Running stresses the heart, but don’t stress out
A new “Research Letter” published in the American Heart Association’s journal Circulation raises the old fear that running long distances — particularly the 42.2-km marathon — could be bad for amateur runners. But according to several experts, including the paper’s author, would-be marathoners should not worry that they are on the road to a heart attack or heart disease, though it is smart not to attempt the marathon distance until you have trained sufficiently.
A group of Spanish physiologists reported that “the strain imposed on the myocardium by competing a full marathon is much greater compared with other distances such as the half-marathon or 10-km races.” They came to that conclusion by measuring the same proteins in runners’ blood that doctors look at to diagnose heart attacks. The biomarkers — cardiac troponins — were elevated in all 63 runners (39 women and 24 men, with an average age of 37) after completing their races, Studies suggests elite runners shouldn’t worry that they are headed for a heart attack, but amateur runners should ease into long distances.
but particularly so among the marathon runners.
But the Spanish team made no claims about heart attack or heart disease risks among the marathon runners. Indeed, the Letter notes that “the release of cardiac troponins after exercise may not be indicative of any cardiovascular dysfunction.”
This is precisely the finding of other studies published over the last decade, including a handful in Circulation, a scientific journal published
for the American Heart Association. “I don’t see anything new here, and the increased likelihood of a troponin bump with marathon vs. shorter distances has been well described before,” Malissa Wood, of Boston’s Massachusetts General Hospital, said by email.
Wood was a co-author of the first major paper on the subject, which appeared in Circulation in 2006. That investigation followed 60 nonelite participants in the 2004 and 2005 Boston Marathons. All had unmeasurable troponin before the marathon, but more than 60 per cent had levels greater than 99 per cent of normal post marathon. Still, the paper concluded: “There are no data to suggest that there are long-term sequelae to the increase in biomarkers.” In other words, no subsequent heart damage.
Paul Thompson, chief of cardiology at Hartford Hospital in Connecticut, has been researching the exerciseheart connection for 40 years. “We’ve long known that troponins increase after exercise,” he said in an email. “The new Research Letter’s small contribution is to suggest that long-term effects should be studied. We all agree with this, and lots of groups, including ours in Hartford, are already doing this.”
“Current endurance athletes should not be worried,” said Thompson. “They always live longer than their sedentary peers, and there remains no conclusive evidence that their exercise is dangerous.”
More on the findings at thestar.com/health