In the 1980's, a 61yo Australian potato farmer won an 875km (544m) race between Sydney and Melbourne in 5 days flat without ever stopping to eat or sleep.

He used a radical low energy shuffling technique, which was a slower pace then his competitors, but he made up for it during the 5 or 6 hours they slept each day. He ended up winning by 10 hours.

https://en.wikipedia.org/wiki/Cliff_Young_(athlete)