system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:If I always feel mentally and physically better after exercising, why do I still avoid it like a whiny toddler?

Motivation not correlating to effect is absolutely befuddling.
gpt
Because exercising for the sake of exercising is completely unnatural, and our brains resist it. We evolved to have a more active lifestyle than we do now in modern times; for 99.9% of human history nobody was running on treadmills. But they were plowing fields and picking turnips and milking cows all day, and that was more than enough physical activity to keep their bodies in shape (not to mention simply not having access to the ultra-calorie dense foods that we have now).

When you think about running on a treadmill (or around the block), your brain and body both know damn well on a primal level that that's a completely fucking pointless activity, from the point of view of your immediate survival. Of course, we know it's not pointless in a more intellectual and long-term sense, but that's irrelevant to our impulses and emotions in the here and now. It's not a natural or organic activity that we have an immediate need to do, so we understandably resist doing it.

It's only relatively very recently that we have adopted this lifestyle where we sit at a computer 8-16 hours a day and don't need to do a whole lot of physical work to meet our basic survival needs. Making exercise for the sake of exercise a thing that makes sense. But again, it's not how we evolved so it only makes sense on an intellectual level. It's always going to go against your biological impulses.