Calories burned running: is speed a factor at all?

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  • Smuterella
    Smuterella Posts: 1,623 Member
    Tuesday I ran 7K in 48 minutes and burned 350 calories

    Thursday I ran 4K between sprinting and walking in 30 minutes and burned 315 calories


    So speed, at least in the case of intervals, increases burn.

    If you are using an HRM to estimate calories, you can't use those numbers as a comparison. The reason is that for some activities, a person might get an exaggerated HR response, due to things anatomical variations (i.e. higher than avg HR), and general conditioning.

    The HRM has no idea what activity you are doing--it just counts heart beats and makes a guess. However, the HRM is only programmed to evaluated steady-state cardio workouts. So, if you are doing something different, it will spit out a number, but it can be significantly inaccurate.

    TTTTHPBT!

    :-)
  • Shadowsan
    Shadowsan Posts: 365 Member
    By the way - I opened the thread purely out of curiosity - my main goal is to improve fitness and get some PB's for my running - weight loss isn't a driving force for me any more, therefore calorie burn isn't that important.

    Then in that case - interval training is your friend. ;)

    What?!?!? He's going for personal bests in time and distance and your advice is to do something completely different? How would he clock his times if he starts interval training?

    Throwing interval training into any routine will force your body to adapt to increased requirements over and above what you would be able to do steady-state, at which point once these adaptations have occurred you will be able to increase your steady state performance.

    I'm by no means saying totally ditch your steady state stuff - i'm saying that putting some interval training in to break plateaus and improve your maximal performance will be a great benefit if you're looking for PB's.

    And to say that only steady state improves steady state performance for time in running... Look at long-distance runners. They practice sprint finishes (which are nearly 400/800m in length) which are well over and above the pace they could hold out at a steady state.
  • Azdak
    Azdak Posts: 8,281 Member
    OK - I just did an experiment with MFP exercise calorie calculator - I took the pace and entered the same value for the minutes of exercise (eg 6 minute mile pace, 6 minutes) - which means that the output is the number of calories per mile. As my weight is a fixed quantity and MFP doesn't know my fitness level we can assume that there are no other factors changing.These are the results.

    pace / cals
    6 / 122
    7 / 124
    8 / 127
    9 / 126
    10 / 127
    12 / 122

    As you can see, there is no linear correlation between pace and cals per mile shown here - meaning either MFP has incorrect values (possible) or that there really is no correlation and that the body doesn't have a peak efficiency in terms of running speed.

    Note that I would define efficiency here in terms of calories burnt - obviously muscle fatigue sets in over a shorter distance at higher speeds.

    This means that the calculator is wrong really.

    Although how wrong is debatable. Obviously to increase speed, you may be able to do that simply by increasing your stride length which would result in nearly the same amount of muscle contractions as the slower speed.

    Which ties in to what I originally said - as your speed increases, the difference in expenditure begins to result in an inverse exponential curve - diminishing returns.


    Can I ask what you are basing this information on? I'm not saying its wrong - I'm just trying to determine if this is something you are deriving for yourself of based on a study.



    My instinct is that most people have a 'natural pace' which is going to be very efficient - running below this pace will burn marginally less efficient but will produce a pretty similar cals burned / mile. As you start to increase from this pace I would expect efficiency to decrease as technique will start to suffer.

    Also - as you pointed out there are two ways to increase speed - the first is to increase cadence (number of foot falls per minute) - the second is to increase stride length. Interestingly - my learning is that during a long distance run you should maintain cadence and alter stride length to manage your effort levels - however to improve your net running speed you need to work on increasing your cadence. I have no idea how this impacts efficiency either.

    You are talking about two different things here. I wasn't sure if that's what you meant, so I didn't go into detail in my other response.

    You plotted out different cal/mile at different speeds. As you discovered, the cals/mile is roughly the same at any given speed. However, that is true as long as: a) the running speed represents a steady-state exertion level, and b) falls within the "umbrella of mechanical efficiency" for any given individual.

    Yes, every person is going to have an "ideal" stride/pace combination at which they are most mechanically efficient--if you plot stride length, for instance, against VO2 (for a constant speed), you will get a "U" shaped curve as you move from short strides to long strides. At some point--the bottom of the "U"--you hit a stride length that is most mechanically efficient FOR YOU and that has the lowest VO2 for that speed. That "ideal" stride is not fixed--it can be moved a bit depending on training.

    As far as training for stride/cadence goes, there is some science out there, but there is also a lot of ideology. As one increases running speed, one soon reaches an optimal cadence. At that point, further increases in speed come from increasing stride length. If you continue to increase speed, you will eventually reach a point where stride length can no longer increase, and you then must increase cadence again (this is what happens in sprinting).

    As said before, each individual body has a "range" of cadences and stride lengths in which it can efficiently perform. I believe that, with training and experience, most people will "naturally" find their optimal cadence/stride length combination.

    As a rule, if you are going to be "off" from your "optimum" stride pattern, there is less of an inefficiency penalty for running w/ a higher cadence/shorter stride than vice versa--lower injury risk as well. However, in addition to increased fitness, one of the effects of interval training is that it naturally increases your stride length as well. These days, the current fad in running is for everyone to try to run like elite Kenyan marathoners--despite the fact that 99% of runners are neither elite, nor are they remotely Kenyan. This is not necessarily a bad thing, since many new runners tend to overstride and since, as a mentioned, if you are going to make a mistake, doing so with shorter strides is less detrimental. However, people should realize that there is no one "optimum" cadence for everyone and they should not be browbeaten into running 180 steps/min if it does not feel comfortable.
  • DavPul
    DavPul Posts: 61,406 Member
    OK - I'm going to rephrase the question because I think some people are missing my point- if my target was to burn, say, 500 calories running - would I always go the same distance irrespective of the speed I was running at?

    Pretty much. If you are running, you will burn essentially the same # of calories per mile, regardless of running speed.

    If you are walking, you will burn essentially the same # of calories per mile, regardless of walking speed.

    If you are comparing running to walking, you will burn exponentially more calories per mile running than walking. (with the exception of more extreme racewalking speeds).

    This doesn't make any sense to me. It's essentially saying that speed makes no difference... Until we rename the activity. So walking at 1mph is the same as 4mph until we call it race walking and running at 5mph is the same as 10mph is the same as 12 mph until we call it sprinting? Seems to me that speed increases effort which increases burn rate. When does more output not require more input?
  • Azdak
    Azdak Posts: 8,281 Member
    So - to summarise:

    The MFP calories burned running might just as well ask you the number of miles you ran - the speed you ran it (and therefore the time it took) isn't relevant.

    In reality, the above calculation can only be used if you are running at a comfortable pace - interval training and pace runs will burn more calories and really the only way to fully understand their impact is to use a HRM.

    Thanks everyone :)

    Well, you still have to have weight, but yes for #1.

    #2 conclusion: no. For the scenario you describe, HRMs provide no additional advantage, and in fact can be way off.
    If you are doing a tempo run, i.e. high or higher-intensity continuous run, then the ACSM calculations will still work, but research has suggested they might overestimate by about 15%. That's more than close enough.

    For full interval training--e.g. sprint repeats or even 1/4 mile repeats--there basically is no practical way to determine calories, and quite frankly, it's not worth the effort. If you need some extra fuel, throw in 200-300 into your meal plan, and call it a day.
  • Azdak
    Azdak Posts: 8,281 Member
    OK - I'm going to rephrase the question because I think some people are missing my point- if my target was to burn, say, 500 calories running - would I always go the same distance irrespective of the speed I was running at?

    Pretty much. If you are running, you will burn essentially the same # of calories per mile, regardless of running speed.

    If you are walking, you will burn essentially the same # of calories per mile, regardless of walking speed.

    If you are comparing running to walking, you will burn exponentially more calories per mile running than walking. (with the exception of more extreme racewalking speeds).

    This doesn't make any sense to me. It's essentially saying that speed makes no difference... Until we rename the activity. So walking at 1mph is the same as 4mph until we call it race walking and running at 5mph is the same as 10mph is the same as 12 mph until we call it sprinting? Seems to me that speed increases effort which increases burn rate. When does more output not require more input?

    This can turn into one of those "muscle weighs more than fat" debates where everyone is using different terms of measurement.

    This discussion is about calories burned per mile, not calories burned per minute.

    It is absolutely true that an increase in speed = an increase in the rate of calories burned per minute. However, when expressing the amount in terms of DISTANCE, when running (or walking), the increased cal/min burn is offset by the decreased time it takes to cover the mile at the faster speed, thus making the calories burned PER MILE (or other unit of distance) the same.

    Walking 3.0 mph has an energy cost of 3 METS. A 100kg person will burn 300kcal in an hour. The pace is 20 min/mile, so they will burn 100 kcal walking one mile.

    Walking 4.0 mph has an energy cost of ~ 4 METs. A 100 kg person will burn 400 kcal in an hour. The pace is 15 min/mile, so they will burn 100 kcal walking one mile.

    So if the question is "how many kcals per mile?", the total will be the same--100 kcals for each mile regardless of speed. If the question is "how many kcals per hour?", then it is obvious that walking faster will burn more kcal per hour.

    It's best to leave sprinting out of this discussion. First of all, no one can sprint for a mile, and, secondly, none of the calculations, data tables, HRM estimates, etc, apply.
  • tubaman58
    tubaman58 Posts: 151
    Running is too slow in absolute terms for wind resistance to have a practical effect (Yes the wind can affect results, it's going 30 or 40 mph, not 6 or 7)
    The best way to estimate calorie consumption is with your heart rate, and that is directly related to your speed.
  • stephvaile
    stephvaile Posts: 298
    Sheldon would point out that you didn't actually ask a question, but you did incorrectly state that work is equal to weight x distance of lever, which is actually the equation for force. What you require is the amount of work done which takes into account the amount of time it took to move a known weight a certain distance.

    What you also seem to be getting confused with is efficiency.

    To use your own analogy, the faster a car travels, the more fuel it will take to maintain a constant speed, but the average car has been designed for the engine to be most efficient when the car is travelling at 50mph. A race car may well be designed to have a maximum efficiency at a higher speed, but a city car much lower.














    OK - I explained the lever thing badly (principle is correct)... work = force * distance. Force is directly proportional to weight as it equals mass * acceleration where acceleration is a constant (gravity). lets say the we want to lift a block of metal 1 meter. if you have a lever lifting the block of metal, and the total distance moved on the counter point to the block is 2 meters, the required force is half that of lifting the metal directly and the total work is the same - in other words if you put a block of metal half the weight of the original on the end of the fulcrum they would balance. Regardless of the lever length, the same amount of work is required to lift the block! Time doesn't impact the work either!

    Efficiency - I think you are just expanding my analogy to confuse the issue - the point is simply that efficiency isn't a constant and speed will have an impact.

    You are right about not actually making my original question clear (although there was a question in the title) - hence later clarification.

    Sheldon would have gotten bored by now and gone home to play with his Spock doll.

    Yeah, think I'm confusing the term power/watts with work.

    I think what Stephvaile said made the point I was trying to make about efficiency far better. I introduced it to help explain the curve you are seeing in burn results.


    what i tend to do is put in my overall time for distance and it evens out walking/running mfp actually to me is low as other sites ie runners world (they also calculate on your weight and distance not speed) and they give much higher burn you could make it very complicated if u wished but it does go on your actual fitness at the speed u are running someone may run 5 miles steady and the walker maybe really pushing it at 5 miles even stevens at end of day i believe intervel training is the best to gain improvement
  • erinn43
    erinn43 Posts: 20 Member
    This is a big debate. I think the faster you are the better the breathing is -that VO Max stuff. Which I so do not bother understanding. Bottom line- you are moving. All of the paces help in overall results. (Better running)
  • I'm not even going to get remotely mathematical like everyone has done I'm going to try and make it simple from someone who has just started running......

    I use a HRM.....MFP usually either overestimates or underestimates calories burned (HRM is the best investment)
    I know for a fact that with me, I burn more calories running, and if I run faster I burn more calories (uphill even more)....my HRM is proof of that
    I also know that when I walk I know I don't burn as many calories, again HRM tells me so.....

    My two cents :)
  • neverstray
    neverstray Posts: 3,845 Member
    I'm not even going to get remotely mathematical like everyone has done I'm going to try and make it simple from someone who has just started running......

    I use a HRM.....MFP usually either overestimates or underestimates calories burned (HRM is the best investment)
    I know for a fact that with me, I burn more calories running, and if I run faster I burn more calories (uphill even more)....my HRM is proof of that
    I also know that when I walk I know I don't burn as many calories, again HRM tells me so.....

    My two cents :)

    Sorry, but this is not correct. All your HRM knows is your heart beat. It does not know how many calories you burn. It's guess is as good as MFPs. As has been said in this thread, MFP is pretty right on, for the most part. I've checked as compared to different things. If your a not picker and think that 25 cals + or - is a big deal, then we'll never agree on this issue. If its within 100, I'm happy. It doesn't matter that much. It's all relative.
  • stephvaile
    stephvaile Posts: 298
    I'm not even going to get remotely mathematical like everyone has done I'm going to try and make it simple from someone who has just started running......

    I use a HRM.....MFP usually either overestimates or underestimates calories burned (HRM is the best investment)
    I know for a fact that with me, I burn more calories running, and if I run faster I burn more calories (uphill even more)....my HRM is proof of that
    I also know that when I walk I know I don't burn as many calories, again HRM tells me so.....

    My two cents :)

    that is because you are effiecent at walking depending on wat speed u are walking lets put it this way when i walk 1 hour at 4miles per hour im not tired or breathless so my heartrate won,t go up if i did intervals 5 mins 4 miles 5 mins 4.5 my heart rate would go up after 4.5 mile an hour my body would be easier running than walking because it gets difficult to walk for long periods at 4.5 + for the average fit person , when u introduce running as a beginner u are running at 4.5 + pace as a beginner your heart rate shoots up as u get fitter 5 miles an hour is a walk in the park so your heart rate lowers the fitter u get do u get me
  • tadpole242
    tadpole242 Posts: 507 Member

    Walking 3.0 mph has an energy cost of 3 METS. A 100kg person will burn 300kcal in an hour. The pace is 20 min/mile, so they will burn 100 kcal walking one mile.

    Walking 4.0 mph has an energy cost of ~ 4 METs. A 100 kg person will burn 400 kcal in an hour. The pace is 15 min/mile, so they will burn 100 kcal walking one mile.

    So if the question is "how many kcals per mile?", the total will be the same--100 kcals for each mile regardless of speed. If the question is "how many kcals per hour?", then it is obvious that walking faster will burn more kcal per hour.

    It's best to leave sprinting out of this discussion. First of all, no one can sprint for a mile, and, secondly, none of the calculations, data tables, HRM estimates, etc, apply.

    Met for walking the dog 3
    Met for Walking at 2.5mph 3.5
    Met for walking at 3.5mph 4.3
    Walking at 4mph give a MET of 5
    So at a 100kg walking at
    2.5mph burns 314 calories (125.6 calories per mile)
    3.5mph burns 451 calories (128.8 calories per mile)
    4mph burns 524 calories (131.25 calories per mile)
    Does not start at 100 calories per mile and the calories burnt increases along with speed.
  • confettibetti
    confettibetti Posts: 405 Member
    I am absolutely certain you'll have a lot of better responses to this, but as far as I understand it's not about speed, but about your effort. So an out-of-shape person who runs for one hour at top speed will burn as much as or even more than the really fit person who runs twice the distance.

    This is why people go the whole length of heart-rate monitors, etc, in order to figure out how much effort they put into the exercize, and to get a better idea about how many calories they burn.

    my thoughts exactly.
  • Shadowsan
    Shadowsan Posts: 365 Member
    If you're wanting to be totally accurate on expended calories only - then it's Watts and/or METs that you should be using to track your expenditure, and then convert back to kcals. Not HRMs.

    HRMs are great for a general user, and unless you're tracking everything meticulously then that is perfectly fine for most people. Remember that for most people, this is a ball-park figure. It doesn't need to be completely accurate.

    So to summarise:

    Speed _is_ a factor when it comes to calorie expenditure for running - but can be heavily influenced by other factors such as running efficiency, your starting VO2 Max (a lower VO2 Max will result in a higher calorific requirement from your anaerobic system whilst you're training near to, or over it), etc. At the same running efficiency, a higher speed will result in an increased calorific requirement - however the increases in energy required whilst training within your VO2 Max become a case of diminishing returns.

    Intervals increase the calorific requirement vs steady state because even though during your active recovery periods you may be running slightly slower, you are forcing your body to work over its standard comfort/efficiency/aerobic capacity levels for short periods which forces you to burn energy LESS efficiently short-term (resulting in more calories to do the work needed during) and longer term helps your body to adapt to increase your ability to train steady state at a higher level. This also forces your body to have to keep expending calories even after you finish training because a) you have probably developed muscle, and b) there is a calorific deficit caused by generating lactic acid that needs to be broken down which requires more energy to do so.

    Incline increases this effect because the amount of torque (the effort required to move) is increased - your feet are in contact with the ground for longer periods which means you are pushing against gravity (as opposed to moving forward in mid-air) more, increasing the energy requirement to move at the same speed as if you were on a flat surface.
  • waldo56
    waldo56 Posts: 1,861 Member
    While I'm not sure how it affects calorie burn rates over slight variations of slow, mechanically efficient speeds....

    In running there are two distinct forces, propulsion force and support force. Propulsion force acts in the horizontal plane, propelling you forward, support force acts in the vertical plane, preventing you from falling down.

    In many ways running is a bit of a controlled fall. With every step you do a quick negative lunge to brake your forward fall.

    The support force required is a function of speed. For sprinters oftentimes the support force is more important than the propulsion force for going faster. This is why squats and lunges will tend to make sprinters faster and vice versa fast sprinters tend to be strong in the squat and lunge.

    Walking has very little in the way of support force (your muscles do very little work holding you up, this is not the case for running) which explains the calorie differences.

    You can see the interplay of support and propulsion force on hills. On the way up you are going slow, landings feel really soft, but it requires a lot of propulsion to go up. On the way down however you can pick up a lot of speed with virtually no propulsion force, however because of the faster speed the support force increases a great deal. On bigger hills most will have to lean back and slow down. You could lean forward and break into an all out sprint almost free of propulsion force, however since support force is a function of speed, the support force required will rise to the same levels as if you were in an all out sprint on flat land.

    Like I said I'm not sure how this effects calorie burn in the jogging area, but in general he who is stronger can run faster when it comes to sprinting (applies to the general population, not outliers), and likewise since support force increases as a function of speed (exponential I believe), running at higher speed does have a higher energy cost than running at slower speeds. Though because you finish faster if you run faster, at jogging pace the calorie cost variance per distance may be fairly negligible. But at higher speeds as the support force really begins to rise, the energy cost of increased speed does become signicant.

    Running a mile at Olympic mile pace burns a lot more calories than running a mile at moderate 10K pace.
  • HisPathDaily
    HisPathDaily Posts: 672 Member
    I feel like I should say something because clearly there aren't enough opinions on this thread yet ;)

    Effort burns calories. The more muscles used, and the more effort they use the more calories it burns.

    Done.

    Now, "today" if I ran 30 minutes at a 7.0 I would burn xxx calories
    Now, "today" if I ran 30 minutes at a 8.0 I would burn xxx + some calories (it's more effort)

    Next month, I may run 30 minutes at an 8.0 and burn less calories than I burned at 7.0 today! Why? I'm more in shape perhaps (and your HRM will 'help' tell you that).

    Now, you could go all out and do some benchmark calculations, determine your VO2 max, etc. But I wouldn't worry about all that ... be fit, eat well, and enjoy life :) ... however I know you just had a question, but it's simply effort, not speed, or distance. There are averages (and rules of thumb) but just like a car, the more you push it, the more it burns ... same as your body.
  • Every mile you burn 100calories. That's a fact. If you run or walk. Now if you ride your bike you will need double time to burn 100 calories. I run about 60 min a day if I bicycle I have to ride for 2 hours to burn the same amount of calories. That's easy to remember for me.
  • timboom1
    timboom1 Posts: 762 Member
    For purposes of the same person, running faster of slower either.

    1) You run the same distance in less time, the differnce is not enough to matter.
    or
    2) You run for the same time, it makes a big difference as you are going farther.

    If you compare two different people then things like effeciency matter more, but for the same person, the differences are not going to be huge. (Running vs. Walking is different however becasue of the different mechanics involved.)
  • stephvaile
    stephvaile Posts: 298
    While I'm not sure how it affects calorie burn rates over slight variations of slow, mechanically efficient speeds....

    In running there are two distinct forces, propulsion force and support force. Propulsion force acts in the horizontal plane, propelling you forward, support force acts in the vertical plane, preventing you from falling down.

    In many ways running is a bit of a controlled fall. With every step you do a quick negative lunge to brake your forward fall.

    The support force required is a function of speed. For sprinters oftentimes the support force is more important than the propulsion force for going faster. This is why squats and lunges will tend to make sprinters faster and vice versa fast sprinters tend to be strong in the squat and lunge.

    Walking has very little in the way of support force (your muscles do very little work holding you up, this is not the case for running) which explains the calorie differences.

    You can see the interplay of support and propulsion force on hills. On the way up you are going slow, landings feel really soft, but it requires a lot of propulsion to go up. On the way down however you can pick up a lot of speed with virtually no propulsion force, however because of the faster speed the support force increases a great deal. On bigger hills most will have to lean back and slow down. You could lean forward and break into an all out sprint almost free of propulsion force, however since support force is a function of speed, the support force required will rise to the same levels as if you were in an all out sprint on flat land.

    Like I said I'm not sure how this effects calorie burn in the jogging area, but in general he who is stronger can run faster when it comes to sprinting (applies to the general population, not outliers), and likewise since support force increases as a function of speed (exponential I believe), running at higher speed does have a higher energy cost than running at slower speeds. Though because you finish faster if you run faster, at jogging pace the calorie cost variance per distance may be fairly negligible. But at higher speeds as the support force really begins to rise, the energy cost of increased speed does become signicant.

    Running a mile at Olympic mile pace burns a lot more calories than running a mile at moderate 10K pace.



    depends on the fitness of the runner olympic runners are exceptionally fit the guy running is 10k pace if putting in more effort could be burning more
  • Aperture_Science
    Aperture_Science Posts: 840 Member
    Every mile you burn 100calories. That's a fact. If you run or walk. Now if you ride your bike you will need double time to burn 100 calories. I run about 60 min a day if I bicycle I have to ride for 2 hours to burn the same amount of calories. That's easy to remember for me.


    hehehehe.... nice one

    You mean "EXACTLY 100 calories, for every person on the planet" fact or "more or less, for me only" fact?
  • Ooooh, Ooooh, teacher, I know! I know! [he said with arm raised]

    Here is the physics answer:

    Work/energy (i.e. calories) is force times distance. Increase calories by going greater distance or using greater force. Distance is obvious. Regarding force, a heavier person will burn more calories going the same distance. Also 5 miles uphill will burn more calories than 5 miles on a flat or downhill surface.

    Power is work/energy per unit time. Going equal distance in shorter time will burn the same energy in less time (more power).
    ^^^ THIS!!!!
  • mikeyrp
    mikeyrp Posts: 1,616 Member
    Interestingly - at my swimming classes we get given a set of exercises which determine the distance we travel, and then instead of a speed to meet we have an RPE (relative perceived effort - 0-10) which we are asked to meet. With running I effectively have the same thing but through a combination key figures (like my 5K race time, VO2, HRM etc) I can convert this into a target pace. This is really useful for increasing fitness and speed - but from what I've read it has very little baring on the cals I burn per mile at a consistent pace (rather than interval/stress training).
  • Aperture_Science
    Aperture_Science Posts: 840 Member
    this thread is spiralling out of control. Who would have thought that a discussion about calroies burn during a run would span 5 pages?
  • mikeyrp
    mikeyrp Posts: 1,616 Member
    Perhaps I should have stated the obvious caveat that I'm talking about the efforts of any one individual - Obviously two different people will burn calories at different rates, in the same way that incline and surface will change the rate of burn too. We should also assume we are comparing running with running - walking, skipping, hopping, kart wheeling, cycling, carrying sacks of gold up hills etc are different mechanics and one would expect them to be different.

    In fact - lets make the whole debate a lot simpler from here on -

    Person A is running 3 miles at a steady pace - will their speed impact the the number of calories they burn?

    (the consensus seems to be only at the extreme ends of their ability)
  • SoDamnHungry
    SoDamnHungry Posts: 6,998 Member
    http://www.runnersworld.com/article/0,7120,s6-242-304-311-8402-0,00.html

    Here you go... This article supports the theory that you burn many more calories running than walking. Speed is probably a factor, but that isn't included here.
  • waldo56
    waldo56 Posts: 1,861 Member
    http://www.runnersworld.com/article/0,7120,s6-242-304-311-8402-0,00.html

    Here you go... This article supports the theory that you burn many more calories running than walking. Speed is probably a factor, but that isn't included here.

    ..it isn't really a theory.

    You do burn more calories running than walking (crazy speedwalking excluded).

    Stande for 30 minutes on straight legs. Stand for 30 minutes without ever locking out your knee joints. Which is more tiring?

    Just the mechanics of running, you have to expend energy to hold yourself up that you don't have to spend while walking.
  • LoriB57
    LoriB57 Posts: 26 Member
    JUST DO IT !! I have become increasingly frustrated with my efforts and my heart monitor. Nutritionally dense calories in, muscle building / cardio calories out! I can lift weights for 45 minutes & my HRM says I burned 150, I can run the same 45 & burn 400! But I know it's necessary to maintain & build muscle too.
  • MSmooth747
    MSmooth747 Posts: 55 Member
    Speed is a factor, I wouldn't use MFP calulations. I wear a heart rate monitor when I run, and when I run faster I burn more calories.
  • Azdak
    Azdak Posts: 8,281 Member

    Walking 3.0 mph has an energy cost of 3 METS. A 100kg person will burn 300kcal in an hour. The pace is 20 min/mile, so they will burn 100 kcal walking one mile.

    Walking 4.0 mph has an energy cost of ~ 4 METs. A 100 kg person will burn 400 kcal in an hour. The pace is 15 min/mile, so they will burn 100 kcal walking one mile.

    So if the question is "how many kcals per mile?", the total will be the same--100 kcals for each mile regardless of speed. If the question is "how many kcals per hour?", then it is obvious that walking faster will burn more kcal per hour.

    It's best to leave sprinting out of this discussion. First of all, no one can sprint for a mile, and, secondly, none of the calculations, data tables, HRM estimates, etc, apply.

    Met for walking the dog 3
    Met for Walking at 2.5mph 3.5
    Met for walking at 3.5mph 4.3
    Walking at 4mph give a MET of 5
    So at a 100kg walking at
    2.5mph burns 314 calories (125.6 calories per mile)
    3.5mph burns 451 calories (128.8 calories per mile)
    4mph burns 524 calories (131.25 calories per mile)
    Does not start at 100 calories per mile and the calories burnt increases along with speed.

    Your MET values are not correct for the speeds you list.