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    HRM - BMR = math

    Posts: 158 Member
    edited February 2 in Fitness and Exercise
    I recently invested in a Polar FT7 Heart Rate Monitor. (watch and chest strap) I have been burning quite a few more cals than I thought I would during a typical workout. Usually noticeably higher than MFP would estimate.

    I was thinking about this the other day, and came to realize that my HRM is probably not subtracting my Basal Metabolic Rate. At least I dont think it does that. (I dont remember reading anyhting like that in the manual) To be honest, during an average workout, the difference would not be much, so I'm not really that concerned with it being a tad high. I realize, while its more accurate than a MFP estimate....its still not perfect. But when I go for a 3+ hour bike ride, the calories burned could actually be a couple hundred or more off, right?

    Am I over thinking this or should I be doing some math after my workouts to track my actual cals burned? My BMR is a smidge over 1 cal per minute. That shiz adds up tho.

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    Replies

    • Posts: 642 Member
      You burn less than half as many calories sleeping then you do awake. So it's actually closer to 2cal/min.

      And are you able to input hrmax and vo2max?? If not and you're out of shape or have a naturally high heart rate and you will get inflated burn numbers
    • Posts: 764 Member
      I use a hrm but I don't deduct anything from the readings, just enter them into mfp, never had a problem and got consistent results
    • Posts: 1,179 Member
      You burn over twice as many calories sleeping then you do awake. So it's actually closer to 2cal/min.

      Wait? what?
    • Posts: 642 Member
      Oh, and to answer your question, yes, all hrms and mfp include BMR.
    • Posts: 2,582 Member
      show previous quotes

      Wait? what?

      Yeah, need some sort of citation on that factoid.
    • Posts: 47 Member
      As long as you are getting your exercise, I think using the HRM is fine. I don't deduct anything, but I usually don't eat my exercise calories either unless I have really been burning the calories that day. I figure if I at least do SOMETHING every day that is above and beyond sitting in my chair, I have accomplished something.
    • Posts: 316 Member
      show previous quotes

      Wait? what?

      yeah would like to see a source for that....
    • Posts: 642 Member
      show previous quotes
      Wait what?
      What's unclear exactly?? Your average guy burns around .8 cal/min sleeping and 2cal/min awake. Jumps to 3 cal/min standing around for say like a job like cashier.

      Edit: sorry, I see the typo I made in the op. I'll correct.
    • Posts: 13 Member
      I have the Timex Zones and one of my MFP' has a polar and she told me that timex gives a higher burn then polar. If I use it for just my cardio I'm getting a reading of 600 to 800 cal burns for 45 mins. If I use it for lifting I get about 400+ burn for a hr . I was told that Polar is more accurate then the Zones but I have adapted to my Zones and I really do love it.
      So in a word I would say just believe what your hrm is saying b/c as you already know mfp burns are sooooooooo far off.
    • Posts: 642 Member
      show previous quotes

      yeah would like to see a source for that....
      It was metabolic chamber study on an average guys calorie expenditure over 24 hours.
    • Posts: 1,302 Member
      show previous quotes
      It was metabolic chamber study on an average guys calorie expenditure over 24 hours.

      Link to the study?
    • Posts: 642 Member
      show previous quotes

      Link to the study?
      Men's health about 7 years ago give or take. Start reading, you will find it eventually.
    • Posts: 815 Member
      I recently invested in a Polar FT7 Heart Rate Monitor. (watch and chest strap) I have been burning quite a few more cals than I thought I would during a typical workout. Usually noticeably higher than MFP would estimate.

      I was thinking about this the other day, and came to realize that my HRM is probably not subtracting my Basal Metabolic Rate. At least I dont think it does that. (I dont remember reading anyhting like that in the manual) To be honest, during an average workout, the difference would not be much, so I'm not really that concerned with it being a tad high. I realize, while its more accurate than a MFP estimate....its still not perfect. But when I go for a 3+ hour bike ride, the calories burned could actually be a couple hundred or more off, right?

      Am I over thinking this or should I be doing some math after my workouts to track my actual cals burned? My BMR is a smidge over 1 cal per minute. That shiz adds up tho.

      Polar does not take into account the amount of calories you would have burned if you were doing nothing. Therefore, you need subtract. My BMR, for example, is 1762. So let's take the 3 hour bike ride example. Let's say I burn 3000 calories according to my Polar watch. I would then figure out based on the BMR how many calories I would have burned sitting on my butt. That comes out to 1.224 calories per minute (1762/(60min * 24hrs). I multiply by 3 hours (1.224 * 180 min) and get 220.5. So, for my 3 mile bike ride I actually burned 2779.5 calories.

      If you don't usually eat back all of your exercise calories, then you can ignore this and just log what your watch tells you. However, if you are trying to get your difference close to zero everyday, then you will need to use this. Also, for people doing workouts where they are not burning as many calories, not taking the difference usually doesn't make a huge difference.

      Forgot to note, there are varied studies on burned calories while sleeping. Studies range from just over 1 calorie per minute to over 2 calories per minute. Unless you decide to do a fun personal science experiment and have the equipment to monitor and calculate everything, you can safely ignore sleep calories and everything else, and just focus on your BMR per minute for 24 hours.
    • Posts: 2,582 Member
      Well, here's an interesting table. Obviously these results vary by person, but it provides a decent relative burn perspective: http://www.health.harvard.edu/newsweek/Calories-burned-in-30-minutes-of-leisure-and-routine-activities.htm
    • Posts: 642 Member
      Well, here's an interesting table. Obviously these results vary by person, but it provides a decent relative burn perspective: http://www.health.harvard.edu/newsweek/Calories-burned-in-30-minutes-of-leisure-and-routine-activities.htm
      It's very obvious these are not tested numbers. But instead met estimations.
    • Posts: 2,582 Member
      show previous quotes
      It's very obvious these are not tested numbers. But instead met estimations.

      Well, I could have mentioned a random number that seems wrong, contradicted myself in the same thread, then told people to look it up in Men's Health probably around 7 years ago. But I thought a citation to something might help people a bit more. Edit: the edit to half the calories burned sleeping kinda takes the whole argument out of this thread. Cheers!
    • Posts: 12,294 Member
      You are correct HRM's don't back that off. But having said that it should be Maintenance (NEAT) cals not BMR that you back off, because if you didn't workout you wouldn't be in a comma, you'd be sitting, standing, etc. all of which burn more than BMR
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