Running and being an academic dean are similar according to Peg Barratt: Everyone tries to give you advice.

“All kinds of people give me advice, and it’s just interesting to kind of collect all that information from lots of people,” she said of both roles.

After collecting that advice, and 18 weeks of steady preparation, she joined 30,000 runners for the 36th annual Marine Corps Marathon early Sunday.

“My son was just starting high school and was running cross country so I was inspired by that,” Barratt, 63, said. “Every morning I walk my dog. So I started walking a little, running a little. Pretty soon I was running a mile.”

Participants got on their mark and set off for the 26.2-mile course at the wave of a flag at 8 a.m., partaking in the fifth largest marathon in the country. Runners – some in uniform – carrying American flags made their way from Arlington, Va., through Rosslyn, Va. and Georgetown, past the monuments and around the Tidal Basin.

“They call it The People’s Marathon. One-third of the people are first time marathon runners,” Barratt said.

She said she watched the racers pass by her Arlington, Va. home in past years and decided that marathon would be the one she will join.

Barratt completed the run in five hours and 33 minutes, she said, just three minutes past her goal time. She averaged 12 minutes and 44 seconds per mile, according to the event website.

“I think it gives you energy. I don’t think it takes energy,” Barratt said.

Three days a week, Barratt factors a run into her routine. She said she is disappointed when she wakes up on the days she is not going for a run – her designated recovery days.

Using a combination of will and physical strength to prepare for Sunday’s race, Barratt said her body gradually adapted to the increasing number of miles she added to her workouts.

“Your body says, ‘I didn’t know you wanted me to run 14 miles. I’ll get ready – next time I can run 14 miles,’ ” she said.

Last New Year’s Eve, she ran her first race, and in the spring Barratt ran the Frederick Half Marathon in Frederick, Md. She said her results – landing sixth out of the 17 women in her age group – encouraged her to try a full marathon.

“If I can do that, I can do the whole thing. So I committed myself to try this,” she said.

Spectators, including Barratt’s family, cheered and lined the route with homemade signs and cow bells.

Physics professor Frank Lee, 48, joined Barratt to mark his first marathon. He said he once saw a T-shirt that said, “If found on ground, please drag to finish line,” which describes his running mentality.

Lee, who began running this summer, said his mantra is, “Go steady and when you’re tired, try to encourage yourself.”

He said he has logged more than 300 miles since he began running. For Lee, the race was more than a personal challenge.

“I’m going to do it because someone dear to me is a breast cancer survivor. I’m going to dedicate this run to her,” he said.

Barratt ran as part of the GW Cancer Institute’s team.