Sunday’s marathon will be Mendes’s 12th in New York. In the 2005 race, his last appearance, he was the oldest finisher, at age 85. He would become the ninth-oldest finisher in the marathon’s history upon completing the course Sunday. The age record would be his alone if, as planned, he finishes again at 94 in 2014  an impressive respiratory and vascular achievement for a man who began running at 46 after kicking a smoking habit of two and a half packs a day.

“You’ve got to have goals in life or you wither away,” said the elfin Mendes, who stands 5 feet 6 inches on his tiptoes, weighs 160 pounds, hums jauntily while he walks and inevitably draws disbelieving looks when strangers learn his age. “It’s no disgrace to fail, only not to try.”

He spoke on Wednesday, his birthday, as he took a brisk stroll around the Central Park reservoir. Dressed in a ball cap that denoted his World War II squadron, with his round face and ski-slope nose, Mendes bore a passing resemblance to Bob Hope, whom he said he met three times during his military service.

Accompanying him were his marathon partners: Carl Landegger, 80, and Daniel Marks, 18. Landegger and Mendes are two of the seven original members of the 72nd Street Marathoning and Pasta Club, whose runners began competing around the world in the 1970s and have helped to conserve Central Park by planting trees and cleaning and restoring water fountains.

Marks is Mendes’s grandson, who jogged a few miles with his grandfather in 2005 as a 13-year-old and has seriously trained this year with 17-mile runs that included excursions over the Brooklyn Bridge.