Tracking Calories Burned Inconsistencies

Alright, I know everyone is different but...

Today at my fitness class, according to my “VeryFitPro” fitness/ HR tracker, I burned 272 calories. My max heart rate was 122, the average was 87. Just to be clear, during the class you never stop and you sweat. It’s an hour long workout and it’s a workout! Having said that, my fitness instructor commented according to her watch, I believe she has a Fitbit, she/we burned 1017 calories.

My question is, is it possible for us to be that far apart? It seems incredulous but what do I know?! This isn’t the first time she made the comment on how many calories burned and my FT has disagreeed.



  • Colleen219
    Colleen219 Posts: 11 Member
    I know calories burned varies based on a number of factors but I'm surprised you're so far apart. When I take classes i think the instructor probably burns less calories than me because she's in way better shape lol and she's always stopping to see what we're doing and help people.
    I burned just over 1000 calories today, I ran 9 miles in about 90 minutes. Max heart rate was 158, average was 143.
  • malibu927
    malibu927 Posts: 17,567 Member
    Sweat doesn't correlate to calories burned. That said, I would believe your tracker over your instructors. 1000+ calories burned in an hour is a very generous estimate for most exercises.
  • FurMom77
    FurMom77 Posts: 6 Member
    Is it possible my device is incorrect or inaccurate?
  • MeanderingMammal
    MeanderingMammal Posts: 7,870 Member
    FurMom77 wrote: »
    Is it possible my device is incorrect or inaccurate?

    More likely the Fitbit. Neither one is correct but 1200 is completely out of the question. About 300 isn't outlandish.
  • dewd2
    dewd2 Posts: 2,449 Member
    Heart rate nor sweat equates to calories burned. Movement and your weight are the factors that determine calorie burn. It is difficult to get an accurate count in a class. The best you can do is guesstimate and adjust through trial and error (are you getting the results you expect).

    FWIW - Running one of the top calorie burners and I'm not sure I could run far enough in an hour to burn 1000 calories. I'd say for certain the instructor was wrong (way wrong).
  • dewd2
    dewd2 Posts: 2,449 Member
    FurMom77 wrote: »
    Is it possible my device is incorrect or inaccurate?

    Yes (all of them are inaccurate). They are good for counting steps. Running watches are good for tracking runs and counting steps. Some even give directions. None are very good at counting calories for everyone.
  • 0ysterboy
    0ysterboy Posts: 192 Member
    Calories burned depends on the intensity of the exercise and your personal ability to burn calories (how big is YOUR engine). This is extremely variable, but I can tell you in a 50 min spin class I usually burn about 325 kcal, and my heart rate would lie in the 120-135 zone for the entire 50 mins. So I think your device gave you a fairly descent number, your instructor less so.
  • AnnPT77
    AnnPT77 Posts: 26,272 Member
    Your device is closer than her device, IMO, without even knowing how tall either of you is, how much you weigh, or what your actual resting/max heart rates or VO2max are. All these devices are making estimates, not measuring calorie burn. HR is only a proxy for calorie-burning work; they correlate somewhat but don't track one another. Devices not measuring HR are using only motion as an input; in either case, the estimate is only as good as their algorithms.

    I'd lay good money she's not burning 1000+ calories in an hour long class. My HRM estimates something in the mid-200s for a 45 minute spin class, in which my average heart rate is around 130, and max in the high 140s to low 150s, set for a 120 pound body weight and a resting to max range of 60-181, age 62. It's not accurate, but - based on better metered exercises and RPE - I think it's probably in the right ballpark. When I was heavier, but already moderately fit, it estimated in the mid-300s. (Note that cycling, especially indoor cycling, is not as body-weight-dependent as most fitness classes, despite what my HRM thinks.)

    BTW: Fit people don't burn materially fewer calories than unfit people doing the same activity at the same intensity and duration, if the same body size. In real life, in fact, they may burn more calories, because they can sustain higher intensity for the class duration. HRMs may estimate lower calories for them because they can do the same amount of work at a lower heart rate, or a more work at the same heart rate . . . it's the work (in more or less the physics sense of "work") that determines calorie burn.

    If your class involves weights in any way, HRMs are especially inaccurate in estimating, and they aren't super great for interval workouts either. If hers uses HR, and yours doesn't, and the class uses weights, that could even account for some of the discrepancy you mention.

    Of the two estimates you have, I'd believe your device as closer. Check out what the MFP database would estimate for the closest exercise form it lists, for a cross-check. (It isn't strictly accurate, either; it's just another estimation point.)

    I know this all sounds pessimistic, but your device should give you pretty consistent calorie estimates from session to session, so you can use them in conjunction with your intake tracking and scale weight to get accomplish your goals nonetheless. :)
  • gamerbabe14
    gamerbabe14 Posts: 876 Member
    The fitness instructor is way, way off. Your tracker seems pretty accurate.
  • angelsja
    angelsja Posts: 860 Member
    Fitbit calculates calories burned + BMR for that time when I go for a 90min walk mine says I burn off approximately 600 calories and I don't break a sweat and hardly get my HR up. I don't know anything about your watch but does it factor in your BMR as well or just calories burned during the exercise
  • stanmann571
    stanmann571 Posts: 5,736 Member
    Obviously, as above, they're both wrong. Yours is probably a touch low, But well within the safe margin of error to eat back.

    Your instructor's is ridonkulously high, unless she weighs 300 lbs and is moving at the speed of a gazelle for 60 minutes straight.

    I get around 800 calories for running 6 miles in 70 minutes(at 230+ lbs)
  • try2again
    try2again Posts: 3,564 Member
    FurMom77 wrote: »
    Is it possible my device is incorrect or inaccurate?

    When I read your post, I immediately thought, "Wow- that sounds like a great tracker!" Your instructor is the one who could use a new one. ;)
  • DX2JX2
    DX2JX2 Posts: 1,921 Member
    Technically it's not terribly outlandish to burn 1000 calories in an hour. It's just not something most normal people can or want to do. Running, swimming, jumping rope, or cycling can all get you there but all would require a really hardcore level of intensity. For example, a 170 pound person would need to run 6 minute miles for 60 minutes straight to burn 1000 calories. That's very fast for anybody but pretty serious competitors.

    Unless you go to the most hardcore gym in existence with the fittest group of gym-goers ever, it's unlikely that an open class is geared to burn 1000 calories per hour.