But 51, in 50 days, across all 50 states?
Sam Thompson finished that feat on Friday in his home state of Mississippi.
He made the runs to raise money for victims of Hurricane Katrina, as the storm's first anniversary approaches, and to raise awareness of the devastation that remains along the Gulf Coast.
Thompson, 25, of Vicksburg, Miss., told The Early Show co-anchor Hannah Storm Monday, "I was hoping to reignite the nation and let people know that everything is not fixed. … There is still just a huge need down there and especially now, approaching the one-year anniversary. I wanted to remind people that there's still a great need and lots of opportunities to help."
While the marathons were "definitely difficult," Thompson says, "I would honestly say that the travel and logistics and all of that were more challenging than the actual running. It was quite a trip, for sure."
He had to run at all hours of the day on different days to catch flights, and Thompson said, "Throughout the 50 days, I did run a marathon at every hour of the day."
His girlfriend, Kirsten Sellereit, a registered dietician, accompanied Thompson in his quest and told Storm she had him on 5,000-plus calories each day after he ran, and at least 1,000 while he was running.
Not only that, Sellereit had Thompson take an ice bath after each run.
The regimen paid off: Thompson says he came through "amazingly well," without any injuries.
Sellereit added, "When I first met him, I just kinda laughed and I shook my head, thinking. 'There's no way it's gonna happen.' And then, he kept talking about it and I was like, 'He's really serious about this.' And then, getting to know him, I knew he could do it, because he's just so driven."
Thompson even ran two marathons one day, accounting for his total of 51 in 50 days.
And he was still going strong at the end, finishing his second-to-last one in a mere 3 hours and 29 minutes.
Next up for Thompson?
"I have started a new mission, it just started yesterday (Sunday): Fifty naps in 50 days, in one state, was the plan."