Yikes! I have been logging wrong all this time!

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tyediri
tyediri Posts: 183 Member
in Fitness and Exercise
So I do a fair amount of walking (at least 40 minutes a day), aerobics and zumba every week. I have been using the MFP settings to calculate my calorie burn, but because I know it wasn't very accurate, I would log 60 minutes of Aerobics as 45 minutes for example, giving me around 350-400cals burn.

My finace bought me a polar ft4 heart rate monitor and I used it for my aerobics class yesterday for the first time. I burned 679kcals in the 60 minutes and my maximum heard rate was 200!!!! So I have been logging nearly half of what I actually burned? I am so confused (and happy)! I was certain I would burn less than what MFP said and I can't wrap my head around the fact that I can eat LOADS more now.

Any chance my Polar hrm is wrong? lol!
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Replies

  • perpchaska
    perpchaska Posts: 8
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    i would say your HRM is probably right - when i did zumba for the first time it said i burned something crazy like 900 calories. i typically burn around 500-600 in a 60 min spin class - and i've been logging the exercise that way/keeping up with my food diary and losing weight - so i'd trust your HR monitor (at least for cardio activities)
  • danidaggers13
    danidaggers13 Posts: 22
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    Hi!
    I use a polar FT4 and swear by it! I've seen much more progress since using it than I did before hand when I was just going by MFP. Also a online exercise community called Bodyrock.tv a huge amount of their followers swear by Polar heart rate monitors too!
  • Holly_Roman_Empire
    Holly_Roman_Empire Posts: 4,440 Member
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    It could be right, and it could be wrong. Heart rate monitors are an estimate, albeit a much more accurate one than what the MFP database has. I hardly ever recommend eating all exercise calories, but if you want to, I'd do it slowly over a week or two. That way, you can monitor if you're gaining weight or not.

    I love Polar HRMs and have one myself, so enjoy it! Just understand that it's an estimate and proceed carefully.
  • HelllYeaHH
    HelllYeaHH Posts: 56 Member
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    seems like there is a double difference now:
    1. used to log 60 mins as 45 mins.
    2. more accurate calorie tracking.

    anyway, use this the way you feel fit. Were you losing weight before or not? Were you hungry all the time? Eating more would mean results are slower.
  • Rerun201
    Rerun201 Posts: 125 Member
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    Probably not.

    My wife and I have both noted the same thing: the calorie estimates for various activities on MFP are usually underestimated based on what our HRMs give us. Go with the HRM reading; takes into account your exertion level (bpm) and in some cases, even your weight and other factors to calculate the calories burned. I even use it to calculate my calorie burn during strength training.
  • mariposa224
    mariposa224 Posts: 1,269 Member
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    HRMs are at least a fairly accurate estimate. I always use my Polar FT4's burn. As you become more fit and weigh less, make sure you're adjusting your weight in the HRM's settings... But as you do become more fit, you will start burning less.
  • DavPul
    DavPul Posts: 61,406 Member
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    140 pound female burning 700 calories in an aerobics class? Another female burning 900 in an hour of Zumba?

    Proceed at your own peril
  • duckiec
    duckiec Posts: 241 Member
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    Be sure you've set your settings properly for weight, height and age, but over all it should be fairly reliable. Don't forget to adjust them for every 5lbs or so change.

    Also, be sure to thoroughly rinse the strap after every workout, and toss it in the washer ever 5 or so - be sure to take off the transmitter and no dryer!! If its dirty the readings can get a little funky, but I've found mine (older FT4) usually goes lower when it's dirty, not higher.

    With those considerations- should be fairly accurate? Of course, any calorie estimate is just that, even based on calculations and heart rate data, I still take my readings with a bit of leeway, same thing with my food tracking, and don't go down to the single calorie each day, but keep things in a range.

    My Zumba classes are 400-600 depending on instructor/playlist or if I'm teaching, so I'd definitely think those results are in range. Enjoy!
  • kgeyser
    kgeyser Posts: 22,505 Member
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    I would be wary of the heart rate monitor. The formula used to calculate burn is most accurate for steady state cardio, but if you are seeing a fluctuation in your heart rate during your workout (any kind of intervals or burnouts where you exercise harder), the formula is less accurate. You also need to consider where your heart rate is during the workout. If you are spending a lot of time in the aerobic zone, it's ok, but if you push it too high, you move into the anaerobic zone and that screws up the formula as well. Even using my FT4, I still only eat a portion of my calories back.
  • dswolverine
    dswolverine Posts: 246 Member
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    I too have the polar Ft4 and I don't think it always accurately measures my heart rate. Sometimes, even though I am running at the same pace for 45 minutes, all of a sudden the wrist watch will say my heart rate is 180, then go back down to 150. Clearly that's not right. I think mine is also kind loopy and I plan to contact the manufacturer, but I have noticed this in the past as well. So just an FYI if yours is acting up as well....
  • Patovader
    Patovader Posts: 439 Member
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    I have a Polar FT4 ad it is fairly accurate, however, even the most accurate HRM's are only 75% accurate when calculating calories burned from exercise.

    As for the realisation that you can suddenly eat a lot more now that you have discovered this fact, I would say tread with extreme caution. if you were gradually losing or maintaining and you suddenly start eating more then I suppose I don't have to point out the obvious...

    Good luck ;-) A
  • Orient_Charm
    Orient_Charm Posts: 385 Member
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    Same here, please check this....
    http://www.myfitnesspal.com/topics/show/1181964-hrm-calories-is-more-than-what-machine-side
  • Commander_Keen
    Commander_Keen Posts: 1,181 Member
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    This happened to me to.. I was using a treadmill and I know they can be off.. so when the treadmill said 500 caloires, I just assume it was 400 calories and called it a day.. Now that I have a HRM, its not off by 100 calories, its off by 300 calories.. thats a huge difference.
  • QuietBloom
    QuietBloom Posts: 5,413 Member
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    Those burns sound way too high IMO. I know my HRM overestimates burns by nearly 40% despite me putting in all my numbers correctly.

    OP, try putting your numbers into the heart rate calorie calculator on this site: Shapesense.com. Calculate your gross burn, and then use that number to calculate your net burn. See how the numbers match up. I would use the lower number myself,
  • JBnyc99
    JBnyc99 Posts: 100 Member
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    140 pound female burning 700 calories in an aerobics class? Another female burning 900 in an hour of Zumba?

    Proceed at your own peril

    Yeah, I was thinking the same thing.

    I suggest you guys check the settings on your HRMs. Read the directions again and recalibrate.
  • action_figure
    action_figure Posts: 511 Member
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    As a former cardiac nurse, I can tell you this: If your heart rate was actually at 200 bpm for any length of time you would have felt light headed, dizzy, somewhat nauseous, and essentially like death warmed over. Unless you are EXTREMELY fit, that is. Even if you are already extremely fit with loads of aerobic conditioning under your belt, you would have been feeling as though you were working at maximum exertion. How did you feel when you were taking that class? If you honestly felt like you were going to die, and you were completely wiped out afterwards, then your HRM is probably correct. If you felt like it was a great class, and you gave it your all, but you still felt energetic and okay afterwards, then your HRM is probably NOT correct. There is a known issue with some polar straps that they will pick up static electricity from the movement of your clothing (especially tech fabrics like wicking and fast dry) in fast paced exercises or windy conditions. This extra electrical activity is interpreted as extra heart beats, artificially elevating your max and average HR, and thus exaggerating your calorie burn. It can be minimized by the use of ultrasound gel. So, I would not look at this as an automatic license to eat more. Look at your progress. You've been taking this same class for a while. What is your weight loss like? Are you hitting the MFP predictions for five weeks out pretty regularly? Or are you dropping weight so fast that it seems like several hundred calories a day are magically disappearing somewhere? Or, are you finding the weight is stubborn and hard to get off? How are you feeling? Listen to your body. Are you hungry? Really hungry? Not bored, not eating to stuff emotions, not thirsty, not having cravings or a fit of the munchies. Are you actually hungry? As in, do you feel like your body needs more protein, more complex carbs, more healthy fats, more nutrients and fuel? If so, you should eat. If it's one of the other things, you should not eat. And if you can't tell the difference that is your first order of business.

    Good luck.

    Acronyms used

    bpm = beats per minute
    HR = heart rate
    HRM = heart rate monitor

    Edit: Spelling is hard.
  • scrapjen
    scrapjen Posts: 387 Member
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    I bought a Polar HRM several months ago after hearing everyone rave about them (I also had a Fitbit previously which I still wear). My HRM had the opposite effect ... almost all my exercise estimates (from machines or other estimates) were high so I had to adjust down with the HRM. I've done lots of comparisons over the last few months, the Fitbit is pretty close in estimating jogging, a little higher than my HRM for the elliptical), Fitbit comes in lower for Jillian DVDs like 30DS, Ripped (which has non-step strength moves, but then I've HRMs aren't really accurate for anything but steady-state cardio, so I'm not sure if my Polar is right for those workouts either).

    I just started a free Zumba class at the church ... it isn't the greatest, I'm barely getting my HRM up and not even breaking 300 for almost an hour. (But it IS free, and close and fits with my schedule and I guess that's better than not doing it).

    I'm not sure if I'm fairly fit, or if I'm just wimpy ... but I rarely get my heart rate very high (sometimes I'll hit 160 ...)
  • Elegra2006
    Elegra2006 Posts: 144 Member
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    Echoing what others have said. Make sure you've set-up your HRM right for you age/height/weight etc. Also, is it one where you set your 'working' range - think Polar call it OwnCal? My HRM records cals burnt when heart rate is over 100 (ie. I'm exercising).

    Your burn does sound rather high. For an average (ish) person, burns are usually 100 cals/10 mins (I know this is simplistic), while working hard.

    I'm 143lb female and going absolutely flat-out at HIIT and Tabata style training, I get between 400-500 cals in 45 mins with max heart rate around high 170s.

    Have an experiment and keep an eye on your HRM while exercising to see what it's recording.
  • action_figure
    action_figure Posts: 511 Member
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    Also, another thought. Your diary isn't open, so I can't see what you're eating routinely, but how is your intake? If you're working at the intensity you think you are, and you're as slender as you appear in your profile picture, you shouldn't be having a huge deficit. You need to fuel that kind of work, and if you're actually working that hard, by all means, eat more. If you are eating properly, then the things I said previously are probably accurate, in the absence of any other medical problems. If, however, you already have a low or low end of normal BMI and you're eating a very low calorie diet, then you could be looking at some other issues, like an eating disorder of some sort. Many anorexic people have highly variable heart rates and could hit those numbers. Although, I want to stress, THAT IS NOT HEALTHY. Note: I am not saying you are anorexic. I am saying that without further data to go on, that this could be a red flag. It is something that would trigger further assessment if I were actually your nurse. :) But YOU know the data. You need to look at your big picture. How much are you eating, how much are you exercising, how hard are you working? How well are you losing weight? What are your goals? Are they realistic goals? Best of luck to you.
  • perpchaska
    perpchaska Posts: 8
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    im 5'9 and weight 215 - so me burning more calories makes sense imo.

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