> I notice how much more clearly I can think after.

If the run is more strenuous, do you still see the same effect?

For me, a 3 miler at a relaxed pace definitely helps me be more focused afterwards.

But if I'm going full tilt up and down hills, or running longer distances, I find myself mentally exhausted afterwards. My theory is that this is due to my mind constantly battling itself on these kind of runs ("THIS HURTS PLEASE STOP NOW" vs. "PUSH PUSH PUSH").

EDIT: I should say both types of runs are relaxing afterwards.