[anon84873628]

>Okay, so that means that no matter how stressed we get, there’s a cap to the energy we can use. But how is that relevant, since it also applies to exercise or other energy utilization by the body? Why does a limited capacity to consume energy only apply to stress?

It doesn't. That limited capacity to consume energy applies to exercise, brain activity, thermogenesis, digestion, and every other biological process as well. It is a fundamental aspect of cellular biology and a major focus in the field of exercise physiology.

Fitness training is the very slow and deliberate process of pushing these limits tiny percentages higher.

I suggest you build some practical and theoretical knowledge of the field before dismissing the paper.

[authorfly]

I absolutely don't doubt you but can you provide some accessible education resources or some sports science/biochemistry papers for the claim around "That limited capacity to consume energy applies to exercise, brain activity, thermogenesis, digestion, and every other biological process as well. It is a fundamental aspect of cellular biology and a major focus in the field of exercise physiology." ?

What energy are we talking about here exactly? ATP?

[anon84873628]

Yes. Metabolism is rate limited by countless chemical reactions. Energy sources need to be broken down and moved around the body. Waste products need to be removed. Mitochondria only work at a certain rate. You can increase the number of mitochondria but that hits a practical ceiling as well.

You can start with the Wikipedia article for Metabolism or search for "metabolic scope" and "metabolic efficiency".

[authorfly]

Ok, I understand some of this. I know that often the structure of proteins (especially e.g. with ATP Synthase) helps drive and time limits energy production or energy signalling. Just like how the plugging/unplugging of sodium channels naturally creates equal windows for sodium to enter Neurons during action potentials, the natural duration of ATP synthase and other processes establishes a sort of time unit, wherever the ATP is.

Please can you expand a little more. I am a novice so I'm sure there must be something here I have missed, and would love to know what that is:

What I am a little confused about is that the consumption of energy is not done at the same time as consumption, unless I am wrong?

For example when muscles are used or repair during hysteresis, the mitochondria produced the ATP used in that reaction long before the event.

I suppose you can argue any energy consumption via chronic stress effects that. However, because it is local, distributed and there are a few forms of stored energy in essence and uses of it (e.g. mitosis/DNA nucleotide production), it's not like having one singular energy total that goes down, is it?

It's feasible that each area of the body can upscale production and produce their different kinds of energy/energy store more efficiently over time, since most of the time the body is not producing ATP at peak rate. Is the argument that doing that would wear out parts of the cells we have faster or something, due to the chronic stress, compared to what they typically see?

I struggle to buy this argument because we know that heavily overweight people consume much more calories (and thus more ATP Synthase etc) for their number of cells but they don't necessarily die much younger until you reach severe levels of being obese.