How many calories am I really burning?

Phaedra2014
Phaedra2014 Posts: 1,254 Member
in Fitness and Exercise
How many calories am I really burning when I run? Most every article I've read says 100 cals per mile but my BodyMedia and HRM show a higher number.

I am 5'2" and weigh 138 lbs. I average a 10-minute mile most days so I'm not really a fast runner.

I did a 10K this weekend and my burn was 815 cals. yes it was outdoors and yes there were stretches that were inclined. Does that sound about accurate?

Replies

  • alpine1994
    alpine1994 Posts: 1,915 Member
    Yeah that's about what I burn too, maybe a bit less. I'm 5'8" and 145 lbs. For the 10K, if you figure 6.2 miles at race pace (faster that you would run on a normal day) plus hills, I think 815 is pretty reasonable.
  • 3dogsrunning
    3dogsrunning Posts: 27,167 Member
    The 100 calories a mile is considered the "average". I believe it is based on a 150 lb individual. People who weigh less will burn a little lower, people who weigh more will burn more.

    A pretty decent way to estimate is .63 x your weight = your net calories per mile, so thats about 85 calories a mile for you. Or 527 for the 6 miles. Even with moderate hills, I wouldn't go as high as 815. I also prefer to err on the side of caution.


    HRMs are not infallible.
  • aarar
    aarar Posts: 684 Member
    I've always gone by the 100 calorie per 1 mile average. I've checked with a few online calculators where you can input your height and weight, distance run & pace and the calorie burn is usually pretty close.
  • MinnieInMaine
    MinnieInMaine Posts: 6,400 Member
    I know when I run, I get more like 120-130 cal per mile especially when I go all out (my fastest is a 10 min mile so you're not alone!) However I weigh about 30 pounds more than you so I'd probably also get a slightly higher burn. Even given that, I'd think somewhere around 700 calories wouldn't be unheard of for a 10k.
  • Azdak
    Azdak Posts: 8,281 Member
    Calories burned is based on intensity (in this case, running speed) and body mass (weight). So, the "100 cal/mile" rule only applies to a small group.

    In your case, it is close. At 10min/mile and your weight, you will burn 10-11 calories per minute. Elevation can increase burn (assuming speed stays nearly the same).

    For a longer (e.g. 60 min) run, something called "cardiovascular drift" will come into play. Over time during a workout, heart rate will gradually increase with no increase in speed or incline. It's a combination of several factors. When this happens, heart rate increases, but calorie burn does not (since VO2 does not increase). The HRM doesn't know the difference because it just counts heart rate. This could account for some of the difference. I have compared the first half to the second half of some of my longer workouts and have found that, in a 45 min workout, the difference in calories burned according my HRM (FT60 with actual VO2, HRmax , and HRrest), was 30%--meaning that during the last 22:30 of the workout, I burned 30% more calories than the first 22:30, even though I did not change the workload and experience little change in perceived exertion.

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