The study, administered at the West-German Heart Center Essen, focused on male marathoners age 50 and up. Among its findings, while the runners had lower than average cholesterol levels and better blood pressure, they had more measurable coronary calcium buildup or plaque than the general population.
The running world has no shortage of high-profile heart attack cases. Famous runners including the health-book author Jim Fixx, who died while running in 1984, to Brian Leigh Maxwell, founder of Powerbar, and Greg Marr, an editor at Silent Sports magazine, all were struck down by heart attacks, despite ostensibly being in perfect health.
The question begged by the German study's findings--and now perpetuated by a study at the Minneapolis Heart Institute--is one that bucks conventional thought: Can athletic activities like long-term marathon training actually contribute to poor heart health?
"Running is a proven healthy activity, but we're looking to find if there can be too much of a good thing," said Dr. Robert Schwartz, the Minneapolis Heart Institute cardiologist heading up the study, which will look at about 50 men who have run marathons for more than 25 years straight.
Cardiac Case Study
John Tantzen, a manager at a technology company from Eagan, Minn., runs up to 60 miles a week. A family history of heart disease pushed Tantzen, 48, into athletics years ago, and since the 1980s he has competed in dozens of races, including running the annual Twin Cities Marathon for the past 27 years straight.
Tantzen is thin and fit, and he has trouble keeping weight on no matter what he eats. But a scan this fall with Schwartz revealed high levels of coronary plaque. "It was a surprise to say the least," Tantzen said.
Doctors immediately put Tantzen on medication. He changed his diet, all but eliminating fried food and pastries, which he ate for years without a second thought.
Tantzen said he has never had high blood pressure. His cholesterol checks always came back normal. But before the scan, he was unaware of the potential for coronary plaque buildup.
"People think they are protected from heart troubles if they are in good shape," said Schwartz. "But diet and other factors can still affect coronary health in the fittest of athletes."
A Second Look
Beyond examining whether elite athletes are immune to cardiovascular maladies, Schwartz's study -- called the Ken Rome Fund Marathon Study--aims to assess potential links between extreme athleticism and coronary plaque buildup, which is a top cause of heart attacks.
Schwartz said stress from years of running--including states of dehydration, exercise-induced high blood pressure, prolonged high pulse rates in events like marathons, and the movement and twisting of arteries while on the run--has unknown long-term effects.
Suggesting running as a potential health hazard sparked controversy with the German study, including editorials in publications like Runner's World that questioned the test's conclusions. Schwartz hopes to provide an objective second look using a more powerful heart scanner.
With a CT scanner at the Minneapolis Heart Institute, Schwartz said his study will include a higher-detail image of each subjects' heart data plus a subject field that's more homogenous and more elite than in the German study.
With money from the Ken Rome Fund, which is named for a Minnesota runner who died of a heart attack last March, and other sources, the Minneapolis Heart Institute has about $100,000 to commit to the study. The entire project will take 20 months.
Schwartz and his team have scanned about 25 runners already, with 25 to go in the initial batch. Results are inconclusive thus far, he said, with subjects like Tantzen showing high plaque levels and other runners exhibiting perfect heart health.
Schwartz hopes to publish findings in a medical journal this winter before moving on to a larger study on the subject, including the analysis of women marathoners as well as runners who are less elite.
"We know that athletics has huge benefits for the heart," said Schwartz, himself a runner. "But what we don't know is how much exercise is too much exercise, or even if there is such a thing."