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Fitbit charge HR inaccurate by a lot?

callumwalker1995
callumwalker1995 Posts: 389 Member
in Social Groups
My fitbit in my workout this morning said I burned 726 calories yet the polar watch with hr monitor chest strap said I burned 1590 because it recognised my hr was about 130 on average whilst my fitbit said 90. DOes the fitbit charge hr have such a bad accuracy like this?

Replies

  • Christine_72
    Christine_72 Posts: 16,049 Member
    When in doubt i always pick the lower number. What workout did you do that could burn 1590 calories?? Does that number sound plausible to you?
  • callumwalker1995
    callumwalker1995 Posts: 389 Member
    2.5 hours, 2k run and 2 hours weights with dropsets/supersets etc
  • malibu927
    malibu927 Posts: 17,562 Member
    HRMs are notoriously unreliable for strength training. Stick with what your Fitbit said.
  • callumwalker1995
    callumwalker1995 Posts: 389 Member
    malibu927 wrote: »
    HRMs are notoriously unreliable for strength training. Stick with what your Fitbit said.

    Why is it unreliable? it monitors my heart rate which is surely more accurate than one being on the wrist?
  • malibu927
    malibu927 Posts: 17,562 Member
    callumwalker1995 wrote: »
    malibu927 wrote: »
    HRMs are notoriously unreliable for strength training. Stick with what your Fitbit said.

    Why is it unreliable? it monitors my heart rate which is surely more accurate than one being on the wrist?

    Because it's only good for steady-state cardio. With all the stopping, resting, reracking, etc. going on when you lift, measuring heart rate to determine calories burned won't be accurate at all.
  • heybales
    heybales Posts: 18,842 Member
    callumwalker1995 wrote: »
    malibu927 wrote: »
    HRMs are notoriously unreliable for strength training. Stick with what your Fitbit said.

    Why is it unreliable? it monitors my heart rate which is surely more accurate than one being on the wrist?

    If you want a demo of why, do the following.

    Sit on a bench or stand just like you would between sets for your rest.
    Note your HR for this level of activity. That's all your body needs from your heart to supply the oxygen to burn the fuel for what you are doing.
    Do your set of whatever.
    Now stand or sit, the same thing - now what is the HR, and how long to drop to the same level - if you even wait that long - betting you won't?
    That isn't elevated higher because your body is burning that much more energy during the rest, it just needs to recharge some glucose to ATP for your next lift - you are basically burning the same as before you started the lift.
    So the entire time it's drifting down - it's elevated - falsely.

    Hence @malibu927 's comment.

    Steady-state in the aerobic zone - not below exercise level, and not into the anaerobic level where HR has no bearing since the fuel used doesn't require oxygen.

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