Fitbit tells me I've burned more calories walking than doing a strenuous workout?

toxikon
toxikon Posts: 2,383 Member
edited November 26 in Health and Weight Loss
I've had my Fitbit Alta HR for a few months now and I'm kind of scratching my head at this.

It says I burn about 150 calories for half an hour of brisk walking. I'm definitely not breaking a sweat during the walk and I'm walking at a comfortable pace.

On the other hand, I do a 30 minute intense strength/cardio class that has me gasping for breath and dripping buckets of sweat by the end, and the Fitbit says I've only burned 100 calories - even when I manually crank the intensity level to "High". There are no breaks in this class, just back-to-back high-rep barbell squats, lunges, cleans, presses, etc.

Anyone else experience this with their Fitbits? I've heard that they can sometimes be inaccurate but this just seems so weird to me.

Replies

  • toxikon
    toxikon Posts: 2,383 Member
    JaydedMiss wrote: »
    fitbit isnt really meant to track weight lifting its a step counter so it makes sense lol it has no idea what your lifting

    It's kind of an active lifting class - my heart rate is definitely in the 'cardio' zone during most of it. Definitely much higher than during my walks. Which is why I'm confused.
  • claritea1
    claritea1 Posts: 23 Member
    edited April 2018
    I’m a 37 yr old f, 5’4”, 170 lbs. Today my Apple Watch says I burned 151 active calories (208 total) for a 34 min, 2 mile brisk walk today. I have found it to be pretty accurate. Sounds like your Fitbit is underestimating your weightlifting calories instead of overestimating your walking calories.

  • SunlightKisses
    SunlightKisses Posts: 12 Member
    The walking calories have been pretty accurate on my Fitbit. I don’t think it’s overestimating your walk at all.
  • Mouse_Potato
    Mouse_Potato Posts: 1,513 Member
    My Fitbit is the same. It says I've burned around 300 calories for an hour of walking, but closer to 250 for a pole fitness class that has me ready to puke by the end of the warmup. However, overall I've found it to be quite accurate, so I just take what it gives me and try to eat accordingly. Effort does not always equal energy, unfortunately.
  • heybales
    heybales Posts: 18,842 Member
    edited April 2018
    Is the distance correct on that walk though?

    It's probably easy enough now (sweating/breathing/hr only indicate how tough on your system, not calorie burn) that the HR-based calorie burn isn't being used.

    Which means the normal daily distance method is.

    If the distance is off - the calorie burn is off.

    When you walk a known distance to compare - confirm it's your avg daily pace - not grocery store shuffle, not exercise level pace. Right in the middle.

    That way as the Fitbit dynamically attempts to calculate distance of each step's impact against expected (for weight and stride length stats) impact - you'll have best chance of accuracy at either side of the range.

    Don't want dead on correct for exercise level pace when that's only 30-45 min of day, and then it's more inaccurate for rest of the hours of the day walking.

    Oh - to the exercise class, review the activity record on Fitbit and confirm it appears it really saw all the high HR there likely was.
    For many it cuts out when HR goes high, for others it just stops reading accurately as HR goes higher.
    So perhaps you were actually higher than cardio zone.
  • DanaDark
    DanaDark Posts: 2,187 Member
    Fitbit is definitely not designed to handle full fledged work outs. It is mainly a step tracker. 150 calories used on a nice brisk half hour walk is pretty much in line with almost all calculators.

    Heart rate and calorie burn while connected, are not indicators of each. Sure would be nice to shed 50 pounds watching a suspense movie.
  • karahm78
    karahm78 Posts: 505 Member
    Your Fitbit isn’t saying you burned that much during the exercise per se.... it is saying your activity level for the day has exceeded the level you have set in MFP. Meaning, if you are set as sedentary but your activity level exceeds that by x calories, it awards you x calories
  • PAV8888
    PAV8888 Posts: 14,303 Member
    I can see your fitbit under-estimating your intense exercise activity if the intense exercise wasn't accompanied by readings that registered on the accelerometer.

    You may want to consider entering a manual activity on your Fitbit for the duration of non step based exercise activities.

    Your MFP adjustment, of course, doesn't just reflect an individual exercise activity. It is a function of the balance of TDEE calories between Fitbit and MFP at the time you look.
  • New_Heavens_Earth
    New_Heavens_Earth Posts: 610 Member
    I had problems with my Alta not recording segments of my circuit weight training and higher intensity cardio workouts, therefore a lower calorie count.

    And that's why I traded it for a Charge HR2. Problem solved.
  • Kst76
    Kst76 Posts: 935 Member
    edited April 2018
    I walked about 3 hours today, roughly 8 miles, and burned 950
    calories according to my fitbit surge.
  • Kst76
    Kst76 Posts: 935 Member
    edited April 2018
    karahm78 wrote: »
    Your Fitbit isn’t saying you burned that much during the exercise per se.... it is saying your activity level for the day has exceeded the level you have set in MFP. Meaning, if you are set as sedentary but your activity level exceeds that by x calories, it awards you x calories

    Not sure about her fitbit. But mine has a built in gps that tracks my distance exactely. It tells me how far i walked, how long, average speed, calories burned, avrage HR etc ..for that particular excersise.
    My hr for the 3 hour was an avarge of 130 to 150.
  • Leannep2201
    Leannep2201 Posts: 441 Member
    Not trying to thread hijack, but I’ve been scratching my head at my Fitbit too. Just got a Charge HR and managed to sync it- but for the last two days it’s given my hundreds of calories extra, just for my normal daily activity!

    So yeah, with you on the head scratching!
  • heybales
    heybales Posts: 18,842 Member
    Leannep2201 wrote: »
    Not trying to thread hijack, but I’ve been scratching my head at my Fitbit too. Just got a Charge HR and managed to sync it- but for the last two days it’s given my hundreds of calories extra, just for my normal daily activity!

    So yeah, with you on the head scratching!

    After first getting it, it's going to need about 2 weeks to figure out some stats that apply to you.
    What is general resting HR - used in the HR-based calorie burn formula for exercise.
    Where is the line when exercise starts - to move from step-based to HR-based calorie burn calculations.
    How often do you work out - used in the HR-based calculation.

    Takes a bit.

    Now, you can review some of that stuff - is HR jumping up during the daily activity a lot because of out of shape?

    Is the distance reported for a known distance walk correct? See my response above for the test.

    It could also be you are much more active daily than you thought if you selected Sedentary on MFP - meaning max adjustment.
    Those adjustments could be very valid and won't change with above info being gained in next 2 weeks.

    If above 4K steps - you are not Sedentary.
    Now - for purpose of syncing - setting to Sedentary is fine - read the FAQ in the Fitbit group. Just larger adjustments when you are no where near.
  • heybales
    heybales Posts: 18,842 Member
    karahm78 wrote: »
    Your Fitbit isn’t saying you burned that much during the exercise per se.... it is saying your activity level for the day has exceeded the level you have set in MFP. Meaning, if you are set as sedentary but your activity level exceeds that by x calories, it awards you x calories

    Except there was no comment that the MFP line for Fitbit calorie adjustment was being read.

    In fact, the way it was written - the actual Fitbit workout was being read to compare.

    I could be wrong, but usually people that are confused phrase it differently.
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