How accurate is the FitBit Flex??

boyd4715

When you say accurate what are you comparing it to?

When I wear it on my wrist - non-dominant - I can see it count steps when I am just typing on the computer -

Do I have a misunderstanding on what this device does and what it records?

vignak2013

So can someone give me the sequence of how and where to log? I just want to know how many calories I'm burning when I'm doing my workouts. If I work out at 5:00AM, when and where do I log my activity? If I put it in MFP first, how do I know what calories to enter? Thanks so much!!

Timshel_

I have the Force (The non-wrist burning kind) and it is a good GENERAL fitness counter. On par with anything in the price range. If you want more accurate you step up in price, buy a Polar or Garmin, and spend for the heart rate monitor. I have that setup and really found it overkill for all but working on time improvement for running.

So how accurate are the Force and Flex units? You will find tons of people that misunderstand what they track and how they calculate calories. In a nutshell, they are wrist worn pedometers. They allow you to enter metrics such as height, weight, age, etc to figure out your calories burned in a day. It tends to error a bit on the high side for base metabolism rate AND for exercise calories, so that pretty much is a wash in my book.

You will see some people talk about the units picking up typing or adding steps while sitting. Well, it is on your arm so that is always possible. I've had it add a few hundred steps, which might sound like a ton, but the reality of how it effects your caloric deficit for weight loss is marginal. For instance, I take about 1800 steps in a mile. A mile burns about 120 calories for me at a 4.0 pace. That extra 200 steps really only misrepresents about a couple dozen calories off. That is like forgetting to log one Hershey Kiss. Even if it logged an extra 1000 steps, calorie wise it doesn't amount to much.

Which is where people depart on usefulness. I personally tend to pay more attention to calories burned in the day overall and worry little about a few 100 calories here and there, least I be weighing and measuring everything in a lab. I wanna live and be healthy and not be a slave to finite numbers. But I digress.

Anyway, you can always log activities on Fitbit for more accurate calories counts. So if you tracked an hour of running, you can go to the Fitbit website, go to Logs, then go to the Activity page. There you search for your activity, then plug in the exact start time, duration and mileage if known. Fitbit overwrites the other tracked exercise without double booking it. You can manually enter calories there too if you have used a HRM in the past and better know that calorie burns.

I tie into MFP and I log my food here. Fitbit dumps over exercise calories based on my tracking on logs. I tend to pay more attention to my MFP remaining calories than looking at any of that on Fitbit as they differ. Works well enough.

One HUGE tip is to make sure you correct the stride length for both walking and running. I measured mine several times to get it right. When I started the step counts were pretty close but my mileage was WAY off. Since correcting them all is pretty good.

As for dominance, the recommendation is to have the unit on the non-dominant had and to make sure the unit is set to non-dominant in the settings. Search the Fitbit site for all kinds of info on it.

So accuracy is good and using it is helpful. Want more accurate, spend more. It is personal preference.

vignak2013

So can someone give me the sequence of how and where to log? I just want to know how many calories I'm burning when I'm doing my workouts. If I work out at 5:00AM, when and where do I log my activity? If I put it in MFP first, how do I know what calories to enter? Thanks so much!!

UpEarly

Mine undercounts my calories by 200-300 a day. I just eat more than it tells me to. The step count is pretty accurate though.

jenapologizes

It is accurate because it's calculating BMR.

TeaBea

It is accurate because it's calculating BMR.

No, not BMR ......but not TDEE either....somewhere in the middle.

Your BMR is zero activity. Your TDEE is BMR + activity + workouts.

FitBits do a decent job at tracking activity (but not workouts)....so with FitBit you get BMR + activity (ie: sedentary). Other methods can be used for workouts.....for steady state cardio HRMs are pretty good.

tonyciccione

I think it overestimates calorie burn for walking. Today I walked for 1h34 (slow pace, something around 4.5 km/h) and it told me I burned 692 calories (I logged the activity with the purpose of verifying its accuracy). Comparing with MFP of Runtastic (on the phone of my friend) it's out by at least 250 calories (which is almost 40-45%).

I didn't lose any weight in the first 2 weeks owning the Flex, because I was eating the calories it told me I could eat. So, I think the flex is kinda ok for normal days, but it gets way off when you reach certain levels of activity

mrsfyredude

I have the flex but I wear it on my ankle (if you wear socks just tuck it in there) that way it only measures when I move my FEET not my hands. Obviously if you're a fidgeter, it's going to measure some of those movements, but since I sit and type most of the day I find this better than wearing it on my wrist.

nebslp

Bump

suzichains

I have it and didn't like it so far

roni79

The flex includes your bmr ( the calories you burn just being, well, alive) for me that's 1600 a day right there. Also though, you should go on the site and make sure calorie estimation is turned off and that you have it set for your non dominate hand / dominate hand. Wearing it on non dominant is most accurate. The setting on the computer needs to match that though.

roni79

And also mine matches the data for my hrm fairly closely too so I use my flex. Just make sure you log the right activity and don't leave it on walking or running when your in a workout class.

SnuggleSmacks

It is not completely accurate in counting steps, as it sometimes ignores things that include keeping your arm still, like pushing a shopping cart, carrying heavy objects or holding hands with someone.

prudybertolino16712

I've had the fitbit flex for a couple of weeks. The calorie count is way off. I walk the dog 2 miles and it says (each time) that I've burned 700 calories. (Don't I wish!) The correct count would be a lot less than that - maybe 100-150.

karen_kennedy

I need help!!!!

Ive recently bought a vivofit just a week ago and have have downloaded the Garmin app, in which ive synched the watch to. My question is: why is it that even though I am not wearing the vivofit overnight and its placed on a stationary object, the vivofit does not begin with 0 but a have calculated calories ive burnt without me having it on in the morning. KM and steps have all started on 0 except calories which is quite strange.

Some HELP would be great..

TeaBea

I need help!!!!

Ive recently bought a vivofit just a week ago and have have downloaded the Garmin app, in which ive synched the watch to. My question is: why is it that even though I am not wearing the vivofit overnight and its placed on a stationary object, the vivofit does not begin with 0 but a have calculated calories ive burnt without me having it on in the morning. KM and steps have all started on 0 except calories which is quite strange.

Some HELP would be great..

I don't know about the Vivifit.....but the FitBit does the same thing. Your body is burning calories 24/7, not just when you're moving around. The number of calories (sleeping all day) would be your BMR (basal metabolic rate).

nancyameyer

I'm a health educator and have been helping people monitor activity, exercise and calorie intake and output for 35 years. My daughter gave me a fitbit for my 70th birthday and I was initially excited about the devise and thought it was supposed to be accurate. However, I have been monitoring it very closely for calorie burn and steps and some of the calculations are misleading. For one the calorie burn includes your basic MRB - the calories you burn just to keep your body functioning.

So lets say for my age, weight and height my BMR (basic caloric need to run my body is 1,200 calories per day. If I eat 1,200 calories per day it keeps me at my current weight if I don't exercise. By the way - 1,200 calories is the lowest a person should take in or you get into starvation mode and your body will conserve calories making it harder to loose weight. If you want to loose weight you do not want to eat all the calories fitbit says you burn without subtracting you BMR from the total calorie burn fitbit says you have achieved.

So be sure to understand that when the fit bit calculates your calorie burn it includes BMR - the calories that your body uses just to function. This is confusing because you should not think you have all these "extra" calories to eat like it tells you in your daily calorie intake tile. So on days when I am very active fitbit will tell me I can eat 1,800 calories - that's 600 calories beyond my BMR. If I ate this many calories no matter how much I exercised I would gain weight. So you need to know your BMR and how much energy you burn with workouts. The workout calculation calorie burn is pretty accurate. In 10,000- steps you can burn up to 500 calories but is fitbit overestimating your steps.

Fitbit does over calculate steps. According to the fitbit site the steps will be off by 10.1%. I have my band on my non-dominate arm but even then you will still register almost every movement your arm makes. I tested my fitbit for two days and anytime I moved my arm I got a step. Even on my non-dominate wrist my steps were over estimated. So go to settings and set your fitbit to the non-dominate arm unless you like to fool yourself about how much activity you are getting. After you reset your fitbit for the non-dominate wrist you still need to reduce your steps by 10.1%.

All this said, the fitbit encourages me get more activity beyond my daily workouts. I keep moving trying never to sit more than 30 minutes at a time. Even with these anomalies, Fitbit is a good reminder to move and to monitor my calorie intake.

Happy fitbitting.

brianpperkins

"Starvation mode" from a "health educator" ... wow.