There are some good exercises listed (with links to demonstrate proper form — and sometimes to show you what to aviod — in video and in word) in Top Bloggers & Strength Coaches spill their 3 favorite exercises.
Exercise makes your consciousness sharper and makes your whole nervous system work in a purposeful, functional way. Exercise conditions the body of which the human brain is an integral part, and both of which the human mind is an integral aspect. We were made to take action in the world; too much sedentary behavior is contrary to our nature, just as irrational behavior is contrary to our nature — when you understand that “rational” describes the nature and manner of functioning of our consciousness, it does not describe some bauble of mind or some kind of “hat” we can put on and take off but which is irrelevant to human life.
(Update, 10:45 AM: redid this paragraph.) The fact that we have emotions is not a counter-argument to this. Emotions are “reactive,” for one thing — part of what I mean by “reactive” is “automatic:” I mean that emotions are hard-wired in us in the sense that we have them and there is nothing we can do about it. And just as our automatic heart beat is neither rational nor irrational, so also our emotions as such are neither rational nor irrational. It is more (1) what we do in response to our emotions and (2) whether we judge something as good or bad for us (which results in love or hate (etc.) being automatically associated with those adjudged things) that is rational or irrational, I think. Another thing to notice is that our emotions sometimes are very generalized, sometimes apply to abstract categories of things, can be thrown askew by bad choices (or by insanity, etc.), can apply to things timeless and universal — i.e., our emotions have been transformed from what animals have to something having characteristics like those of the products of reason. Does this not suggest and imply that our emotions happen in context of (or “as conditioned by”) a rational form of consciousness? (The Greeks were the first, to my knowledge, to differentiate — explicitly and philosophically — emotion from ideas. They identified that emotions are transient and particular, but ideas were timeless and universal. Notice how contrast is the engine of induction — the Greeks drew conclusions by contrasting emotions and ideas. But we should also contrast human emotion with animal emotion — to see that our emotions are radically transformed by the rational consciousness that evolution gave us.)
Exercise because it’s healthy — for both body and mind. And we need to do whatever we can for the health and proper functioning of our mind, as reason is our tool of survival.