How is Endomondo data being taken into account? A small experiment

[ManuelCarro]

Hi.  I have Charge HR and my fitbit account linked to Endomondo (*). This morning I did some weight exercise (chest, biceps, hamstrings, abs) while the Endomondo app was on with after having selected "Weight Training" and "Basic Workout" (which means do not set goals, just record time / distance).  When I finished I _paused_ Endomondo, so no data is being sent to the central server.  Then:

- I consulted FitBit; Endomondo's workout did not appear, and the daily calorie expense was 1156 cals. after having finished the workout.

- I consulted Endomondo, which reported 653 calories for the workout.

- I _finished_ the Endomondo workout, which sends the data to their server and subsequently synchronizes with the FitBit server.

- I went to the FitBit application; the workout reported by Endomondo was there, with the amount of calories that Endomondo had reported.  Howeer, the total number of calories for the day was 1541.  

So, from the 653 calories that Endomondo had calculated, FitBit only added 385.  Therefore it is not just adding them up, but it's adding _some_ of them, which tells me:

- Fitbit does not trust its own calorie count.  I was not moving / running, so for this workout (unlike what could happen when walking / running), distance or height do not play any role.

- Fitbit is doing some adjustment to what comes from Endomondo, which means it does not trust Endomondo.  That could be reasonable since Endomondo does not have real-time information about heart rate and I am not sure it uses in any way the phone sensors to deduce which kind of movement was being done.  Also, its exercise category is very rough (weight training can be very different with very different energy requirement).

Can anyone enlighten me?  Am I doing right in linking both accounts?  Does Endomondo data make FitBit to be more precise in deciding the amount of calories used?  Or is it just the other way around --- i.e., introducing lack of accuracy?

Thanks for any idea / help!

(*) I was using MapMyRun / MapMyFitness until I discovered that MapMyX measurements were not  being synched to FitBit, so FitBit could not use that information to refine their idea about what kind of exercise I was doing.

[ManuelCarro]

More data, this time from a different experiment: walking.  Endomondo knows the distance & speek I am walking, so I supposed this can be reliably taken into account by FitBit.  The setup is similar to before.  I took an evening walk and after it I compared FitBit data, EndoMondo data in isolation, and FitBit data after synchronizing with Endomondo:

- FitBit data (for the day) after walk, without Endomondo: 2662 calories, 7.73 Km.

- Data from Endomondo (walk alone): 343 Cal., 5.17 Km.

- Data in FitBit after synchronizing with Endomondo: 2540 calories, 7.73 Km.

So FitBit corrected its calorie count (¿probably based on the distance received from Endomondo?), but did not correct the *distance*, which Endomondo probably got more accurate data because it was acquired with a GPS (in an area with very good GPS signal).

Could anyone clarify how this works?

[slysam]

I have have had a Fitbit for years and have used most of the apps in the app gallery. But keep in mind things do change and I haven't looked at this as closely lately because I realized it doesn't really matter. When you log something (or when another app logs it for you) than whatever is logged should replace Fitbit's estimate. It isn't that Fitbit doesn't trust it's own data, that is just how it is set up. People generally log an activity to correct Fitbit's data. It will have to do with the information Endomondo is sending over to Fitbit. With your strength workout (I never used Endo to log strength training so I am not sure how it works...), do you log specific times? The workout needs to be stamped to the specific time it replaces. Many apps that let you log strength workouts do not do it this way. I noticed when I used Endomondo it logged weird intervals of activity that made no sense to me so I stopped using it. I didn't trust its data and discovered apps I liked better.

I will say, the total Endomondo gave you for the workout should be its estimate including the calories you would have burned living. That is because what it is replacing on Fitbit will be a total for a given time period including the calories you would have burned anyway. Most estimates do include those base line calories burned, but some do not. If you log something that dosn't it will credit with fewer total caloreis burned. If it is using a total, it is possible that there really wasn't as big of a difference between Fitbit and Endo's estimates as you thought. What did Fitbit credit just for the time period of your workout? My heart rate monitor app has logged workouts and there was literally no change to the calorie burn for the day (though this never happens for weight lifting, it tends to be for more step based activities). That is because the two estimates actually matched each other.

[ManuelCarro]

Hi.  Thanks for sharing your experience.  I do not have answers for some of the issues you raise; I have been trying to find how endomondo calculates energy for strength training, for example, and I just found some generic references to the "compendium of physical activities", which does not contain so many sports-related activity.  The activities Endomondo logs are of the right length and at the right time.

But, regardless of whether Endomondo data is right or not (which FitBit in principle does not know), I still did not find an explanation of how FibBit combines it with its own data.  If you read my second example  / experiment, it is clearly not added to FitBit data and it does not replace FitBit data for the period of time corresponding to the exercise.

Best!

[ManuelCarro]

Hum, rereading my posts there is obviously something missing: I should have logged the mount of calories registered by the Charge HR before starting the exercise to see how much energy expense was registered by the HR... will do that next time.