Calories burned running: is speed a factor at all?

When I run 5k at an easy pace I burn around 250 calories, when I run it at race pace I burn around 490. I use a HRM. I've found MFP estimates to be completely inaccurate as far as calories burned are concerned.

Calories/mile is (almost) constant for a given person - slight variations are due to air resistance, movement of other body parts than the legs (running style) etc., but as a rule of thumb, the calories burned per mile is constant. As someone else pointed out, it's just basic physics.

However, there are a lot of other effects that differ with speed/effort. Really getting your heart pumping does so many great things to your body other than just the calorie burn. Several studies conclude that high intensity training sort of relocates the fat, so you will have less fat around the internal organs and on your belly, which is great for your health. So basically, if one simply wants to lose weight, doesn't like to get sweaty and has plenty of time it's great to take a long walk. But the health benefits from interval training or other high intensity cardio are far superior to walking or jogging.

Yup - the secondary effects from increasing intensity are just as important if not more so than plainly calories burnt. Increasing your bodys ability to carry oxygen and expend more energy via aerobic respiration is extremely important. Because by training this, you also increase your bodys ability to expend more calories via aerobic respiration at lower intensity - just like doing weight training and increasing your muscle mass increases your resting metabolic rate.

http://www.runnersworld.com/article/0,7120,s6-242-304-311-8402-0,00.html

In "Energy Expenditure of Walking and Running," published last December in Medicine & Science in Sports & Exercise, a group of Syracuse University researchers measured the actual calorie burn of 12 men and 12 women while running and walking 1,600 meters (roughly a mile) on a treadmill. Result: The men burned an average of 124 calories while running, and just 88 while walking; the women burned 105 and 74. (The men burned more than the women because they weighed more.)

http://www.ncbi.nlm.nih.gov/pubmed/15570150
CONCLUSION:
Running has a greater energy cost than walking on both the track and treadmill. For running, the Leger equation and ACSM prediction model appear to be the most suitable for the prediction of running energy expenditure. The ACSM and Pandolf prediction equation also closely predict walking energy expenditure, whereas the McArdle's table or the equations by Epstein and van der Walt were not as strong predictors of energy expenditure.

http://w4.ub.uni-konstanz.de/cpa/article/viewFile/450/390
The study presented here shows that running has a higher energetic cost compared to
walking the same distance, what might be associated to a higher vertical oscillation on
gravity center during running. This knowledge may be useful on exercise prescription in order
to achieve negative caloric balance, also considering factors as time for exercise practice
and orthopedic limitations.

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.

Basing my opinions on 4 years of sports science research (i.e. reading a LOT of books and plenty of practical tests) at university.

There are admittedly lots of factors in this, like you've said. Making your body do the most inefficient things is the best way to increase calorie expenditure. And the body itself does have a natural speed (which varies per person) at which they are at their most efficient.

As for interval training and its effects - interval training generally if you're sprinting as fast as you can for 30 seconds and then go to a steady state running/walking for 2/3 mins to recover and then go again... Not only trains your aerobic system (which uses aerobic respiration, which is extremely efficient per gram of glucose), but also trains your anaerobic/lactic acid system (which is inefficient by comparison - anaerobic respiration typically can produce about 2ATP per molecule of glucose - aerobic respiration for the same molecule of glucose can provide about 30ATP. 15 times more efficient)

So if you wanted to really burn lots of calories, you'd do plenty of high intensity intervals, with active recovery between for your aerobic system to address the balance before going again.

Intuitively, it seems walking would be a more energy efficient means to travel a given distance than running (not a more time efficient means). With running your are expending additional energy lifting your body weight off the ground. When walking, one foot remains in contact with the ground at all times. This explains the higher calorie burn associated with running as compared to walking.

Exactly. You're fighting against a force (in this case, gravity).

It's also why for instance, if you stood still doing squats with bodyweight for the same amount of time you tried running for, you would also burn more calories.

Where's Sheldon Cooper when you need him....?!

How about we actually refer to some properly published and peer-reviewed studies instead of basing it on uninformed theory and hearsay....

http://www.ncbi.nlm.nih.gov/pubmed/15570150 - CONCLUSION: Running has a greater energy cost than walking on both the track and treadmill

http://www.ncbi.nlm.nih.gov/pubmed/11296999 - CONCLUSIONS: These findings demonstrated that walking at speeds > or =8.0 km.hr(-1) resulted in rates of energy expenditure that were as high or higher than jogging at the same speeds. This study also showed that the faster you go over a given distance, the higher your energy consumption.

Basically the faster you go, the more energy you use over the same distance. Also walking is easier than running until you get to 8km/h at which point it is more efficient to run.

The posters above doing the calculations were oversimplifying things by assuming equal efficiency at all speeds and ignoring things like the energy used in absorbing the shock of each step, which is obviously higher when running at higher speed.

How about we actually refer to some properly published and peer-reviewed studies instead of basing it on uninformed theory and hearsay....

http://www.ncbi.nlm.nih.gov/pubmed/15570150 - CONCLUSION: Running has a greater energy cost than walking on both the track and treadmill

http://www.ncbi.nlm.nih.gov/pubmed/11296999 - CONCLUSIONS: These findings demonstrated that walking at speeds > or =8.0 km.hr(-1) resulted in rates of energy expenditure that were as high or higher than jogging at the same speeds. This study also showed that the faster you go over a given distance, the higher your energy consumption.

Basically the faster you go, the more energy you use over the same distance. Also walking is easier than running until you get to 8km/h at which point it is more efficient to run.

The posters above doing the calculations were oversimplifying things by assuming equal efficiency at all speeds and ignoring things like the energy used in absorbing the shock of each step, which is obviously higher when running at higher speed.

But these studies are comparing walking against running. Mike's original question was about the difference between running speeds. So how about we read the original question rather than deciding what we "think" the OP is asking?

The second study indicates higher energy consumption for higher speeds of running over the same distance.

Running calories are pretty much the same per mile.

Walking calories are pretty much the same per mile, up to, say 5mph, where your mechanics start getting forced.

Running burns more calories per mile than walking.

http://www.runnersworld.com/article/0,7120,s6-242-304-311-8402-0,00.html

Work is force times distance. Force is mass times acceleration. Ergo work is mass times acceleration times distance. Intervals require more acceleration than steady state running...more energy/calories if your intervals are at sufficient frequency.

Acceleration is not the same as speed. It is the rate of change in momentum.

You just turned me on. *ahem*

I was hoping for help here as I 'm about to go run. I typically run 4 miles at about a 10min/mi pace. I always believed faster meant more calories burned but since no one seems to agree that this is infact true, I will just enjoy my run at what ever time it ends up being :-)

Where's Sheldon Cooper when you need him....?!

Sheldon Cooper would be useless because:

1) He would consider this beneath him and refuse to contribute
2) He knows nothing about sports and exercise whatsoever
3) He is a fictional character.

Perhaps ones sense of humour and ability to tolerate humour decrease proportionately to the speed and distance you run.......?

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?

my personal experience thus far: I started running on our high school track the beginning of July. Having never run before, I obviously didnt just start running my full distance right away. I have found that it doesnt matter how much distance I cover, what matters is the amount of effort used that changes the calories burned. (I use a heart rate monitor and stop watch faithfully). I consistantly do 3 miles - two of them running with the same calorie burn almost with in the 10's each day. But in the beginning when I was only able to walk the 3 miles the calorie burn was alot less - because the heart rate wasnt increased from effort.)

so my advice - as you try to improve your times, you should see an increase in calorie burn on your heart rate monitor. (becareful not to just use the MFP values as they can be off depending on your fitness level and the "average" person they base their calories on)