Jews, Exercise, and Drew

Having just got back from my first jog in a few weeks (bad Drew, bad. For people who would like to call me a hillul haShem, this is your chance.), and certainly the first in this cold, wintry weather (granted, I did play basketball each of the last two Saturday nights and have lifted here and there (again, something I need to do with more frequency, though I did lift today and yesterday, so that's a good start to the week in that department), so I'm not totally lazy (hmm, this seems like this might be a cycle)), I have decided I would post about Jews and exercise. Two things helped stimulate my thought for this posting. One was Gil's posting about it, though it was the comments on that posting that really got me thinking about the subject. A second stimulus was an e-mail from my mother in which she said,

For some reason, a lot of the Orthodox young men strike me as being scrawny. ... Am I generalizing way too much? Also, a lot of the more mature Orthodox men strike me as being out-of-shape and plump.

She also inquired as to my exercising, but we're not going to discuss that now, as she would not be happy with my lack of exercise as of late. But I agree with her observations.
When I initially began exercising, it was before I became frum, so I didn't think about couching my reasoning, or justification, in religious terminology, but rather saw it simply as keeping up one's health is the right thing to do in addition to it making me feel good after having endeavored in it. Now, in my being a committed Jew and, more significantly, in my being a rabbinical student, I have to consider exercise within a halakhic framework. For me, the most personal reason is the hermeneutical take on Deuteronomy 4.15 (דברים ד,טו וְנִשְׁמַרְתֶּם מְאֹד, לְנַפְשֹׁתֵיכֶם): "And you shall guard yourselves very much, for your souls." The line is speaking about keeping the Torah and the commandments, etc., though one can take it out of its context (as the rabbis have done many times over with various scriptural quotes) and see it as saying to guard one's body, to keep it up.
Inasmuch as that may be a personal reason, a grander reason is on account of how Jews are perceived (known as חילול השם) - it doesn't look good to not be such a healthy nation.
Another reason is similar to the previous in that since we are created in the shadow, or image, of God (Gen. 1.27), we should do what we can to give honor to such a divine image. Not off hand do I know its location in Bereshis Rabbah, but there is a midrash that one of the rabbis was going to the bathhouse when his students asked him what he was doing, whereupon he replied going to fulfill a מצוה, a commandment, that of being in the image of God, so we see a rabbinic expression of taking this descriptive line in Genesis and transforming it into an actual commandment of looking presentable.
I hope I have done justice to this topic and further hope that people consider this well.