Will an athlete who runs for an hour at moderate pace and is not tired at the end burn more calories than an out of shape person who runs for an hour a way shorter distance but is exhausted at the end?
Assuming both have the same weight and such
What I want to know basically is if your body gets stronger will it need less energy to perform the same amount of work?
In: 1708
yes and yes
To move a given mass a given distance takes a given amount of energy regardless, so going further faster burns more calories. Athletes can go further faster because their body is trained to store more energy in the form of glycogen (instead of fat) and so has more readily available energy for continuous exertion. Also their heart and lungs are stronger allowing them to take in oxygen and exhale more CO2 at a greater rate, thus reducing lactic acid build up which is typically what makes you feel “tired”.
Training helps athletes be slightly more efficient because they have better technique. Also, because their heart and lungs are more efficient, they burn most of their energy aerobically, which is much more efficient than the anaerobic energy production an out of shape person falls into when their heart and lungs can’t keep up.
This is part of the challenge with trying to lose weight solely through moderate exercise. With moderate exertion your body will actually get more efficient and so you need to counter this by upping your intensity. You basically need to exercise until you feel tired because breaking down that lactic acid also burns a lot of calories too.
>if your body gets stronger will it need less energy to perform the same amount of work?
Yes it will. See *Burn* by Herman Pontzer of Duke University. Pontzer measured the metabolisms of Hadza hunter-gatherers in Tanzania who engage in massive amounts of physical activity every single day. He found that their energy output was the same (corrected for body size and composition) as sedentary Westerners, despite their activity level. Over time, the body adjusts its energy output as exercise increases to maintain it within a narrow window. Pontzer calls this “constrained daily energy expenditure”. He writes, *”The bottom line is that your daily activity level has almost no bearing on the number of calories you burn each day.”* (p. 103)
He also measured the metabolism of extreme athletes, like those running across the United States–effectively a marathon per day. He found that their energy expenditure decreased over time:
>But by the end of the race, 140 days later, their bodies had changed. Even with the same crazy marathon-a-day workload, runners were burning 4,900 kcal per day–still impressive, but a 20 percent decrease from the first week of the race. Some of that decrease could be attributed to the smaller hills out east and having lost a bit of weight over the course of the event, but at least 600 kcal per day seemed to have just vanished from their daily energy budget. This was energy compensation, their constrained metabolism at work: faced with an enormous exercise workload, the runners’ bodies were reducing expenditure on other tasks to try to keep daily energy expenditures in check. The enormous cost of a daily marathon was more than the energy compensation could fully absorb–their daily expenditures during the final weeks of the race were still well above their prerace values–but their bodies were trying. (p. 271)
Calories burned walking a mile = 100 /
Calories burned jogging a mile = 100 /
Calories burned sprinting 100m = 6
However, let’s say you sprinted 100m ten times with a minute rest between each Sprint. On paper you burn 60 calories. But this is a FAR greater option for burning fat and expending calories. This is because sprinting increases your RESTING metabolism a lot more. This is called EPOC (excess post-exercise oxygen consumption). The Sprinting example above burns less calories DURING compared to walking or jogging, but for the rest of the day, you are burning a crazy amount of calories and drastically changing your hormones to promote fat loss. After walking or jogging, that’s it. This is why sprinters are always more cut and lean compared to distance runners.
From what I’ve heard if you run a mile or walk a mile you burn the same amount of calories. I’m not sure if that’s true
I was fat. When I first started running, I could barely run. It took me an hour to go nowhere and I was wrecked afterwards. The weight barely budged.
I pushed myself. I got fitter, stronger, faster… but was still fat.
But a time came when I was fit-but-fat and so I could run haaard for a longer time.. I felt alive after those runs. Energised and ready to go.
It was those hard, fast, alive runs that caused the weight to melt off in just weeks. Everything until then was just prologue.
I could feel my body dealing with the hard, long, fast runs for hours after I stopped… literally just slimming me down.
The slow, ploddy, fat-man runs just had me hurting after and having a sit down.
That’s not science, it’s just what happened. 🙂
If you are asking just to satisfy your curiosity, the answer is yes. And to add on, not something easily explained to a 5 year old (or anyone unfamiliar with the subject). Basically, your breathing, weight, stride, familiarity with the exercise, and much more all play a part. A calorie is a measurement of energy, so more work = more calories burned. But the measurement of the work is hard to quantify.
If asking in the context of losing weight or getting in shape, the ELI5 answer is: it doesn’t really matter. Were talking a few hundred calories difference at the most, a small chicken breast is like 500 calories.
Most likely you will burn more calories… as muscle burns more calories than fat… your base burn rate is increased.
This is easy to answer. The correct answer is that it is the effort you exert that burns the calories, not the actual distance the weight bar (for example) has moved. Burned calories are expelled as CO2 in our breath, and water as sweat/urine/etc. if two people climb a flight of stairs, and one arrives sweaty and out of breath and the other arrives with nary a change in heart rate, one has burned more calories than the other. Can you guess who?
It is kind of both in some circumstances and not in others. For example, a bike- if you take a 30 min ride on a recumbent bike where you lean your upper body against the back of the seat and just move your legs, you’ll burn slightly less calories than on an upright bike at the same resistance for the same time if you’re engaging your core muscles while doing it, so in that case the effort does increase the outcome. In your example, it’s affected by the persons PRE, which is the perceived rate of exhaustion. you’re probably not as exhausted as your body thinks you are. but if two people were to run the same distance at the same speed, the person with worse cardiac endurance would have a greater payoff.
exercise needs to be a static thing to continually improve. If you do the same exact workout every single day, you’ll improve to a point and then plateau. In order to leave the plateau, you need to increase the duration, intensity, or both of the work out
>if your body gets stronger will it need less energy to perform the same amount of work?
“Work” is a term from science that equals Force times Distance. If for example you pick up a box and carry it to the other side of the room it will always be the same amount of work done regardless how much or how little you struggle.
However, struggling increases energy cost. Arms shaking, maybe you need to set it down and take a breather then pick it back up. Even the systems for breathing and transfer of energy to muscles require energy themselves.
When running you’re basically the box itself and also the Force moving it a given Distance. The same rules apply, energy spent not on directly completing the task is lost efficiency.
TL;DR: Struggling decreases the *efficiency* of energy spent on the task, therefore increasing the total spent.
Bonus: Levers are interesting in the conversation of work. Remember W=F*D, so if you increase the distance (longer lever) it decreases the force required (less effort) to achieve the same amount of work (rotation).
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