This weekend I participated in our Lions Club's highway cleanup. We have a stretch of road about a mile long that we walk over every couple of months and clean of any trash we find.
It's great to provide some community service. It's also good exercise. Bending over, going up and down inclines in the median, carrying the bag of trash all exercise muscles that I don't typically exercise. And at this point, any exercise I can get is a very good thing. I sure felt it afterwards.
For a lot of people this kind of work is part of an everyday routine, but for a desk jockey like me physical labor is something I have to go out of my way to do. One disadvantage of desk jobs is that they're sedentary, so weight gain can creep up on you (as it did me) unless you take active steps to exercise and eat right.
Volunteering and sweating out in the sun for a couple of hours is one way to do that.