human energy

[pirateeye]

i'd like some opinions please

i walk a lot and enjoy it, i like walking fast and far with my dogs.
this evening i had to go walking with my sister for an hour and she happens to be quite a slow walker so i did not enjoy the walk as much, feeling it was slow and boring. when i got home we got into discussing human energy and what you use when walking. one said you use the same amount of energy walking slow, walking fast or running a mile. i always thought you used more energy the faster you go...no matter what the distance...(like walking one mile would use less energy than running one mile?)...like a car uses more fuel the faster it goes?..but apparantly humans are not like cars...:)

anyone know really if you use the same amount of energy walking a mile as running it or do you use more?

[Margaret M.]

It can all get quite complicated with the target heart rates, zones, etc., and there are many differing opinions. Some say if you want to burn fat, work out slow and low but if you want to burn calories work out fast. The following explanation makes sense to me and I have yet to see someone who saunters along, even for long distances, lose any weight.

From link below: I want you to do me a favor. I know you're gonna hate it, but please do it anyway. I promise you it'll make life so much simpler, make things so much clearer, and save us so much time in the coming months.

I want you to go back to school with me for a minute, and review some math.

Now, when I teach this stuff to trainers, as soon as they hear "math" their eyes glaze over and they look like a collective herd of deer caught in the headlights of a Mack truck. But, honestly, how are you going to talk sensibly about calories, diets like "40/30/30," percentages of calories from protein, decoding a food label, or anything else along those lines without unfuzzy-ing up some of the basics in the math department?

Which brings me to the area of "fat burning" zones.

See, one of the biggest misunderstandings and "myth-conceptions" in the field of exercise and weight loss has been around the field of fat burning. Aerobic teachers are constantly admonishing their students to work at a slower rate so they can "burn more fat." Almost all cardio equipment in the gym has a "fat burning" program, and we fitness professionals are constantly bombarded with questions from clients about how to get their heart rate in the target "fat burning zone."

The misconceptions come from a basic confusion between percentages and absolute amounts. See, at rest, the body is always burning a mix of fuels. All other things being equal, it doesn't like to burn protein, so that leaves fats and carbohydrates (more technically, fatty acids and glucose). At rest, the "average" person burns about 70 percent fat and 30 percent carbs. As one moves from rest to activity, the percentage of fuel coming from fat decreases and the percentage coming from carbs increases. The more intense the exercise, the more carbs and the less fat in the mix, until you reach the point called the "anaerobic threshold" where you're going at about your intensity limit. At that point, 99 percent or more of your fuel is pure carbohydrate and 1 percent or less is coming from fat.

Now, this situation has led many people to assume that in order to "burn fat" they need to exercise at lower intensities. They're missing the boat. Why? Because while at rest, although a higher percentage of your calories is indeed coming from fat, you are ultimately burning a lower absolute number of calories. At higher intensity exercise, the percentage of calories from fat goes down, true—but it is a percentage of a significantly higher number.

So, let's say you're exercising at a fairly low intensity that burns, oh, 100 calories in a half-hour. Let's say that 70 percent of those calories come from fat. Your neighbor, however, is working out much harder, outside the magical "fat burning" zone: She's burning up, say 300 calories in that same half hour, but only 50 percent of those calories are from fat. Now do the math. You're burning a higher percentage of fat, but 70 percent of your 100 calories equals 70 fat calories burned. Your neighbor, on the other hand, is burning a lower percentage of fat, but she has burned up 50 percent of 300 calories, or 150 fat calories, more than twice what you've burned in the same period of time!
http://health.msn.com/fitness/articlepage.aspx?cp-documentid=100121314

[Riffman]

Energy = 0.5mv2

Thus energy increases to the square of velocity.

Thus when travelling faster you have a great kinetic energy. It follows therefore that you need a great propulsion force to achieve that energy taking into account Newtons 3rd law of motion: every action has an equal and opposite reaction.

Also the air drag increase according to the equation:

Drag = Cd * A * 0.5 * r * V^2

Which boils down to the same idea that it increase with the square of velocity. Thus you required more energy to overcome the drag at the higher speed.

So when running you use more energy than walking if you are covering the same distance.
[lol]

[rockchick]

Work = distance x force.
Force = mass x acceleration

So, the faster you go, the higher your acceleration, so you should do more work, which uses more calories - right? Well, not exactly.

There's one more factor - time. When you're going faster, you will complete the distance in less time. So you're working harder, for shorter periods.

The end result is that when you're going from Point A to Point B, you traverse the same distance, which uses the same amount of work. You will use the same calories whether you walk or run...but if you run, you will burn those calories at a higher rate, in less time.

[gollach]

Work = distance x force.
Force = mass x acceleration

So, the faster you go, the higher your acceleration

Well, not really. The faster you go, the higher your speed.

Whether or not you have higher acceleration is going to depend on how long it takes you to reach your faster speed. Once you reach that speed and stay there, your acceleration becomes zero.

[NickInTheNorth]

Well, not really. The faster you go, the higher your speed.

Whether or not you have higher acceleration is going to depend on how long it takes you to reach your faster speed. Once you reach that speed and stay there, your acceleration becomes zero.

It's an awful long time since I did anything requiring me to have any theoretical understanding of acceleration, but surely even at a constant speed every change in direction is an acceleration, even if maintaining the same velocity?

[joxville]

Energy = 0.5mv2

Thus energy increases to the square of velocity.

Thus when travelling faster you have a great kinetic energy. It follows therefore that you need a great propulsion force to achieve that energy taking into account Newtons 3rd law of motion: every action has an equal and opposite reaction.

Also the air drag increase according to the equation:

Drag = Cd * A * 0.5 * r * V^2

Which boils down to the same idea that it increase with the square of velocity. Thus you required more energy to overcome the drag at the higher speed.

So when running you use more energy than walking if you are covering the same distance.
[lol]



Also, to reduce the drag effect, remember to run with your mouth shut, it would be like driving with the car window open:D

[Tristan]

Work = distance x force.
Force = mass x acceleration

So, the faster you go, the higher your acceleration, so you should do more work, which uses more calories - right? Well, not exactly.

There's one more factor - time. When you're going faster, you will complete the distance in less time. So you're working harder, for shorter periods.

The end result is that when you're going from Point A to Point B, you traverse the same distance, which uses the same amount of work. You will use the same calories whether you walk or run...but if you run, you will burn those calories at a higher rate, in less time.


Well, not really. The faster you go, the higher your speed.

I agree the faster you go, the higher your speed


Whether or not you have higher acceleration is going to depend on how long it takes you to reach your faster speed. Once you reach that speed and stay there, your acceleration becomes zero.

Well not really. Yes you as person are not accelerating compared to an outside observer but if you are running or walking your legs are in constant movement - always changing speed and direction and therefore accelerating. In addition there is the effect of working against gravity which applies another level of acceleration.
We engage our legs more while we run therefore we will do more work and burn (slightly) more calories running over a given distance.
Probably not worth worrying about, get out there and get moving

[rockchick]

Well, not really. The faster you go, the higher your speed.

Whether or not you have higher acceleration is going to depend on how long it takes you to reach your faster speed. Once you reach that speed and stay there, your acceleration becomes zero.

To reach the higher speed within the same distance, the rate you accelerate at will be higher.

The principal is the same - if you traverse a single mile, whether you walk it in 20 minutes or run it in 5, you use the same calories over that distance. Which was the point of the thread...

if you run for 20 minutes you will use many more calories than if you walk for 20 minutes, and cover more distance.

[joxville]

Personally, I'd just use the car.:D

[Kevin Milkins]

Not wanting to be crude, however I have heard that sex = a 1mile brisk walk.
I know which one I like the best.


And I dont even have to buy the drinks.:lol::lol:

[joxville]

Not wanting to be crude, however I have heard that sex = a 1mile brisk walk.
I know which one I like the best.


And I dont even have to buy the drinks.:lol::lol:


Does someone else have to be involved?:D