Exercise is not mere “burning calories” or “building muscle.”
A good definition and understanding of exercise has to take into account the fact that exercise is practicing moving through a complex, fractal environment safely, efficiently, powerfully, and mindfully in a species-appropriate way.
It is using and conditioning the muscles, ligaments, tendons, fascia, bones, hormones, biochemistry, and — most importantly — the brain and nervous system to survive and thrive in this world.
Optimal thought and optimal fitness through reason, logic, science, passion, and wisdom.