I ran a marathon last Sunday and felt great the next day and the next and the next! If you've ever been thinking about doing a marathon, I highly recommend it. No matter how long it takes you to cross the finish line, doing so is the BEST!
I do want to air a couple of peeves (I feel entitled since I consider myself a seasoned runner now.)
Race walkers, I love the fact that you're there but please, don't walk abreast and make us runners try to dodge you, risking injury.
First-timers - especially young ones who haven't tuned in your vocal volume -- please refrain from telling everyone within earshot your experiences. We're trying to concentrate.
That said, I really, really, appreciate all the volunteers and people on the sidelines (especially residents of the route) who come out and cheer us on, give us water, first aid, and vaseline to prevent blisters. You are the salt of the earth!