It was the death heard around the running world.
In July 1984, acclaimed author and running guru Jim Fixx died of a heart attack while trotting along a country road in Vermont.
Fast-forward 35 years, and Boston Marathon race director Dave McGillivray is amplifying the message that being fit and being healthy aren't the same things.
He should know. Six months ago, the lifelong competitor underwent open-heart triple bypass surgery after suffering chest pain and shortness of breath while running.
As marathons, ultramarathons, and swim-bike-run triathlons continue to explode in popularity, doctors are re-prescribing some longstanding advice: Get a checkup first and talk with your doctor about the risks and benefits before hitting the road.
For McGillivray, 64, the writing was on his artery walls. Both of his grandfathers died of heart attacks; his father had multiple bypasses; his siblings have had heart surgery; and a brother recently suffered a stroke.
"I honestly thought that through exercise, cholesterol-lowering medicine, good sleep and the right diet, I'd be fine," he says. "But you can't run away from your genetics."
Studies have shown those who exercise regularly are more likely to survive a heart attack and recover more quickly than couch potatoes.
But new research is providing a more nuanced look at "extreme exercise" and the pros and cons of running long.
Spanish researchers have found signs suggesting that full marathons like Boston may strain the heart. They measured substances that can signal stress and found higher levels in runners who covered the full-length marathon distance compared with those who raced a half-marathon or 10K.
The researchers say only about one in 50,000 marathoners suffers cardiac arrest, but a high proportion of all exercise-induced cardiac events occur during marathons - especially in men ages 35 and older.
McGillivray says his doctor has cleared him for Monday's 123rd running of the Boston Marathon, which he'll run at night after the iconic race he supervises is in the books.
"Heartbreak Hill will have special meaning this year," McGillivray says.
Australian Associated Press