"Only those who risk going too far can possibly find out how far they can go."

– T.S.Eliot

300 miles running non-stop: Has been done

500 miles non-stop: Will be attempted

Biggest obsticle is "sleep running"

Pam Reed completed a 300 mile non-stop run (read article)

Dean Karnazes Sets His Sights on 500 Mile Run (read article)