I don't find a deeper meaning in running. I don't think running past all of the minutia along a road or trail while I focus on my running form or listen for cars about to run me over makes me any more connected to the world around me. If that's what I wanted, I would move more slowly, with my senses directed outward. That's not what I do when I run, though.
My dominant focus when running is internal. sure, I'm aware of the world around me. I have ears and eyes that sense my surroundings, and I allow myself to be distracted by interesting things in my environment. I don't feel connected to those things in anything other than a voyeuristic sense, however.
No, when I set out for a run, I'm not thinking about my fatter former self. I'm not thinking about some leaner meaner future version of me. I'm just thinking about putting one foot in front of the other. That's all.
So, why do it? Because I want to, damnit.
Ok, now that we've got that out of the way... My selfishness in this could be taken at face value, which would make me... well, selfish, or one might observe that the selfishness itself serves a higher purpose. My running, after all, does offer some benefits that go beyond my personal satisfaction.
How so? Well, running is part of what helps me remain healthy and strong. It's part of what makes me more mentally and emotional prepared for daily life. It makes me a better me. A better me, in turn, is better to the people around me, and more effective at inspiring the kinds of changes I value in the world around me.