What exactly are rest days? Are you not really supposed to do anything, or are you just not supposed to jog, or what? On my rest days I've still been taking long walks (walked a 5K race today), I just haven't been doing my C25K. I read someone's blog today where they said their C25K progress drastically improved when they used a rest day as a true rest day - no long walks, hikes, etc. What are your thoughts?