Calories burned running: is speed a factor at all?

ixap

To be fair, I probably should have asked how far on in their training schedule they were before recommending anything. My bad.

Me too I suppose, LOL, I just assumed based on the fact that she's walking more than running.
azalais7, how far are you in your training schedule, so we can give you good advice?

ninerbuff

I've been told that if I walk 5 miles I burn exactly the same amount of calories as if I run 5 miles.

I'm just done a lot faster running

I've read several successtories in papers etc. of people losing huge amount of weight by "just" walking. Never hit the gym or ran, just walking - every day.

I thought this to be true too till a physics professor showed me different. On average, you burn approximately 50 more calories per mile running it than walking it. Now 50 calories for a mile isn't that big a deal, but if you ran 4 miles and walked 4 miles, 200 calories difference is significant.

A.C.E. Certified Personal and Group Fitness Trainer
IDEA Fitness member
Kickboxing Certified Instructor
Been in fitness for 28+ years and have studied kinesiology and nutrition

tappae

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.

So, I know this is kind of a hijack, but I don't know why everyone trusts their HRMs so much. It really doesn't seem likely that you could burn twice as much over a given distance just by going faster (even if there is some slight difference).

Let's try a thought experiment: Say I go out and run a mile at an easy pace and keep my heart rate around 140. MFP database and my HRM agree that I'll burn around 135 calories. Instead, let's say I sprint all out and get my heart rate up to max. Then, I stop and take a break, but not long enough for my heart to recover much. Then, I sprint again. I repeat this for the whole mile and finish in about the same amount of time. My average heart rate for the run is going to be much higher in the second case and my HRM will give me a much higher calorie burn estimate, but I will have done virtually the same amount of work and therefore will have burned approximately the same number of calories.

Put another way: let's say I run 3 miles in 30 minutes. MFP and HRM will agree that I burned about 400 calories. Let's say I'm not feeling great and I have to stop and rest a few times, but always less than one minute so my heart rate stays elevated. On this day maybe I finish in 33 minutes. The database will still say I burned about 400 calories (since I did the same work). My heart rate monitor will say that I burned more than that because my heart rate was elevated for a longer amount of time.

rkr22401

This is another reason HRM's are not so good for strength training. HRMs are pretty good for steady state cardio. Less so for intervals and the like. I believe most manufacturers say so in their literature.

meerkat70

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).

It's slightly more complex: http://www.runnersworld.com/article/0,7120,s6-242-304-311-8402-0,00.html

jhardenbergh

Well you basically burned the same amount of calories in less time, so I would say speed is a factor in calorie burn, but probably because your heart rate was higher during the faster portion of your run. I would think terrain would be a factor too, if part of your run was uphill you would more than likely burn more calories as well.

Crochetluvr

I did an experiment a couple days ago when I went water jogging. Normally I jog in the 4 1/2 ft. area and the water is up to my chest. I cant move fast but I have to use more effort. I used my HRM to measure my pulse rate...it never got past 111.

Then I decided to move down into the 3 1/2 ft area of the pool and started jogging again. My heart rate shot up to 138!

So I can only assume that the faster I move, the more calories I was burning for the same amount of time.

BrawlerBella

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.

AGREED, well put!

I use my HRM with the Endomondo app. The app takes heart beat into consideration to give you a gross caloric burn.

rkr22401

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).

It's slightly more complex: http://www.runnersworld.com/article/0,7120,s6-242-304-311-8402-0,00.html

Of course it is. Isn't everything? But the laws of physics still apply. The difference is in the simplifying assumptions used. We already discussed the differences (mechanics of running, efficiency, etc) at length.

meerkat70

deleted cause I just can't be arsed ... :-D

LiveEnjoyEndure

This is one of the most intese threads I have read in a long time! Physics does not answer biology questions.

The issues are VERY complex indeed. At the end of the day all variables taken into account calories are a measure of energy. Our bodies burn energy based on the activity we do. The more vigorous, the more energy we burn. Muscles burn the most energy in the least amount of time. Therefore the more muscles you use the more calories (energy) you will metabolism (burn).

The length of the cardio will make a difference, so the longer you workout the more energy you will use.

The type of exercise will effect the calories you use vis-a-vis cardio vs strength. Cardio will use more calories because you are not just using you skeletal muscles, but also your respiratory and cardio vascular system (intensely). Ironically many people cycle and run like they are doing a strength workout (low cadence). Which does not use the cardio vascular system in an intense way.

Your running form (efficiency) will also effect the calories you burn. Do I nee to spell it out?

Prior activity will effect the process of metablism, that is, do you have stores of glycogen in muscles and liver, or does your body need to metabolise lipids to generate energy. Also the contents of your stomach, when you last ate and what nutrients you take on board in what form will also effect metabolism and calories burnt.

rkr22401

I don't disagree at all. For the record, I never said running and walking burn the same number of calories. Of course running burns more calories than walking. I was simply saying this is not some violation of the laws of physics. There are perfectly reasonable explanations why this is the case.

Everything you just explained is related to the physics of how the body uses energy. Physics is simply why the universe (including our bodies) behaves in the way it does. It is true the factors are too complex to boil down to an equation.

pattyg1821

Well the more you weigh the more calories you burn. Just last night I did 30 mins of interval training on treadmill. High speed was 4.5 which is basically running for me and high incline was 7 -since I am 5'2 and when I was finished I had been on treadmil for 30mins 30 sec and burned 204 calories and went 1.47 miles.

Most time I do max speed about 3 with incline of 5 and if I do for 20mins I will burn about 122 cals

To answer I think yes....Because you are going to get your heart rate up unlike just walking keeping your heart rate normal