Calories burned running?

zekerella
zekerella Posts: 58 Member
in Fitness and Exercise
Hello!!

So I am a triathlete who is trying to get to race weight (16% body fat) I have about 20lbs to lose.

I want to net anywhere between 1200-1500 calories a day.

I noticed a month ago that my Heart Rate Monitor that I wear on my bike's calculation of my calories burned is about HALF of what MFP and other "calculate calories burned" and "Calculate calories burned based on average HR" sites state.

So Ive been halving my calories burned and eating those calories back. (So I biked an hour - MFP says I burned 600 calories, I log 300)

BUT then while I was running today I had a thought. Studies and sites all state (common knowledge) that 1 mile ran is an average of 100 calories burned. I went on a 5 mile run today burning 497 calories on MFP and I averaged 165bpm HR.

Do I still half it? Or am I severely under eatting because I am probably burning more than I think when I run?

I know that is complicated....hoped you all followed me on this. Opinions?

Replies

  • Mr_Knight
    Mr_Knight Posts: 9,532 Member
    net calories burned running = 0.63 * body weight in pounds * miles run
  • Amadbro
    Amadbro Posts: 750 Member
    I'd skip all the guessing and get a bodybugg..I got one a few months ago and it's one of the best purchases I've ever made
  • 3dogsrunning
    3dogsrunning Posts: 27,167 Member
    net calories burned running = 0.63 * body weight in pounds * miles run

    I would go with this.

    You are on the lighter side, so you would be under 100 calories per mile, although it would be 80-90 so not a huge difference until you get to your longer runs.

    Do you know your VO2 max? Did the online calculator account for that? Can you adjust the setting on your HRM for that?

    The fitter you are, the more likely the HRM estimates will be off. Check out Heybales posts or Azaks blog on them. I'm going to look for a link.
  • 3dogsrunning
    3dogsrunning Posts: 27,167 Member
    Heybales spreadsheet

    http://www.myfitnesspal.com/topics/show/813720-spreadsheet-bmr-tdee-deficit-macro-calcs-hrm-zones

    If you have a Polar
    http://www.myfitnesspal.com/topics/show/548645-setup-polar-hrm-for-more-accurate-calorie-burn-for-known-bmr

    Azdak
    http://www.myfitnesspal.com/blog/Azdak/view/new-hrm-how-to-make-the-calorie-estimate-more-accurate-183102
    http://www.myfitnesspal.com/blog/Azdak/view/the-real-facts-about-hrms-and-calories-what-you-need-to-know-before-purchasing-an-hrm-or-using-one-21472
  • lizsmith1976
    lizsmith1976 Posts: 497 Member
    One thing that has been problematic for me is that HRMs give GROSS calories burned. Let's say your BMR is 2,400. I know that's high - I'm using it to make math easy.

    So your body burns 100 calories an hour whether you do anything or not. Training for tris (like me) means sometimes training 3-7 hours a day for long runs, bike rides, etc. So let's say you do a 6 hour bike ride and your HRM says you burned 2,400 calories. Well you would have burned 600 anyway, just breathing. So net it's 1,800. So then ideally I would plan to eat an additional 900 that day - which I would probably exceed ;-)
  • zekerella
    zekerella Posts: 58 Member
    wait. why 900 and not eat back the 1800?
  • Morgaath
    Morgaath Posts: 679 Member
    Read the article, for all the details, but the part you want is in the chart below.

    What's the Burn? A Calorie Calculator
    You can use the formulas below to determine your calorie-burn while running and walking. The "Net Calorie Burn" measures calories burned, minus basal metabolism. Scientists consider this the best way to evaluate the actual calorie-burn of any exercise. The walking formulas apply to speeds of 3 to 4 mph. At 5 mph and faster, walking burns more calories than running.
    Your Total Calorie Burn/Mile --- Your Net Calorie Burn/Mile
    Running
    .75 x your weight (in lbs.)
    .63 x your weight
    Walking
    .53 x your weight
    .30 x your weight
    Adapted from "Energy Expenditure of Walking and Running," Medicine & Science in Sport & Exercise, Cameron et al, Dec. 2004.

    http://www.runnersworld.com/weight-loss/how-many-calories-are-you-really-burning?page=1
  • zekerella
    zekerella Posts: 58 Member
    I'd skip all the guessing and get a bodybugg..I got one a few months ago and it's one of the best purchases I've ever made

    that seems too good to be true! Is it really accurate? Has it worked for you? I think im undereatting...but its so hard to tell!! If it rerally works Id totally want one.
  • ATT949
    ATT949 Posts: 1,245 Member
    I'd skip all the guessing and get a bodybugg..I got one a few months ago and it's one of the best purchases I've ever made

    that seems too good to be true! Is it really accurate? Has it worked for you? I think im undereatting...but its so hard to tell!! If it rerally works Id totally want one.

    Yes, maybe.

    All devices that give calorie estimates use "formulas". The brain dead ones use only height, weight, and gender to estimate. That's going to be accurate for some folks but wildly inaccurate for others (most).

    The more data you put into something, the more accurate the results will tend to be.

    A body bugg/FitBit/Fuelband/etc. will tend to be less accurate than some others because they don't use HR for calculations and, a company has to compromise more things to hit a price point ("You can have it accurate, you can have it cheap, you can have it well made - pick two."). Those factors would tend to make me think that they didn't pay the $$ to license algorithms from FirstBeat the way that Garmin, Suunto, and Polar did.

    As far as I've been able to tell, the most accurate calorie estimates you can get for around $500 are to use FirstBeat Athlete software (about $75) in conjunction with the top of the line Polar, Suunto, or Garmin HRM's (910, 610, 620) but you'll have to tweak the 610 and 910 by downloading a file to get it to record heart rates in a modified way*.

    With that combination, you'll get to 5 to 10% accuracy when you're exercising at a high VO2 level. That is the figure cited in the white papers that you can download from firstbeat.fi

    Next step down are those high end HRM's, then something that uses HR to calc calories, then formulas//MFP.

    If you're using the HRM but not using "R-R recording" + FBA, the inaccuracy jumps to 10% to 20% (I think 20% is correct - check the white papers).

    The formulas that MFP uses are very similar to the ones that are on Runner's World so they could be absolutely correct or they could be laughably incorrect.

    It depends on how efficient a runner you are (in my case) and how well you ran. Some days, my opening mile is 110 calories while it's been as low as 82 calories. No formula can tell me anything but "average" whereas my Garmin/FirstBeat Athlete combo will give me a very accurate reading regardless of my conditioning level, the weather, the grade, etc.


    *I don't have a 620 yet but I believe that it does not need to be tweaked the way the 910 and 610 do.

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