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
It’s the effort for sure. The body isn’t a simplified physics textbook problem. It has all kinds of inefficiencies and optimizations. Your mechanical motion is indescribably complicated if we want to completely describe it with physics formulae. And that doesn’t even include biological changes and adaptations over time. So no, your calories burned has a loose connection to the “work” being done. Whatever you perceive your effort multiplied by time yields a far more accurate accounting of calories burned.
Basically, what determines calories burned is how much work you do, not the *percieved effort* and not the *aerobic effort*.
Running is tricky because people do actually substantially increase their running efficiency, but that’s biomechanical. So let’s pretend that you have two athletes who are the same size and weight and have equal *running economy* — how biomechanically efficient they are at running. However, one is much more fit than the other.
If your two athletes run at the same speed for an hour, they’ll of course cover the same distance. They’ll also burn the same number of calories. The less-fit one will have a much higher perceived exertion (“level of suck”) and the run will have been for him much more aerobically challenging.
If your two athletes run at the same level of exertion for the same length of time, then the more-fit one will go faster and will expend more calories. For two athletes of the same weight, for most running speeds, calorie burn rate is roughly proportional to running speed.
In cycling, we actually measure power put into the pedals directly. That’s not the same as the power a human has to put out to make that happen, but the efficiency for cycling doesn’t vary very much from one person to another (it’s around 22%), so it’s really easy to accurately compute calories burned from measured effort on the bike. For two athletes, doing 200 W for an hour might be an all-out, soul-draining effort for one and a walk in the park for another. It doesn’t matter — both will have expended just under 700 calories.
Grand scheme of things excercise actually burns fuck all calories, the people that can burn more per session are usually those that don’t need to. I.E not trying to lose fat.
Trained person can do more work by spending more energy. But it’s about the same amount of work per energy spent. It’s rather physics, than biology.
Human muscle tissue consumes about the same amount of energy per amount of work. So, feeling of exhaustion is related to amount of work per amount of muscle.
If two people have different amount of muscles, they will burn the same amount of calories for the same work. But weaker person would be more tired.
Interestingly, the amount of calories spent can be estimated by the amount of breathing. If you breathe heavily, you’re spending a lot of calories.
Sometimes anaerobic energy consumption kicks in in muscles, which doesn’t require oxygen instantly to be consumed, but it will require the molecules to be replenished later.
But anaerobic breathing also sends chemical signals to increase the amount of mitochondria in cells. Also it improves the capillary network. That’s why HIIT is beneficial, it causes muscle cells to utilize anaerobic breathing causing the improvements I mentioned.
Also, does intensity matter?
i.e. X amount of kilometres in Y minutes versus X amount of kilometres in Y/2 minutes.
I’ve wondered this about running vs. walking. If I walk a mile, I feel nothing. No effort. Doesn’t feel like exercise at all. If I run that same mile at a 12min/mile pace because I’m slow and out of shape, I feel like I’m dying. Drenched in sweat. Face bright red. Need to lay on the floor for 20 minutes recovering. Surely I burn more calories running the same distance than walking?
Effort matters. But I have to say, exercise would be a lot more appealing if rather than focus on calories burned (assuming your exercising for weight loss), set your goals differently.
Set them towards *performance*, just a suggestion. Something you can measure that has nothing to do with the number on the scale.
Pick something that matters to you. Focus on that.
And if your goal IS weight loss, also focus more on putting the fork down. If exercise is boring you to the point where you’re going through the motions rather than mentally focused training, cutting calories takes less effort.
It’s a wee bit of both. Think of the body like a truck and exercising as towing a trailer. When towing you are burning fuel (calories) in order to get the truck and trailer from point A to point B.
Now if you have a brand new 2021 Dodge Ram 3500 with a diesel (athlete) and compare it to the same truck but from 1994 (out of shape person), it starts to click. Yes there is a certain level of fuel/calories/energy it takes to move both set ups from point A to B.
You also have to look at efficiency though. The 94 isn’t going to get near the miles per gallon of the 21. It’s going to have to burn more calories to get the same amount of work done because of its lack of efficiency.
Simply put yes you burn less calories the more in shape you are. As you get into shape you need to continue to push yourself rather than stick with the old routine or you will just plateau.
It’s not really a 1-to-1. Both are factors. If you hold a 90 pound weight over your head for an hour you’ll burn a bunch of calories, but you haven’t technically done any actual “work.”
To your latter question, not _significantly_.
By and large, it takes the same amount of energy to do the same thing, regardless of fitness. But the _same thing_ is important. If the weight is different, height, weather… that’s not the same thing. Ultimately what you are doing is moving your body against the forces of gravity, air pressure, friction, and so on. As long as all those are the same, the fitness component is small.
There are _some_ efficiency gains from training — that is, your body wastes less energy when it converts it to useful work — but they are not substantial, just a few percentage points (most of the wasted energy is converted to heat).
So the reason a trained athlete is faster or stronger or whatever is because they are able to use more energy than the beginner.
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