running same distance slow vs fast. Same calories. Or not?

yirara
yirara Posts: 9,389 Member
in Fitness and Exercise
So there's something that I've been wondering for a while. Running calories are fairly easy: Distance * weight * an efficiency factor. Simples. For some reason my brains want to tell me that running a 10k in 40 minutes burns less calories than doing this in 90 minutes, or a half marathon in 90 minutes vs 3 hours. The weight over distance is the same. Repeating the same movement over a longer time should not make a difference as the movement is just slower. Of course the BMR part of this will be higher for a slower run, but overall it's not a lot. Anyone dare to comment?

Replies

  • ninerbuff
    ninerbuff Posts: 48,489 Member
    Energy expenditure is different based on intensity.

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  • Theoldguy1
    Theoldguy1 Posts: 2,454 Member
    You're burning calories pretty much on the distance travelled regardless of the time. Some say may be slight differences depending on the efficiency of your gait at various speeds but big factor is distance travelled.

    Q: To lose weight, am I better off running lots of slow miles, or fewer but faster miles?
    A: The simple answer is that running at any speed expends approximately 100 calories per mile. Running a seven-minute mile will burn a few more calories than running a 10-minute mile because of the added effort. But most people can't log lots of additional miles at a faster pace without becoming overly fatigued or injured. So you're likely to accumulate more miles—and burn more calories—over the course of each week by running at a slower pace.

    To lose weight, your energy expenditure (moving and exercising) must exceed your energy intake (eating and drinking). You can do this by eating less, exercising more, or a combination of both. Plenty of slower miles can help create a steady calorie deficit that will lead to weight loss.

    —Bryan K. Smith, Ph.D., is an assistant research professor at the University of Kansas Energy Balance Laboratory and Center for Physical Activity & Weight Management.

    https://www.runnersworld.com/nutrition-weight-loss/a20805271/lose-weight-with-help/#:~:text=Q: To lose weight, am,because of the added effort.
  • BrianSharpe
    BrianSharpe Posts: 9,249 Member
    It's physics, it takes a given amount of energy to move a mass over a distance. 10km is 10km whether you run it in 65 minutes or 45. One of the errors many HRMs make when estimating calories is assuming that calories expenditure has a linear relationship with heart rate, if that were true an unfit new runner with a high HR would be burning more calories than a fitter one running the same distance and speed (if one weighed more than the other there would be a difference)
  • jjpptt2
    jjpptt2 Posts: 5,650 Member
    There will likely be a difference based on efficiency at differing speeds, but it'll be negligible. For all intents and purposes, it takes the same energy to move you across a set distance regardless of how fast you go.
  • heybales
    heybales Posts: 18,842 Member
    ditto to the running form and BMR difference and wind resistance are negligible between the paces compared to just the main calorie burn. If route is the same.

    This has been brought out before, as more accurate than HRM formula.
    https://exrx.net/Calculators/WalkRunMETs

    This is unlike bike riding (since that was your other topic) where air resistance can start becoming the major influence and therefore per distance calorie burn doesn't work the same.
  • yirara
    yirara Posts: 9,389 Member
    Yes, I know these calculators. I know it's difficult to argue against one's brain. I remember having seen a study a couple of years ago about influence of pace on calorie needs. If I remember correctly there was a sweet spot where running was easiest and calorie expenditure lowest, and above and below it was a bit higher. How much though I can't remember.
  • viajera99
    viajera99 Posts: 252 Member
    edited May 2021
    Another point to understand is the difference between gross and net expenditure.

    (All numbers are made up for illustration!)

    A 150lb runner completes a 10 mile race in one hour and burns 1000 Kcals. If she had been sitting on the couch for that hour, she would have burned 60 Kcals. Net excess expenditure is 940 Kcals. (940 Kcal/hour)

    A 150lb beginner completes a 10 mile race in two hours. If he had been sitting on the couch for those two hours, he would have burned 120 Kcals. Net excess expenditure is 880 Kcals. (440 Kcal/hour)

    The faster runner and the slower runner expend similar calories per mile, but much different calories per hour.
  • Theo166
    Theo166 Posts: 2,564 Member
    An interesting question. Google says that running faster burns slightly less calories
    snider-energy-cost-1445628601.png?resize=768:*


    Source Article
    https://www.runnersworld.com/nutrition-weight-loss/a20823469/mythbusting-running-a-mile-always-burns-the-same-calories/
  • heybales
    heybales Posts: 18,842 Member
    yirara wrote: »
    Yes, I know these calculators. I know it's difficult to argue against one's brain. I remember having seen a study a couple of years ago about influence of pace on calorie needs. If I remember correctly there was a sweet spot where running was easiest and calorie expenditure lowest, and above and below it was a bit higher. How much though I can't remember.

    https://exrx.net/Aerobic/WalkCalExp

    That chart doesn't take into account a person's own running form efficiency due to their body structure.
  • yirara
    yirara Posts: 9,389 Member
    heybales wrote: »
    yirara wrote: »
    Yes, I know these calculators. I know it's difficult to argue against one's brain. I remember having seen a study a couple of years ago about influence of pace on calorie needs. If I remember correctly there was a sweet spot where running was easiest and calorie expenditure lowest, and above and below it was a bit higher. How much though I can't remember.

    https://exrx.net/Aerobic/WalkCalExp

    That chart doesn't take into account a person's own running form efficiency due to their body structure.

    Oh, this is interesting. Thanks a lot.
  • IheartPGH
    IheartPGH Posts: 39 Member
    yirara wrote: »
    Yes, I know these calculators. I know it's difficult to argue against one's brain. I remember having seen a study a couple of years ago about influence of pace on calorie needs. If I remember correctly there was a sweet spot where running was easiest and calorie expenditure lowest, and above and below it was a bit higher. How much though I can't remember.

    The "sweet spot" is referring to running efficiently. Stride, pace, foot travel, etc. If your pace is too fast, your heart rate will be too high. You'll enter the cardio zone rather than the fat burning zone. Body weight will have an influence on all of this, as will experience, distance traveled, and so forth. It's not a clear-cut, apples to apples answer.
  • jjpptt2
    jjpptt2 Posts: 5,650 Member
    edited May 2021
    never mind... not important.
  • springlering62
    springlering62 Posts: 7,413 Member
    Analog_Kid wrote: »
    From my own personal experience... I use the MapMyRun app. If I run an 8 minute mile, I burn 140 cal. If I run a 10 minute mile, I burn 140 calories. What this taught me is to stop killing myself trying to get faster. My goal is to burn calories and manage my weight. I'm not looking to break speed records. As a result, my runs are much more enjoyable and a lot less painful.

    This makes me feel much less…..inferior!

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