Do you run (or workout), how common is this, and if you do run can you give me some advice?

I have been puzzling over this for a while now. I was not an athletic person growing up. (The opposite, really.) And it seemed like the people around me almost universally weren’t, either.

In the past few years, though, I’ve come to find that almost everyone I associate with works out regularly and most of them include running as at least part of their training (all 4 of my coworkers, most of my incoming class at school, my roommate…) It is more unusual not to work out than to work out among the people I know.

Are my friends and coworkers freakos or do most people actually get some form of regular exercise? Is it just because we’re in our 20s? Live in California? Have I inadvertently selected for runners/athletes in my social circle?

I have tried some googles without much success. So I would like some anecdotal data if you’re willing to share: do you work out? If so, how and how often? What about the people close to you? Is working out common or uncommon among people you know?

I also have a follow-up question since I expect this question to be disproportionately answered by runners: I am running my second 5K a week from Sunday. My goal for the first was simple: finish; don’t die. This time I want to actually improve on my time. Do you have any good advice on how to do that?