I heard about this on the radio this morning:
link
Running Marathons May Lead to Heart Complications, Study Finds
March 13 (Bloomberg) -- Marathon runners are at risk for high blood pressure and heart complications, as endurance training can stress the cardiovascular system, researchers said.
Marathon runners had increased blood pressure and stiffness in the aorta, the major artery to the heart, researchers said in a study to be presented on March 15 at the American College of Cardiology meeting in Atlanta. Findings from the research were released today.
While moderate exercise has a protective effect and people who don’t exercise have a higher risk of developing heart- related problems, exercising too much can do harm, said Despina Kardara, a researcher from the Athens Medical School and Hippokration Hospital in Athens and lead author of the report.
“The cardiovascular system is like a sports car engine,” said Kardara in a statement released with the study. ”If you do not use it, it will decay, but if you run it too fast for too long, you might burn out.”
The runners in the study trained about 10 to 19 hours a week, for periods ranging from about 2 to 20 years, the researchers said. Standard marathons mean running 26.2 miles (42 kilometers) from start to finish.
The scientists used an evaluation index called pulse wave velocity that measures stiffness in the aorta. The test showed marathon runners had a higher wave velocity, indicating rigid artery walls. Stiffness in the aorta causes high blood pressure, and can be an indicator of cardiovascular disease and predictor of heart attack and related death, Kardara said.
Control Group
The scientists evaluated blood pressure levels and flexibility of the arteries in 49 people who ran marathons, and in 46 people -- similar in age, height and cardiovascular risk factors -- who weren’t endurance athletes, according to the research. The runners had higher blood pressure and reduced heart rate, and those with more-intense exercise regimens showed more stiffness in the arteries, according to the study. Only seven of the runners were women.
”This is important because stiff arteries lead to high blood pressure and can impair the heart, keeping it from performing properly,” Kardara said.
The research was supported by Hippokration Hospital, the Athens Medical School and the Athens Classic Marathon Organizing Committee.
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I'm not sure what to think about this. Anyway, averaging 10-19 hours of running a week is a lot and more than I'll ever do.