calories burned while running

[Special K]

I have a few questions about calories burned while running.

1. How accurate are pages like this:

link

I realize they aren't perfect, but how big a margin of error are we talking? 5%? 10%? 50%?

2. The page above gives data for running at 8 mph for 1 minute. Does the number of calories burned scale linearly with the the speed? Does running at 12 mph burn 1.5x as many calories as running at 8 mph?

3. Does the number of calories burned depend on how difficult the exercise is perceived to be? For example, let's say an untrained guy runs a mile in 8 minutes and struggles through it. By the time he is finished running, he is exhausted.

Now let's say that same guy follows a regular running program. After a few months of this, he is able to run that same 8 minute mile without much difficulty. Does he burn fewer calories in this case compared to when he first started running? I would think not since his muscles must still do the same amount of work to propel his body down the track/sidewalk/treadmill, but then again his heart and CVS would likely not be working as hard.

My purpose in asking these questions is to hopefully develop a number of calories to consume to offset a given amount of cardio added into my workout routine. I would like to incorporate more running into my routine, but I don't want to lose any muscle mass. Consequently, I would need to eat more to offset the extra calories burned by running.

On the other hand, I don't want to eat too much extra and gain fat.

BTW, if anyone knows of a running or exercise science forum where this question would be more appropriate, feel free to provide a link.

 

[StageLeft]

That chart looks ok, maybe a touch high for running. At 180 I've estimated that running around 6.5 mph I burn maybe 600 extra calories/hour.

I would think that running 15 mph would burn at lot more than 50% more than 10 mph. As we know, running a mile burns a lot more actual calories than walking a mile (despite the earlier myth to the contrary) because a person is jumping up and down, essentially; it is difficult. Increasing speed while running is like with cycling, a small increase can be disproportionatly difficult. For example, I know that cycling at 20 mph probably uses about half the calories as cycling at 26 mph.

In your case of an untrained guy, he's less efficient and capable and so a 170 lb elite runner would burn far fewer calories running a mile at 8 mph than a couch potato, no doubt about it....but then again his heart and CVS would likely not be working as hard.
I think that is the point. He will be under greater duress and probably sweating harder.

 

[MetalMat]

I general I say around 100 calories per mile, maybe +/- 20.

 

[brikis98]

All of these calorie formulas are very rough estimates. Individual metabolism, level of training, running mechanics, and many other factors can make a pretty big difference in those numbers. The approach that I would recommend is to use these estimates as a base and then monitor your diet & exercise for a while so you can gauge how accurate they are. For example, if after a couple weeks you find that your weight has dropped, that probably means you are underestimating the calories burned during your running. If your weight goes up, you are overestimating it. Tweak the numbers accordingly, and continue monitoring for the next couple weeks. Continue doing this until your calorie estimates start matching what you see in the actual world. It's a bit tedious and takes a while, but eventually, you'll have a pretty good feel for how many calories you burn from a given run. You'll never be 100% accurate, but you should be able to get it close enough. Just remember to monitor your weight over longer periods of time (1-2 weeks), as your weight can fluctuate on a daily basis due to many unrelated factors, but over a longer period, the true trend should be more visible.

 

[Special K]

Originally posted by: MetalMat
I general I say around 100 calories per mile, maybe +/- 20.

Independent of the speed?

 

[RagingBITCH]

The treadmill calorie counter is just a formula based off of the weight you put in and the speed you put in, just like the page you linked to above is. It's based on so many different factors like brikis mentioned.

It's all kind of trial and error anyway - you really don't know exactly how many calories you need to maintain weight - it's just a guess based on how active you are, etc.

Back when I cared about calorie count when running, I'd take 10-15% off the number displayed on the treadmill - I'd rather err on the side that the number displayed is over what I really burned, rather than under.

If you'd like a more scientific answer, RunnersWorld has a decent forum for runners. In terms of when a guy is more efficient - does he burn the same number of calories - I'd say the trained guy burns more calories. (I disagree with Skoorb) Your body becomes more efficient and like anyone who trains, uses more energy (burns calories) than someone who is untrained/doesn't work out. But that's just my two cents.

 

[SWScorch]

Originally posted by: Special K

Originally posted by: MetalMat
I general I say around 100 calories per mile, maybe +/- 20.

Independent of the speed?

Speed actually doesn't make all that much of a difference when you're discussing calories per mile, since it takes you less time to run faster. You burn more calories per minute, but since you're running less time it works out to be about the same. The rule of thumb is 100 calories per mile, running or walking, although hills require more energy so they increase the amount of calories burned.

 

[SWScorch]

Originally posted by: RagingBITCH
If you'd like a more scientific answer, RunnersWorld has a decent forum for runners. In terms of when a guy is more efficient - does he burn the same number of calories - I'd say the trained guy burns more calories. (I disagree with Skoorb) Your body becomes more efficient and like anyone who trains, uses more energy (burns calories) than someone who is untrained/doesn't work out. But that's just my two cents.

If you're more efficient, you would use less fuel. If elites burned more calories per mile than less-trained runners, you would see elites running out of fuel at mile 18 of a marathon. The better trained you are, the more economical your metabolism, the less fuel you burn, the less calories you expend. This is the point of long runs when marathon training; you teach your body to burn glucose and fat more efficiently so you don't hit the wall (total glycogen depletion) as soon or at all.

 

[Special K]

Originally posted by: SWScorch

Originally posted by: Special K

Originally posted by: MetalMat
I general I say around 100 calories per mile, maybe +/- 20.

Independent of the speed?

Speed actually doesn't make all that much of a difference when you're discussing calories per mile, since it takes you less time to run faster. You burn more calories per minute, but since you're running less time it works out to be about the same. The rule of thumb is 100 calories per mile, running or walking, although hills require more energy so they increase the amount of calories burned.

For some workouts, I will set a constant time and speed. In this case, the calories burned for a given speed is important, because the time of the run will not change. If the run feels good, then I will leave the time the same and increase the speed on the next workout.

How do calories burned vary with running speed? Is it linear?

Also, how could walking burn the same number of calories as running? Or are you assuming that someone who walks for a workout will walk for a much longer period of time than if they had run, which would burn an equal number of calories over the course of the entire workout?

 

[spacejamz]

my nike+, polar heart rate monitor and the calorie counter on the treadmill (after entering my age and weight) always gave me different readings (although the nike+ and the polar were fairly close)...

I trust the polar reading the most since it actually measures your heart rate during the whole workout...

 

[chalmers]

If you have to run, look up High Intensity Interval Training on google. It's much more efficient than running for hours on end.

 

[SociallyChallenged]

Originally posted by: chalmers
If you have to run, look up High Intensity Interval Training on google. It's much more efficient than running for hours on end.

It depends on the individual's goals. Cross-training with it if one's goals are aimed toward endurance is a good idea and it's very helpful for those looking to do sprints. However, if one wants to be a well developed endurance runner, then many miles will have to be run. HIIT is not the cure-all, but should be added to those looking to improve their cardio in any respect.