What is it about running that compels some people to run 26.2 miles, often several times a year, and others to put almost as much energy into proving that too much running is a risky business? Gina Kolata, writing in the New York Times, wonders where the intensity starts, and where it ends. Kolata reports that when a recent editorial in the journal Heart asserted that “chronic extreme exercise appears to cause excessive ‘wear-and-tear’ on the heart,” it sparked a raging conflagration of the long smoldering debate about health benefits and risks of running. Why the rage? The best answer comes from Paul Thompson, a cardiologist, exercise researcher and endurance athlete, who, Kolata reports, says “a lot of people use their athleticism in an attempt to show they are a superior human being.” That unfortunate tendency, says Thompson, doesn’t go unresented, and consequently “people love to find studies that support the bias that too much exercise is bad.” Read more from Gina Kolata.