SURGE OF OLDER RUNNERS IN BOSTON MARATHON

THE BOSTON GLOBE

A record 596 runners age 65 and older set to compete today

Running a marathon is a humbling experience.

There is the delirium that comes from hitting the wall. There are the cramps that will not vanish, the blistered feet that sting with every footfall, the depleted quads that plead for a chair. There is the realization that you are not as fit as you had hoped.

And then there is this: watching someone twice your age plow past you on Heartbreak Hill.

Last year, while struggling to complete my second Boston Marathon, I noticed a disturbing trend (disturbing for my ego, at least): A lot of folks eligible to collect Social Security were serving me their dust as they surged ahead on the grueling course.

This may be an increasingly common experience.

Over the past decade, the number of older runners participating in the Boston Marathon has more than quadrupled. A record 596 runners age 65 and older have registered for Monday’s race, 47 of whom are age 75 and older.

This year’s oldest runner will be Keith Wood, 83, a retired accountant from Sultan, Wash., who decided to start running marathons at the tender age of 72. He has since run about 40 marathons, which he said includes ultramarathons, or races as much as double the 26.2-mile distance of a marathon.

“It was just something to do,’’ he said.

He takes pride in passing more junior runners. “I laughed when one guy told me that I intimidated him,’’ he said.

Wood hopes to finish this year in 4 hours and 30 minutes, about 40 minutes slower than he ran a decade ago. “My stride isn’t what it was,’’ he said. “I keep thinking I should be running faster.’’

Officials from the Boston Athletic Association said they lack sufficient records to cite the oldest runner to complete the Boston Marathon, which began with 15 men in 1897 - a few shy of the 27,000 runners expected this year.

The oldest man to run in the past decade was Jerzy Kuszakiewicz, 87, of Granite Shoals, Texas, whose finishing time was an impressive 5:19:01 in 2002.

Last year, of 464 runners age 65 and older who registered to run, more than 83 percent finished the race. The fastest was a 65-year-old from Canada who ran in an astounding 3:04:52 - about an hour better than my best time over five marathons - and fast enough to have qualified to run in the youngest age bracket.

Guinness World Records cites the oldest woman to complete a marathon as Gladys Burrill, who was 92 when she finished the 2010 Honolulu Marathon in Hawaii, in just under 10 hours.

The record for the oldest man to finish a marathon has been in dispute since Fauja Singh, of London, claimed to be 100 years old when he finished last year’s Toronto marathon in 8 hours and 25 minutes. (Guinness would not certify his record because he lacked a birth certificate, which apparently was not routinely issued when he was born in India. He did reportedly have a passport showing he was born in 1911, as well as a letter from the queen congratulating him on his 100th birthday.)

Dave McGillivray, race director of the Boston Marathon, said there are no special accommodations made for older runners aside from slower qualifying times. An 80-year-old man, for example, has to have run a recent marathon in less than 5 hours to qualify, and a woman of the same age has to have finished in 5 hours and 30 minutes. Others win a spot in the race by raising money for a charity.

Asked why the number of older runners has surged, he said: “Those of us who started running and racing in the ’70s and ’80s, and who survived the injury plague, are still running,’’ he said. “But we are older.’’

He does not worry about the health risks for elderly runners. “It’s the younger ones I am more worried about,’’ he said. Doctors caution that older runners should have a full health screening before running a marathon and stop if they experience chest pain, dizziness, shortness of breath, or other symptoms of a heart problem.

They said that most people 65 and older are more vulnerable to injuries such as stress fractures and tendinitis, because of the increased brittleness of bones, reduced elasticity of tendons, and atrophy of muscles. They also tend to have reduced aerobic capacity and heal slower than younger runners.

“I encourage people of all ages to run, as long as they have first been evaluated,’’ said Dr. Ryan Friedberg, a sports medicine physician who for years has treated marathon runners at Beth Israel Deaconess Medical Center. “My biggest concern is the guys who want to cross something off their bucket list.’’

At 70, Pete Stringer, a retired writer from Osterville, plans to run his 30th Boston Marathon Monday. He may have slowed in recent years, but he said he has not lost his endurance.

“People expect you to look frail at my age, so I think it’s motivating to see a guy with white hair finish the marathon ahead of younger runners,’’ he said.

Motivating, perhaps, for those watching from the sidelines.

Last year, I finished the marathon just after Clarence Hartley, then 81, who was the oldest runner. The retired lieutenant colonel in the Air Force from Young Harris, Ga., began running at age 75 and persisted through two bouts of cancer.

“I knew Lance Armstrong beat cancer, and I thought, ‘If he could beat it, I could beat it,’ ’’ he said.

He has since gone on to set running records for his age.

We met shortly after he finished in 4:26:09. After I waited about 10 minutes in line to use a Porta-Potty, it was my turn. As I went to open the door, a State Police trooper stepped in front of me and ordered me to stand back.

“This man just finished the marathon,’’ he told me, pointing at the seemingly unfazed man more than twice my age.

I stepped back.

He beat me again.