(15-06-10) Subclinical Atherosclerosis Common in Middle-Aged MarathonersATLANTA (EGMN) ?

Middle-aged male marathon runners may be at substantial
cardiovascular risk.



Jonathan Schwartz
A CT coronary angiography study of 25 middle-aged male runners, each of whom
had completed the Twin Cities Marathon in Minnesota annually for the past 25
consecutive years, demonstrated they had significantly greater mean volumes of
coronary calcified plaque (274 mm3) than did age-matched sedentary controls
(169 mm3) who underwent 64-slice CT angiography for a variety of clinical
indications, Dr. Jonathan Schwartz reported at the annual meeting of the
American College of Cardiology.
The marathoners also had higher coronary calcium scores and greater
noncalcified plaque volumes than did controls. These differences did not
achieve statistical significance, however. Still, the veteran marathoners were
no better off in these domains than were the sedentary controls, noted Dr.
Schwartz, an intern at the University of Colorado, Denver.
CAD risk might get overlooked in patients who are dedicated marathoners, the
investigators said. In a sense, completing a race or a hard training workout is
like passing an informal stress test. Also, high-mileage runners often have
excellent Framingham risk scores. Indeed, the avid Twin Cities marathoners had
favorable lipid profiles and low resting heart rates and body mass indexes. But
such presumptions can lead to a false sense of security about cardiovascular
health, as the CT angiography findings show.
?The bottom line here is just because you run a lot of marathons and you?re
very active doesn?t mean you?re protected from coronary artery calcification,?
Dr. Schwartz said in an interview. ?Benefits to long-term, high-volume
endurance training for overall health include favorable body mass index, heart
rate, and lipid panel, but these may be counterbalanced by metabolic and
mechanical factors that enhance coronary plaque growth.?
Dr. Jonathan Schwartz?s father and coinvestigator in the study was Dr. Robert
S. Schwartz of the Minneapolis Heart Institute. Dr. Robert Schwartz speculated
that avid distance runners may spend many hours training and racing under
metabolically demanding conditions.
They are tachycardic, in lactic acidosis, under oxidative stress, their blood
pressure is increased, and they are possibly leaking calcium into the blood
because of microtrauma to weight-bearing bones, he said. ?You can injure the
artery by smoking, or you can injure the artery by acidosis and hypertension.
Is it essentially the same common pathway? We don?t have an answer.?
He added that this study confirms earlier work by Dr. Stefan M?hlenkamp of the
University of Duisburg-Essen, Germany, who studied 108 apparently healthy
middle-aged German marathoners and found they had significantly higher coronary
artery calcium scores and significantly lower Framingham risk scores than did
age-matched controls. During 21 months of follow-up, four marathoners, all with
coronary artery calcium scores of 100 or more, experienced coronary events
(Eur. Heart J. 2008;29:1903-10).
Dr. Robert Schwartz noted that the Twin Cities Marathon veterans, many of whom
have completed numerous other marathons in addition to their 25 Twin Cities
finishes, are ?not your typical marathoner.? The investigators are expanding
their study to include women marathoners and younger veterans of fewer races.
Their study was funded by the Ken Rome Foundation. They reported having no
financial conflicts.
Elsewhere at the meeting, Dr. Despina Kardara reported that a group of Greek
marathoners had stiffer arteries than did age- and gender-matched controls.
The 49 marathoners, mean age 38, included 7 women. All had trained an average
of 15 hours per week for 11.6 years. Their mean pulse wave velocity ? a measure
of aortic stiffness ? was 6.9 meters per second, significantly greater than the
6.3 m/sec seen in controls who were not runners.
Although the marathoners? 60-bpm mean resting heart rate was 6 bpm lower than
in controls, their mean brachial blood pressure of 126/78 mm Hg was
significantly higher than the mean of 115/71 mm Hg for controls. The findings
raise the possibility that a long-time, high-volume, high-intensity exercise
training program may be harmful, according to Dr. Kardara of Athens Medical
School.
Her study was supported by the Athens Classic Marathon Organizing Committee.
She reported having no financial conflicts.

Source : univadis.it

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