Two men -- a 21-year-old student and a 40-year-old experienced triathlete -- died, apparently of cardiac arrest, while running the Philadelphia Marathon and Half Marathon Nov. 20. That same day in Pittsburgh, KDKA News anchor Susan Koeppen collapsed while jogging with friends in Shadyside. Ms. Koeppen, who was training for a half marathon, reported by Twitter she has a defibrillator now.
In October, a 35-year-old fireman died while running the Chicago Marathon.
So is running long distance hazardous to your heart? It sure was for Phidippides, the first marathoner. After the Athenian army defeated the Persians at the battle of Marathon in 490 B.C., Phidippides is said to have run in about three hours the 25 miles back to Athens to deliver the news. According to legend, he uttered the word "Nike" (victory) and expired.
(The official marathon distance of 26 miles, 385 yards was established in 1908 so that the race in that year's Olympic Games would finish precisely in front of the box where Britain's royal family sat.)
"The stress of a marathon can cause the heart to manufacture the same proteins as when you are having a heart attack," said Moira Davenport, a sports medicine physician at Allegheny General Hospital and a marathon runner herself.
Between 6 and 17 percent of sudden cardiac deaths are associated with exertion, said John D. Kelly, a sports medicine physician at the University of Pennsylvania.
So if you put too much stress on your heart, catastrophe can occur. But it isn't likely, Dr. Davenport said. About one in every 50,000 marathoners dies during a race. The incidence of sudden cardiac arrest among the general population is 50 times as great, she said.
Training for a marathon actually is protective of the heart, if it is done properly, Dr. Davenport said.
"If you run more than 45 miles a week, research indicates your risk is significantly less than if you run fewer than 35 miles a week," she said.
But "the benefits of running are not a blanket immunity from what your genes are going to do to you anyway," Dr. Davenport cautioned.
Most of those who've died running marathons had pre-existing heart problems, she said. Ms. Koeppen will have heart surgery to correct a valve problem.
But otherwise healthy athletes can suffer cardiac arrest if they put too much stress on their hearts. Phidippides, for instance, is alleged to have run the 140 miles over mountainous terrain to ask the Spartans for help, and the 140 miles back after they said no, and then fought in the battle of Marathon before making his legendary run. He was probably pretty tired when he set out.
If you don't want to wind up like Phidippides, have your physician check you out thoroughly for pre-existing conditions before engaging in exercise that will stress your heart, Dr. Davenport said.
"Train properly. Don't attempt a race much longer than what you've practiced for, [and don't] run it at a pace faster than what you ran in training. Remember that even if it's the race of your life, it isn't worth your life."
Jack Kelly: firstname.lastname@example.org or 412-263-1476.