Also 48 hours and six days are recognized for world records by the IAU. http://www.iau-ultramarathon.org/ http://www.iau-ultramarathon.org/ There's also this:

Also 48 hours and six days are recognized for world records by the IAU. http://www.iau-ultramarathon.org/ http://www.iau-ultramarathon.org/ There's also this: https://en.wikipedia.org/wiki/Self-Transcendence_3100_Mile_Race https://en.wikipedia.org/wiki/Self-Transcendence_3100_Mile_R...