But the retired music teacher from the Upper West Side is determined to complete the Nov. 6 marathon as he’s the only person to have finished the 26.2-mile race every year since it became a five-borough event 40 years ago.
"I may not be ready, but I’ll do it," Obelkevich said.
He figures if he can't run, he'll walk at about 4 mph to finish in about 7 hours.
"I’m not going to try to break a world record or to win the race, but it’s nice to do a so-called 'respectable time,'" the marathoner said.
"I'd be a finisher even with seven hours. Not too happy, but I'd be able to finish."
He has competed under even worse conditions.
Obelkevich, who was born upstate and moved to the city in 1961 to attend Columbia University, once ran with a broken rib he suffered weeks earlier in a cycling crash in the '80s.
"It was healing [but] it was hard to get out of bed," he said.
"I couldn’t laugh too much because it would hurt too much. I ran it anyway."
He ran one of his best times that year at about 4 hours and 8 minutes, he said.
Obelkevich first ran the marathon in 1974 with 259 others, looping around Central Park through heat, downpours and a crowd of about 100 spectators to finish in just over 4 hours, he said.
"The first year was tough. I don’t think I’d ever run more than 6 miles and didn’t know if I could finish."
He dropped out of the 1975 race but signed up again the next year when the New York Road Runners expanded the 26.2-mile course into every borough.
Up to that point in his life, Obelkevich had mostly spent his time in upper Manhattan after moving there for college.
"Almost everything I was running except for Manhattan was something brand new. That was quite an experience to get a tour of New York," he said.
"I’m not sure I’d ever been to Staten Island before. Certainly, I’d never gone over the Verrazano Bridge and run up Fourth Avenue in Brooklyn."
That year, there were 2,090 runners and even more spectators.
"It was a huge scale of difference," Obelkevich said. "To have crowds all along the way, just an entirely different experience."
In those early years, stretches of the course were so clogged with spectators that there was only about a 4-foot-wide gap for racers to pass through in single file.
But there were some desolate stretches too, like one along the East River just north of the Queensboro Bridge.
"We’d see two or three people per mile. And mostly, they’re drunks. They’d say, 'wuddisgoingon?'" Obelkevich remembered.
He remembers Jews in Williamsburg calmly telling runners "Way to go" as they passed into livelier neighborhoods, with spectators singing, dancing and blaring boom boxes.
Obelkevich had shared his marathon streak with a former investment manager, Tucker Andersen, who owns the Upper West Side apartment that Joe DiMaggio lived in during his 72-game hit streak.
But Andersen injured his knee in 2009 and had to sit out that year's race, ceding the streak to Obelkevich.
Now he's trailed by only two men — David Laurance and Richard Shaver — who each have 38 races, according to the New York Road Runners.
In the meantime, Obelkevich has no plans on miss an event.
"It would take a major catastrophe to prevent me from participating," he said.
"Yeah, death would stop me, I guess."