THE WASHINGTON POST ARTICLE REPORTING
THE RESULTS OF MY ANNUAL PRE- AND POST-BOSTON MARATHON
BLOOD DRAWING RESULTS
From: "Jeffrey Lowe" <jeffrey.lowe@bea.doc.gov>
To: <mcrun@mcrrc.org>
Date: 10/30/01 11:37AM
Subject: A provocative article from today's Washington Post
Running Danger?
Surprising Studies Suggest Marathons May Prime System for Heart Attack
By Heidi Splete
Special to The Washington Post
Tuesday, October 30, 2001; Page HE01
Race organizers preparing for Sunday's Marine Corps Marathon had more than logistics and stepped?up security precautions to think about. They also faced a startling new finding that marathon runners, long assumed to be among the most heart?and?lung?healthy athletes, may put themselves at elevated risk for a heart attack by taking such long runs.
In one of two new studies appearing in the respected American Journal of Cardiology, researchers found surprisingly high ?? and potentially dangerous ?? inflammation and clotting factors in the blood of middle?aged male runners shortly after they completed the Boston Marathon.
The reaction of Marine Corps Marathon officials? Cautious skepticism. "There's much greater risk of heart attack associated with daily living than with running a marathon," said Lt. Cmdr. Scott Pyne, medical director for this year's Marine Corps event.
None of the runners in the Boston Marathon studies ?? published in the Oct. 17 issue of the cardiology journal ?? showed symptoms of actual cardiac distress. But researchers said the presence in the runners' bloodstream of temporarily high levels of creatine kinase?MB and C?reactive protein ?? the first, a marker for muscle injury and the second, a risk factor for clotting and heart attack ?? showed they were temporarily at increased risk.
"C?reactive protein goes up whenever there's muscle damage" ?? whether to an overtaxed heart or to limbs that take a pounding over a 26.2?mile marathon, said Arthur J. Siegel, director of internal medicine at Boston's McLean Hospital and the study's lead author.
Siegel said the increase seen in blood clotting probably came from the skeletal muscle injury that occurs in all marathoners who run hard enough to "hit the wall" (become physically exhausted).
Muscle inflammation causes overproduction of blood clotting factors such as the von Willebrand factor, which was found in higher concentrations in the runners' post?race samples than in their pre?race samples. High levels of white blood cells and a protein called D?dimer also confirmed that clotting was taking place ?? a possible precursor for intravascular thrombosis, the formation of a clot within a blood vessel.
But even if overused skeletal muscles ?? and not an overtaxed heart ?? caused the excess blood clotting, Siegel said, the chemical changes could still predispose a runner to a heart attack. "If a coronary clot occurs, that triggers heart muscle damage," he said. "The bottom?line message is that regular exercise is a pathway to cardiovascular health, but ?? as with alcohol and the heart ?? you can get too much of a good thing. Marathon running is such an example as it transcends fitness goals, leading to a danger zone."
Starting in 1996, Siegel and colleagues collected blood samples on the morning before the Boston Marathon from at least 82 male marathoners ?? all of them physicians averaging 47 years old with no reported history of smoking or heart disease. The researchers then compared these samples to others collected from the same runners within four hours after the race and on the morning after.
Siegel, a former marathoner himself, said all the study participants fit the profile of "hard core" runners. "These runners were faster than average, experienced and logging at least 40 to 50 miles per week. . . . They trained hard ?? harder than many mid?packers."
An accompanying study in the same cardiology journal ?? also written by Siegel ?? showed that blood proteins called troponins ?? late?stage indicators of potential heart attacks ?? remained at indeterminate levels in the runners after the marathon. Siegel speculated that troponin levels might be more reliable indicators of heart attack risk than creatine kinase MB levels; testing creatine kinase MB levels, he said, could lead to "a false positive" diagnosis of a heart attack.
Other sports and exercise experts also avoided an alarmist reading of the study findings.
Even if endurance exercise temporarily increases the risk of heart attacks, people still suffer them less often while marathoning than in the course of everyday activities, said Benjamin Levine, a cardiologist and physiologist at the Institute for Exercise and Environmental Medicine in Dallas. "People who exercise regularly are still at less risk for a heart attack than those who don't," he said.
Further studies are needed, said Siegel, to assess the risk of running a marathon compared to shorter?duration exercise.
For now, he suggested, marathon runners should take the following precautions:
* Take aspirin prophylactically to reduce the risk of excessive clotting, as many people at risk for heart attacks do. One aspirin daily ?? even a baby tablet dose ?? will block clotting from tissue injury, said Siegel. But he advised runners to consult a doctor first to rule out problems or interactions with other medications.
* Train smart. Take at least six months to build endurance prior to a marathon so skeletal muscles will be ready for a beating.
* Take your personal medical history into account. Runners with known heart risks should think twice about a marathon, Siegel said.
As evidenced by the turnout at Sunday's Marine Corps race, devoted marathon runners are not likely to let the study results deter them.
Denny Pinch, a Washington area personal trainer and marathon coach who has trained more than 500 competitors, said one pair of studies wasn't enough to make him change his methods. "If there is more evidence that this is a problem," he said, "I will follow whatever guidelines the medical profession might suggest to limit the risk factors."