Power vs Energy
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blambo61
Posts: 4,372 Member
If a person walks a certain distance, the energy expended getting there is the same no matter how fast you go to get there. If you get someplace fast, the power level you operated at to get there was higher than if you went slower but the energy expended (cals) is the same whether you go fast or slow.
How does going faster help us then in loosing cals? I think the answer is that the higher power levels required for going faster (or lifting heavier) will increase our base metabolism rate. I'm not sure how that works but maybe going faster helps develop bigger mitochondria to handle the power levels required to go faster which then require more energy to function when peak loads are not placed on them thus upping the bmr. Any biologists out there to explain?
How does going faster help us then in loosing cals? I think the answer is that the higher power levels required for going faster (or lifting heavier) will increase our base metabolism rate. I'm not sure how that works but maybe going faster helps develop bigger mitochondria to handle the power levels required to go faster which then require more energy to function when peak loads are not placed on them thus upping the bmr. Any biologists out there to explain?
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If a person walks a certain distance, the energy expended getting there is the same no matter how fast you go to get there. If you get someplace fast, the power level you operated at to get there was higher than if you went slower but the energy expended (cals) is the same whether you go fast or slow.
How does going faster help us then in loosing cals? I think the answer is that the higher power levels required for going faster (or lifting heavier) will increase our base metabolism rate. I'm not sure how that works but maybe going faster helps develop bigger mitochondria to handle the power levels required to go faster which then require more energy to function when peak loads are not placed on them thus upping the bmr. Any biologists out there to explain?
I think you're overthinking things...
IIRC from physics class 20+ years ago...Work (ie energy expended) = force exerted x distance
If you keep distance constant, then the variable must be force.
If you have two objects of equal mass, it takes a greater force to move one faster than the other....ergo, more energy expended0 -
You aren't a sphere in a vacuum. To go faster your muscles need to do more contractions. Each contraction requires a certain amount of energy, more contractions = more energy expended.0
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If a person walks a certain distance, the energy expended getting there is the same no matter how fast you go to get there. If you get someplace fast, the power level you operated at to get there was higher than if you went slower but the energy expended (cals) is the same whether you go fast or slow.
How does going faster help us then in loosing cals? I think the answer is that the higher power levels required for going faster (or lifting heavier) will increase our base metabolism rate. I'm not sure how that works but maybe going faster helps develop bigger mitochondria to handle the power levels required to go faster which then require more energy to function when peak loads are not placed on them thus upping the bmr. Any biologists out there to explain?
Erm.... no, not even a little bit. To get someplace faster, you expend MORE energy because you worked harder than the slower pace. Because you had to fight gravity harder, your muscles required more oxygen and your body put off more heat, your heart rate had to increase. All the things that happen when one exercises. If you burned 300 calories going from point A to point B at 3.0 mph, you're for sure gonna burn more than that going from point A to point B at 6.5 mph. Jogging is harder than walking, and thus, you expend more energy putting out the extra effort to increase your speed.
ETA: In case there's about to be an argument about walking, this is still the case. More effort is required to walk at 4 mph than to walk at 2.5 mph.0 -
CoffeeNCardio wrote: »If a person walks a certain distance, the energy expended getting there is the same no matter how fast you go to get there. If you get someplace fast, the power level you operated at to get there was higher than if you went slower but the energy expended (cals) is the same whether you go fast or slow.
How does going faster help us then in loosing cals? I think the answer is that the higher power levels required for going faster (or lifting heavier) will increase our base metabolism rate. I'm not sure how that works but maybe going faster helps develop bigger mitochondria to handle the power levels required to go faster which then require more energy to function when peak loads are not placed on them thus upping the bmr. Any biologists out there to explain?
Erm.... no, not even a little bit. To get someplace faster, you expend MORE energy because you worked harder than the slower pace. Because you had to fight gravity harder, your muscles required more oxygen and your body put off more heat, your heart rate had to increase. All the things that happen when one exercises. If you burned 300 calories going from point A to point B at 3.0 mph, you're for sure gonna burn more than that going from point A to point B at 6.5 mph. Jogging is harder than walking, and thus, you expend more energy putting out the extra effort to increase your speed.
ETA: In case there's about to be an argument about walking, this is still the case. More effort is required to walk at 4 mph than to walk at 2.5 mph.
Sorry, but I'm an engineer and understand energy and power very well. I don't know biology very well. If you go 10miles/hr for 30 min you go five miles. If you go 5miles/hr for and 1 hr, you go five miles. Both will expend the same energy (Energy=Force x Distance). You will have been operating at a higher power setting (Power=Force x Velocity) when you go faster but for only 1/2 the time with my example. The energy expended is the same for both. I'm not including small factors like wind resistance or heat expended.
Effort at a given instant is associated with your power level. Effort over time or distance is associated with energy expended.0 -
I purposely posted this knowing how the power and energy thing worked to get people to think and also to get feedback on why it will overall be better to go faster on the biological level (assuming you don't get injured).0
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juggernaut1974 wrote: »If a person walks a certain distance, the energy expended getting there is the same no matter how fast you go to get there. If you get someplace fast, the power level you operated at to get there was higher than if you went slower but the energy expended (cals) is the same whether you go fast or slow.
How does going faster help us then in loosing cals? I think the answer is that the higher power levels required for going faster (or lifting heavier) will increase our base metabolism rate. I'm not sure how that works but maybe going faster helps develop bigger mitochondria to handle the power levels required to go faster which then require more energy to function when peak loads are not placed on them thus upping the bmr. Any biologists out there to explain?
I think you're overthinking things...
IIRC from physics class 20+ years ago...Work (ie energy expended) = force exerted x distance
If you keep distance constant, then the variable must be force.
If you have two objects of equal mass, it takes a greater force to move one faster than the other....ergo, more energy expended
True but you are not doing it as long so the energy is the same. Power is not the same. Promise!0 -
I purposely posted this knowing how the power and energy thing worked to get people to think and also to get feedback on why it will overall be better to go faster on the biological level (assuming you don't get injured).
Biology and engineering aren't really related. To move faster a person has to convert ATP into ADP at a higher rate.
ETA: It's in the proportions, not the time. You burn greater calories per minute at a faster rate. If I were to walk 2 miles at 3 mph I would burn 226 calories in 40 minutes. If I were to run 2 miles at 6 mph I would burn 316 calories in 20 minutes. Doesn't matter that it was a shorter time for the same distance.0 -
I purposely posted this knowing how the power and energy thing worked to get people to think and also to get feedback on why it will overall be better to go faster on the biological level (assuming you don't get injured).
Biology and engineering aren't really related. To move faster a person has to convert ATP into ADP at a higher rate.
Power is the time-rate of energy. You are talking about power. Biological systems have mass and are moved by forces. They do relate in that context.0 -
I purposely posted this knowing how the power and energy thing worked to get people to think and also to get feedback on why it will overall be better to go faster on the biological level (assuming you don't get injured).
Biology and engineering aren't really related. To move faster a person has to convert ATP into ADP at a higher rate.
Power is the rate of energy. You are talking about power. Biological systems have mass and are moved by forces. They do relate in this context.
No, they really don't. We aren't machines.0 -
I purposely posted this knowing how the power and energy thing worked to get people to think and also to get feedback on why it will overall be better to go faster on the biological level (assuming you don't get injured).
Biology and engineering aren't really related. To move faster a person has to convert ATP into ADP at a higher rate.
ETA: It's in the proportions, not the time. You burn greater calories per minute at a faster rate. If I were to walk 2 miles at 3 mph I would burn 226 calories in 40 minutes. If I were to run 2 miles at 6 mph I would burn 316 calories in 20 minutes. Doesn't matter that it was a shorter time for the same distance.
I wonder what is being used for the calculations. It isn't energy = force x distance or they would be the same.0 -
I purposely posted this knowing how the power and energy thing worked to get people to think and also to get feedback on why it will overall be better to go faster on the biological level (assuming you don't get injured).
Biology and engineering aren't really related. To move faster a person has to convert ATP into ADP at a higher rate.
Power is the rate of energy. You are talking about power. Biological systems have mass and are moved by forces. They do relate in this context.
No, they really don't. We aren't machines.
We have no mass and don't respond to forces?0 -
If a person walks a certain distance, the energy expended getting there is the same no matter how fast you go to get there.
Running burns more calories. See this study:
ncbi.nlm.nih.gov/pubmed/15570150
Higher intensity exercise does increase the metabolic rate. There are numerous reasons for this, including increased muscle repair, and there's evidence it increases thyroid function:
ncbi.nlm.nih.gov/pubmed/16380698
Increased lymph flow probably plays a part too.
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I purposely posted this knowing how the power and energy thing worked to get people to think and also to get feedback on why it will overall be better to go faster on the biological level (assuming you don't get injured).
Biology and engineering aren't really related. To move faster a person has to convert ATP into ADP at a higher rate.
ETA: It's in the proportions, not the time. You burn greater calories per minute at a faster rate. If I were to walk 2 miles at 3 mph I would burn 226 calories in 40 minutes. If I were to run 2 miles at 6 mph I would burn 316 calories in 20 minutes. Doesn't matter that it was a shorter time for the same distance.
I wonder what is being used for the calculations. It isn't energy = force x distance or they would be the same.
They must be including factors for wind, increasing friction forces as a function of speed, or more heat loss while going faster. I acknowledge all these could use up more energy while going faster.
My bio question is will it also result in an increased bmr by going faster consistently. I think it will.0 -
I purposely posted this knowing how the power and energy thing worked to get people to think and also to get feedback on why it will overall be better to go faster on the biological level (assuming you don't get injured).
Biology and engineering aren't really related. To move faster a person has to convert ATP into ADP at a higher rate.
ETA: It's in the proportions, not the time. You burn greater calories per minute at a faster rate. If I were to walk 2 miles at 3 mph I would burn 226 calories in 40 minutes. If I were to run 2 miles at 6 mph I would burn 316 calories in 20 minutes. Doesn't matter that it was a shorter time for the same distance.
I wonder what is being used for the calculations. It isn't energy = force x distance or they would be the same.
You're right, because we have chemistry in our bodies that means we don't use that equation. The type of fuel used for energy is different at different speeds, which impacts the amount of calories burned. That's part of the ATP/ADP equation I mentioned. There's also oxygen consumption and muscle use difference between the two that have to be accounted for.0 -
CoffeeNCardio wrote: »If a person walks a certain distance, the energy expended getting there is the same no matter how fast you go to get there. If you get someplace fast, the power level you operated at to get there was higher than if you went slower but the energy expended (cals) is the same whether you go fast or slow.
How does going faster help us then in loosing cals? I think the answer is that the higher power levels required for going faster (or lifting heavier) will increase our base metabolism rate. I'm not sure how that works but maybe going faster helps develop bigger mitochondria to handle the power levels required to go faster which then require more energy to function when peak loads are not placed on them thus upping the bmr. Any biologists out there to explain?
Erm.... no, not even a little bit. To get someplace faster, you expend MORE energy because you worked harder than the slower pace. Because you had to fight gravity harder, your muscles required more oxygen and your body put off more heat, your heart rate had to increase. All the things that happen when one exercises. If you burned 300 calories going from point A to point B at 3.0 mph, you're for sure gonna burn more than that going from point A to point B at 6.5 mph. Jogging is harder than walking, and thus, you expend more energy putting out the extra effort to increase your speed.
ETA: In case there's about to be an argument about walking, this is still the case. More effort is required to walk at 4 mph than to walk at 2.5 mph.
Sorry, but I'm an engineer and understand energy and power very well. I don't know biology very well. If you go 10miles/hr for 30 min you go five miles. If you go 5miles/hr for and 1 hr, you go five miles. Both will expend the same energy (Energy=Force x Distance). You will have been operating at a higher power setting (Power=Force x Velocity) when you go faster but for only 1/2 the time with my example. The energy expended is the same for both. I'm not including small factors like wind resistance or heat expended.
Effort at a given instant is associated with your power level. Effort over time or distance is associated with energy expended.
That's not even true for cars, which get different gas mileage at different speeds. (In the real world, factors like wind resistance actually exist and affect results.)
For the human machine, running is not as efficient a movement as walking -- you'll get there faster, but you must expend more energy than you would if you walked the same distance.0 -
Cherimoose wrote: »If a person walks a certain distance, the energy expended getting there is the same no matter how fast you go to get there.
Running burns more calories. See this study:
ncbi.nlm.nih.gov/pubmed/15570150
Higher intensity exercise does increase the metabolic rate. There are numerous reasons for this, including increased muscle repair, and there's evidence it increases thyroid function:
ncbi.nlm.nih.gov/pubmed/16380698
Increased lymph flow probably plays a part too.
Thanks0 -
I purposely posted this knowing how the power and energy thing worked to get people to think and also to get feedback on why it will overall be better to go faster on the biological level (assuming you don't get injured).
Biology and engineering aren't really related. To move faster a person has to convert ATP into ADP at a higher rate.
Power is the rate of energy. You are talking about power. Biological systems have mass and are moved by forces. They do relate in this context.
No, they really don't. We aren't machines.
We have no mass and don't respond to forces?
Yes, but we aren't simple machines. We aren't talking about a hypothetical single force pushing a stationary box up a frictionless inclined plane at a constant rate of acceleration in a vacuum here.
Running (for example) increases heart rate more than walking (for example), so more heart beats = more energy spent. More breaths taken by the lungs = more energy spent. Maybe a glycogen spike is needed ...more digestion...more energy. There are probably other body systems and functions as well that will speed up and increase energy burn when vigorously exercising vs. walking at a moderate pace.
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I purposely posted this knowing how the power and energy thing worked to get people to think and also to get feedback on why it will overall be better to go faster on the biological level (assuming you don't get injured).
Biology and engineering aren't really related. To move faster a person has to convert ATP into ADP at a higher rate.
ETA: It's in the proportions, not the time. You burn greater calories per minute at a faster rate. If I were to walk 2 miles at 3 mph I would burn 226 calories in 40 minutes. If I were to run 2 miles at 6 mph I would burn 316 calories in 20 minutes. Doesn't matter that it was a shorter time for the same distance.
I wonder what is being used for the calculations. It isn't energy = force x distance or they would be the same.
They must be including factors for wind, increasing friction forces as a function of speed, or more heat loss while going faster. I acknowledge all these could use up more energy while going faster.
My bio question is will it also result in an increased bmr by going faster consistently. I think it will.
Even if you could have machines or humans do work in a vacuum, there would be differences. Just as with a machine, humans have limited abilities regarding both torque and horsepower. Within these finite limits you also have to be able to provide a constant source of fuel. Even assuming a person could eat enough to fuel maximum effort work around the clock, the mechanics of a human would not endure it for long. The muscles would fail, the digestive system wouldn't keep up, and the joints and bones would be quickly stressed.
If the power vs energy equation were always a constant, it wouldn't matter. But they are not. I'd challenge you to provide any example of a mechanical device in operation that could be driven by any selection of engine or motor and be equally efficient. It won't exist.
And unlike mechanical devices, the human body can adapt somewhat based on use. If a motor vehicle is always designed to carry heavy loads at low speeds, it can't adapt. But if a person were to do the same, their body would adapt to the demands at hand. That same person could then slowly transform from a heavy lifter type build to a marathon runner build due to change of use and gradual adaptation.0 -
lynn_glenmont wrote: »CoffeeNCardio wrote: »If a person walks a certain distance, the energy expended getting there is the same no matter how fast you go to get there. If you get someplace fast, the power level you operated at to get there was higher than if you went slower but the energy expended (cals) is the same whether you go fast or slow.
How does going faster help us then in loosing cals? I think the answer is that the higher power levels required for going faster (or lifting heavier) will increase our base metabolism rate. I'm not sure how that works but maybe going faster helps develop bigger mitochondria to handle the power levels required to go faster which then require more energy to function when peak loads are not placed on them thus upping the bmr. Any biologists out there to explain?
Erm.... no, not even a little bit. To get someplace faster, you expend MORE energy because you worked harder than the slower pace. Because you had to fight gravity harder, your muscles required more oxygen and your body put off more heat, your heart rate had to increase. All the things that happen when one exercises. If you burned 300 calories going from point A to point B at 3.0 mph, you're for sure gonna burn more than that going from point A to point B at 6.5 mph. Jogging is harder than walking, and thus, you expend more energy putting out the extra effort to increase your speed.
ETA: In case there's about to be an argument about walking, this is still the case. More effort is required to walk at 4 mph than to walk at 2.5 mph.
Sorry, but I'm an engineer and understand energy and power very well. I don't know biology very well. If you go 10miles/hr for 30 min you go five miles. If you go 5miles/hr for and 1 hr, you go five miles. Both will expend the same energy (Energy=Force x Distance). You will have been operating at a higher power setting (Power=Force x Velocity) when you go faster but for only 1/2 the time with my example. The energy expended is the same for both. I'm not including small factors like wind resistance or heat expended.
Effort at a given instant is associated with your power level. Effort over time or distance is associated with energy expended.
That's not even true for cars, which get different gas mileage at different speeds. (In the real world, factors like wind resistance actually exist and affect results.)
For the human machine, running is not as efficient a movement as walking -- you'll get there faster, but you must expend more energy than you would if you walked the same distance.
I know wind resistance increases as a function of velocity squared and is significant at higher speeds where it is a big factor compared to friction (cars). At low running speeds, it will not be any where as significant. It will require a higher power level to overcome but not much. Power integrated over time is energy. That is why we pay our power bills in Kw-hrs which is a unit of energy.
I agree real-world, more energy will be expended by going faster. Double the speed isnt double the calories though for the same distance due to factors discussed on this thread. It increases it some more but the dominant effect is as I originally stated (energy =force x distance).
My main interest is how going fast changes the bmr.0
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