stair climbs show up in the activity all but does the move goal algorithm use them?

To try to answer myself I spent a few minutes walking up stairs and got the following active calorie burn (no workout app).

Then I tried waking an equal distance on flat ground:

It definitely seems like it’s taking the accelerometer into account when computing casual (no exercise app) calories.

 

[j-a-x]

I would bet dollars to donuts that you'll register more calories when you use the exercise app.

I just did another experiment. I did a 15 minute walk (0.94 miles) which is comparable with yesterday but instead of just letting my watch do its thing, I started a "walk" workout. Total calorie burn came in at 65 calories. It's a bit higher than the value from yesterday but that makes sense just like you said. The working app is definitely more accurate, but at least we know that the "casual" move goal tracking is reasonably accurate.

 

[MrRELENTLESS]

There's days I get my exercise ring filled without ever starting a workout in the without app. I uses your heart rate during strenuous activities that get your heart rate up and the watch knows your doing something that's getting your blood pumping raising your heart rate

 

[j-a-x]

There's days I get my exercise ring filled without ever starting a workout in the without app. I uses your heart rate during strenuous activities that get your heart rate up and the watch knows your doing something that's getting your blood pumping raising your heart rate

Actually no. If you don’t start an exercise it doesn’t look at the heart rate data. It only looks at arm motion data and steps and maybe flights of stairs.

 

[Cordorb]

do the test using inside track so the wind speed and temperature are more the same.

and did I read the word DONUTS in an exercise thread

DROP and give me 25 !!!

 

[JackieInCo]

If you walk a mile at a 3.5 mph pace without selecting a workout, you'll occasionally get some HR readings. The AW doesn't know that you're working out, so it calculates calorie burn by tracking your movements and the vigorousness of your arm swings.

Not necessarily. Last winter, I went out walking at midnight as I always do and many times, it was about 15 degrees outside. I had my hands in my coat pockets nearly the entire time and still got credit for my entire 4-5 mile walk.

 

[ftaok]

Not necessarily. Last winter, I went out walking at midnight as I always do and many times, it was about 15 degrees outside. I had my hands in my coat pockets nearly the entire time and still got credit for my entire 4-5 mile walk.

But your hands are still bouncing in your pockets. If you're pushing a cart or a stroller, that's when you'll lose credit. Happened to me when I push my lawn mower.

 

[JackieInCo]

But your hands are still bouncing in your pockets. If you're pushing a cart or a stroller, that's when you'll lose credit. Happened to me when I push my lawn mower.

I got credited for not my lawn yesterday with about 20 minutes. I've also noticed that I can hold my iPad in both my hands at home and walk for five minutes and get five minutes exercise. This is with me holding then straight out holding the iPad so their barely moving.

 

[j-a-x]

For me I notice I do often but not always get “move goal” credit when I don’t swing my arms freely.

I think the few times where I expected move goal credit and didn’t get it may have been cause by not doing activities where I swung my arms, but there are even more counter examples.

At least I know now that if I’m doing something like weights I really do need to start a workout as it doesn’t register any activity otherwise.