Estimating Exercise Calories - Beware!

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mleipe
mleipe Posts: 54
in Fitness and Exercise
Wow!

I hit the gym across the street for an hour every work day at lunch. This has been a big part of my weight loss success with the added benefit that I'm very, very fit right now.

One of the things I really like to do is go hard ton the elliptical machines, hard programs at the highest resistance level for an hour. The machines (Cybex) typically register 1000 - 1200 calories for the hour. I've never really questioned this as I've been losing weight.

Recently, though, the past couple of months, my weight loss has really stalled. I figured that this had to be either because I'm underestimating what I'm eating or over-estimating my exercise calories.

I got into a mode where I was really rigorous about ensuring that I record everything I eat as precisely as possible. This didn't help, so I figured I was probably over-estimating my exercise calories, which I often "eat back".

So this past week end someone gave me a Polar exercise watch with chest strap heart rate monitor and I figured I'd give it a try today to see if maybe the machines I usually use at the gym are estimating high. I did an hour on the Cybex elliptical and guess what?

The machine said I'd burned 1102 calories in an hour - the HRM said 663! Wow! So basically, I've been over-estimating the number of exercise calories I burn to the tune of 400 - 500 calories per working day! That certainly explains why my weight loss has stalled.

Why will I now start recording the the HRM's exercise calorie measurements rather than those from the machine? Several reasons:

1) It knows my height, age, weight, and, most importantly, my heart rate throughout my work-out. The machine only asks for my weight and, although it has heart rate sensors, I never use them because to do so I have to reach into an unnatural and uncomfortable position - they are poorly placed.
2) I think it's best to underestimate your exercise calories on principle, just as I believe it's best to over-estimate your caloric intake. I call this erring on the side of caution.
3) I'm just not losing weight and, as noted above, I'm very honest, rigorous and precise in tracking my food.

So what's the message here? Be very, very careful of how your estimate your exercise calories, especially if you plan to "eat back" most of them. There is a very good chance that you are significantly over-estimating your exercise calories and therefore permitting yourself to eat much more than you should be to succeed in your weight loss journey.

p.s. I was highly amused to find that MFP, if I just enter 60 minutes of elliptical trainer, tells me I've burned 1260 calories, almost twice what the HRM, which knows exactly how hard I worked, said.

Replies

  • fionarama
    fionarama Posts: 788 Member
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    thats scary stuff. I gonna buy one! I kind of majorly undereat as I find I don't lose weight otherwise and I think this kind of thing is why. I think the food calorie counting is inaacurate as we.ll
  • Mexrose
    Mexrose Posts: 46
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    I read an article that most machines overestimate calories burned by 15%.
  • AZKristi
    AZKristi Posts: 1,801 Member
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    I've always suspected that MFP and cardio displays overestimate calories burned significantly. In practice I've been reducing those numbers by 20-30% since I started MFP and I've had some success. Myabe Santa will bring me a HRM this year as it is at the TOP of my wishlist!

    The only cardio machine where it truly feels like I'm burning the number of calories that it says I am is the StairTreadmill. I set this to fat burn and it makes me sweat like a pro. Love it!

    Thank you for posting this, I've always suspected it but am grateful for the confirmation!
  • msmayor
    msmayor Posts: 362 Member
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    I to was soooo suprised by the numbers from my treadmill compared to my HRM...once I thought I burned 600 calories but it was more like 380's which is a big difference since I eat my workout cals....it took me awhile then the lightbulb went off in my head and I was online shopping for a hrm......I always suggest to those who want to lose weight - get a HRM and a food scale because you really don't have any idea!!!
  • carrie_eggo
    carrie_eggo Posts: 1,396 Member
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    That is why some people do not eat their exercise calories! Imagine if your calories in the foods you are eating were inaccurate too!!!
  • Allyson1985
    Allyson1985 Posts: 148
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    I feel you on that one. I went with MFP, saw a stalled weight loss, and now that I have my own HRM with chest strap, BAM! weight is coming off again.

    I won't go without my HRM, and I definitely don't go off what MFP says I burned.
  • Espressocycle
    Espressocycle Posts: 2,245 Member
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    Lacking a HR monitor, I use the estimates in the database which are adjusted for height, weight, etc. Still, I do wonder if I am really burning 400 calories hoing to and from work every day.
  • KBGirts
    KBGirts Posts: 882 Member
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    Before I even got all the way though your post I was already thinking that the machine doesn't know your height, weight, etc. Some machines ask you for it but I don't know if that helps that much. HRM is definitely the best way to go!!! I don't have one yet and so I get nervous a lot when logging workouts because, like you said, I would rather underestimate how much I've burned. Sometimes I will purposefully not log a light workout for this reason.... and for a hard workout, I won't eat all the calories back.
  • usmcmp
    usmcmp Posts: 21,220 Member
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    The more you work out the less calories your body burns doing the same exercise over and over. Your body gets more efficient. You may have burned that many at first but you have to change things up.
  • Crystal817
    Crystal817 Posts: 2,021 Member
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    I always under estimate my exercise calories and have never had a problem! :wink:
  • KBGirts
    KBGirts Posts: 882 Member
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    Lacking a HR monitor, I use the estimates in the database which are adjusted for height, weight, etc. Still, I do wonder if I am really burning 400 calories hoing to and from work every day.

    Yeah I wonder sometimes too. Someone had stated that burned 700 calories playing softball.... I find this hard to believe, when I used to play softball and didn't get near the workout I do now as a runner/cyclist. It takes a good bit of running or biking to burn 700 calories in the same amount of time this guy said it took him to burn playing softball.
  • Dave198lbs
    Dave198lbs Posts: 8,810 Member
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    my general rule when I dont have my HRM and I get a good sweat going is to calculate any workout that lasts longer than 10 minutes at about 10 calories per minute
  • sarahhoward24
    sarahhoward24 Posts: 12 Member
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    I know the feeling , i wear my HRM for every bit of exercise i do now its amazing the differences between the figures
  • morethanlilies
    morethanlilies Posts: 20
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    I'm waiting for my Polar HRM to be delivered to my house from Amazon! I have a bad feeling that MFP has been overestimating calories burned for me, as well. I do the couch potato to 5k running plan and The Shred for my workouts; I am already dreading the idea that I may have been burning fewer calories that MFP tells me I am. We'll see come Tuesday when my HRM gets here...
  • mom24princesses
    mom24princesses Posts: 12
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    I agree the HRM are more accurate than the machines. I recently got my Polar FT60 and it shows that I'm burning on average 100-300 MORE than the machines estimate. Makes sense why I have been losing 3lbs a week when I have MFP set to lose only 2lbs a week even after eating back every single one of my exercise calories.
  • Coyla
    Coyla Posts: 444 Member
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    I noticed this, too. It's kind of frustrating, and I wonder why the machines are designed to give us such a high number?

    There is something else to consider, however, and that's the after-burn effect. The more intense the workout, the more calories you'll burn in the 2 or 3 hours after you've finished, even while at rest. None of these calories will be counted. (And, of course, there's also strength-training and the calories your body burns while building/repairing muscle.)

    I'm not saying after-burn makes up for all those extra calories, but it does give a little more wiggle room.
  • dewgirl321
    dewgirl321 Posts: 296 Member
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    Well at least you figured out why you weren't losing! I had a similar eye-opening experience. I had been using an elliptical and blindly posting (and eating) the exercise calories on the machine. Then I went to a different gym, used a different brand elliptical, worked extra hard and was more sweaty than usual, and it showed my calories as 100 less than usual. At that point I knew I couldn't trust either of them! I got a BodyBugg that week, which has given me much more confidence in my fitness level and the amount of calories I should eat.
  • sugarbeans
    sugarbeans Posts: 676 Member
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    Great post!!! This is why I usually only eat half of the calories I enter on here.. if not less. I always felt it was high and you just confirmed it =)
  • CMmrsfloyd
    CMmrsfloyd Posts: 2,383 Member
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    This is exactly why I invested in a heartrate monitor with chest strap as soon as I got interested in exercising. For the first month or so of my weightloss I did the calorie counting only, no exercise. Then I figured I didn't want to still be flabby when I get to my goal so I started exercising, but I'd seen the many comments on here about how horrible the exercise calorie estimates can be, so I splurged and got myself the Polar FT4 HRM. Best investment I've made since joining MFP, aside from my kitchen scale. Accuracy gets important especially as you get smaller and have less room for error.
  • mrandolph69
    mrandolph69 Posts: 197 Member
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    I had this same epiphany when I got my Polar FT7 a couple of months ago. Thankfully, I had not been eating back my calories!

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