Why are my calorie counts going backwards while I sleep?

[SelfishMom]

I've been wearing my Band for about four months, but only started paying close attention to the calories burned numbers a couple of weeks ago. There have been a few times when I checked my calories burned number before going to bed, and then synced my Band in the morning and found that the calories burned number for the day before was actually lower than when I checked it at bed time.

I thought maybe I was just imagining things, so last night before going to sleep, around 11pm, I took a picture of my Band and it read that as of that moment I'd burned 1,705 calories. Based on past calorie patterns I should have added about 60-70 more calories in that first hour of sleep before the band started over at midnight.

When I woke up this morning and synced, however, the calorie count from yesterday read 1,694. How is that possible?

Am I wrong in assuming that the count starts over at midnight? Is some other time period being used for the daily summary? The chart on the Microsoft Health dashboard goes from midnight to midnight.

 

[gadgetrants]

Interesting question. I think your intuition is spot on, by the way...everything should run midnight-to-midnight. The only catch is I wonder if you're comparing:

(a) late-night estimate on the Band

to

(b) next-day report on the Dashboard

Of course, if you replace (a) with "late-night estimate on the Dashboard" it should be exactly the same as what you see on the Band (plus or minus a few calories since the last sync). Anyway, the reason why I wonder is that maybe there are some on-the-phone or on-the-Dashboard recalculations going on around midnight (i.e., before the day's final numbers are logged). For example, some smoothing of sedentary (aka BMR) burn might be applied. We've seen something similar happen to workout data (esp. heartrate reported on the Band during the workout vs.what shows up on the Dashboard and phone) so something similar might happen to overall calorie data at the end of each day. It's a theory, anyway.

If I happen to be up near midnight I'll take a peek at my own data and report back!

​-Matt

 

[SelfishMom]

Ah, so if I understand what you're saying, there may be some estimates happening on the Band, and then when I sync it the more accurate numbers show up on the Dashboard? That would make sense. It's not such a huge difference that I'm too worried about it, but it did make me think that I was going crazy for a few days.

 

[gadgetrants]

Gee, I wish I could be concise -- that is exactly what I meant to say! LOL

-Matt

 

[DroidUser42]

I've got another idea - when you put the Band into sleep mode, it cuts off all syncing. When you check the Dashboard, it only has information up to the last sync. But first thing in the morning, that last sync will be from before you went to bed.

Now that your Band has been awake for some time and had a chance to sync, to your phone, and the phone to the dashboard, check your dashboard again.

 

[gadgetrants]

Hmmm, checking back in...

At 11:17 PM:

- Band = 2015
- Phone = 2015
- Dashboard = 2015

At 7:20 AM next day:

- Phone = 2072
- Dashboard = 2072

I checked as soon as I turned off Sleep mode...seems that everything synced up right away. Also seems that the change from 11 to midnight was the expected increase of ~60-70 calories.

​-Matt