Calories burned are incorrect - too low for some activities

[porcelina]

HI all,

I am a new member and looking for some help.

I have been tracking and logging fitness and food for many years now via sparkpeople.com. I also used to use a polar hrm for tracking calories burned when I was initially losing weight around 4-5 years ago. Neither of these had the same level of detail as the fitbit, and so I am still getting used to everything and figuring out how it all works. However, I am getting a bit perplexed!

At my goal weight (139 lbs) according to my HRM, I was burning about 400 cals on a 30 minute run and around 600 for an hours high intensity circuits class, sometimes 700 for Body Attack. Spark people would give a lower cal burn because it was more of an estimation than an accurate reading. 

I have been using my fitbit charge hr now for around a week - I have worn it for a 32 minute run, during a 45 minute Body Attack class and then for GRIT strength and CX worx this morning. Each of my burns seems a little low in my opinion: 169 for GRIT, 341 for my run, 356 for Body Attack.

The run probably makes sense to me as it was a gentle run as I am getting over a chest infection, however the gym classes don't. I don't wish to blow my own trumpet or sound conceited but I worked really hard - and always do - in GRIT and Attack. Also, a lot of my friends have fitbits and their burn was a lot higher than mine, and we were all pushing equally as hard together!

I am wondering if I have something set up wrong, or if I am using it incorrectly? The polar unfortunately is broken and it was a couple of years ago when I was using it, so it could be that over the years my body has gotten used to working at high intensity during these activities and so I don't burn as much - however I still feel just as pooped at the end of the sessions as I used to do!! Maybe I need to find some more intense workouts!

Any help would be gratefully received. Thank you.  

[amc1963]

my fitbit Charger HR calorie burner is incorrect, before I start each morning, it already states I have burned over 500 calories. please help

[SebringDon]

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@amc1963 wrote:

my fitbit Charger HR calorie burner is incorrect, before I start each morning, it already states I have burned over 500 calories. please help

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@amc1963

Your daily calorie burn includes both your activity calorie burn and your Basal Metabolic Rate, or BMR, which is the calories your body burns each day for maintenance; keeping your heart pumping, breathing, digesting food and the like. Your BMR is based on your height, weight, age and gender.

If you don't include your BMR in your daily calorie burn, there's no way to accurately calculate the amount of food you should eat each day to maintain, lose, or gain weight. The Fitbit dashboard shows data for periods prior to getting your Fitbit so you can see what that basic number, BMR, is for your particular settings. You'd have to eat that many calories per day if you did nothing but lay in bed all day, or you'd lose weight.

As you are active throughout the day, you'll burn additional calories from that activity. Fitbit's food plan calculates your Daily Calorie Estimate by combining both those calorie burns and adjusting that number based on how fast you want to lose weight.

The four-part series of forum posts, Fitbit's Food Plan Demystified, listed in my signature will tell you most everything you need to know to set up and execute a successful Food Plan.

Hope this helps!

[brigids]

I have a similar issue, in that I wear a Mio Link HRM and connect to both Wahoo and S-Health for exactly the same workout as I'm monitoring via Fitbit Charge HR.

Every time, the fitbit calorie count is lower than both Wahoo and S-Health. 

For example:

today - 41 mins exercise bike: 

S-Health - 269 calories, avge heart rate 147 bpm.

Wahoo - 397 calories, avge heart rate 148 bpm

Fitbit - 247 calories, avge hear rate 147.

I'm willing to accept that Wahoo may be overestimating my calorie burn, but fitbit is always lower than the S Health, and the longer the workout the larger the different. I'd love to know how/why

[Sree]

Same issue with hiit workouts - my Fitbit underestimates these calories burned. But it overestimates the calories burned walking or running. How can calories burned on a walk with my dog, come even close to the calories burned in a grit class - I am inclined to retuning this pointless device, unless they fix this

[catbrat101]

I really bought the Fitbit to keep track of calories burned and first time out on my elliptical it's only giving me half the calories burned as I normally would have tracked in the past with a Polar heart rate monitor.  Is there a way to fix this since the Fitbit's main purpose for me was calories burned! $168 dollar watch?

Eek! Or have I done something incorrectly???

[kiacker]

I use my Charge HR along with the link-up to SparkPeople for additional tracking. The dramatic drop in calories logged doesn't make any sense. For example: A week ago I logged 7,025 steps, walked 3.66 miles on a paved flat path in town, did 31 active minutes, and it says I burned 2458 calories. Today I logged 12,969 steps, walked 6.76 miles through prairie and marsh lands, had 74 active minutes but burned fewer calories at 2290 than I did a week ago with fewer steps, miles, and active minutes. Why??? It doesn't make sense that the calories burned are LESS even though there were more steps, miles, and active minutes recorded.

I have reset it multiple times to no effect. Very frustrating when it used to work just fine. Do I now have to log my activities separately to make them register?? And if so, what's the point of having the fitbit??

[LenaFit]

@catbrat101 @Sree @brigids Welcome to the Community! Sounds like you've been searching for the best information for optimal accuracy during your workouts. 

@SebringDon Provided some awesome tips to refer to! I wanted to throw out a few suggestions as well. 

Keep in mind that our Fitbit Charge HR's accuracy can be impacted by:

- Personal physiology

- Location it is worn

- Type of movement 

This is super important to note! Since accuracy is affected by a variety factors, it's not the best idea to compare the Fitbit Charge HR with other devices. 

To help improve your calorie accuracy, I encourage you to double check that the information within your profile is current! 

1. Log into your Fitbit account

2. Click the gear icon in the upper right-hand corner 

3. Click on Settings 

4. Here is where you can make any edits or changes 

I hope this helps! 

[catbrat101]

Thanks Lena but yep all my profile info is in place with age, sex, height, goals etc. 

I did 20 mins on my elliptical this afternoon which is normally around 165 calories burned for me at my age, weight, speed (used to have a Polar HR chest band) and Fitbit logs the cals at about half.  I've got scrawny wrists so I don't know if that's why it doesn't pick up properly?  I don't know for sure, it's day 1. 🙂 

I will mess with it more but I'm disappointed.  I should have done research BEFORE purchasing not after as I did want this for calories burned knowledge. I appreciate the input though.

[Sree]

In my opinion this became so useless, that I just returned the Fitbit - if all it is going to do well, is be a glorified pedometer - I don't need it. My phone already gives me my steps. I needed a proper calorie counter - and Fitbit ( perhaps all wrist based wearables) failed

[ufrnd]

I agree! I have stayed with the Fitbit hoping that some sort of solution would happen, but up to this point nothing has changed. The calorie count is not accurate especially on high intensity exercise.



Sent from my iPhone

[Sades]

I found holding down the side button for a few seconds and putting it in 'exercise mode' while exercising made the calorie count a little more accurate. Still lower than I thought, but better.

Sent from my BlackBerry 10 smartphone on the Bell network.

[ufrnd]

I do that each time I workout. I have tried all of the tricks and resets...it is still off. I have, like most in this thread, a chest monitor and the difference can be significant.

Personally, I feel as if the fit bit calculates on an average heart rate opposed to a fluctuating heart rate. So in higher intensity workouts the fit bit does not make the jump to the higher heart rate in reference to calories burned. Instead, it seems to calculate at an average heart rate.

I hope that makes some sense...



Sent from my iPhone

[veloguy]

Same problem with Surge. Cycling calorie calculater says I burned 1460 cal. for a 25 mile ride at avr. 14 MPH  Fitbit says 146 cals !  All bio settings are correct.  This sucks.

[calrenbowie]

Remember your fitbit needs to be at least two inches from your wrist to give an accurate reading.  the closer it is to the wrist the lower your calories will be because it is not geting every heart beat.

I tested this out when I first got my fitbit. I found that it is more accurate when it is two fingers widths from that knobby bone on your wrist.

Hope this helps 🙂

[catbrat101]

I'll just say (since my previous reply didn't really articulate what I was trying to say) the wristband doesn't fit great.  It's hard to get it so you have 2 fingers from the wrist bone and it be comfortable at the same time.  

I will say since that first day and seeing the calorie count being off for the elliptical I started power walking instead and so far I'm really happy with my Fitbit! 

[AussieSteveH]

Exactly the Sam here. I'm on the elliptical tight now. Fitbit says 142cal elliptical says 235. Quite a disparity.

[AussieSteveH]

Using surge on an elliptical that your arms are stationary. Constantly correctly reading HR. FB 204 cal elliptical 338cal. I'm going with elliptical as it is likely calculated using physics. Ie a known mass travelling at a known speed with known resistance for a known tyime would be simple to calculate energy used.

[Savateuse]

I'm  having exactly the same issue. It seems like none of the Fitbit models calculate activity calories burned accurately.  Doesn't that sort of defeat the purpose of the Fitbit?   I've been deleting the Fitbit generated activities and manually entering my Active calories burned.  I paid a lot for a glorified pedometer.  Sure is pretty though...

[AussieSteveH]

Hey Fitbit: how about sliding in some advanced user settings that let the user adjust the algorithm for calories burned for specific activities that can be measured on the exercise equipment. This will go a long way to increasing the accuracy of overall calories burned. Maybe just an energy rate percentage wheel that users can select and adjust to match that displayed on the equipment.

[Julia_G]

Studies show that most people significantly overestimate the calories burned from activity.

If your Charge HR is giving you a reasonably accurate measurement of your heartrate, and your profile information is correct, for an aerobic activity like elliptical, the Fitbit is more likely to be correct than the machine.  (The same is not necessarily true for activities like weight lifting.)