It's 2:45 a.m., and you've just won the Tournament of Champions national debate competition. What do you do to wind down?

North Texans Nick and Olivia Rogan went to Waffle House.

"We were running on adrenaline all day," Nick said. "We went to Waffle House afterwards, and we were all falling asleep where we sat."

The brother-and-sister team – two of triplets all in their senior year – were one of three teams from the Greenhill School in Addison to compete in this year's Tournament of Champions in Lexington, Ky. They debated in the policy style, in which teams of two argue for and against a specific resolution. This year's topic addressed U.S. public health assistance to sub-Saharan Africa.

The key to their success was preparation, said Jonathan Paul, one of the school's debate coaches.

"There's a persuasive speaking component to it, of course. But research is huge," he explained.

Students debate the same topic all year long, continually fine-tuning their arguments while searching for innovative angles that are difficult for the opposing side to rebut.

Mr. Paul said he guessed Nick and Olivia prepared for six to eight hours a day during the month before the tournament.

"I totally curtailed all socializing – people got kind of upset," Olivia said, laughing.

Their mom, Charlotte Rogan, said she knew how important the win was to her children. Brother and sister had debated as a team for all four years of high school.

Ms. Rogan said she credited coaches Mr. Paul and Aaron Timmons with the win. Mr. Timmons, Greenhill's other debate coach, was inducted into the Tournament of Champions Coaches Hall of Fame this year.

"Greenhill inspired and coached them," she said. "I've appreciated that a lot."

But the students' success doesn't end there. Olivia received early acceptance to Yale University. Nick, after scoring a perfect 2400 on his SAT, was accepted to Harvard University. Their sister, Stephanie, has made plans to attend the University of Pennsylvania.

For now, though, Ms. Rogan said Nick and Olivia will relax and enjoy the feeling of being national champions.

"It was such a win – elation and exhaustion at the same time," she said. "For it to end this way is just phenomenal."