Boston race director Dave McGillivray echoes that advice. He had triple bypass surgery last fall after suffering chest pain and difficulty breathing while running. McGillivray has a message for anyone who has coronary artery disease or a family history of it: "Being fit and being healthy aren't the same things."
Thirty-five years ago this summer, acclaimed author and running guru Jim Fixx's heart attack death while jogging gave the world a wake-up call that runners aren't immune to heart problems.
New research is providing a more nuanced look at "extreme exercise" and the pros and cons of running long.