The original cardio causes heart disease post is still one of the most-linked and viewed on the blog
Now reader Ben has alerted me to this article on a presentation given at the ACC (American College of Cardiology) meeting.
ATLANTA -- A group of elite long-distance runners had less body fat, better lipid profiles, and better heart rates than people being tested for cardiac disease, but, paradoxically, the runners had more calcified plaque in their heart arteries, according to a study reported here.
Investigators performed computed tomography angiography on 25 people who had run at least one marathon a year since 1985, according to senior author Robert Schwartz, MD, of the Minneapolis Heart Institute and Foundation. They compared the athletes with 23 control patients who were undergoing the same scan for symptomatic or suspected heart abnormalities.
In controls, the calcium plaque volume was 169 mm3compared with 274 mm3 for the elite runners (P=0.028), the researchers reported at the American College of Cardiology meeting. The runners also had a higher calcium score and higher noncalcified plaque volume, although those differences did not reach statistical significance.
So if you recall, in the German study I wrote about in Cardio Causes Heart Disease, they found that there was more myocardial damage (actual heart attacks) in runners than "risk factor" matched controls and about the same compared to age and sex matched controls.
Meaning; a given runner in the German study could be predicted to be more likely to have had a heart attack by MRI than a person with the same age height weight , smoking history, etc., who was sedentary. Take two subjects who otherwise look the same from a risk standpoint (which we know is kind of worthless anyway) and the sedentary one is more likely to have healthy coronary arteries.
And if compared to a person of the same age and sex, the runners in the German study had about the same chance of having had a heart attack, but this was despite being less likely to be obese, hypertensive, smoke. etc., all those things that cardiologists tell us "cause" heart attacks.
Now we have a group on a different continent, only 7 hours away from me in Minnestoa, who read the German study, and sought to replicate it using CCTA.
Sidebar: CCTA is coronary CT angiography - this is actually a two part test where a CAC or coronary artery calcium score is first assessed, then contrast is given so the inside of the coronary arteries can be seen - this two step test allows both calcified plaque and non-calcified plaque that is invisible on a simple CAC test to be evaluated
They did this CCTA on 25 marathon runners they recruited, and compared them to 23 age and sex matched controls and it looks like the runners had more coronary atherosclerosis than the controls by all three numerical parameters of the CAC part of the exam. Only the plaque volume reached statistical significance, though.
Some things to note:
This is a tiny study. To get statistical significance with this few patients is, well, perhaps significant (clinically)
Read the bit about the controls:
"...control patients who were undergoing the same scan for symptomatic or suspected heart abnormalities.
Did you catch that?
The control population was not asymptomatic normal volunteers, it was drawn from people who had symptoms (chest pain and shortness of breath, etc.) or who had symptoms and had a previously abnormal test - usually a test known as MPI - or nuclear medicine myocardial perfusion imaging - usually called a "stress test" in the vernacular. How do I know this if the abstract does not say this? I do these exams every week at my imaging center, so I know why they are done.
So the controls came from a population that has (Bayes theorem here) a much higher a priori probability of having coronary disease than average, and yet the runners still beat them in having more evidence of coronary atherosclerosis.
That is really very impressive, and not in a good way. I'll do a longer post when the paper is published.
My three hypotheses all remain viable:
Weak form: Chronic Steady state aerobic training* (CSSAT) does nothing to prevent or reverse atherosclerosis
Mild Form: Some effects of CSSAT may be beneficial or neutral, but they are overridden by the inflammation promoting effects of the diets favored by those who train this way.
Strong Form: CSSAT itself promotes the inflammatory state via cortisol, cytokines, inadequate recovery, etc.
* I am using the word training to include both the weekly running and the long events, as it is impossible so far to distinguish the two
PS - If anyone has access to the actual abstract or has seen the presentation, maybe you can forward that to me..
Here is the title:
Schwartz J, et al "Does longterm endurance running enhance or inhibit coronary artery plaque formation? A prospective multidetector CTA study of men completing marathons for least 25 consecutive years" ACC 2010; Abstract 1271-330.