We all have different reasons for exercising. I recently started up crossfit again because I was tired of feeling (and looking) weak. My boyfriend is probably the #1 fan of my doing crossfit, because he thinks it makes me a nicer person. (Apparently I get cranky when I don't get my endorphin high. Harumph.)
But if a better bod and a better 'tude don't convince you/r friends, how about a stronger brain?
Having had one grandparent who died in the advanced stages of Alzheimer's, and another who lived for ten years with really bad short term memory loss, this is no joke.