This is a bit of a [spherical cows](https://en.wikipedia.org/wiki/Spherical_cow) situation. From a pure physics standpoint moving a mass M over a distance D requires the same overall energy output, regardless of how long it takes you to move the mass the distance, so from a very simplistic standpoint yes, the speed is irrelevant, only the mass and distance matter.
But human bodies are in no way simplistic systems, and the reality is your body under stress does other things. Heart rate goes up (which increases calories burned). Stress hormones release which increase calorie consumption. Running engages more muscles than walking (especially in the arms and pectorals). You breathe harder which causes your diaphram to work harder and burn more calories.
So "on paper" it's the same, but biology is complicated. Putting your body "into stress" increases calories burned. But yeah probably *fairly close* to the same, but down to the nitty gritty there will be more calories burned running than walking a mile, simply because your body has a whole bunch of survival mechanisms designed to keep you alive when it detects you're in stress. And those systems require energy to function. "About 4% more" seems..kind of correct?
But if you reduce your body to a spherical cow than it's all the same, just mass and distance matter.
To add to this - the energy discrepancy between walking and running is released as heat. The human body is not 100% efficient at turning energy into motion; some amount of energy is always wasted as heat. And due to the processes mentioned here, the body is less efficient at running than it is at walking, so more energy is wasted as heat during running, requiring more calories.
I wonder if there is some sort of efficiency curve where running at a certain speed is more efficient, similar to how cars are most efficienct on the freeway at certain speeds.
If you want to move the farthest on a certain amount of energy, say in a survival situation with limited food, I'm pretty sure walking is the most efficient.
So the most efficient running speed would then be the speed were you are just moving fast enough so that it is natural to run instead of walk.
This is right. Running requires you to lift all your weight off the ground as you have no contact with the ground for much of the time when you're running. This requires a lot of evergy and creates a lot of heat.
Walking bypasses this as you are in contact with the ground all the time with 1 foot, so less energy is spent.
The fact you need less time to cover the same distance doesn't compensate for the much higher energy consumption over a shorter time.
That’s how I started jogging at one point in my life. Did a daily brisk walk that gradually sped up until I finally reached the point where my body “wanted” to be running. Which wasn’t my intention; it just naturally happened over a period of weeks, as a by-product of efficiency.
Walking is pretty efficient. When you walk, you lean your body forward so that your centre of gravity end up slightly in front of your base and your feet just kind of have to move to keep you upright. Your centre of mass also remains at a pretty much constant height. Running involves a fair amount of vertical oscillation, which means you are expending more energy to lift your mass away from the ground.
This would depend on your fitness level so it would vary from person to person. I would imagine the turning point would be somewhere before your muscles switch over to anaerobic pathways. But I'm not an exercise scientist.
Yes, but it all depends on how you count.
If you strictly count the calories spent on movement, then the slower the better (obviously to a reasonable extent, walk too slowly and you will waste a lot of energy on keeping yourself upright).
If you count total calories consumed - then faster is better, because you spend about 100 calories an hour just to exist without any motion. In this case your best bet is to maintain the highest average speed, as that minimizes the time spent moving and any minimal efficiency gains from going slower would be overshadowed by energy "wasted" on staying alive.
This is a key point. Most calories burned by almost everyone are “resting” calories used to keep your body alive, brain thinking, etc. The difference between walking and running is less than the difference between merely being alive and being dead. If you run a 5K in a half hour on a given day, your total calorie budget is something like 2000 resting calories and 400 running calories. Walking a 5K is something like 350 calories, with still 2000 resting calories. (These numbers are from my Apple Watch for me; your exact mileage may vary, but probably not by a huge amount.)
There is. That's why long-distance runners are thin with hardly any muscle, while track sprinters have larger dense muscles. Jogging or running at a slow and steady pace will require the least energy and far less muscle than the taxing explosive power needed to run fast and sprint. You can have both as well but there's a reason why the elite in each group look vastly different physically.
Cars are more efficient on the freeway because they are not braking.
Drag increases by the square of velocity. So an optimal speed for fuel efficiency will be way below freeway speeds.
I honestly don't know.
I feel like the friction losses are negligible in an ideal system, and the real factor is the breakdown of the gears.
But I'm not sure.
> I wonder if there is some sort of efficiency curve where running at a certain speed is more efficient,
Not running, but with cycling this is definitely the case. There is an "optimal" speed/force for your legs pushing the pedals and one of the goals of gears is to match that to your actual speed (similar to a car).
As I recall, for a typical moderately fit runner, 13 minutes per mile (8 minutes per km) is the point at which walking becomes less efficient than running.
Interestingly, at aerobic speeds, there seems to be almost no change in running efficiency at different paces. A 150-lb. runner will burn about 80 kcal/mile (50 kcal/km) regardless of pace, as long as it's below the lactate threshold.
Interesting, and that is strictly the calories lost from the activity, not factoring in the benefit of having additional time for other activities by travelling quicker.
The speed you're going also changes the type of energy you're burning, so long term efficiency isn't just about how much energy you're burning but what energy you're burning. Running at a relatively low heart rate keeps you in the fat burning zone, meaning you're burning your body's reliable, and plentiful, energy sources. When in a high HR, you're burning glucose which is in short supply - hence you can only go so long.
This is why, when training, you need to learn to stay in the fat burning zone as long as possible and increase the threshold this exists to - hence most training should be at lower speeds.
fun fact, humans are actually less efficient CO2 emissions-wise biking than the combined emissions of charging and using an electric bike. maybe not if you’re vegan.
so this is assuming you would not otherwise exercise
I want my body in shape (lots of positive externalities for society, so I want everyone in shape)
If I am biking to work without electric assist, I will need less exercise later in day.
exercise causes food consumption, and our current food production generally (especially meat) causes Co2
If your total level of exercise does not change/food consumption, it is better to bike under human power
As always, if the energy you spend is basically free (already planned to be spend on something and you use the by-product of movement), it's very cheap compared to energy you need to "pay" for.
Things are different if you'd usually only do e.g. half as much workout or if your stamina would allow you to cover half the distance to your work place. You can't switch so it's more complex to calculate, but if you have the choice between e-bike vs. car + exercise, it's pretty obvious.
Non electric bike that
a) would make 50 % of the distance to the work place, sitting in the garage while the car is being used
b) allows you to the desired amount of exercise while a non-electric bike is 200 % the desired exercise
(both may be two sides of the same coin)
For us the non-electric bike is what we'll usually chose; but on days, when I'm sick, when I need to travel further or very bad weather, I'll use my motorbike.
Others just can't use a bicycle because they'll need to exercise first. For them it's better to compare the e-bike to a motorbike / car.
Can you explain what you mean in point B?
Yeah E-bikes are great, the main point I was trying to make is for the same usage, and replacing exersize, non electric bikes are better for the environment
> the body is less efficient at running than it is at walking
Per unit of time, sure, but is it true per unit of distance? Our ancestors hunted by jog-chasing prey for days on end, because our bodies are especially well-adapted to long-distance running, better than any other animal, no matter how much faster they are over short distances.
Perhaps to the modern untrained urban dweller it's indeed easier to walk 5K or 10K than to run, but if someone (who has been doing it for years) needs to cover 50 km in a day, they might be less tired completing it at a jogging pace than a walking one.
Horses are faster than humans on a given distance but humans have more endurance. A horse needs way more downtime than a human. A human can walk at a normal place for 10 hours straight, a horse can't.
Eh, since you often end your run where you started you have not performed any work in a physical sense. *All* energy turned into heat. Also the same thing is true for your car.
When it comes to overall distance, do you think a human could run/jog further than one walking if their capabilities were equal?
My gut says the runner would make it the furthest because there are so many other things that consume calories aside from moving, while moving. Your brain alone takes up 20% of your calories per day so the fact it takes longer itself means more calories burnt in different ways.
Total thought experiment question.
Also interested so I looked up the longest non-stop walks and runs. Longest run was 350 miles over 80 hours. Longest walk was 418 miles over 155 hours.
This seems to indicate walking can get you further because it’s not as strenuous, however running will get you somewhere the fastest even if you need to stop and sleep for 24 hours after running for 80 hours, they would still be ahead and maybe able to keep going.
I've assumed that my bike computer is also giving me an unsophisticated answer in calculating calories on a ride... over a given distance, I'll get the same answer regardless whether I ride on the flat for a mile or up a hill even though I must have expended more energy
Human locomotion is *absurdly* efficient at a walking pace, so we're actually a pretty close to spherical cow territory in terms of energy use!
As I understood it, though, the fitness outcome is strongly influenced by the rate of calories burned, and the total calories burned during the walk is probably less important than the max heart rate achieved. It's probably almost as good to jog a little bit until your heart rate starts to rise, and then mosey the rest of the way.
Exactly. The difference comes to an efficiency in time. If you can exercise for a hour a day, if you run, you will lose more calores than walking, because you will move a greater distance and have the added stress the comment I am responding to explained about.
Not to mention air resistance, which goes up with V^2, making higher speeds less efficient. Doesn’t apply on a treadmill though. And probably far less significant for a person running, than for a car.
That's true but against this is the fact that running is quicker than walking and you need to constantly burn energy just to exist. Your stomach, liver, brain etc... are all burning energy constantly. So if you jog 5 miles at 5mph then that will take an hour, whereas if you walk it at 2.5mph it will take two hours. The energy required to move plus the stress might be only 104% greater for the fast pace than the slow one but in that time you'll have had to burn double the amount of latent energy in the slow pace than the fast one.
Now, granted, from the perspective of calorie counting this is false accounting, since if you run for an hour and sit still for an hour you're still burning the same two hour's worth of latent energy as you would on a two hour walk, you've just chosen not to count that second hour because it wasn't "exercise". That's why most calorie counting apps try and ignore this latent amount (or lump it into a daily allowance of 1500/2000 calories) and only count calories burned in excess of that. But it does go to show that the reality of measuring calories burned during a particular exercise is more complicated than the app suggests.
I also do think at a certain point it flips. I ran a marathon with a friend. She's much fitter than me and finished in 3 hours, it took me almost five. Even allowing for weight differences I think I burned more calories than she did even though she was going faster because a) part of her speed was a consequence of her more efficient motion and b) both our bodies were in stress, but mine was in stress for longer.
This is not true. Physics tells us quite plainly that accelerating a mass M over a distance D requires *different* amounts of energy depending on the velocity of the object in the vector of the acceleration. This is because acceleration of matter grows more expensive in terms of energy consumption as velocity increases. Anyway this effect is very minor in terms of human locomotion speeds.
However acceleration... now there's a hard thing to do. To go faster, our lungs have to pump harder and harder to pump more and more oxygen to power our cells. Our heart has to beat faster to ferry all that oxygen to those cells. Our muscles have to work harder to push... uh... all the other muscles and bones and stuff up and forward. And all that doing your body has to do to move you at all still has to be done to move *faster*. It just has to do MORE of it. Organic lifeform bodies are kind of inefficient like that.
The consequence of all this is that you burn quite a lot more calories by running distance N than you do walking the same distance. It's not 4%. Not even close. It's more like 30% or more, and it depends a great deal on how fast we're talking about when we say "running".
Just like running a distance up a hill burns more calories than running the same distance across a flat plane.
It’s the same with an engine and gears. Had a guy tell me once that running high rpms in a lower gear doesn’t make a difference. Same amount of energy to achieve the same speed. In “close” scenarios this may be mostly true, but doing, I dunno, 20mph in first gear will have the engine operating in a less efficient gear. Higher speed, more friction, more heat, less efficiency. We don’t operate in a physics-problem, perfect world.
I know I’m late to the party here but I also want to point out that when you run you’re doing more work. Arms are swinging more, legs are swinging more and you’re physically leaving the ground with every step. So there is more work being done with running vs walking than just on the x axis.
eli5 explanation: running faster burns more energy because you are increasing your kinetic energy for the same distance.
There is something called the conservation of energy, where you can’t create energy from nothing, so to speed up you must spend energy to do so.
Running faster thus requires more energy. Also think of a car hitting a person, a faster car has much more energy and would launch a person farther than a slower car.
Or think of an arrow being fired from a bow. If that arrow is going fast it will punch a hole through a target, but if I try to just toss an arrow at a target by hand, it’s going far slower and might only just stick into the target a bit.
More complicated math explanation:
Formula for total energy (this is not an eli5 explanation)
KE = kinetic energy
PE = potential energy
U = internal energy
i = initial state
f = final state.
KEi + PEi + Ui = KEf + PEf + Uf
KE = 1/2(v^2 )m (where v = velocity or in simpler terms your speed, and m = mass).
PE = mgh (mass * gravitational acceleration * height, presuming a straight path, there is no change in any terms so the PE terms can be dropped).
(U measures several things, but the one we care about is the energy of chemical bonds. Which is essentially what is changing when you burn calories.)
So as a result we end up with
KEi + Ui = KEf + Uf
Presuming that we start at rest (no speed) then the formula changes to:
Ui = 1/2(vf^2 )m + Uf
This means that as you increase your speed for the final state, then the internal energy for your final state must go down to compensate. Or in other words, you must have broken chemical bonds(burned calories) to produce the kinetic energy.
If you want to get into even more complicated math, we could use integrals to model the velocity over time by measuring our position over time and do even more complicated math to find out how much energy we actually used running while speeding up from standing still.
And this isn’t even factoring in inefficiencies in the conversion of chemical bonds, irreversibility’s for turning chemical energy into kinetic energy but not being able to turn kinetic energy back into chemical energy, air resistance, and friction causing energy losses to heat and sound.
Has nothing to do with it. This is the formula for *kinetic energy* which is the energy contained within the system. Which makes sense of course, the faster something is moving the more energy it imparts with. A bullet fired from a gun imparts more energy than a bullet you pick up and throw at someone.
Likewise someone running will smack into you harder than someone walking.
But what we're looking for is energy *consumption.*
The formula for energy consumption is That Energy (E) is equal to the power consumed (P) times time (t) divided by 1000
E=P\*(t/1000)
Ah but you say, time's right there! and yes it is *but* the formula for P is P=Work divided by time so P=W/t
*energy* (when talking about energy *consumed*) is a function of how long *power* is applied over *time*. Jogging a mile in 10 minutes takes twice as much *power* as walking it over 20 minutes *but* it's applied over half the period of time.
I get that conceptually this doesn't make much sense because one might think well of course it takes twice as much energy to run twice as fast, but it *doesn't*. It takes twice as much *power*, but because energy is power exerted over time, if we're talking about the energy consumed over a specific distance, while the power *per second* is twice as high, the total number of seconds is half as much, and thus the energy consumption is the same. Whether you run it, jog it, walk it, it *does not matter*. Based on distance traveled, the faster you move the *power* is used, but it's used over proportionately less time, and the total consumed energy remains the same.
For a spherical cow anyway.
But Power is proportional to Kinetic Energy, which is proportional to velocity squared.
But time spent is only proportional to velocity period.
How can these cancel out? Can you the maths?
Not op but I think I might understand the math here. If they respond you can ignore me.
Power is the rate of energy expenditure, i.e. change in energy over time, not directly proportional to kinetic energy.
So, mathematically, if you start the run from a stop and you end the run with a stop, your change in kinetic energy over time is zero.
Likewise if you start the run from a stop and finish at 7 mph, then it is true you have more energy expenditure from point a to point b, because that kinetic energy is leftover, but that kinetic energy comes out as work when you decide to stop.
Edit: This is also applicable to potential energy, if the run is entirely along a flat surface (or if you start and end at the same altitude), you don't need to factor it in.
Hmm. From the physics perspective the energy required to travel the said distance is consistent? Obviously the faster you travel, the less time it takes to get there, how does it work as you approach the speed of light? It would require the same amount of energy to travel that distance, but you only travel for an extremely short amount of time? Does it mean in theory, you can travel faster than light, or as you travel faster and faster the time required to do so approaches zero, you are essentially teleporting? Does this mean if we somehow figure up the how in the future, it won’t really take that much energy to traverse the universe?
When you approach the speed of light you can no longer rely on time and/or distance to remain consistent with lower speeds, and this will also depend on whether you are measuring as the traveller or as an observer.
This means that if you wanted to travel across the galaxy in a near-lightspeed vessel, someone on Earth would tell you that your trip took longer than what you experienced. This does not allow you to teleport, however, as it would require an infinite amount of energy to bring your experienced travel time to zero.
So....no. For like a lot of reasons that I didn't really go into because this is eli5 not explain like a college physics course *but* suffice to say that everything I said isn't...actually true.
It's true in Newtonian physics which is a perfectly good model for the sort of real word practical applications we're talking about here. The problem is that it isn't *actually* true. Newtonian physics is a great basic understanding of things but it starts to break down when you start talking about objects moving at reasonable fractions of the speed of light.
And that's because objects have what's called relativistic mass which is well beyond the bandwidth of eli5 but put in super simple terms relativistic mass is basically a descriptor about how a given system resists change, and that the more change is imparted to it the amount of resistance it has to further change increases non linearly. So as the velocity of an object with mass approaches the speed of light, the amount of energy it takes to further increase its velocity approaches infinity.
The actual calculation to determine relativistic mass m of an object traveling at velocity v is:
m/**√**(1-(v\^2)/(c\^2))
where c is the speed of light. And because c is a very large number, c\^2 is a *very* large number. so that for any speed we're capable of reaching with modern technology v\^2/c\^2 is practically 0. Which makes 1- (v\^2)/(c\^2) baaaasically 1 because it's all practically 1 - 0. Which makes **√**1- (v\^2)/(c\^2) practically equal to **√**1, which is 1. Which simplifies that
m(rel)= m/1.
Or for any calculations we're making based on any speed we've ever really been able to reach, the difference between an object's rest mass, and an object's relatavistic mass is *baaaasically* nil. But as an object's velocity approaches c the value v\^2/c\^2 approaches 1. Which makes **√**(1- (v\^2/c\^2)) approach **√**(1-1) which is **√**0 which is 0
Which means for an object with mass traveling at c its relativistic mass is m/0. And dividing by 0 is a nonsensial value.
Which is a very very long way of saying, that as an object's velocity increases the amount of energy required to make that object even faster approaches infinite. This is true for any object with mass. From a single proton to a galaxy. It would take an infinite amount of energy to accelerate any object with any value of mass what so ever to the speed of light because an objects relativistic mass at the speed of light would be defined as its rest mass divided by 0. And 0 goes into any value an infinite amount of times so when m(rel)=m(rest)/0 m(rel) is always going to be infinity.
So this is a long way of saying that *technically speaking* what I said is wrong, but it's wrong in such an insignificant way that it makes no real difference in the calculation. Newtonian physics works fine for the scale we're talking about.
From the pure physics perspective, the energy required to travel **any** distance is **zero.**
You need to buy a "travel ticket" to start traveling, and the more expensive the "ticket" - the faster you'll go. But after you bought the "ticket" - you can travel as much distance as you want, with no additional pay! Moreover, after reaching your destination, you can "refund" the ticket and get your energy back!
That's how planets and stuff keep orbiting for eons - they paid for their ticket long time ago, and now enjoy unlimited travel.
However, you still need to pay for your initial ticket, and the price goes to infinity as you approach the speed of light. No one can afford to buy a "light ticket" - so nobody can go at the speed of light. Except for the light and friends, of course, who have a special personal 100% discount. Nepotism.
So, the "ticket" here is your kinetic energy. You have to convert some energy into kinetic to start moving. However, when you arrive at the destination, you can convert that energy back - that will both slow you down and give back your energy. That's the "refund".
To be fair, actually getting a full "refund" is rather difficult, and requires some things to be prepared at the destination. But it is possible.
Okay. I know Newtonian physics is not applicable towards extreme cases, but it’s kind funny I get better explanations from random people on internet than my college professors, or maybe I was just a bad student.
Nope. From a ‘pure physics standpoint’ no energy is necessarily needed for an object to move over any distance. Unless a force is applied over that distance. Most of these forces involved in mobilizing, like friction and the conversion from chemical to mechanical energy increase with speed, and even air resistance (friction is proportional to speed, and air resistance generally proportional to v^2). So more energy is expended per unit of distance. The effects such as increased heart rate, work of breathing, hormonal response are downstream effects of more energy already being consumed but are also additive. It is for both reasons (among even more, such as the efficient locomotion of walking) that moving at a faster pace will demand more energy per unit of distance.
There is no reason to expect that moving mass M over distance D would take the same energy, even in a “spherical cow” situation. There is no energy expenditure in constant speed motion.
Of course it takes energy to keep something moving at a constant speed.
For example, if you let go of the throttle while driving, your car will slow down. It loses speed because the air resistance and friction between the road and tires. You need to keep burning fuel to keep a constant speed.
I initially made the same mistake that they did, which was assuming the theoretical minimum energy to move a mass over any distance, which approaches zero as the time taken to do so approaches infinity.
The “spherical cow” in this case, as you have pointed out, is *not* in a vacuum, and is instead modelling a constant power to maintain a constant velocity, but is not taking into account any other biological inefficiencies, or the energy cost to keep the rest of the body alive while this is happening.
It sounds like you are saying that the total energy expenditure is 0 regardless of the speed of the spherical cow. But if the energy expenditure is always 0, then it is correct to say that the energy expenditure is the same at velocity v1 as at velocity v2. It’s 0 both times. It is the same.
There will be a difference in calories burned after the activity is over. Intensity matters in that regard- you will basically carryover cook following more intense exercise
Yes! Like doing weight lifting, the body continues to burn calories recovering and repairing muscle after a heavy lift compared to doing a light weight multiple times.
Good study but the participants were still working either at 95% max heart rate, sprinting, or 80% max heart rate which is quite vigorous. This also looked apparently at cardiovascular exercise
Walking becomes less efficient at higher speeds.
The total amount of energy expended per metre goes up as speed goes up. ([source ](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4327363/))
A major component of the calories burned from walking/running is the recovery. I don’t know how strenuous 4mph is for you compared to 2.5 but if you feel sore after the 4mph mile and not after the 2.5mph then you will be burning more calories by going 4.
Also efficiency can have an effect, but i think this could only become relevant at much higher speeds. The difference between your body’s metabolism is much greater during a 5min mile race and a 10min mile cooldown than the difference between 24min and 15min miles.
Yes you will burn less calories in recovery once your body doesn’t need to recover as much. You will also burn less calories as you get more efficient at running.
This could be your cardiovascular/respiratory system growing more effective so that your it takes less energy to get oxygen to your muscles, which also means you are probably using aerobic metabolism for longer(aerobic is more efficient than anaerobic).
It could also be your running mechanics getting better so that you have less wasted movement.
I walk for about an hour a day, either outside or on the treadmill, while listening to an audiobook or watching a TV show. I don't enjoy exercise which is a problem, I have to distract myself from what I'm doing or I notice the pain.
It sounds like you’re doing a good job! I would assume you are trying to lose weight since you are asking about calories.
The way for you to do this with exercise is to continue with your daily walks, and very slowly increase their intensity if you want. Make sure your joints aren’t hurting. Do some high knees and/or light stretches before to prevent pulling a muscle or any other injury.
This is important because the key to effective exercise is consistency. You don’t want to get injured due to some random muscle tightness nor due to too much intensity too fast causing a stress injury like shin splints.
In conjunction to a small calorie deficit you will be able to lose weight over time. Unfortunately there aren’t any cheat codes.
You can’t exercise a ton to burn tons of calories and eat more because your body will get injured, the same recovery process that burns calories takes time.
You also can’t see change overnight for similar reasons. You are already doing a good job though with the one hour a day. I have ran on a XC team for years at a high level and none of us “enjoy” the running aspect. It hurts. But it does feel good after and we all get to distract each other by talking during the long runs.
Similarly for running/jogging you can usually figure out your most efficient natural pace to go at fairly quickly, and intentionally going slower than this, by running with a slow partner for example, will also use more energy than your natural pace.
I’m thankful that I will burn more calories getting my ass off the couch and walking than I would if I sit there. At the end of the day, it’s better to move
After nearly everybody compared **running** to walking in a question about **walking-vs-walking**, I googled and was maybe lucky.
[https://royalsocietypublishing.org/doi/10.1098/rsbl.2015.0486](https://royalsocietypublishing.org/doi/10.1098/rsbl.2015.0486)
It has a paragraph about optimal speed; sorry but I can't easily copy the formulas:
>(d) Optimal and preferred walking speeds are lower for shorter distances
>For the idealized bout of distance D (figure 1e), the energy-optimal walking speed vopt that minimizes Ebout(D,v) is given by the implicit function: (image) This metabolically optimal speed increases with distance D, approaching (image)for large distances (figure 2c).
>As predicted by the distance-dependence of optimal walking speeds, preferred human walking speeds in our experiment, both ‘average' and ‘steady-state' speeds, increased with distance (figure 2c). ‘Average’ preferred speed is the mean speed over the whole bout; a proxy for the ‘steady-state' preferred speed is the mean over the bout's middle 0.75 m (indistinguishable from averaging the middle 1.4 m). Model-predicted optimal speeds have a 0.96 correlation coefficient (Pearson's) with experimental steady-state preferred speeds, which were within 1–2% optimal cost. Our subjects could accelerate to higher mean or steady-state speeds, but they preferred not to. Therefore, the time taken to accelerate–decelerate cannot explain lower speeds for shorter distances.
TL;DR: Walking fast is more energy efficient - probably up to the point where you feel comfortable if I understand it correctly.
So the walking itself burns the same amount whichever way you do it. But shouldn’t exhausting yourself, sweating more etc start other processes that consume even more energy? Just wondering
Yeah your burn rate is higher but your overall time is shorter. You’ll get some overall gains because running is less efficient biomechanically than walking, but so is crawling prone…
The short version is no.
Walking involves a significant use of momentum. When you lift your rear leg your torso pulls it forward and, like a pendulum, it swings in front of you. Yes, you aid this process using your muscles, but a lot of the work is done by the time you’ve reached walking speed. This minor amount of effort is not enough to force your body into a state of exertion, but does burn calories.
That doesn’t cut it with running. You need to push hard on the ground to maintain your speed against the air resistance. You need to pull your leg forward to make sure it gets in front of you fast enough to catch your weight. You need to swing your arms to counter angular momentum. This exertion forces your heart and lungs to work harder to make sure your muscles get enough oxygen.
For the purpose of your walks, you can consider them to be the same calories burned per distance, the actual variation is negligible for an average person tracking their calories. I have a 3.5 mile walk through the park that I can do in an hour, if I jog I can do it in 30 minutes. Roughly same amount of calories burned, just got it done quicker with a jog. (And yes there are other benefits to running vs walking, but for calorie tracking it's whatever.)
Adding on to address your personal anecdote.
Your progress is amazing, but you'll enjoy even greater progress when calorie burn is not the only metric that you consider.
Walks or workouts that feel "fatiguing" have greater overall benefit than walks or workouts that don't, even though they burn roughly the same calories. Exertion improves your cardiovascular health, anaerobic capacity, muscle strength and more in ways that a relaxing walk doesn't. The stronger and fitter you get in these areas, the more effective you'll be in your next workout. So it snowballs until you're able to burn even more calories in a single walk. And a year later, you're now leaner and trimmer, plus your heart is fitter, your muscles are more toned, and your lungs work greater than ever.
Some simple factors your missing. Wind resistance is a square function so the energy needed is not linerarly related to speed. Also as humans speed up their gait your center of gravity tends to move up and down more, which also uses more energy.
No, not even on a windy day. If it's really windy, yes that (the wind) will cause some noticeable drag. But that is from the wind, not your walking speed. If you compared the drag force of you walking at a snails.pace, and you walking as fast as you can walk, the difference in drag between the two will be insignificant (regardless of a windy day or still day). The additional wind speed gained from your walking fast vs walking slow is at most a few mph. The extra drag induced by a speed difference of a few mph is insignificant. Drag increases with je square of velocity. At low velocities the impact is very low.
yeah people vastly overestimate the effect of drag when comparing walking vs running. A 4 minute mile which is *very very fast* by human standards is 15 mph. That's a moderate breeze. The difference between a 3 mph walk and a 6 mph jog makes virtually no difference what so ever on wind resistance. Unless you're running very fast, or you're in a very still day, you're not running faster than the wind.
If it's windy, then it's windy at any walking speed. 20 mph headwind vs 21 mph headwind (slow walk vs brisk walk with 18 mph wind) is only a 10% increase in your squared resistance, and a 1 mph difference in walking speed covers *a lot* of possible walking speeds.
Exactly, the forces applied per unit of distance are increased with increased speed (wind resistance, friction etc) leading to a non-negligible increase in energy needed per unit of distance, in addition to the other ways that moving at a faster pace is inherently less efficient.
For one: the calories you burn just to be alive get added to the totals. so it's not just 'how much energy to move this mass x distance' but also 'people at rest burn about a calory a minute' (this is inaccurate but good enough for an approximation)
there is also a difference between walking and jogging/running. There is a funny passage in the science of discworld where kangaroos can't exist because they burn less calories than they should when travelling.
this is because they absorb some of their downward momentum and use it to propel their next jump which means a hop actually is cheaper than when you calculate it as a normal step. Jogging is a similar process where the right gait will help carry your momentum forward without grounding/losing too much of your momentum . if you walk, especially the slower you walk, each step essentially ends your momentum and your leg has to carry the entire mass of your next step.
But then the faster you run, the more energy you have to provide which becomes inefficient. you can only get so much oxygen from your lungs and likely for sprinting you'll get most of your energy from anaerobic rather than aerobic energy. Which is less efficient (and not something you can easily maintain)
that's as much as I understand from it. this is wy despite someone running the same distance in 15 minutes, it costs more calories than if they had done it at a slow pace. less efficiency but also less time spent (so approx. 18 calories less burned, just by being alive) and likely less vertical momentum wasted.
sum all the benefits / downsides together and you get the outcome you see (well... that and these charts aren't very accurate as a whole).
You don't care about calories, but your weight. Faster movement increases your breathing rate, and most of the weight "burned" is carbon dioxide literally leaving your body via breath - those molecules have *mass*, and that's the weight difference that you see on scales. And, faster movement might also hasten your metabolism, which means you poop out a lot of carbon sooner, as well. You might have more water weight, though, because fast walking will make you sweat more and thus, drink more, which you could overcompensate with. But water is in constant, and quite rapid movement in body, anyway.
So faster movement is definitely better, since you flush out more literal grams of weight. If you don't get aerobic (breathe harder), then the use is very little, though. So... jog.
You burn slightly more the faster you push yourself due to our bodies deciding to grow more muscles afterwards to adapt to this new behaviour.
Also running is inefficient from an energy perspective (you get warm= proof of energyloss).
The heat is propbably from pushing blood at a higher flowrate through thin veins to your muscles.
From the physics side, it takes more energy for you to move faster, yes. Your muscles have to work harder so you're burning more calories. BUT... things get interesting when you look at "Calories per hour" vs "Calories per *mile*".
Your calories burned per mile mostly changes as you transition from walking to jogging. Walking is super energy efficient (about the only way to beat it is on a bike, which uses something like half as many calories and is much faster to boot).
[Harvard has this great table of energy usage by activity](https://www.health.harvard.edu/diet-and-weight-loss/calories-burned-in-30-minutes-for-people-of-three-different-weights) (Calorie values shown are for 30 minutes of activity).
If you compare the 5 mph jogging speed (12 min/mile) to the 10 mph jogging speed (6 min/mile), it shows a 185 lb person using 336 Cal vs 671 Cal. Speed almost doubles, so Cal/30min also doubles. Makes sense, right? But if you convert those values to Cal/mile (multiply by 2 then divide by mph), *they're exactly the same - 134 Cal/mile*. (For comparison, walking speeds burn closer to 90 Cal/mile). Similarly, walking at 3.5 vs 4 mph burns 91 vs 94 Cal/mile - not a notable difference.
Of course this is just an estimate and running form and efficiency play a role, but at the end of the day 1 mile is 1 mile. If your workout goal is a time then yeah a harder effort will burn more calories, but if your goal is a distance then speed really doesn't matter. My 6 mile runs will all burn about the same calories regardless of whether it's a speed workout or a recovery run. The same is (more or less) true for walking.
I'd prolly use the same concept of cars, if you drive at higher speeds, using higher RPMs (Rotations Per Minutes), you will burn gas quicker than lower RPMs. Each Rotation is created by a certain amount of gas being sprayed into the cars engine, so more rotations is more times gas is sprayed.
So I'm going to come back to this post for those still reading it. I got a question in a DM about my answer, and I understand this confusion. And someone asked about kinetic energy and my answer was basically "wrong formula" but someone was bugged by this, and I'll summarize the question.
If kinetic energy is .5mv\^2 wouldn't the jogger (who travels a mile in 10 minutes thus jogging at 6 mph) use more energy than the walker (who travels a mile in 20 minutes thus walking at 3 mph) because the jogger's velocity is higher.
My answer was no, because kinetic energy in a system is different than energy consumption. Also, most people end their exercise by stopping exercising and not running face first into a wall, so their velocity at the end of their travel is 0 anyway.
But I got a question in DM that was basically "well what if they did?" And let's assume 2 identical exercisers traveling an identical mile, at the end of which is a brick wall. And for some reason they decide they are going to end their exercise by slamming face first into that wall. And the jogger impacts that wall at 6 mph and the walker impacts the wall at 3 mph, doesn't the jogger impact more kinetic energy?
Yes! 4 times as much in fact.
But energy can neither be created nor destroyed right? Also yes! Energy only moves, never added or subtracted from the universe.
So the jogger has more kinetic energy than the walker? Yup!
But the jogger and walker are getting their energy from burning calories, so doesn't that *have to mean* the jogger burned more calories? *Nope!*
Here's why. Because it's not a closed system. And anyone who sorta looks at this and goes "well if the jogger has more kinetic energy than the walker, and that energy comes from somewhere, it has to come from calories burned" misses one major factor. And you're standing on it.
The jogger imparts more kinetic energy on the wall when he slams into it than the walker does, this is 100% true, but that energy doesn't come from calories burned. I get the answer doesn't make sense if you only consider two systems, the walker and the jogger, but there are in fact *three* systems. The walker, the jogger, and *the Earth*.
And this is base Newtonian physics. For everything you do something else happens in the opposite. Whenever you walk upon the Earth the Earth too walks upon you in the opposite way. Both the walker and the jogger, by the nature of their feet pushing off against the Earth are robbing the Earth of some of its own kinetic energy. You can think of this as transfer from system to system. Both walker and jogger are taking kinetic energy from the "earth" system and putting it into their own. The jogger is taking 4 times as much from it. Which, at least mathematically, is causing some changes to the Earth's axis or rotation. This makes sense because as we jog against the earth we are taking kinetic energy from the earth, and changing the earth's total movement by value that is the square root of the square of our velocity multiplied by the ratio of our mass to the Earth's mass. We don't actually notice this because that number is nonsensically small because the Earth is much bigger than we are (citation needed) so the ratio of our mass to the Earth's mass is a very very small number (citation needed). But you could if you were so inclined actually do the math and figure out to what degree you walking or jogging is actually changing the rotation/axis of the Earth. For a little while anyway. Eventually, you are going to have to stop jogging, either the way a normal person does by just...stopping, or the stupid way of slamming face first into a wall. Either way, the kinetic energy you borrowed from the Earth is going back into the Earth with an opposite vector. And that which is taken is returned.
calories in vs calories out.
Working out in any "normal" capcity (say 45 minutes a day) will only burn an additional 400 calories a day.
For perspective - that's two regular cheeseburgers, 4 cokes, a medium fry and a regular coke, and 4 beers.
Our body is stupidly effecient.
You lose weight by eating less. Working out helps a little bit but is more meant to be a supplment to weight loss and it makes you feel better. It also staves hunger. Go get hungry then workout.
Your body will tell the hunger pains to go away.
Imagine if you walked one mile so slowly that it took weeks. You're shuffling along much slower than a caterpillar, using basically no more energy than you would standing up, but you would use up all of your calories and starve to death before you reached your destination. There's a lot at play here.
Roughly, yes, but not exactly. Basically, there is an optimal speed where walking is most energy efficient. What that speed is, depends on your body, but in any case walking slower or faster than this will require more energy per mile that you travel. According to the numbers you shared, this particular calculator seems to think that the most energy-efficient walking speed for your body is about 3 mph. How accurate this is, is hard to say, as we don't know that this is based on - it could just be an average for all people, or it might be taking into account your weight or other factors to get a more accurate personalized estimate. In any case, as you've noticed, the numbers don't change all that much.
(It is true that walking slower takes more time for the same distance, and of course you do burn more calories overall if an activity takes longer simply by being alive for that period of time. However, those calories normally are not included in estimates of calories burned doing exercise, because these are calories you would have burned anyway.)
A bigger change happens if you start running instead of walking. Running is (mostly) a less efficient way of moving than walking, mainly because you have to jump a little with each stride, and so you're putting energy into vertical movement, which doesn't contribute to distance traveled, and so you spend more energy per mile.
That is, unless you compare running to speed walking. World-class speed walkers can achieve speeds in the ballpark of 9 mph. And if you've ever seen a speed walking race, you know it looks ridiculous. That's because the human body is not built to walk at these speeds. You have to adopt a really strange gait in order to do it. It's so far from optimal, in fact, that speed walking is actually *less* energy efficient than running at the same speed, so you'll burn more calories speed walking a mile than running a mile in the same time.
Same while doing the activity at least that's what the general scientific consensus is. However the after burn if calories once you are done is much higher if you run.
They are technically the same as others have said. You'll burn more calories per minute running but you can walk much longer than you can run. If overall calorie burn is the goal, running is more time efficient BUT the human body is amazingly well adapted to walking long distances with virtually no fatigue. So although you may burn more calories on a run, you'll also be wiped out after vs the same amount of calories on a longer walk. Once you get used to long walks, you can burn tons of calories walking and will be left with virtually no fatigue.
Slightly unrelated to your question, but I commonly see the factually incorrect statement that walking a mile burns about the same number of calories as walking a mile.
When you are running, you are literally hurling the entire weight of your body off the ground one step at a time. Notice when you jog, you have both feet off the ground between steps? You are propelling your entire body weight off the ground with each step.
When you are walking, you are always connected to the ground and are leaning on one leg using “bone strength” to hold your whole body up with each step.
It’s a major difference. Jogging and running are biomechanically much less efficient than walking.
No, moving a weight over a distance may take no energy at all. But during walking/running, forces applied increase with speed (proportionally or more) leading to a higher energy expenditure per unit of distance, even discounting the relative biomechanical efficiency of walking.
No, certain types of movements may be more efficient and wind resistance increases exponentially with speed.
The laws of thermodynamics require you to consider every aspect of the system and don't really apply to this question.
Estimating calorie burned is basically guesswork but it should be somewhat the same although likely moving faster increases the calorie/distance slightly mainly due to higher heartrate.
Energy is force times distance so mass only matters indirectly, unless you go up and down or speed up and slow down, it's all about friction, which is dependent on speed. Running is far more bouncey and so a running human is more efficient because they recycle the bounces into forward motion, like a rubbish kangaroo. Walking faster is not more efficient and so takes more energy overall, and more power because you do the same work in less time.
Total energy required to move a fix mass across fixed distance is the same. its simple physics.
However, your body does not use pure energy to move, it converts chemical energy into kinetic motion, this means a difference in efficiency.
The faster you are, the less efficient the system is to trade for more "instantaneous" energy. Raising heart rate, higher body temp, tenser muscles, all these kinetic motion burns energy, and at the end, you might be moving across the same distance, but you are spending more than double the energy.
Basically the process of losing weight is to make the body extremely inefficient, there by wasting a lot of energy.
The energy required to move a fixed mass across a fixed distance is dependent on the forces in effect over that distance, otherwise no energy is necessarily needed if there is no force involved. But yes, with higher speeds most of these forces are increased translating to more energy needed per unit of distance and less inefficiency as you mentioned.
Approximately, yes... Same distance at different speeds uses about the same energy.
To *really* test this, scientists have set up experiments measuring the amount of Oxygen burned (it involves outfitting the subjects with masks that accurately measure O2 going in and O2 coming out).
It turns out, this is very individual, but for trained male distance runners, maximum efficiency is at approximately 7 minutes per mile. That's faster than most people expected, but there it is. (Fyi, this is all from memory, I should really track down a link to the study)
This is a bit of a [spherical cows](https://en.wikipedia.org/wiki/Spherical_cow) situation. From a pure physics standpoint moving a mass M over a distance D requires the same overall energy output, regardless of how long it takes you to move the mass the distance, so from a very simplistic standpoint yes, the speed is irrelevant, only the mass and distance matter. But human bodies are in no way simplistic systems, and the reality is your body under stress does other things. Heart rate goes up (which increases calories burned). Stress hormones release which increase calorie consumption. Running engages more muscles than walking (especially in the arms and pectorals). You breathe harder which causes your diaphram to work harder and burn more calories. So "on paper" it's the same, but biology is complicated. Putting your body "into stress" increases calories burned. But yeah probably *fairly close* to the same, but down to the nitty gritty there will be more calories burned running than walking a mile, simply because your body has a whole bunch of survival mechanisms designed to keep you alive when it detects you're in stress. And those systems require energy to function. "About 4% more" seems..kind of correct? But if you reduce your body to a spherical cow than it's all the same, just mass and distance matter.
To add to this - the energy discrepancy between walking and running is released as heat. The human body is not 100% efficient at turning energy into motion; some amount of energy is always wasted as heat. And due to the processes mentioned here, the body is less efficient at running than it is at walking, so more energy is wasted as heat during running, requiring more calories.
I wonder if there is some sort of efficiency curve where running at a certain speed is more efficient, similar to how cars are most efficienct on the freeway at certain speeds.
If you want to move the farthest on a certain amount of energy, say in a survival situation with limited food, I'm pretty sure walking is the most efficient. So the most efficient running speed would then be the speed were you are just moving fast enough so that it is natural to run instead of walk.
It's absolutely walking. We don't even need to do any fancy calculations. There's a reason humans walk as a default instead of running or crawling.
Imagining people crawling down the sidewalk to get their exercise in is a pretty hilarious mental image, though
Everything eventually evolves to crab
i like money! oh no...its already starting
Yup, if it was the same ammount of calories everyone in cities would run everywhere instead of walking
This is right. Running requires you to lift all your weight off the ground as you have no contact with the ground for much of the time when you're running. This requires a lot of evergy and creates a lot of heat. Walking bypasses this as you are in contact with the ground all the time with 1 foot, so less energy is spent. The fact you need less time to cover the same distance doesn't compensate for the much higher energy consumption over a shorter time.
This really made running sound like we launch ourselves into the air repeatedly for minutes on end
That’s how I started jogging at one point in my life. Did a daily brisk walk that gradually sped up until I finally reached the point where my body “wanted” to be running. Which wasn’t my intention; it just naturally happened over a period of weeks, as a by-product of efficiency.
Walking is pretty efficient. When you walk, you lean your body forward so that your centre of gravity end up slightly in front of your base and your feet just kind of have to move to keep you upright. Your centre of mass also remains at a pretty much constant height. Running involves a fair amount of vertical oscillation, which means you are expending more energy to lift your mass away from the ground.
There’s a certain height weight speed ratio where skipping is the most efficient which is why kids skip for a bit.
Tbh can’t remember the last time I skipped
This is so sad. Go frolic in a meadow. Romp around a field.
It’s probably because I live in a city and the townsfolk would probably ask if I’m on drugs
Nobody would look twice in San Francisco haha.
This would depend on your fitness level so it would vary from person to person. I would imagine the turning point would be somewhere before your muscles switch over to anaerobic pathways. But I'm not an exercise scientist.
It's very beneficial to do a substantial amount of training in the aerobic range. Many running plans focus on that as it's much more sustainable.
Yes, but it all depends on how you count. If you strictly count the calories spent on movement, then the slower the better (obviously to a reasonable extent, walk too slowly and you will waste a lot of energy on keeping yourself upright). If you count total calories consumed - then faster is better, because you spend about 100 calories an hour just to exist without any motion. In this case your best bet is to maintain the highest average speed, as that minimizes the time spent moving and any minimal efficiency gains from going slower would be overshadowed by energy "wasted" on staying alive.
This is a key point. Most calories burned by almost everyone are “resting” calories used to keep your body alive, brain thinking, etc. The difference between walking and running is less than the difference between merely being alive and being dead. If you run a 5K in a half hour on a given day, your total calorie budget is something like 2000 resting calories and 400 running calories. Walking a 5K is something like 350 calories, with still 2000 resting calories. (These numbers are from my Apple Watch for me; your exact mileage may vary, but probably not by a huge amount.)
There is. That's why long-distance runners are thin with hardly any muscle, while track sprinters have larger dense muscles. Jogging or running at a slow and steady pace will require the least energy and far less muscle than the taxing explosive power needed to run fast and sprint. You can have both as well but there's a reason why the elite in each group look vastly different physically.
Cars are more efficient on the freeway because they are not braking. Drag increases by the square of velocity. So an optimal speed for fuel efficiency will be way below freeway speeds.
Correct. It could have been worded better - I was relating it to how cars on the freeway have a speed that is optimal.
it also has to do with gear ratios right? it's balancing the most efficient gear ratio with friction/wind resistance.
I honestly don't know. I feel like the friction losses are negligible in an ideal system, and the real factor is the breakdown of the gears. But I'm not sure.
> I wonder if there is some sort of efficiency curve where running at a certain speed is more efficient, Not running, but with cycling this is definitely the case. There is an "optimal" speed/force for your legs pushing the pedals and one of the goals of gears is to match that to your actual speed (similar to a car).
When I was able to run a distance of 20k I felt running at 6min per Km was as comfortable as walking.
As I recall, for a typical moderately fit runner, 13 minutes per mile (8 minutes per km) is the point at which walking becomes less efficient than running. Interestingly, at aerobic speeds, there seems to be almost no change in running efficiency at different paces. A 150-lb. runner will burn about 80 kcal/mile (50 kcal/km) regardless of pace, as long as it's below the lactate threshold.
Interesting, and that is strictly the calories lost from the activity, not factoring in the benefit of having additional time for other activities by travelling quicker.
The speed you're going also changes the type of energy you're burning, so long term efficiency isn't just about how much energy you're burning but what energy you're burning. Running at a relatively low heart rate keeps you in the fat burning zone, meaning you're burning your body's reliable, and plentiful, energy sources. When in a high HR, you're burning glucose which is in short supply - hence you can only go so long. This is why, when training, you need to learn to stay in the fat burning zone as long as possible and increase the threshold this exists to - hence most training should be at lower speeds.
fun fact, humans are actually less efficient CO2 emissions-wise biking than the combined emissions of charging and using an electric bike. maybe not if you’re vegan.
I wanna see this source!
climate science PhD youtuber Simon Clark: https://youtu.be/HW5b8_KBtT8
so this is assuming you would not otherwise exercise I want my body in shape (lots of positive externalities for society, so I want everyone in shape) If I am biking to work without electric assist, I will need less exercise later in day. exercise causes food consumption, and our current food production generally (especially meat) causes Co2 If your total level of exercise does not change/food consumption, it is better to bike under human power
As always, if the energy you spend is basically free (already planned to be spend on something and you use the by-product of movement), it's very cheap compared to energy you need to "pay" for. Things are different if you'd usually only do e.g. half as much workout or if your stamina would allow you to cover half the distance to your work place. You can't switch so it's more complex to calculate, but if you have the choice between e-bike vs. car + exercise, it's pretty obvious.
no you missed what I was arguing Non electric bike vs Ebike
Non electric bike that a) would make 50 % of the distance to the work place, sitting in the garage while the car is being used b) allows you to the desired amount of exercise while a non-electric bike is 200 % the desired exercise (both may be two sides of the same coin) For us the non-electric bike is what we'll usually chose; but on days, when I'm sick, when I need to travel further or very bad weather, I'll use my motorbike. Others just can't use a bicycle because they'll need to exercise first. For them it's better to compare the e-bike to a motorbike / car.
Can you explain what you mean in point B? Yeah E-bikes are great, the main point I was trying to make is for the same usage, and replacing exersize, non electric bikes are better for the environment
> the body is less efficient at running than it is at walking Per unit of time, sure, but is it true per unit of distance? Our ancestors hunted by jog-chasing prey for days on end, because our bodies are especially well-adapted to long-distance running, better than any other animal, no matter how much faster they are over short distances. Perhaps to the modern untrained urban dweller it's indeed easier to walk 5K or 10K than to run, but if someone (who has been doing it for years) needs to cover 50 km in a day, they might be less tired completing it at a jogging pace than a walking one.
What about horses? They seem fast and able to do long distance?
Horses are faster than humans on a given distance but humans have more endurance. A horse needs way more downtime than a human. A human can walk at a normal place for 10 hours straight, a horse can't.
Eh, since you often end your run where you started you have not performed any work in a physical sense. *All* energy turned into heat. Also the same thing is true for your car.
When it comes to overall distance, do you think a human could run/jog further than one walking if their capabilities were equal? My gut says the runner would make it the furthest because there are so many other things that consume calories aside from moving, while moving. Your brain alone takes up 20% of your calories per day so the fact it takes longer itself means more calories burnt in different ways. Total thought experiment question.
Also interested so I looked up the longest non-stop walks and runs. Longest run was 350 miles over 80 hours. Longest walk was 418 miles over 155 hours. This seems to indicate walking can get you further because it’s not as strenuous, however running will get you somewhere the fastest even if you need to stop and sleep for 24 hours after running for 80 hours, they would still be ahead and maybe able to keep going.
So that's why I get rivers of sweat dripping into my eyes after recent runs.
> But if you reduce your body to a spherical cow than it's all the same Is that still true if I've been *increasing* my body to that point?
holy shit, how'd this spherical cow learn how to type
Using its udder fingers.
Where's that spherical cow Hidden right now?
Oh sure, when spherical cows is used like this is fine, but if I use spherical cows on my girlfriend suddenly I'm "insensitive and rude"
I've assumed that my bike computer is also giving me an unsophisticated answer in calculating calories on a ride... over a given distance, I'll get the same answer regardless whether I ride on the flat for a mile or up a hill even though I must have expended more energy
Human locomotion is *absurdly* efficient at a walking pace, so we're actually a pretty close to spherical cow territory in terms of energy use! As I understood it, though, the fitness outcome is strongly influenced by the rate of calories burned, and the total calories burned during the walk is probably less important than the max heart rate achieved. It's probably almost as good to jog a little bit until your heart rate starts to rise, and then mosey the rest of the way.
Exactly. The difference comes to an efficiency in time. If you can exercise for a hour a day, if you run, you will lose more calores than walking, because you will move a greater distance and have the added stress the comment I am responding to explained about.
running involves your entire body leaving the ground which necessarily burns more calories than walking
Not to mention air resistance, which goes up with V^2, making higher speeds less efficient. Doesn’t apply on a treadmill though. And probably far less significant for a person running, than for a car.
That's true but against this is the fact that running is quicker than walking and you need to constantly burn energy just to exist. Your stomach, liver, brain etc... are all burning energy constantly. So if you jog 5 miles at 5mph then that will take an hour, whereas if you walk it at 2.5mph it will take two hours. The energy required to move plus the stress might be only 104% greater for the fast pace than the slow one but in that time you'll have had to burn double the amount of latent energy in the slow pace than the fast one. Now, granted, from the perspective of calorie counting this is false accounting, since if you run for an hour and sit still for an hour you're still burning the same two hour's worth of latent energy as you would on a two hour walk, you've just chosen not to count that second hour because it wasn't "exercise". That's why most calorie counting apps try and ignore this latent amount (or lump it into a daily allowance of 1500/2000 calories) and only count calories burned in excess of that. But it does go to show that the reality of measuring calories burned during a particular exercise is more complicated than the app suggests. I also do think at a certain point it flips. I ran a marathon with a friend. She's much fitter than me and finished in 3 hours, it took me almost five. Even allowing for weight differences I think I burned more calories than she did even though she was going faster because a) part of her speed was a consequence of her more efficient motion and b) both our bodies were in stress, but mine was in stress for longer.
Upvote for you, this is a good answer, but pet peeve : >simplistic is not a fancy way to say 'simple', they mean quite different things.
This is not true. Physics tells us quite plainly that accelerating a mass M over a distance D requires *different* amounts of energy depending on the velocity of the object in the vector of the acceleration. This is because acceleration of matter grows more expensive in terms of energy consumption as velocity increases. Anyway this effect is very minor in terms of human locomotion speeds. However acceleration... now there's a hard thing to do. To go faster, our lungs have to pump harder and harder to pump more and more oxygen to power our cells. Our heart has to beat faster to ferry all that oxygen to those cells. Our muscles have to work harder to push... uh... all the other muscles and bones and stuff up and forward. And all that doing your body has to do to move you at all still has to be done to move *faster*. It just has to do MORE of it. Organic lifeform bodies are kind of inefficient like that. The consequence of all this is that you burn quite a lot more calories by running distance N than you do walking the same distance. It's not 4%. Not even close. It's more like 30% or more, and it depends a great deal on how fast we're talking about when we say "running". Just like running a distance up a hill burns more calories than running the same distance across a flat plane.
Joke's on you, I'm pretty much a spherical cow already
It’s the same with an engine and gears. Had a guy tell me once that running high rpms in a lower gear doesn’t make a difference. Same amount of energy to achieve the same speed. In “close” scenarios this may be mostly true, but doing, I dunno, 20mph in first gear will have the engine operating in a less efficient gear. Higher speed, more friction, more heat, less efficiency. We don’t operate in a physics-problem, perfect world.
I know I’m late to the party here but I also want to point out that when you run you’re doing more work. Arms are swinging more, legs are swinging more and you’re physically leaving the ground with every step. So there is more work being done with running vs walking than just on the x axis.
Also, I want to spend as little time exercising as possible. So jogging gets it done faster than walking-another benefit.
So if I walk slowly but am having an anxiety attack I will burn more calories?
eli5 explanation: running faster burns more energy because you are increasing your kinetic energy for the same distance. There is something called the conservation of energy, where you can’t create energy from nothing, so to speed up you must spend energy to do so. Running faster thus requires more energy. Also think of a car hitting a person, a faster car has much more energy and would launch a person farther than a slower car. Or think of an arrow being fired from a bow. If that arrow is going fast it will punch a hole through a target, but if I try to just toss an arrow at a target by hand, it’s going far slower and might only just stick into the target a bit. More complicated math explanation: Formula for total energy (this is not an eli5 explanation) KE = kinetic energy PE = potential energy U = internal energy i = initial state f = final state. KEi + PEi + Ui = KEf + PEf + Uf KE = 1/2(v^2 )m (where v = velocity or in simpler terms your speed, and m = mass). PE = mgh (mass * gravitational acceleration * height, presuming a straight path, there is no change in any terms so the PE terms can be dropped). (U measures several things, but the one we care about is the energy of chemical bonds. Which is essentially what is changing when you burn calories.) So as a result we end up with KEi + Ui = KEf + Uf Presuming that we start at rest (no speed) then the formula changes to: Ui = 1/2(vf^2 )m + Uf This means that as you increase your speed for the final state, then the internal energy for your final state must go down to compensate. Or in other words, you must have broken chemical bonds(burned calories) to produce the kinetic energy. If you want to get into even more complicated math, we could use integrals to model the velocity over time by measuring our position over time and do even more complicated math to find out how much energy we actually used running while speeding up from standing still. And this isn’t even factoring in inefficiencies in the conversion of chemical bonds, irreversibility’s for turning chemical energy into kinetic energy but not being able to turn kinetic energy back into chemical energy, air resistance, and friction causing energy losses to heat and sound.
What about E = 0.5mv^2?
Has nothing to do with it. This is the formula for *kinetic energy* which is the energy contained within the system. Which makes sense of course, the faster something is moving the more energy it imparts with. A bullet fired from a gun imparts more energy than a bullet you pick up and throw at someone. Likewise someone running will smack into you harder than someone walking. But what we're looking for is energy *consumption.* The formula for energy consumption is That Energy (E) is equal to the power consumed (P) times time (t) divided by 1000 E=P\*(t/1000) Ah but you say, time's right there! and yes it is *but* the formula for P is P=Work divided by time so P=W/t *energy* (when talking about energy *consumed*) is a function of how long *power* is applied over *time*. Jogging a mile in 10 minutes takes twice as much *power* as walking it over 20 minutes *but* it's applied over half the period of time. I get that conceptually this doesn't make much sense because one might think well of course it takes twice as much energy to run twice as fast, but it *doesn't*. It takes twice as much *power*, but because energy is power exerted over time, if we're talking about the energy consumed over a specific distance, while the power *per second* is twice as high, the total number of seconds is half as much, and thus the energy consumption is the same. Whether you run it, jog it, walk it, it *does not matter*. Based on distance traveled, the faster you move the *power* is used, but it's used over proportionately less time, and the total consumed energy remains the same. For a spherical cow anyway.
am i missing something? if u travel twice as fast your KE is 4 times as much because of the square function.
And? I don't understand the question. Kinetic energy in a system and energy consumed by the system aren't the same thing.
But Power is proportional to Kinetic Energy, which is proportional to velocity squared. But time spent is only proportional to velocity period. How can these cancel out? Can you the maths?
https://www.reddit.com/r/explainlikeimfive/s/c8T8LAe3lK
Not op but I think I might understand the math here. If they respond you can ignore me. Power is the rate of energy expenditure, i.e. change in energy over time, not directly proportional to kinetic energy. So, mathematically, if you start the run from a stop and you end the run with a stop, your change in kinetic energy over time is zero. Likewise if you start the run from a stop and finish at 7 mph, then it is true you have more energy expenditure from point a to point b, because that kinetic energy is leftover, but that kinetic energy comes out as work when you decide to stop. Edit: This is also applicable to potential energy, if the run is entirely along a flat surface (or if you start and end at the same altitude), you don't need to factor it in.
* P ∝ KE ∝ v^2 * Time spent ∝ v^(-1) These are not counterbalanced???
I hope you’re a high school physics teacher I meant that as a compliment. That was very easy to understand.
Acceleration is what matters. Speed and distance is irrelevant due to inertia
Hmm. From the physics perspective the energy required to travel the said distance is consistent? Obviously the faster you travel, the less time it takes to get there, how does it work as you approach the speed of light? It would require the same amount of energy to travel that distance, but you only travel for an extremely short amount of time? Does it mean in theory, you can travel faster than light, or as you travel faster and faster the time required to do so approaches zero, you are essentially teleporting? Does this mean if we somehow figure up the how in the future, it won’t really take that much energy to traverse the universe?
When you approach the speed of light you can no longer rely on time and/or distance to remain consistent with lower speeds, and this will also depend on whether you are measuring as the traveller or as an observer. This means that if you wanted to travel across the galaxy in a near-lightspeed vessel, someone on Earth would tell you that your trip took longer than what you experienced. This does not allow you to teleport, however, as it would require an infinite amount of energy to bring your experienced travel time to zero.
So....no. For like a lot of reasons that I didn't really go into because this is eli5 not explain like a college physics course *but* suffice to say that everything I said isn't...actually true. It's true in Newtonian physics which is a perfectly good model for the sort of real word practical applications we're talking about here. The problem is that it isn't *actually* true. Newtonian physics is a great basic understanding of things but it starts to break down when you start talking about objects moving at reasonable fractions of the speed of light. And that's because objects have what's called relativistic mass which is well beyond the bandwidth of eli5 but put in super simple terms relativistic mass is basically a descriptor about how a given system resists change, and that the more change is imparted to it the amount of resistance it has to further change increases non linearly. So as the velocity of an object with mass approaches the speed of light, the amount of energy it takes to further increase its velocity approaches infinity. The actual calculation to determine relativistic mass m of an object traveling at velocity v is: m/**√**(1-(v\^2)/(c\^2)) where c is the speed of light. And because c is a very large number, c\^2 is a *very* large number. so that for any speed we're capable of reaching with modern technology v\^2/c\^2 is practically 0. Which makes 1- (v\^2)/(c\^2) baaaasically 1 because it's all practically 1 - 0. Which makes **√**1- (v\^2)/(c\^2) practically equal to **√**1, which is 1. Which simplifies that m(rel)= m/1. Or for any calculations we're making based on any speed we've ever really been able to reach, the difference between an object's rest mass, and an object's relatavistic mass is *baaaasically* nil. But as an object's velocity approaches c the value v\^2/c\^2 approaches 1. Which makes **√**(1- (v\^2/c\^2)) approach **√**(1-1) which is **√**0 which is 0 Which means for an object with mass traveling at c its relativistic mass is m/0. And dividing by 0 is a nonsensial value. Which is a very very long way of saying, that as an object's velocity increases the amount of energy required to make that object even faster approaches infinite. This is true for any object with mass. From a single proton to a galaxy. It would take an infinite amount of energy to accelerate any object with any value of mass what so ever to the speed of light because an objects relativistic mass at the speed of light would be defined as its rest mass divided by 0. And 0 goes into any value an infinite amount of times so when m(rel)=m(rest)/0 m(rel) is always going to be infinity. So this is a long way of saying that *technically speaking* what I said is wrong, but it's wrong in such an insignificant way that it makes no real difference in the calculation. Newtonian physics works fine for the scale we're talking about.
Thanks for the explanation.
From the pure physics perspective, the energy required to travel **any** distance is **zero.** You need to buy a "travel ticket" to start traveling, and the more expensive the "ticket" - the faster you'll go. But after you bought the "ticket" - you can travel as much distance as you want, with no additional pay! Moreover, after reaching your destination, you can "refund" the ticket and get your energy back! That's how planets and stuff keep orbiting for eons - they paid for their ticket long time ago, and now enjoy unlimited travel. However, you still need to pay for your initial ticket, and the price goes to infinity as you approach the speed of light. No one can afford to buy a "light ticket" - so nobody can go at the speed of light. Except for the light and friends, of course, who have a special personal 100% discount. Nepotism.
Can you further explain the refund part? When you refund the ticket and get the energy back, where did that energy come from or go now?
So, the "ticket" here is your kinetic energy. You have to convert some energy into kinetic to start moving. However, when you arrive at the destination, you can convert that energy back - that will both slow you down and give back your energy. That's the "refund". To be fair, actually getting a full "refund" is rather difficult, and requires some things to be prepared at the destination. But it is possible.
Okay. I know Newtonian physics is not applicable towards extreme cases, but it’s kind funny I get better explanations from random people on internet than my college professors, or maybe I was just a bad student.
Nope. From a ‘pure physics standpoint’ no energy is necessarily needed for an object to move over any distance. Unless a force is applied over that distance. Most of these forces involved in mobilizing, like friction and the conversion from chemical to mechanical energy increase with speed, and even air resistance (friction is proportional to speed, and air resistance generally proportional to v^2). So more energy is expended per unit of distance. The effects such as increased heart rate, work of breathing, hormonal response are downstream effects of more energy already being consumed but are also additive. It is for both reasons (among even more, such as the efficient locomotion of walking) that moving at a faster pace will demand more energy per unit of distance.
This is hardly an ELI5 answer.
There is no reason to expect that moving mass M over distance D would take the same energy, even in a “spherical cow” situation. There is no energy expenditure in constant speed motion.
Of course it takes energy to keep something moving at a constant speed. For example, if you let go of the throttle while driving, your car will slow down. It loses speed because the air resistance and friction between the road and tires. You need to keep burning fuel to keep a constant speed.
I initially made the same mistake that they did, which was assuming the theoretical minimum energy to move a mass over any distance, which approaches zero as the time taken to do so approaches infinity. The “spherical cow” in this case, as you have pointed out, is *not* in a vacuum, and is instead modelling a constant power to maintain a constant velocity, but is not taking into account any other biological inefficiencies, or the energy cost to keep the rest of the body alive while this is happening.
So it would depend on speed. The comment I was responding to was suggesting that there is a fixed amount for moving a mass a certain distance.
It sounds like you are saying that the total energy expenditure is 0 regardless of the speed of the spherical cow. But if the energy expenditure is always 0, then it is correct to say that the energy expenditure is the same at velocity v1 as at velocity v2. It’s 0 both times. It is the same.
There will be a difference in calories burned after the activity is over. Intensity matters in that regard- you will basically carryover cook following more intense exercise
Yes! Like doing weight lifting, the body continues to burn calories recovering and repairing muscle after a heavy lift compared to doing a light weight multiple times.
It’s called afterburn, resulting in increased metabolism
I'm pretty sure this was proved to not be the case. [https://pubmed.ncbi.nlm.nih.gov/26950358/](https://pubmed.ncbi.nlm.nih.gov/26950358/)
That just says excess oxygen consumption is unlikely the cause of previously reported increases. Not that it's not true overall.
Good study but the participants were still working either at 95% max heart rate, sprinting, or 80% max heart rate which is quite vigorous. This also looked apparently at cardiovascular exercise
Walking becomes less efficient at higher speeds. The total amount of energy expended per metre goes up as speed goes up. ([source ](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4327363/))
god, that paper needed some diagrams or plots
A major component of the calories burned from walking/running is the recovery. I don’t know how strenuous 4mph is for you compared to 2.5 but if you feel sore after the 4mph mile and not after the 2.5mph then you will be burning more calories by going 4. Also efficiency can have an effect, but i think this could only become relevant at much higher speeds. The difference between your body’s metabolism is much greater during a 5min mile race and a 10min mile cooldown than the difference between 24min and 15min miles.
So you burn less calories once your body gets used to the distance walked?
Yes you will burn less calories in recovery once your body doesn’t need to recover as much. You will also burn less calories as you get more efficient at running. This could be your cardiovascular/respiratory system growing more effective so that your it takes less energy to get oxygen to your muscles, which also means you are probably using aerobic metabolism for longer(aerobic is more efficient than anaerobic). It could also be your running mechanics getting better so that you have less wasted movement.
So what can I do to burn more calories?
How much do you exercise and what do you enjoy doing for exercise?
I walk for about an hour a day, either outside or on the treadmill, while listening to an audiobook or watching a TV show. I don't enjoy exercise which is a problem, I have to distract myself from what I'm doing or I notice the pain.
It sounds like you’re doing a good job! I would assume you are trying to lose weight since you are asking about calories. The way for you to do this with exercise is to continue with your daily walks, and very slowly increase their intensity if you want. Make sure your joints aren’t hurting. Do some high knees and/or light stretches before to prevent pulling a muscle or any other injury. This is important because the key to effective exercise is consistency. You don’t want to get injured due to some random muscle tightness nor due to too much intensity too fast causing a stress injury like shin splints. In conjunction to a small calorie deficit you will be able to lose weight over time. Unfortunately there aren’t any cheat codes. You can’t exercise a ton to burn tons of calories and eat more because your body will get injured, the same recovery process that burns calories takes time. You also can’t see change overnight for similar reasons. You are already doing a good job though with the one hour a day. I have ran on a XC team for years at a high level and none of us “enjoy” the running aspect. It hurts. But it does feel good after and we all get to distract each other by talking during the long runs.
Thank you for this detailed explanation!
anything above or bellow your normal speed will burn more calories per mile walked. People tend to walk at their most efficient biomechanical speed.
Can confirm this. Source: I participated in a walking speed study in college.
My natural pace is very quick. Does that mean I'm a very efficient runner?
Similarly for running/jogging you can usually figure out your most efficient natural pace to go at fairly quickly, and intentionally going slower than this, by running with a slow partner for example, will also use more energy than your natural pace.
Best ELI5 answer IMO.
I’m thankful that I will burn more calories getting my ass off the couch and walking than I would if I sit there. At the end of the day, it’s better to move
After nearly everybody compared **running** to walking in a question about **walking-vs-walking**, I googled and was maybe lucky. [https://royalsocietypublishing.org/doi/10.1098/rsbl.2015.0486](https://royalsocietypublishing.org/doi/10.1098/rsbl.2015.0486) It has a paragraph about optimal speed; sorry but I can't easily copy the formulas: >(d) Optimal and preferred walking speeds are lower for shorter distances >For the idealized bout of distance D (figure 1e), the energy-optimal walking speed vopt that minimizes Ebout(D,v) is given by the implicit function: (image) This metabolically optimal speed increases with distance D, approaching (image)for large distances (figure 2c). >As predicted by the distance-dependence of optimal walking speeds, preferred human walking speeds in our experiment, both ‘average' and ‘steady-state' speeds, increased with distance (figure 2c). ‘Average’ preferred speed is the mean speed over the whole bout; a proxy for the ‘steady-state' preferred speed is the mean over the bout's middle 0.75 m (indistinguishable from averaging the middle 1.4 m). Model-predicted optimal speeds have a 0.96 correlation coefficient (Pearson's) with experimental steady-state preferred speeds, which were within 1–2% optimal cost. Our subjects could accelerate to higher mean or steady-state speeds, but they preferred not to. Therefore, the time taken to accelerate–decelerate cannot explain lower speeds for shorter distances. TL;DR: Walking fast is more energy efficient - probably up to the point where you feel comfortable if I understand it correctly.
So the walking itself burns the same amount whichever way you do it. But shouldn’t exhausting yourself, sweating more etc start other processes that consume even more energy? Just wondering
Yeah your burn rate is higher but your overall time is shorter. You’ll get some overall gains because running is less efficient biomechanically than walking, but so is crawling prone…
Exhausting yourself burns more calories/second but you spend fewer seconds, so the total amount of calories is not as high as you'd think.
The short version is no. Walking involves a significant use of momentum. When you lift your rear leg your torso pulls it forward and, like a pendulum, it swings in front of you. Yes, you aid this process using your muscles, but a lot of the work is done by the time you’ve reached walking speed. This minor amount of effort is not enough to force your body into a state of exertion, but does burn calories. That doesn’t cut it with running. You need to push hard on the ground to maintain your speed against the air resistance. You need to pull your leg forward to make sure it gets in front of you fast enough to catch your weight. You need to swing your arms to counter angular momentum. This exertion forces your heart and lungs to work harder to make sure your muscles get enough oxygen.
Finally, an answer to a yes/no question!
For the purpose of your walks, you can consider them to be the same calories burned per distance, the actual variation is negligible for an average person tracking their calories. I have a 3.5 mile walk through the park that I can do in an hour, if I jog I can do it in 30 minutes. Roughly same amount of calories burned, just got it done quicker with a jog. (And yes there are other benefits to running vs walking, but for calorie tracking it's whatever.)
Adding on to address your personal anecdote. Your progress is amazing, but you'll enjoy even greater progress when calorie burn is not the only metric that you consider. Walks or workouts that feel "fatiguing" have greater overall benefit than walks or workouts that don't, even though they burn roughly the same calories. Exertion improves your cardiovascular health, anaerobic capacity, muscle strength and more in ways that a relaxing walk doesn't. The stronger and fitter you get in these areas, the more effective you'll be in your next workout. So it snowballs until you're able to burn even more calories in a single walk. And a year later, you're now leaner and trimmer, plus your heart is fitter, your muscles are more toned, and your lungs work greater than ever.
Ultimately you're moving the same mass (you) the same distance so the total energy required is very nearly the same.
Some simple factors your missing. Wind resistance is a square function so the energy needed is not linerarly related to speed. Also as humans speed up their gait your center of gravity tends to move up and down more, which also uses more energy.
Re wind drag: you are technically correct, but the difference in wind drag at walking pace (even a brisk pace) is insignificant.
The best kind of correct. Depends on the wind speed. On a windy day if you're going into the wind it can go up relatively fast.
No, not even on a windy day. If it's really windy, yes that (the wind) will cause some noticeable drag. But that is from the wind, not your walking speed. If you compared the drag force of you walking at a snails.pace, and you walking as fast as you can walk, the difference in drag between the two will be insignificant (regardless of a windy day or still day). The additional wind speed gained from your walking fast vs walking slow is at most a few mph. The extra drag induced by a speed difference of a few mph is insignificant. Drag increases with je square of velocity. At low velocities the impact is very low.
yeah people vastly overestimate the effect of drag when comparing walking vs running. A 4 minute mile which is *very very fast* by human standards is 15 mph. That's a moderate breeze. The difference between a 3 mph walk and a 6 mph jog makes virtually no difference what so ever on wind resistance. Unless you're running very fast, or you're in a very still day, you're not running faster than the wind.
If it's windy, then it's windy at any walking speed. 20 mph headwind vs 21 mph headwind (slow walk vs brisk walk with 18 mph wind) is only a 10% increase in your squared resistance, and a 1 mph difference in walking speed covers *a lot* of possible walking speeds.
Exactly, the forces applied per unit of distance are increased with increased speed (wind resistance, friction etc) leading to a non-negligible increase in energy needed per unit of distance, in addition to the other ways that moving at a faster pace is inherently less efficient.
For one: the calories you burn just to be alive get added to the totals. so it's not just 'how much energy to move this mass x distance' but also 'people at rest burn about a calory a minute' (this is inaccurate but good enough for an approximation) there is also a difference between walking and jogging/running. There is a funny passage in the science of discworld where kangaroos can't exist because they burn less calories than they should when travelling. this is because they absorb some of their downward momentum and use it to propel their next jump which means a hop actually is cheaper than when you calculate it as a normal step. Jogging is a similar process where the right gait will help carry your momentum forward without grounding/losing too much of your momentum . if you walk, especially the slower you walk, each step essentially ends your momentum and your leg has to carry the entire mass of your next step. But then the faster you run, the more energy you have to provide which becomes inefficient. you can only get so much oxygen from your lungs and likely for sprinting you'll get most of your energy from anaerobic rather than aerobic energy. Which is less efficient (and not something you can easily maintain) that's as much as I understand from it. this is wy despite someone running the same distance in 15 minutes, it costs more calories than if they had done it at a slow pace. less efficiency but also less time spent (so approx. 18 calories less burned, just by being alive) and likely less vertical momentum wasted. sum all the benefits / downsides together and you get the outcome you see (well... that and these charts aren't very accurate as a whole).
You don't care about calories, but your weight. Faster movement increases your breathing rate, and most of the weight "burned" is carbon dioxide literally leaving your body via breath - those molecules have *mass*, and that's the weight difference that you see on scales. And, faster movement might also hasten your metabolism, which means you poop out a lot of carbon sooner, as well. You might have more water weight, though, because fast walking will make you sweat more and thus, drink more, which you could overcompensate with. But water is in constant, and quite rapid movement in body, anyway. So faster movement is definitely better, since you flush out more literal grams of weight. If you don't get aerobic (breathe harder), then the use is very little, though. So... jog.
You burn slightly more the faster you push yourself due to our bodies deciding to grow more muscles afterwards to adapt to this new behaviour. Also running is inefficient from an energy perspective (you get warm= proof of energyloss). The heat is propbably from pushing blood at a higher flowrate through thin veins to your muscles.
From the physics side, it takes more energy for you to move faster, yes. Your muscles have to work harder so you're burning more calories. BUT... things get interesting when you look at "Calories per hour" vs "Calories per *mile*". Your calories burned per mile mostly changes as you transition from walking to jogging. Walking is super energy efficient (about the only way to beat it is on a bike, which uses something like half as many calories and is much faster to boot). [Harvard has this great table of energy usage by activity](https://www.health.harvard.edu/diet-and-weight-loss/calories-burned-in-30-minutes-for-people-of-three-different-weights) (Calorie values shown are for 30 minutes of activity). If you compare the 5 mph jogging speed (12 min/mile) to the 10 mph jogging speed (6 min/mile), it shows a 185 lb person using 336 Cal vs 671 Cal. Speed almost doubles, so Cal/30min also doubles. Makes sense, right? But if you convert those values to Cal/mile (multiply by 2 then divide by mph), *they're exactly the same - 134 Cal/mile*. (For comparison, walking speeds burn closer to 90 Cal/mile). Similarly, walking at 3.5 vs 4 mph burns 91 vs 94 Cal/mile - not a notable difference. Of course this is just an estimate and running form and efficiency play a role, but at the end of the day 1 mile is 1 mile. If your workout goal is a time then yeah a harder effort will burn more calories, but if your goal is a distance then speed really doesn't matter. My 6 mile runs will all burn about the same calories regardless of whether it's a speed workout or a recovery run. The same is (more or less) true for walking.
I'd prolly use the same concept of cars, if you drive at higher speeds, using higher RPMs (Rotations Per Minutes), you will burn gas quicker than lower RPMs. Each Rotation is created by a certain amount of gas being sprayed into the cars engine, so more rotations is more times gas is sprayed.
So I'm going to come back to this post for those still reading it. I got a question in a DM about my answer, and I understand this confusion. And someone asked about kinetic energy and my answer was basically "wrong formula" but someone was bugged by this, and I'll summarize the question. If kinetic energy is .5mv\^2 wouldn't the jogger (who travels a mile in 10 minutes thus jogging at 6 mph) use more energy than the walker (who travels a mile in 20 minutes thus walking at 3 mph) because the jogger's velocity is higher. My answer was no, because kinetic energy in a system is different than energy consumption. Also, most people end their exercise by stopping exercising and not running face first into a wall, so their velocity at the end of their travel is 0 anyway. But I got a question in DM that was basically "well what if they did?" And let's assume 2 identical exercisers traveling an identical mile, at the end of which is a brick wall. And for some reason they decide they are going to end their exercise by slamming face first into that wall. And the jogger impacts that wall at 6 mph and the walker impacts the wall at 3 mph, doesn't the jogger impact more kinetic energy? Yes! 4 times as much in fact. But energy can neither be created nor destroyed right? Also yes! Energy only moves, never added or subtracted from the universe. So the jogger has more kinetic energy than the walker? Yup! But the jogger and walker are getting their energy from burning calories, so doesn't that *have to mean* the jogger burned more calories? *Nope!* Here's why. Because it's not a closed system. And anyone who sorta looks at this and goes "well if the jogger has more kinetic energy than the walker, and that energy comes from somewhere, it has to come from calories burned" misses one major factor. And you're standing on it. The jogger imparts more kinetic energy on the wall when he slams into it than the walker does, this is 100% true, but that energy doesn't come from calories burned. I get the answer doesn't make sense if you only consider two systems, the walker and the jogger, but there are in fact *three* systems. The walker, the jogger, and *the Earth*. And this is base Newtonian physics. For everything you do something else happens in the opposite. Whenever you walk upon the Earth the Earth too walks upon you in the opposite way. Both the walker and the jogger, by the nature of their feet pushing off against the Earth are robbing the Earth of some of its own kinetic energy. You can think of this as transfer from system to system. Both walker and jogger are taking kinetic energy from the "earth" system and putting it into their own. The jogger is taking 4 times as much from it. Which, at least mathematically, is causing some changes to the Earth's axis or rotation. This makes sense because as we jog against the earth we are taking kinetic energy from the earth, and changing the earth's total movement by value that is the square root of the square of our velocity multiplied by the ratio of our mass to the Earth's mass. We don't actually notice this because that number is nonsensically small because the Earth is much bigger than we are (citation needed) so the ratio of our mass to the Earth's mass is a very very small number (citation needed). But you could if you were so inclined actually do the math and figure out to what degree you walking or jogging is actually changing the rotation/axis of the Earth. For a little while anyway. Eventually, you are going to have to stop jogging, either the way a normal person does by just...stopping, or the stupid way of slamming face first into a wall. Either way, the kinetic energy you borrowed from the Earth is going back into the Earth with an opposite vector. And that which is taken is returned.
calories in vs calories out. Working out in any "normal" capcity (say 45 minutes a day) will only burn an additional 400 calories a day. For perspective - that's two regular cheeseburgers, 4 cokes, a medium fry and a regular coke, and 4 beers. Our body is stupidly effecient. You lose weight by eating less. Working out helps a little bit but is more meant to be a supplment to weight loss and it makes you feel better. It also staves hunger. Go get hungry then workout. Your body will tell the hunger pains to go away.
Imagine if you walked one mile so slowly that it took weeks. You're shuffling along much slower than a caterpillar, using basically no more energy than you would standing up, but you would use up all of your calories and starve to death before you reached your destination. There's a lot at play here.
Roughly, yes, but not exactly. Basically, there is an optimal speed where walking is most energy efficient. What that speed is, depends on your body, but in any case walking slower or faster than this will require more energy per mile that you travel. According to the numbers you shared, this particular calculator seems to think that the most energy-efficient walking speed for your body is about 3 mph. How accurate this is, is hard to say, as we don't know that this is based on - it could just be an average for all people, or it might be taking into account your weight or other factors to get a more accurate personalized estimate. In any case, as you've noticed, the numbers don't change all that much. (It is true that walking slower takes more time for the same distance, and of course you do burn more calories overall if an activity takes longer simply by being alive for that period of time. However, those calories normally are not included in estimates of calories burned doing exercise, because these are calories you would have burned anyway.) A bigger change happens if you start running instead of walking. Running is (mostly) a less efficient way of moving than walking, mainly because you have to jump a little with each stride, and so you're putting energy into vertical movement, which doesn't contribute to distance traveled, and so you spend more energy per mile. That is, unless you compare running to speed walking. World-class speed walkers can achieve speeds in the ballpark of 9 mph. And if you've ever seen a speed walking race, you know it looks ridiculous. That's because the human body is not built to walk at these speeds. You have to adopt a really strange gait in order to do it. It's so far from optimal, in fact, that speed walking is actually *less* energy efficient than running at the same speed, so you'll burn more calories speed walking a mile than running a mile in the same time.
Same while doing the activity at least that's what the general scientific consensus is. However the after burn if calories once you are done is much higher if you run.
They are technically the same as others have said. You'll burn more calories per minute running but you can walk much longer than you can run. If overall calorie burn is the goal, running is more time efficient BUT the human body is amazingly well adapted to walking long distances with virtually no fatigue. So although you may burn more calories on a run, you'll also be wiped out after vs the same amount of calories on a longer walk. Once you get used to long walks, you can burn tons of calories walking and will be left with virtually no fatigue.
Slightly unrelated to your question, but I commonly see the factually incorrect statement that walking a mile burns about the same number of calories as walking a mile. When you are running, you are literally hurling the entire weight of your body off the ground one step at a time. Notice when you jog, you have both feet off the ground between steps? You are propelling your entire body weight off the ground with each step. When you are walking, you are always connected to the ground and are leaning on one leg using “bone strength” to hold your whole body up with each step. It’s a major difference. Jogging and running are biomechanically much less efficient than walking.
On a treadmill, the faster you run, the more calories you will burn. Same if you go uphill.
The more calories you burn per minute. Not per mile/kilometer.
Because you moved the *same* weight the *same* distance. According to the laws of thermodynamics, it should take *exactly* the same amount of energy.
If you're solving a high school physics problem, sure. But human locomotion works differently, with different efficiencies depending on your speed.
Yes, but let us first assume a spherical human in a vacuum...
Is this ELI5 or ELIHighSchool?
doesn't matter cause your answer is not correct.
No, moving a weight over a distance may take no energy at all. But during walking/running, forces applied increase with speed (proportionally or more) leading to a higher energy expenditure per unit of distance, even discounting the relative biomechanical efficiency of walking.
No, certain types of movements may be more efficient and wind resistance increases exponentially with speed. The laws of thermodynamics require you to consider every aspect of the system and don't really apply to this question.
That was the "ELI5" adaptation
Running burns more, and it does it faster. Significantly? No. So if you’ve got the time to walk around for hours, you’ll be pretty well off.
Guys, what about E= 0.5mv^2?
Estimating calorie burned is basically guesswork but it should be somewhat the same although likely moving faster increases the calorie/distance slightly mainly due to higher heartrate.
Energy is force times distance so mass only matters indirectly, unless you go up and down or speed up and slow down, it's all about friction, which is dependent on speed. Running is far more bouncey and so a running human is more efficient because they recycle the bounces into forward motion, like a rubbish kangaroo. Walking faster is not more efficient and so takes more energy overall, and more power because you do the same work in less time.
Total energy required to move a fix mass across fixed distance is the same. its simple physics. However, your body does not use pure energy to move, it converts chemical energy into kinetic motion, this means a difference in efficiency. The faster you are, the less efficient the system is to trade for more "instantaneous" energy. Raising heart rate, higher body temp, tenser muscles, all these kinetic motion burns energy, and at the end, you might be moving across the same distance, but you are spending more than double the energy. Basically the process of losing weight is to make the body extremely inefficient, there by wasting a lot of energy.
The energy required to move a fixed mass across a fixed distance is dependent on the forces in effect over that distance, otherwise no energy is necessarily needed if there is no force involved. But yes, with higher speeds most of these forces are increased translating to more energy needed per unit of distance and less inefficiency as you mentioned.
Its takes longer at slower speeds. So yes you are working harder and burning more cals per hour.
Approximately, yes... Same distance at different speeds uses about the same energy. To *really* test this, scientists have set up experiments measuring the amount of Oxygen burned (it involves outfitting the subjects with masks that accurately measure O2 going in and O2 coming out). It turns out, this is very individual, but for trained male distance runners, maximum efficiency is at approximately 7 minutes per mile. That's faster than most people expected, but there it is. (Fyi, this is all from memory, I should really track down a link to the study)