Finishing Casper's marathon course in just under four hours, Dean Karnazes checked his watch and immediately started giving interviews.

He barely seemed winded.

Running 26.2 miles would be a huge accomplishment for most people, but Karnazes is just getting warmed up. Monday's run in Casper was No. 9 in his schedule of 50 marathons in 50 states in 50 days.

"I want to issue a wake-up call to the country," Karnazes said. "We need to start being more active. I think we'd be happier if everyone was in better shape."

He finished the Casper course in 3 hours, 54 minutes. (The course record is 2:43:45.) On Sunday, he ran the Boulder Backroads Marathon in Colorado and placed 103rd.

A group of students from North Casper Elementary School came to watch Karnazes cross the finish line at the Holiday Inn on the River shortly after noon.

"We read an article to the class on Friday as a current event, and after that, the kids begged us to come see it," said fourth-grade teacher Stacey Mittelstadt.

Shortly after finishing, Karnazes gave each of the 24 students a high-five, then raced the kids for a short sprint.

Karnazes, 43, said he has been a runner since kindergarten, when he started running home from school.

"My parents and my own kids are all runners," he said. Karnazes said he is taking his whole family with him as he travels to each state.

"Running a marathon course in every state is a great way to see the country," he said. In fact, Monday was the first time he had been to Wyoming.

Monday's run wasn't a formal race, but eight runners joined him for the 26-mile jaunt. Karnazes said he enjoyed the run along the river and even saw several birds and jumping fish.

"You've got to do something about this altitude, though," Karnazes joked. "I'm from San Francisco, and this was a real struggle."