HRM Overestimates??

Pspetal
Pspetal Posts: 426 Member
in Fitness and Exercise
Is it possible for a HRM to overestimate calories burned? I bought a new Polar FT4 HRM with a chest strap and it has been showing me a much bigger numbers than the gym treadmills, ellipticals, my previous estimates for strength training, etc. Like today for instance, the elliptical says I burned 850 cals but the HRM says I burned 1030 cals. 40 mins of jogging at 5.2 mph shows up as 450 cals while the treadmill says 300.
I was worried that I might be overestimating calories burned, but I now seem to have the opposite problem!
Any thoughts? Could the HRM numbers be right?

Replies

  • Ecce_Signum
    Ecce_Signum Posts: 226 Member
    Silly question but are you sure you input the correct figures into the HRM? Gym machines normally give a higher calorie burn than a HRM as does MFP.
  • dawlschic007
    dawlschic007 Posts: 636 Member
    I noticed this at first, too. The HRM numbers tend to be more accurate though since they factor in your height/weight/sex/age and keep a constant recording of your HR, where as the machines do not ask all that info. You'll notice though that once you get acclimated to doing certain exercises that your heart rate will not go as high and you'll burn less calories, which may end up matching with what the machines say.
  • Pspetal
    Pspetal Posts: 426 Member
    Yes I did... My age, weight, sex all those things. I don't really trust the gym machines anyway and usually discount about 30-40% of their calorie burn count, So for example when I workout really hard on the elliptical machine for an hour, I count it as 650 or so while the machine says 1000. The HRM though keeps giving me estimates higher than mfp or the gym machines do.
  • Amanda21202
    Amanda21202 Posts: 210 Member
    Does the gym equipment take into consideration your height/weight/sex etc?
  • Pspetal
    Pspetal Posts: 426 Member
    Height, weight and age yes. Not sex.
  • EatClean_WashUrNuts
    EatClean_WashUrNuts Posts: 1,590 Member
    The HRM though keeps giving me estimates higher than mfp or the gym machines do.

    MFP is not correct. It has use an average algorithm.

    I would 1) reset your HRM. 2) if it persists, go exchange it for a new one.
  • Anthonydaman
    Anthonydaman Posts: 854 Member
    Your HRM sounds faulty, mine doesn't start showing any significant calorie burn for almost 10 minutes which is completely different than the calorie counters on machines, which start showing calorie burn the second you start moving.
  • FHART626
    FHART626 Posts: 11
    ^^^^I agree with the replier above me. Mine doesn't show anything for some time after I start a workout.
  • Amanda21202
    Amanda21202 Posts: 210 Member
    I would 1) reset your HRM. 2) if it persists, go exchange it for a new one.


    I suggest this too! I have the same HRM and luckily had no problems at all. It does sound like it's overestimating
  • Keeda
    Keeda Posts: 21 Member
    My HRM does the same thing! I wear it during all my exercise and get double the numbers that MFP gives or the machines. I have a very low resting heart rate (45-50) and then it jumps pretty high when I do exercise (150-175). I have made the decision to enter in my calories burned and only eat half of them back. I would love to find out how accurate these things actually are!
  • mzjessicaxo
    mzjessicaxo Posts: 330 Member
    it depends what you're doing when you start. If you start with stretching or a warm up (slow pace on treadmill etc) it will take time to start to go up, just as you see your heart rate slowly increasing.

    5.2 is a running setting on a treadmill so this would have jump started her heart rate!

    The other thing I would suggest is to check the metric/imperial setting on your HRM :)
  • Simplicity
    Simplicity Posts: 383 Member
    I bought the ft4 also. I have noticed that the calorie burns are quite high too. I'm 188lbs and burning 680 calories doing insanity's pure cardio workout. That's roughly 40 mins of getting my heart rate averaging 170-180 I know this is high but I'm a bit out of shape. I then take away my RMR and get about 630 calories, it feels about right but I wouldn't know for sure. Last time I used a polar HRM I was 170lbs and only really jogged with it!
    Don't forget to minus your resting heart rate as polar don't do this.
    Let me know if you find up anything I guess mine might need resetting too
    Ben
  • Pspetal
    Pspetal Posts: 426 Member
    My HRM doesn't show me calories burned till I stop recording the workout. So I don't know how much time into the workout it starts counting cals burned.
    I set the target heart rate zone on it as 135-175. During my workouts, it shows that my heart rate is constantly between 150 and 175. Is something wrong with my target heart rate zone setting? Should I change it? Do the numbers vary by what zone you set it at?
  • mygrl4meee
    mygrl4meee Posts: 943 Member
    I have the same one. I do mostly cardio but I do bike and do the stairstepper at the Y. It is about 20 to 50 calories more than the machines. the longer I am on there the more the machines are coming in under.
  • Pspetal
    Pspetal Posts: 426 Member
    I didn't know I was supposed to subtract my resting heart rate from the total calories burned number. Thanks for that bit of information!
  • BlackTimber
    BlackTimber Posts: 230 Member
    HRM's are designed for the athlete to be able to judge and control a workouts intensity. The calorie function is just another calculation. Will be close for some and way off for others.
  • Doodlewhopper
    Doodlewhopper Posts: 1,018 Member
    You can check your burn by using this calculator: http://www.calories-calculator.net/Calories_Burned_By_Heart_Rate.html


    There are Gross Calories and there are Net Calories. If you have to input daily activity levels such as active, sedentary, etc in the equipment or HRM I would suspect that this may be the problem. One may be indicating Gross and the other Net.

    I havent read this item but I hope it gives an accurate explanation.

    http://www.shapesense.com/fitness-exercise/articles/net-versus-gross-calorie-burn.aspx
  • Mokey41
    Mokey41 Posts: 5,769 Member
    My HRM doesn't show me calories burned till I stop recording the workout. So I don't know how much time into the workout it starts counting cals burned.
    I set the target heart rate zone on it as 135-175. During my workouts, it shows that my heart rate is constantly between 150 and 175. Is something wrong with my target heart rate zone setting? Should I change it? Do the numbers vary by what zone you set it at?

    If it's an FT4 you should be able to push the top right button while working out to toggle between HR, calories, time, etc as you workout. The zone you set has no effect on the math it does, or anything else for that matter.
  • Pspetal
    Pspetal Posts: 426 Member
    Thank you so much everyone for the information, advice and suggestions! You guys are great!
  • RobfromLakewood
    RobfromLakewood Posts: 684
    I used to only look at the machines numbers asa guide to comparative work, if it said I did a 500 calorie burn, I figured a 600 calorie burn the next day meant I did a 20% increase in work, but the numbers were not likely very accurate.

    Weirdly enough, I got a heart rate monitor that had me burning less calories per exercise than the MFP estimates, but overall, for the day, they matched up pretty well. I began to suspect that the MFP was setting up the numbers for the exercise, plus some residual calorie burn that happens as your heart rate is still going for a bit after the exercise.

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