Is it true that your body adjusts to the same cardio...

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emilysusana
emilysusana Posts: 416 Member
edited October 2016 in Fitness and Exercise
I've read that your body adjusts to the same cardio routine, for example, if you always run 3 miles, your body eventually does this more efficiently, i.e. by burning fewer calories. My question is, how many fewer calories are we talking about here? I usually estimate my runs at about 100 calories per mile. If I've been running for awhile, should I drop this number down? I do find that I run faster as I do it more, trying to push myself a little harder.

Also, some background info: running is not my only activity. I do strength training 3 days a week, interval sprints on a treadmill for 25 minutes one day a week, one long a week (I'm up to 6.5 miles) and one short run (3 miles). I'm just trying to log my runs with as much accuracy as I can.
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  • cwolfman13
    cwolfman13 Posts: 41,874 Member
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    changes in energy expenditure due to becoming more efficient is pretty insignificant. I cycle and lift...been doing it for four years plus...
  • RoxieDawn
    RoxieDawn Posts: 15,488 Member
    edited October 2016
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    I have become a little more efficient in my running, but I am a better runner and its not really about burning calories it about building fitness, getting stronger, etc. etc. etc.

    This formula is very close to my HRM for calorie burning... (your weight)*(distance)*(0.63)?



  • canadianlbs
    canadianlbs Posts: 5,199 Member
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    I've read that your body adjusts to the same cardio routine, for example, if you always run 3 miles, your body eventually does this more efficiently, i.e. by burning fewer calories.

    afaik, physics doesn't really care how much you're suffering ;) pain =/= calories burned.

    that's discouraging at first when you sweat and flail for 30 minutes and discover you burned a quarter teaspoon of fat for the whole thing. but it pays off later on, when you can burn ten times as much in the same time and still feel like you're not even trying that hard.
  • bwogilvie
    bwogilvie Posts: 2,130 Member
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    You can improve running economy a bit, but the upper limit is around 5-6%, and it won't come from just running the same 3-mile workout: research suggests that interval training is the best way to improve economy (IIRC, it's short, intense anaerobic intervals that are best, like sprints).

    If you lose weight, though, you'll burn fewer calories because you have less body mass to move around.

    And if you use a heart rate monitor (HRM) to estimate calories, it might report that you're burning fewer calories. As you adapt to running, your body gets more efficient at transporting oxygen to your running muscles, including enlarging your heart (especially the left ventricle). As a result, you need fewer heartbeats to run at the same speed. Your HRM might interpret that as burning fewer calories, depending on what equation it uses to estimate calories. Some higher-end models take your fitness level into account, but the cheaper ones just use an equation based on heart rate, weight, gender, and age.
  • Chieflrg
    Chieflrg Posts: 9,097 Member
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    Your body weight * miles * .64 = calories burned.

    Extremely accurate.
  • canadianlbs
    canadianlbs Posts: 5,199 Member
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    Chieflrg wrote: »
    Your body weight * miles * .64 = calories burned.

    Extremely accurate.

    interesting. is that regardless of speed?

  • BrianSharpe
    BrianSharpe Posts: 9,248 Member
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    The caloric expenditure for a mile of running does not change significantly unless you've lost a lot of weight, it's mass x distance, the only thing that really changes as you get fitter is that your heart rate will usually drop but that's just one relatively small muscle....
  • bwogilvie
    bwogilvie Posts: 2,130 Member
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    Chieflrg wrote: »
    Your body weight * miles * .64 = calories burned.

    Extremely accurate.

    interesting. is that regardless of speed?

    Yes, that is regardless of speed. The relationship between running speed and calorie expenditure is pretty much linear. If you run a mile at 9 mph, you'll burn the same number of calories as if you were running a mile at 6 mph. You'll be burning 1.5 times as many calories per minute, but it will take you only two thirds of the time, so it evens out (3/2 * 2/3 = 1).
  • canadianlbs
    canadianlbs Posts: 5,199 Member
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    neat, thx.
  • NorthCascades
    NorthCascades Posts: 10,970 Member
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    Chieflrg wrote: »
    Your body weight * miles * .64 = calories burned.

    Extremely accurate.

    I don't think that's very accurate at all. It says I burn exactly the same number of calories whether I'm running up a hill or on flat ground.
  • Chieflrg
    Chieflrg Posts: 9,097 Member
    edited November 2016
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    Chieflrg wrote: »
    Your body weight * miles * .64 = calories burned.

    Extremely accurate.

    I don't think that's very accurate at all. It says I burn exactly the same number of calories whether I'm running up a hill or on flat ground.

    If you run up hill 100% add 10% to you run, most people run uphill AND downhill which evens out. Its very accurate and considered the gold standard for many decades in the running world.

    If you were to run an hour straight up hill, we are only talking about 50 calorie difference which really isn't anything to throw a red flag up if you didn't add 10%.
  • TrishSeren
    TrishSeren Posts: 587 Member
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    Chieflrg wrote: »
    Your body weight * miles * .64 = calories burned.

    Extremely accurate.

    This is probably a blonde question but does this work for kms in the same way?
  • powered85
    powered85 Posts: 297 Member
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    Chieflrg wrote: »
    Your body weight * miles * .64 = calories burned.

    Extremely accurate.

    interesting. is that regardless of speed?

    This is about spot on what my Fenix3 connected to a heart rate monitor tells me for calories burned during a 5 mile run. And that's one with significant hills.

    Without the hrm connected it seems to overestimate by around 100cals on the same 5mi run.
  • Chieflrg
    Chieflrg Posts: 9,097 Member
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    TrishSeren wrote: »
    Chieflrg wrote: »
    Your body weight * miles * .64 = calories burned.

    Extremely accurate.

    This is probably a blonde question but does this work for kms in the same way?

    I just converted quickly with a calculator, this would get you in same ball park.

    Body weight * km * .397 = calorie burned

  • sinbos
    sinbos Posts: 28 Member
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    Regardless of speed - i guess if i walk there is a different formula? I dont change only the speed in that case but also the gait.
  • Hornsby
    Hornsby Posts: 10,322 Member
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    This needs some clarification. That formula is for jogging/running. So yes, it is "regardless of speed" if you are talking about jogging. Walking, the number is .3.
  • McCloud33
    McCloud33 Posts: 959 Member
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    Chieflrg wrote: »
    TrishSeren wrote: »
    Chieflrg wrote: »
    Your body weight * miles * .64 = calories burned.

    Extremely accurate.

    This is probably a blonde question but does this work for kms in the same way?

    I just converted quickly with a calculator, this would get you in same ball park.

    Body weight * km * .397 = calorie burned

    I got a different number (.45kg/lb x 1.61 km/mi x .64 = .46)
  • TR0berts
    TR0berts Posts: 7,739 Member
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    McCloud33 wrote: »
    Chieflrg wrote: »
    TrishSeren wrote: »
    Chieflrg wrote: »
    Your body weight * miles * .64 = calories burned.

    Extremely accurate.

    This is probably a blonde question but does this work for kms in the same way?

    I just converted quickly with a calculator, this would get you in same ball park.

    Body weight * km * .397 = calorie burned

    I got a different number (.45kg/lb x 1.61 km/mi x .64 = .46)

    That would be wrong. If some mythical person weighed 1 lb and ran 1 mile, then (s)he would burn 0.64 Cals.

    If, in Chief's example, BW is still in lb, then his formula is correct. If, however, the person's BW is in kg, then it would be BW * km * 0.87 = Cals.

  • BrianSharpe
    BrianSharpe Posts: 9,248 Member
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    sinbos wrote: »
    Regardless of speed - i guess if i walk there is a different formula? I dont change only the speed in that case but also the gait.

    Regardless of speed....yes and no. The formula doesn't work for persons race walking at speeds in excess of 5mph due to the inherent mechanical inefficiency of race walking (surprisingly it actually burns more calories than running)