Running: Does speed impact calories burned?

nyiballs

I know this topic exists in other spots, but I wanted to add a wrinkle.

From a physics perspective, Work = Force x Distance. So moving a 120 kg object 5km is the same amount of work, whether it's done in a minute or an hour.

To that end, you'd imagine that someone walking 3 miles would burn the same calories as someone running 3 miles. The runner would just burn those calories much more quickly and have more time to enjoy the rest of their day.

From a physiological standpoint though, calories burned are just as much a factor of keeping your heart rate in the cardio burn zone. So walking may only get you to 100 bpm, while running you may hang at 160 bpm, which would make you burn more calories on your run.

So this got me thinking... If my goal is to run 3 miles, If I knock it our at an 8 minute mile pace, my time is 24 min, but if I go at a 9 minute pace, my time is 27 minutes. At both of those paces, my heart rate is still going to be above 150, but at the slower pace, I'll have an extra 3 minutes that I'm running. So... would it be reasonable to assume, that, to a point, you can actually burn more calories by running slightly slower over a fixed distance? My gut tells me yes...

My instinct is that if you are running based on a fixed distance, you will maximize your burn by running at the slowest possible pace that will keep your HR at or above 150.

Wanted to hear some other thoughts though...

Strokingdiction

How about this angle:

What is the hardest? To slowly jog for a mile or to sprint for a mile? The work that's required to keep a body in motion at a top speed is far greater than the work required to keep a body in motion at a slow speed.

The same goes for cars. The faster they go, the more energy it takes to move them. A car going 150 miles per hour will burn more gasoline than a car going 10 miles per hour even though they are traveling the same distance.

You're missing a variable in your equation.

brianpperkins

http://www.runnersworld.com/weight-loss/how-many-calories-are-you-really-burning?page=single


Your Total Calorie Burn/Mile .75 x your weight (in lbs.)
Your Net Calorie Burn/Mile .63 x your weight


Adapted from "Energy Expenditure of Walking and Running," Medicine & Science in Sport & Exercise, Cameron et al, Dec. 2004.

aswearingen22

All I know is I burn roughly 100 calories per mile no matter how fast/slow I go. The only thing that will increase that burn is if there is hills and wind.

Paco4gsc

From a physics perspective, your scenario is a little off. Yes, Work = Force x Distance, but remember Force = Mass x Acceleration. To increase your speed over a fixed distance, you need more acceleration. With fixed mass and distance, more acceleration means more work/energy needed. Hope this helps.

However, in terms of running, there are ways to improve running efficiency and thus increase speed without much change in calorie expenditure and vice versa. In general though, run faster = burn more calories.

Halasana

Yes, speed affects calories burned very much. The physiological standard for calorie burn is calculated using METs, or Metabolic Equivalent of Task, which takes body weight into consideration along with speed. Definitions:

"It is commonly used in medicine to express metabolic rates measured during a treadmill test. Two definitions of the MET are essentially equivalent:
• 1 MET is equivalent to a metabolic rate consuming 3.5 milliliters of
oxygen per kilogram of body weight per minute.
• 1 MET is equivalent to a metabolic rate consuming 1 kilocalorie per
kilogram of body weight per hour."

Here is the equation for calculating calorie burn by converting METs to calories consumed per minute:

kcal/min = METs x body weight in kilograms ÷ 60.

That's per minute . . . to calculate the calories burned per hour, omit the final step (÷ 60).

To see the table of METs that you can plug into your equation, go here: http://www.buchholzmedgroup.com/new_content/CA_PREVENTION/MET table Exercise.pdf

Note: there are a limited number of exercises and activities for which METs have been tested and standardized.

samamps88

How about this angle:

What is the hardest? To slowly jog for a mile or to sprint for a mile? The work that's required to keep a body in motion at a top speed is far greater than the work required to keep a body in motion at a slow speed.

The same goes for cars. The faster they go, the more energy it takes to move them. A car going 150 miles per hour will burn more gasoline than a car going 10 miles per hour even though they are traveling the same distance.

You're missing a variable in your equation.

This analogy is not applicable as cars unlike humans do not improve their efficiency as they improve.

By this I mean if you take a person who can run comfortably at a 5min/mile pace versus a person who is Comfortable at 10min/mile then the two will still burn roughly the same amount of calories running the same distance (assuming all other factors are the same, age height weight ect)

As you train your body adapts to the work load this is the reason that if you always do exactly the same thing you wil plateau.

This is a very imprortant factor to bear in mind. So yes speed will affect the calories burned but not a great deal it is distance that is the key in calculating burn in runnning.

So using your example if you run 3miles in 30mins you will burn less calories per minute than if you run 3miles in 21mins however you are running 7minutes longer so at the end of the day running 3miles will burn roughly the same calories no matter what speed you run it at.

Bear in mind this is for steady state running- sprinting or intervals use different energy systems and therefore will have different outcomes and obviously you have the work/rest to take into account but we wont get into that.

astronomicals

However, in terms of running, there are ways to improve running efficiency and thus increase speed without much change in calorie expenditure and vice versa. In general though, run faster = burn more calories.

ummm..no.... slower is less efficient, thus, running the same distance would burn more calories at a slower pace. your conclusion doesnt match your statement prior.

leslisa

I didn't read the above posts so I apologize if someone already said this. I researched the daylights out of above topic and from .edu sites and .gov sites here's some numbers.
Running (6-minute mile) .115 x weight x min = cals burned on run
Running (8-minute mile) .095 x weight x min = cals burned on run
Running (9-minute mile) .087 x weight x min = cals burned on run
Walking, normal pace, asphalt road .036 x weight x min = cals burned on run
Walking, normal pace, fields & hills .037 x weight x min = cals burned on run

Then you have to subtract what you would have burned sitting on your butt:
Sitting Still .009 x weight x min = cals burned sitting

Cals burned on run - cals burned sitting = extra cals that may be consumed.

For me (I am anywhere from 125 - 135 lb at any given time so this is an average):
Walking 1 mile: 43 cals
Running slow 1 mile: 65 cals
Running fast 1 mile: 98 cals

Note that the calculators I found do vary slightly based on who is publishing the work.

Cheers!

mamahannick

All I know is I burn roughly 100 calories per mile no matter how fast/slow I go. The only thing that will increase that burn is if there is hills and wind.

This.
Yes, incline or hills or obstacles or whatever would increase calories burned, but in general a mile is a mile. I also burn roughly 100 calories per mile. That can be a 9-minute mile or a 12-minute mile , but the burn is still the same.

iplayoutside19

All I know is I burn roughly 100 calories per mile no matter how fast/slow I go. The only thing that will increase that burn is if there is hills and wind.

You forgot time. More time equals more calories.

Linnaea27

I didn't read the above posts so I apologize if someone already said this. I researched the daylights out of above topic and from .edu sites and .gov sites here's some numbers.
Running (6-minute mile) .115 x weight x min = cals burned on run
Running (8-minute mile) .095 x weight x min = cals burned on run
Running (9-minute mile) .087 x weight x min = cals burned on run
Walking, normal pace, asphalt road .036 x weight x min = cals burned on run
Walking, normal pace, fields & hills .037 x weight x min = cals burned on run

Then you have to subtract what you would have burned sitting on your butt:
Sitting Still .009 x weight x min = cals burned sitting

Cals burned on run - cals burned sitting = extra cals that may be consumed.

For me (I am anywhere from 125 - 135 lb at any given time so this is an average):
Walking 1 mile: 43 cals
Running slow 1 mile: 65 cals
Running fast 1 mile: 98 cals

Note that the calculators I found do vary slightly based on who is publishing the work.

Cheers!

Excellent info, I'm posting so I can reference this later.

aswearingen22

All I know is I burn roughly 100 calories per mile no matter how fast/slow I go. The only thing that will increase that burn is if there is hills and wind.

You forgot time. More time equals more calories.

No, I didn't forget time. If on a flat course, and it takes me 6 mins to run a mile (hahaha), I'll burn 100 calories, if on that same flat course, I walk the mile in 18 mins, I'll burn 100 calories. I've been running for about 12 years, I've probably walked/run every speed from 7min miles to 18 min miles at 5k's with my kids, it's always roughly 100 calories per mile, regardless how little or how long it takes me. When I'm lighter, it's more like 90 calories per mile. My DH who is heavier, burns more like 120 calories per mile. The time is irrelevant.

nyiballs

That goes back to my original question/point.

Work = Force x Distance and Force = Mass * Acceleration

Therefore:
Work = Mass x Acceleration x Distance

If you run at a fixed pace, your acceleration is zero. If you interval train, you have positive AND negative acceleration that cancel each other out. Over the course of a run, the net acceleration would be constant relative to your average overall pace.

So... to me... it would appear that speed does have a slight impact, but the difference in acceleration between let's say a 3mph pace and a 6mph pace over a decent time period is rather small. So, in fact, mass and distance are really the largest determining factor in calories burned, and pace has a minimal impact.

Strokingdiction

That goes back to my original question/point.

Work = Force x Distance and Force = Mass * Acceleration

Therefore:
Work = Mass x Acceleration x Distance

If you run at a fixed pace, your acceleration is zero. If you interval train, you have positive AND negative acceleration that cancel each other out. Over the course of a run, the net acceleration would be constant relative to your average overall pace.

So... to me... it would appear that speed does have a slight impact, but the difference in acceleration between let's say a 3mph pace and a 6mph pace over a decent time period is rather small. So, in fact, mass and distance are really the largest determining factor in calories burned, and pace has a minimal impact.

You also have to take into account what the human body is designed for.A slow walk is where we are most efficient but a fast walk equal to that of a slow jog will burn more calories than the slow jog because it isn't easy for our bodies to do. Thus not even the acceleration portion of the equation applies accurately.

Simply put: human bipedal motion cannot be reduced to a simplistic physics equation.

MeanderingMammal

If you run at a fixed pace, your acceleration is zero.

Not sure about how you run, but when I'm running my legs and arms are going through a cyclic acceleration and deceleration process that moves my total bodymass predominantly forwards, with a little bit of vertical motion.

I think that your logic is a little flawed as you appear only to be thinking about kinetic energy, rather than the conversions and complexity of movement.

n_unocero

dcarr67

All I know is I burn roughly 100 calories per mile no matter how fast/slow I go. The only thing that will increase that burn is if there is hills and wind.

You forgot time. More time equals more calories.

No, I didn't forget time. If on a flat course, and it takes me 6 mins to run a mile (hahaha), I'll burn 100 calories, if on that same flat course, I walk the mile in 18 mins, I'll burn 100 calories. I've been running for about 12 years, I've probably walked/run every speed from 7min miles to 18 min miles at 5k's with my kids, it's always roughly 100 calories per mile, regardless how little or how long it takes me. When I'm lighter, it's more like 90 calories per mile. My DH who is heavier, burns more like 120 calories per mile. The time is irrelevant.

Time isn't irrelevant. Lets say you run a 10 min mile and burn 100 cal. If you run it in 7 min and burn the same 100 cal, you have 3 minutes where your body is still burning calories. So over that 10 minutes, you burn more by running faster.

blues4miles

All I know is I burn roughly 100 calories per mile no matter how fast/slow I go. The only thing that will increase that burn is if there is hills and wind.

This.
Yes, incline or hills or obstacles or whatever would increase calories burned, but in general a mile is a mile. I also burn roughly 100 calories per mile. That can be a 9-minute mile or a 12-minute mile , but the burn is still the same.

My experience is different. But I am heavier and slower. It's pretty much entirely an equation based on how much you weigh, time and distance. I tend to burn about 100 calories per mile once I hit a certain tipping point in my speed (right now that's about a 13:45 min-mile at my current weight, and at lighter weight it's been 12-something). If I jog slower than that (yes I can jog slower than that) it will be less. I can maybe get it to 125 per mile if I get into faster runs. But eventually in order to get faster I am gonna have to lose weight. Meaning the same speed will burn less calories. So it's probably always going to be 100 +/- 20 or so for jogging. I use a Garmin with a heart rate monitor (though I don't think the Garmin uses the HRM for the calorie burn) but have verified their numbers by a variety of other sources on the 'net and they seem pretty solid.

Azdak

a lot of inaccurate replies....

try a heart rate monitor

Love the irony.

froeschli

Physics would also tell you there was no work done if you lifted a barbell and put it back to where it started. (No change in energy level or some such - sorry the memory is a bit dim...)
As opposed to theory deceleration or putting stuff back on the floor does not give us our energy back.

Anyhow, as for running, you burn more energy when running faster simply because it enables you to go farther in the amount of time you have.
For me, over the course of a season I usually end up burning less over the same distance, because I lose weight and get faster. Reducing two factors - weight and time.