TrainerRobin's Question re Calorie Burn

TrainerRobin
TrainerRobin Posts: 509 Member
edited September 26 in Health and Weight Loss
Okay, I've answered a number of questions on MFP. Now it's my turn to ask y'all for your feedback! :laugh:

The advice I'm looking for is reputable academic/medical studies/research on the issue, not general opinions. Being from the fitness industry, I get (and give) plenty of that. I'm looking for some specific data/reference articles that address my issue. I've got numbers of experienced/qualified folks in the industry who've argued every side of this issue (myself included). I'm looking for specific research on the subject so I can ascertain which view is substantiated by research.

Do calorie burn numbers (e.g., burning 500 calories on an hour run) already take into consideration the underlying calorie burn, or is an adjustment necessary to get these numbers right?

Let me use myself as an example: My BMR x 1.2 (sedentary so as not to double count the calorie burn from exercise) is 1770 calories (or 73.75 calories per hour). When I burn 500 calories by running for an hour, does that number (500 calories) take into consideration that 73.75 calories that my body is utilizing for basic functions (other than the running), or ignore that element?

Why do I care? If I should be subtracting the 73.75 calories from the number my HRM (or other source) says I'm burning, but I'm not, then I'm overestimating my calorie burn by almost 15%. If I eat my exercise calories, then I'm overeating by 15% which is a significant margin of error in my calorie computations.

Again, I've provided the standard industry answer to lots of clients on this one (with the caveat that I've never seen conclusive data on the issue), so that's not the feedback I'm hoping for. But if you have research/data you can point me toward, I'd be VERY appreciative!! I've googled and searched to no avail.

This is just one of those things that has always bugged me that I'd LOVE to get a definitive answer on (if possible).

Thank you!!! :drinker:

Replies

  • jkohan
    jkohan Posts: 184 Member
    I can't give you scientific evidence..posting from work.....just common sense.

    If I'm burning calories sitting at my desk--when I get to the gym, it only makes sense to back out the baseline burn to track actual calories burned during exercise..since MFP already adds in the baseline burn.
  • TrainerRobin
    TrainerRobin Posts: 509 Member
    I can't give you scientific evidence..posting from work.....just common sense.

    If I'm burning calories sitting at my desk--when I get to the gym, it only makes sense to back out the baseline burn to track actual calories burned during exercise..since MFP already adds in the baseline burn.

    This may be true. But the frustrating thing is that there are so many things, within the fitness/weight loss world, where fact contradicts common sense. Thus my search for something to substantiate what seems to be logical.

    I'm kind of a geek that way. I like answers that are based on research and sound analysis! :)
  • yyzdnl
    yyzdnl Posts: 127 Member
    If you are looking for answerers in research papers you are probably looking in the wrong place. The question should be going to the manufacturer of the device reporting the calories burned.

    My HRM doesn't ask me about my normal daily activity so I assume it is just estimating the numbers I burned during monitoring and could care less what I use to estimate my calorie burning through normal activity.
  • superboltman714a
    superboltman714a Posts: 4
    I don't know how that works exactly. But using your example, you would be only 3.2% over your daily max if you eat all the extra "allowable" calories, if you ate 1770 normally. Not much when estimating. The other non recorded use of calories by moving around should compensate. I don't eat all the extra calories I earn by exercise, so I don't worry about it. I think all the calories that are suggested are only good for estimating anyway. I am an engineer and can obsess on the numbers, people on this site are probably also.
    We should be encouraged to just keep close to our range and be consistant and we will get where we want to get to eventually.
  • TrainerRobin
    TrainerRobin Posts: 509 Member
    Oh, don't misunderstand. This isn't one of those things that I'm concerned with on a practical basis. It's just one of those issues that I've never found good research on and would love to! :)

    And I know that most folks on here won't have anything other than personal opinions on the issue, but there are so really well-informed professionals who answer questions on this site, too. I'm crossing my fingers to hear from one of my fellow fitness "geeks." :drinker:
  • forty3fab
    forty3fab Posts: 148 Member
    I cannot give you scientific data either, sorry. But after reading so many different opinions on here, I do backout my "living burn" calories out of the number on my HRM for every workout. I battle with all those questions, the correct calorie burn, how many calories to eat, should I go with the Harris-Benedict equation numbers or MFP numbers, it is an obsession to get the most accurate information, so I understand what you are going though. I wish you the best in getting the answer you are looking for!
  • thcri
    thcri Posts: 459 Member
    My HRM doesn't ask me about my normal daily activity so I assume it is just estimating the numbers I burned during monitoring and could care less what I use to estimate my calorie burning through normal activity.

    My HRM did ask me. I use my HRM on two devices and both devices when setting up ask in different ways about my daily activity and times of work outs were asked.

    I question this to as I know MFP has work outs listed for things like dishes and other things at work that allow you to add. I don't think they should be added because the calories doing dishes for example are not much more than what you would burn normally.
    I will be watching this thread.
  • robertf57
    robertf57 Posts: 560 Member
    Ok,

    The answer is, it depends. You have to look at the actually study from which you are obtaining the calorie estimate and how it was determined. In a research setting, this is usually done with indirect calorimetry in which Oxygen consumption and CO2 generation is precisely measured and the calories burned determined. This would be TOTAL calories for the period measured, There would be no adjustment for the baseline energy utilization of the organism (person).

    Measurement based on estimates from things like heart rate have significant variability and really aren't precise enough for the baseline calorie burn to make a important difference. However, in creating the estimating equations, standard scientific techniques would have been used and thus would likely be based on total calorie expenditure for the period.
  • hroderick
    hroderick Posts: 756 Member
    Because my goal is weight loss I back mine out so if I'm wrong I would rather underestimate burn than overestimate.

    My polar has enough data to calculate but bmr, but how they incorporate that data would be up to the formula designers and probably inconsistent across brands, models, and software versions. Because of this inconsistency a survey of manufacturers would be better than a study.

    I find my hrm easy to user but sorely lacking on documentation and user controls for things like that.
  • Angie80281
    Angie80281 Posts: 444 Member
    I've wondered this myself, and am very interested to see if you get a good reply. Thanks for asking it!
  • chuisle
    chuisle Posts: 1,052 Member
    Bump! Would love to hear the answer, interesting question!
  • TrainerRobin
    TrainerRobin Posts: 509 Member
    Because my goal is weight loss I back mine out so if I'm wrong I would rather underestimate burn than overestimate.

    My polar has enough data to calculate but bmr, but how they incorporate that data would be up to the formula designers and probably inconsistent across brands, models, and software versions. Because of this inconsistency a survey of manufacturers would be better than a study.

    I find my hrm easy to user but sorely lacking on documentation and user controls for things like that.

    You nailed it. It's very hard to find information from the various manufacturers,or for that matter, even a good comparison of the different HRMs on the market. If you ever find that, let me know! :)
  • myofibril
    myofibril Posts: 4,500 Member
    I agree with pretty much everything Robertf57 said above.

    Without checking the algorithms / formulas that each HRM manufacturer uses it is impossible to tell with certainty. However, it is a reasonable to presume that resting energy expenditure has been included in calorie burn and so there is no reason to deduct it. How do we come to this conclusion? Well, by what we know about how HRMs work when calculating calorie expenditure. Hold on to your hats as this might get quite long and boring (skip to the end to get to the point if you can't be bothered with the technical stuff.)

    A good starting point is the research section of Polar's site based on their OwnCal feature:

    http://www.polar.fi/about_polar/who_we_are/research/OwnCal

    This includes a number of studies and references (including a unpublished trial conducted by the Cooper Institute no less...)

    Probably one of the better studies to consider is this one:

    http://www.ncbi.nlm.nih.gov/pubmed/15966347

    This highlights the important correlation between VO2 max and maximal HR. Why is it important? Well, I'm glad you asked...

    HRMs do not measure energy expenditure (calories burned) to any degree. The only real accurate way to assess this is through oxygen uptake (VO2) What HRMs monitors do is ESTIMATE calories burned due to the relationship between heart rate and VO2. This relationship is only really valid where oxygen is utilised in a consistent manner. In other words steady state cardio. Any exercise where there is an inbuit degree of sharp change (weight training or HIIT for example) will skew the result dramatically.

    Now the Keytel study linked above highlights the following: "The participants then completed three steady-state exercise stages on either the treadmill (10 min) or the cycle ergometer (15 min) at 35%, 62% and 80% of VO2max, corresponding to 57%, 77% and 90% of maximal heart rate."

    So, for example working at approximately 77% of maximal heart rate corresponds with 62% VO2max. Lets say your tested VO2 max is equivalent to 10 METS. Therefore you are working at 6.2 METS (62% of 10) Further your weight in kilogrammes is 80kgs. We get an estimate of calories burned per hour by multiplying METS by weight in kgs. In this case 6.2 x 80 = 496 calories or thereabouts.

    The final piece of this equation is what are METS? This is the Metabolic Equivalent of a Task. It is a ratio comparing your metabolic rate when at rest to that when you are performing a task. 1 MET is the oxygen consumption of an adult seated and doing sod all (a bit like me now...) Lets say you maximum MET rate is 10 as shown in the example above. This is a multiple of your MET value at rest (ie 1) The base value has already been included. Therefore given what we now know about the link between METS, VO2max and how HRMS estimate calorie burn it is reasonable to assume that you do not need to deduct the calories you would have normally utilised at rest. They have already been accounted for given the ratio of MET values to each other.

    Finally there is a huge caveat here. That is the above is only really good if you have a HRM which allows you to manually input certain key data based on your individual stats: normal HR, HR Max, VO2 max, age, gender, weight. If it doesn't your calorie burn will be based normally on average MET values such as those shown in the Compendium of Physical Activities. Given that this has a significant potential for variance between individuals the calorie burn shown in a low spec HRM is probably so inaccurate as to be useless. By all means track trends over time with it but do not rely on the specific number.

    In my opinion HRMs are great for tracking fitness goals. Calorie burn? Not so great.

    Hope that helps from your fellow fitness geek ;)
  • PoleBoy
    PoleBoy Posts: 255 Member
    I answered this question for myself.

    I wore my Polar HRM while I slept one night. In the morning I knew that it gave the total expenditure, not the additional.
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