Fitbit Users?

HeyJudii

Have you noticed readjustments of historical data?

Hopefully I can clearly explain my question.

I have been using a Fitbit to monitor and encourage activity for about 9 months. Overall it has helped tremendously in making me more active and successful in my quest for healthy living.

One caveat though. I have noticed that when I go back to review previous Fitbit site data, to make tweaks in my daily/weekly activity level, that data will have changed, usually decreased. I am aware of this, because I am a data geek, so I create various charts, spreadsheets, logs, etc., (Hey, it passes the time ) to review and use for encouragement.

I would chalk this up to user error when entering the information, but screen shots (and the reports Fitbit emails each week) don't lie. In addition, last night I got up at 11:34pm to use the can. I checked my Fitbit and it showed that I had burned 3713 calories up until that point. I then synced the app.
But, this morning when I again synced the app, it showed 3663! Now, I know that I had burned close to that by the time I went to bed several hours earlier, and I know what I burn while at rest (9 months of consistent data). So, unless I was clinically dead for an hour and a half, between 11:34pm and midnight, I'm not sure I understand the downward adjustment.

I understand this is not a big deal, because my weight loss has been consistent and encouraging, but it is annoying to my perfectionist side.

(I posted this on the Fitbit site, and while I got agreement from some other owners, nothing from tech support.)

stacimarie1015

I don't overly analyze my #s. I do recall that Fitbit has 2 settings for choosing your daily calorie goal. One uses actual as of the time you sync calorie burn. It seems to consider what you have burned so far for the day and assumes BMR for the rest of the day. You earn more calories as you move. The other sets today's calorie goal based on your past history, and estimates what you'll burn based on what you have done in the past. I wonder if yours is using the historical to predict the current day, and then when you look back on a day later its change to reflect actual rather than predictive?

Personally I do not worry about the specifics because I assume some error. Right now I'm set to maintenance. I am not really concerned with changing the # on the scale but I am doing strength training and want to tone while I still remove some of the extra around my midsection. (I know, can't spot reduce.) So though I set for maintenance I actually try to have a slight deficit according to the device. That will cover for inaccuracies and perhaps have a small deficit.

RAinWA

My Fitbit will change between a sync close to midnight and the next morning just like you described. Usually between 25 and 50 calories burned difference.

I always just assumed when it did it's 11:59 p.m. sync it just readjusted its expectations of my activity for the day and never worried much about it.

heybales

You can't manually force a sync from your Fitbit account to your MFP account, first thing to keep in mind.

Otherwise MFP would be overloaded with syncs and crash even more than it does.

Fitbit sends new data when it's 100 higher than prior sync.
At BMR rate of burn sitting or sleeping in the evening, that's usually going to take over an hour.

And to that point - when you check your MFP goals and info based on an evening sync, say 4 hrs before midnight - MFP estimates that 4 hrs to be at whatever rate you selected as activity level on MFP.
Even sedentary is 1.25 x BMR.

But if you are sitting and then sleeping that final 4 hrs - Fitbit will sync again at some point, and by the next morning MFP will learn it wasn't 1.25 x BMR, but rather BMR.
So it will correct itself to a new lower daily burn amount, eating goal will be lowered, and if you hit your eating goal at 8pm, it'll be over the next morning.

But if you go to the couch and bed about the same time, the adjustment is about the same amount - so just leave yourself in the green by that much.

Or it can be calculated out to know what the difference is.

HeyJudii

heybales wrote: »

You can't manually force a sync from your Fitbit account to your MFP account, first thing to keep in mind.

Otherwise MFP would be overloaded with syncs and crash even more than it does.

Fitbit sends new data when it's 100 higher than prior sync.
At BMR rate of burn sitting or sleeping in the evening, that's usually going to take over an hour.

And to that point - when you check your MFP goals and info based on an evening sync, say 4 hrs before midnight - MFP estimates that 4 hrs to be at whatever rate you selected as activity level on MFP.
Even sedentary is 1.25 x BMR.

But if you are sitting and then sleeping that final 4 hrs - Fitbit will sync again at some point, and by the next morning MFP will learn it wasn't 1.25 x BMR, but rather BMR.
So it will correct itself to a new lower daily burn amount, eating goal will be lowered, and if you hit your eating goal at 8pm, it'll be over the next morning.

But if you go to the couch and bed about the same time, the adjustment is about the same amount - so just leave yourself in the green by that much.

Or it can be calculated out to know what the difference is.

My question isn't about syncing with MFP. Soley a Fitbit sync question.

HeyJudii

RAinWA wrote: »

My Fitbit will change between a sync close to midnight and the next morning just like you described. Usually between 25 and 50 calories burned difference.

I always just assumed when it did it's 11:59 p.m. sync it just readjusted its expectations of my activity for the day and never worried much about it.

Makes sense. Messes with my need for eternal accuracy and perfection, but, oh well, I guess I'll survive.