Stupid Question, but I haven´t found a reliable answer yet

Options
ullrichMEX
ullrichMEX Posts: 58 Member
in Fitness and Exercise
Hi pals.

I have a question for all of you and I hope anyone can clarify it for me. My question is straigth forward:

Let´s say my normal Basal (or Resting) Metabolic Rate is 2400 cal per day. That means 100 cal pero hour under normal daily activities, right?

So, if I workout for 1 hour and my Heart Rate Monitor estimates that I burned (for example) 400 cal.....

Does that mean that: (A) I actually burned and extra 400 cal in that hour (apart of the BMR of 100 cal) or (B) that means that the 400 cal burned during my workout INCLUDE the 100 cal pero hour coming from my BMR .

Under the (B) scenario the net caloric burn by exercise should be only 300 cal. and eating back the 400 cal (that our HRM says) could be concounterproductive because in fact we would be eating 100 cal MORE than the calories we burned...


I swear I have been researching a lot and I have not found a definitve answer to this. please help!
«1

Replies

  • crystal8208
    crystal8208 Posts: 284 Member
    Options
    bump! This is a great question... curious too!
  • dls06
    dls06 Posts: 6,774 Member
    Options
    Have you read these?

    http://www.myfitnesspal.com/topics/show/3047-700-calories-a-day-and-not-losing

    http://www.myfitnesspal.com/topics/show/6556-the-answers-to-the-questions

    http://www.myfitnesspal.com/topics/show/9433-expectations

    http://www.myfitnesspal.com/topics/show/10589-for-those-confused-or-questioning-eating-your-exercise-calo
  • bcl003
    bcl003 Posts: 331 Member
    Options
    I definitely agree on that logic, the answer would be great!
  • hellraisedfire
    hellraisedfire Posts: 403 Member
    Options
    I would say that it would be 300 calories burned, not 400. Your body would be burning 100 of those calories anyway. And personally I prefer to be safer than sorry with that :) If you eat 400 calories back, make sure it's not bad food. Have you ever heard of anyone getting fat from eating fruit all day? :)
  • ElizabethRoad
    ElizabethRoad Posts: 5,138 Member
    Options
    I would say that it would be 300 calories burned, not 400. Your body would be burning 100 of those calories anyway. And personally I prefer to be safer than sorry with that :) If you eat 400 calories back, make sure it's not bad food. Have you ever heard of anyone getting fat from eating fruit all day? :)
    From eating a bunch of fruit on top of their regular diet, yes.
  • cmriverside
    cmriverside Posts: 34,080 Member
    Options
    It's 100 calories. You make that many mistakes in a day of logging food. This is not an exact science.

    The HRM counts all the calories you burned in that amount of time, and doesn't "take off" your RMR. Technically, you could manually subtract the hundred calories. But the HRM is not an exact count, either. It is based on an algorithm that is inherently flawed...so either way you're using estimations.

    Try it one way or the other for a month. Adjust if necessary.
  • Quasita
    Quasita Posts: 1,530 Member
    Options
    You have to remember that the monitor counts all of your activity at that time, not just the exercise, unless it is specified to do so. Some advanced exercise monitors might automatically subtracts your BMR calories from the exercise count, but I highly doubt that most do. So, If you want a really accurate count, I would subtract the BMR calories for that same amount of time.

    That or you could get a monitor that is built to monitor total calories no matter what. Product specifications and instruction manual should specify that, or you could ask the manufacturer. Personally, I use a BodyMedia Fit Link, which monitors 100% of the time instead of just work outs, so I focus more on my running deficit and time put in than calorie burn in that specific time period where I was working out. However, it adds the burn up for me instead of me having to figure out how it fits into the day.

    100 calories is not going to be a huge issue, most people flex around that much per day anyway. However, if they difference was more than a half a snack's worth of calories, I'd be more concerned.
  • BrianSharpe
    BrianSharpe Posts: 9,248 Member
    Options
    That's one of the reasons I don't eat back all of my exercise calories. (plus I allow for a reasonable margin of error on food portions etc)
  • kyle4jem
    kyle4jem Posts: 1,400 Member
    Options
    Have you ever heard of anyone getting fat from eating fruit all day? :)
    Yes, I have.

    If you eat more than your TDEE in fruit & veg you will get FAT.

    To the OP, your logic is correct. The answer is B... you will have burned an extra 300 Calories because 100 of the 400 you would have burned anyhow, and probably a bit more.

    Remember your AMR (actual metabolic rate) is your BMR + your activity factor (i.e. sedentary, lightly active etc) and that's what you need to take into account when you exercise and your HRM says you've burned 400 calories, so in the example you've given, it would be 100 Calories BMR x 1.2 (sedentary activity factor) = 120 so really you've burned 280 additional Calories. Just enough to treat yourself to a Magnum (ice cream lolly). :wink:

    That's what I do anyhow, and then only eat back about 70% of my exercise Calories over the week to account for margins of error. It seems to be working :happy:
  • AllanMisner
    AllanMisner Posts: 4,140 Member
    Options
    I posed a similar hypothesis a few weeks back (maybe a month or so, time flies). I think you would back it out. But that said, what is 100 calories and considering that is an average, your waking hours would burn more than your sleep time. So, the math gets to be even less significant. The point is 100 calories isn't going to do all that much to jeopardize your metabolism. As a result, I would take the most conservative calculation (reducing HRM exercise by the average basic for that same period of time) if you eat all of your exercise calories. Otherwise, you may not be getting the deficit you thought you were.
  • rextcat
    rextcat Posts: 1,408 Member
    Options
    filessharenatorcom_YG6vv_GIF_Collection_of_someone_eating_popcorn-s320x240-181195.gif
  • smuehlbauer
    smuehlbauer Posts: 1,041 Member
    Options
    Put more effort into the exercising than the math.
    300-400 calories. Not that big of a difference. A tablespoon of peanut butter....
    Put your base info into MFP - enter your food and exercise honestly and the process will work.
  • earnestfarley
    earnestfarley Posts: 14 Member
    Options
    It would seem you could resolve this within 2 days. On day 1 wear your monitor all day and note the result. On day 2 wear your monitor AND do your exercise.... I, however, only factor the calories I have eaten and the calories I burn during exercise.
  • MoooveOverFluffy
    MoooveOverFluffy Posts: 398 Member
    Options
    my answer is B.

    if you go over by 100 calories, i dont think that's a huge crisis though..............
  • Chipmaniac
    Chipmaniac Posts: 642 Member
    Options
    I don't think you can say definitively unless you know exactly what algorithm the HRM is using in its calculations.

    There's an easy way to estimate it indirectly though. Wear you heart rate monitor while you are sitting doing nothing. Make sure your heart rate is near your normal resting heart rate. See how many calories it calculates per minute. Subtract this amount from any exercise calculations going forward.
  • pope369
    pope369 Posts: 159 Member
    Options
    Put more effort into the exercising than the math.
    300-400 calories. Not that big of a difference. A tablespoon of peanut butter....
    Put your base info into MFP - enter your food and exercise honestly and the process will work.

    ^^^This.

    Don't over-think it. I've seriously debated getting a HRM, but after seeing success by honestly logging what I've eaten and what exercise I've done, I don't see that a HRM would have helped.
  • dad106
    dad106 Posts: 4,868 Member
    Options
    HRM''s when set up correctly(age, weight, gender and height) and used during steady state cardio(not weight lifting, or worn at rest) are 80% accurate at estimating. Add in Vo2max or tweak Max heart rate and you go up to about 90% accurate at estimating.

    Personally I never subtracted anything from either of my HRM's and lost 29 pounds.. so obviously I was doing something right.

    Ditch the whole subtraction idea and just eat 100 less calories if you are that worried.
  • bighouse51
    bighouse51 Posts: 30 Member
    Options
    It doesn't quite average out like that. Your BMR may be 2400; however, you dictate that by entering your daily lifestyle activity level. If you were sedentary, then, the BMR would not be 2400. Also, don't assume that 100 calories is gone every hour as your energy expenditure is different throughout the day. First, it's important to know that a "calorie" a unit of heat used to measure energy. You are burning additional calories during strenuous activity such as exercise. Example... it takes 140 calories for a 180 pound man to run 1 mile (approx.) Secondly, your metabolic rate remains elevated as your body works to "recover" from the additional energy expended to compensate for the demands you are placing on your body. After running, your BMR can remain elevated for nearly an hour; however, a good session of weight training, i.e. squats and deadlifts can have your BMR skyrocketed for 18 to 24 hours AFTER exercise. Yes, you will actually be burning additional calories as you sit on the couch later thay night recovering from the weight training session.

    Long story short, DO NOT back out any calories from what your body does naturally, its a well oiled machine. Your body will hit your 2400 regardless of how much addtional work you put in. If your starting point is 2400, and you burn 600 working out in an hour... your adjusted number is 3000, NOT 2900.

    And, since you posted this looking for an answer (or possibly some advice)... get a good session of squats and deadlifts in once a week... you won't have to worry about those 100 calories at all. :)

    Hope this helps.
  • NoAdditives
    NoAdditives Posts: 4,251 Member
    Options
    +/- 100 calories doesn't make much of a difference.
  • chubberlang
    chubberlang Posts: 30
    Options
    Interesting topic!
    There are many examples where calculation of cals burnt can be misleading For example sedentary lifestyle multiplied by bmr provides my tdee. If i sit at a desk at work all week but at weekends i am really active, gardening, washing car, housework etc should sendentary be changed in order to adjust my target cals? Also many gym machines seem to over estimate cals burnt. For example 40 mins on my gym crosstrainer shows 600 cals burnt - seems a lot? I do feel that sometimes the recording of additional cals through excercise is really on the high side and that the overall activity level should be adjusted. For example if you go to the gym 4 times a week and workout for say total of 4/5 hours but have a desk job should you record sedentary lifestyle? At what point does excercise influence your lifestyle rating?

Categories