A controversial new study is raising questions about health benefits of distance running.
A Minnesota heart doctor found that long-time marathoners have more plaque in their arteries than non-runners.
It's impressive when someone finishes a marathon. Even more impressive, those who run marathons year after year. But a study of 50 men who all ran the twin cities marathon 25 years in a row, has shocking results.
John Tantzen was a study participant. He says, "I thought that we were going to find that I was a very healthy person and no heart disease."
That study found those men, including John Tantzen, actually had more plaque in their arteries than those who don't run.
Tantzen says, "my first perception was yeah! 90th percentile good and it was like stunning when I read further into the details and it was 95th percentile bad."
Dr. Robert Schwartz was a researcher in the study. He says, "we would have expected they had less plaque because these are very fit people typically good healthy lifestyle lots of exercise of course healthy eating habits, in fact they had slightly more plaque, a big surprise."
Cardiologist Dr. Robert Schwartz of the Minneapolis Heart Institute at Abbott Northwestern is one of the study's authors. He says the study did not show why they have more plaque, but he has some thoughts. He says, "if you think about it as a person who has been running all those years, higher blood pressure, higher heart rates, metabolic by-products."
Tantzen thinks for him its likely family history and diet. He adds, "it's hard to get enough calories to train that much and it's so easy to fall into junk food."
Dr. Schwartz will continue to monitor the marathon runners to see if their higher plaque affects their long term health. He says for now, its too early to tell ultra marathon runners to slow down.
The control group of 25 non-runners included people with diabetes and those who were overweight or smokers and still the ultra marathon runners had more plaque.