As a frequent runner, not marathons, and a father of a son who routinely runs marathons, I was shocked to read the following in MedScape News:
Long-Term Marathon Running Linked With Increased Coronary Calcification
By Michael O’Riordan
Atlanta, Georgia – Long-term marathon training and racing might not be as good for the heart as some runners think, a new study suggests. Researchers have shown that long-term marathon runners, those who have completed at least 25 marathons over the past 25 years, have increased coronary calcium and calcified plaque volume.
This study, at first glance, seems astounding. It is well known that Marathon Runners have fewer heart attacks than the average person.
Presenting the results of the study at the American College of Cardiology 2010 Scientific Sessions, Schwartz, along with senior investigator Dr Robert Schwartz (Minneapolis Heart Institute, MN), his father, said that at least three runners have died this year during marathons, and three runners died during the 2009 Detroit Marathon, a race that included nearly 4000 finishers. Runners are typically considered a healthy subgroup of the general population, so these deaths are usually high profile and attract a great deal of media attention. One recent estimate suggests the rate of sudden cardiac death among marathoners is rare, roughly 0.8 per 100,000 participants.
These unexpected sudden deaths during the marathons led a father/son physician team to explore for reasons:
Metabolic and Mechanical Stress
In this study, the father-and-son team, both runners, wanted to assess coronary artery plaque in an elite group of marathon runners and compare their arteries with a control group. They identified 25 runners who completed the Minneapolis-St Paul Twin Cities Marathon every year for 25 consecutive years, thus completing a minimum of 25 marathons.
All subjects underwent coronary computed tomography angiography (CTA) using a 64-slice machine. Compared with controls, marathoners had significantly more calcified plaque volume–274 mm3 for the marathoners and 169 mm3 for the controls–and higher calcium scores and noncalcified plaque volumes, although the latter two measures did not reach statistical significance.
Robert Schwartz told heartwire that patient age, systolic blood pressure, total cholesterol, LDL cholesterol, and triglyceride levels were similar between the marathoners and controls, but heart rate, weight, and body-mass index were lower in the runners. Also, HDL-cholesterol levels were significantly higher in the runners than in the controls. The average total- and LDL-cholesterol levels were 190 mg/dL and 115 mg/dL, respectively, in the marathon runners, which suggests that diet is not is the reason for the increased calcification.
There has to be a reason!
Asked about the possible mechanisms, Jonathan Schwartz said they don’t know why the runners had more plaque in the arteries than the controls and that the findings are “counterintuitive.” However, he pointed out that metabolic and mechanical stresses might be a contributing factor. For example, long-distance runners train at increased heart rates and blood pressures, as well as spend increased time in an anaerobic state, possibly leading to antioxidant damage. Also, damage to the bones might lead to calcium leaking into the bloodstream. They stressed, however, such possible explanations need to be explored further.
Aristotle, probably the World’s wisest man, taught his pupils about two and a half thousand years ago, that there existed in nature: A GOLDEN MEAN.
Too much or too little of anything is no good. Each of us, who have experienced life, knows that Aristotle was right. Take it easy and enjoy the trip. You only have one ticket.