I'm pretty sure you're mis-using your body.
You're probably doing the best you can to take care of it, but my guess is that:
A: You have a Goal, and
B: Even if you do have a System, it's aimed the wrong way.
I (along with Scott Adams from Dilbert fame) have talked about systems and goals before, but a quick recap might be useful:
Standalone goals are for suckers. Goal driven actions generate a one-time event that seldom gives you anything near the satisfaction you think they will.
Examples of goals are weighing a certain amount, lifting a certain amount, finishing (or winning) a race, or making a definite amount of money.
Systems are for winners. Systems are built and designed by you to continually increase your ability, agency, happiness, or whatever it is you want on a long term timeline.
Systems pass you through any goal you want without making it an end-state.
Examples of systems are habits, rituals, or practices.
There's enough crossover between systems and goals that an endless debate is possible about where the line is drawn (Will a system bring you a goal? Is a good goal an excellent system?), but if you're pragmatic then that debate ain't worth having.
So, back to the system you're using to mis-use your body.
What I see in most cases is a system designed to deliver comfort. Let me give you some examples.
It's comfortable to live in a temperature range of 72, so you set your thermostat there.
It's comfortable to eat when you're hungry, so you schedule meals to occur right at (or worse, slightly before) the time you get hungry.
Alternately, it's UNcomfortable to exercise hard, so you walk around the block. Once.
How is this mis-using your body? Isn't it OK to be comfortable?
Sure, comfortable is fine, and it's an enjoyable state to pass through, but it's just a reference point. Reference points, unless constantly checked and tested with their opposite states, tend to become less and less useful for guidance.
A system designed to deliver comfort will ultimately bring you to stasis much faster than you otherwise needed to get there. Ultimate stasis, of course, is death.
Alternatively, a system designed to deliver growth will place you in alternating states of comfort and discomfort. You'll enjoy the comfort states all the more, and you'll have a clear reference point for what uncomfortable really is.
You'll also twist your mind around the idea that being uncomfortable is actually just as enjoyable as being comfortable once you learn to control your perspective, but that's another blog post.
Finally, you'll be able to distinguish between life-threatening and merely uncomfortable, an ability that is quickly being lost by the majority of First World citizens.
What are some general ideas for building a system that drives you on to growth? In this case, "the use of your body", think about the boundaries of your everyday physical world, then decide to make a practice of testing them.
How cold can you get? How hot can you get? How long can you go without eating? How much weight can you lift? How long can you hold your breath? How well can you write? How accurately can you draw? How easily can you start up and hold a conversation with a stranger? How well can you build something, from a simple box of cardboard all the way to a building of rammed earth? How well can you hug?
Yes, hug and draw. Physical ability is not always an objectively measurable thing, and the ability to subjectively analyze your performance and then make adjustments that increase that performance is one of the rare attributes of a growth minded person.
All of these are pass-through goals delivered by a system dedicated to growing the use of your body. It is an on-going and ever fruitful task, regardless of the outcomes temporarily achieved.
At the end of the day, as long as you're aiming generally toward growth and you're NOT using comfort as a guide but rather as a reference point, you'll be well on your way to using, rather than mis-using that wonderful body of yours.
Too much reading...
How about dessert?