HRM vs FitBit calories

Takes2long
Takes2long Posts: 367 Member
in Fitness and Exercise
I used to wear my HRM to my kickboxing/karate classes. Some of the burns were 500+. Super intense classes, and it felt like I burned that and more. My HR can and does go 170 and higher in class. It goes to 190+ while I'm running. I've been tested, and was told that's normal for me. My HR comes down pretty fast when I slow down, so I don't need to be alarmed.

My question is since I was wearing a HRM, and mine can get really high, could that cause me to get a higher burn? I've had my FitBit flex for almost a week. I've worn it to class, and also while cleaning out a barn stall. Normally, i would have guessed a burn of at least 400 for either activity. However, FitBit gave me the adjustment of 194 for one day in particular.

Today, for example, if I go into my FitBit settings and look at every 5 minute increment during exercise, I calculate my burn to be 219.7. But the adjustment on MFP gives me a burn of 45. Why? Does it have something to with the setting on MFP as being moderately active?

I feel I'm working with the same intensity. I'm wondering if my FitBit isn't working properly, OR, my HRM was just overestimating because my HR goes up fast, and stays there while I'm active.

I'm so confused about what going on. I feel like I'm still working hard, but having LESS to show for it. I don't understand how the burns are being adjusted, and they seem so small.

Replies

  • thatjosiegirl
    thatjosiegirl Posts: 362 Member
    I have a tendency to believe that the HRM is probably more accurate when you are doing steady state cardio, and FitBit is more accurate with light activity.
  • SameMe_JustLess
    SameMe_JustLess Posts: 245 Member
    Search for this topic, there are tons of threads with very detailed answers, but in a nutshell the Flex is a fancy pedometer. It will not give you and accurate calories burn for the gym, fitness classes, etc. It is meant to count steps and get you moving.
  • Pirate_chick
    Pirate_chick Posts: 1,216 Member
    I have a tendency to believe that the HRM is probably more accurate when you are doing steady state cardio, and FitBit is more accurate with light activity.

    agreed. I wear my fitbit for day to day activities, life essentially, and I wear my HRM when working out.
  • Philp0718
    Philp0718 Posts: 136 Member
    Search for this topic, there are tons of threads with very detailed answers, but in a nutshell the Flex is a fancy pedometer. It will not give you and accurate calories burn for the gym, fitness classes, etc. It is meant to count steps and get you moving.

    100% correct. A HRM is more accurate for monitoring exercise, while fitbit is for everyday activities.
  • lydiaannepage
    lydiaannepage Posts: 172 Member
    Search for this topic, there are tons of threads with very detailed answers, but in a nutshell the Flex is a fancy pedometer. It will not give you and accurate calories burn for the gym, fitness classes, etc. It is meant to count steps and get you moving.

    Yup this... your fitbit is guessing purely based on your steps which while helpful over a whole day of just regular activities will not give you much of an accurate reading for anything that gets your heart rate up and gets those extra calorie burns. Your HRM is the only good guide for what you are burning during workouts and high intensity activities :smile:
  • Takes2long
    Takes2long Posts: 367 Member
    OK. Thanks. I tried to do a quick search for this issue, and didn't find what I was looking for. I'll look more when I can have some uninterrupted time. I know FitBit has very active minutes. LOL...I think I'm being very active in class, but it's saying I'm not.

    Again, thanks! I guess I though it was going to give me a better idea of what I'm doing day to day, and not just a fancy pedometer.:tongue:
  • nilbogger
    nilbogger Posts: 870 Member
    Yes, it does have to do with your activity level settings. FitBit is giving an estimate of your burn each day based on how much you move and adjusting MFP calories accordingly.

    If you select moderately active MFP is assuming you burn a certain number of calories through your daily activity. FitBit will adjust if you burn more. So the FitBit is not saying you only burned 194 calories from that workout, it's saying you burned appromixately 194 more caloires than MFP figured you would being moderately active.

    If you chose sedentary or lightly active the adjustment would be greater.
  • Takes2long
    Takes2long Posts: 367 Member
    Yes, it does have to do with your activity level settings. FitBit is giving an estimate of your burn each day based on how much you move and adjusting MFP calories accordingly.

    If you select moderately active MFP is assuming you burn a certain number of calories through your daily activity. FitBit will adjust if you burn more. So the FitBit is not saying you only burned 194 calories from that workout, it's saying you burned appromixately 194 more caloires than MFP figured you would being moderately active.

    If you chose sedentary or lightly active the adjustment would be greater.

    That makes sense!! Thanks for all the help :happy:
  • sodakat
    sodakat Posts: 1,126 Member
    Yes, it does have to do with your activity level settings. FitBit is giving an estimate of your burn each day based on how much you move and adjusting MFP calories accordingly.

    If you select moderately active MFP is assuming you burn a certain number of calories through your daily activity. FitBit will adjust if you burn more. So the FitBit is not saying you only burned 194 calories from that workout, it's saying you burned appromixately 194 more caloires than MFP figured you would being moderately active.

    If you chose sedentary or lightly active the adjustment would be greater.

    That makes sense!! Thanks for all the help :happy:

    This is what I was thinking, too. I've only had my Fitbit Flex for a little more than 2 weeks but it has been spot on providing calories according to my activity level, deficit level and goal. I am really please with it. I have mine set for lightly active and "kinda hard" on the Fitbit settings for how much of a deficit (750 cals a day for 1.5 pounds lost a week). It is working. Both reports I've received from Fitbit have me at the exact deficit to lose 1.5 pounds (within a few cals for the week!) and I have lost 1.5 pounds both weeks. I am eating almost all of my calories I "earn" that Fitbit adds to MFP. Honestly I think this is the greatest tool ever.

    I have done heavy yard work with lots of lifting (moving rocks, etc) and hiked up a trail with steps built in the hillside, both activities are not really Fitbit stepping activities but I did not add either one to my exercises on MFP. I'm just letting Fitbit Flex do its thing and IMO it is doing it exactly right. Oh, and on the one day in the last 2 weeks that I was not as active, it gave a negative adjustment for the first part of the day but eventually I did enough stuff to bring my calorie amount back up the MFP goal. So, it works on days there is little movement.

    I do not think it only measures steps. I found this out when I used my push mower for the first time wearing Flex. It gave me more steps than my sHealth pedometer tracker on my phone. I questioned that and got some advice here: trust Fitbit. I no longer use my pedometer on my phone. Fitbit is all I need. Granted I don't lift yet, but really I am not sure I would add those at first anyway. I am set up to start in August; maybe I will change my mind then. Don't imagine as a newbie lifter I will burn too much though. Hah, hah.

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