I reviewed the study (link shown earlier) and the conclusions are misleading and narrowly focused. 1. Coronary artery blockage doesn't become a major problem until >95% (or so), so having slightly more than average buildup by age 50-60 is not indicative of a health issue. 2. The study did not measure running. Instead it awarded credits for strenuous exercise. A roofer might fall into the >7.5 hrs/week category, for example, yet not be able to run from his mailbox to the house. 3. Other factors, such as increased diameter of coronaries due to endurance exercise, might offset increased subclinical buildup.
Earlier evidence has suggested that, physiologically, elite ultra-endurance athletes have increased diameter and dilation of the coronaries,45, 50 partly due to adaptations of the vascular structure, and possibly an increase in the caliber or number of resistance arterioles.50 So, although there can be increased atherosclerosis in endurance athletes compared with sedentary males with a similar risk profile,41 it may not necessarily translate into adverse clinical outcomes due to the presence of enlarged coronary artery size and dilatory capacity.
4. The study did not measure heart attacks or coronary artery disease. It only measured an indicator that MIGHT raise the risk of these issues.
5. The study was very narrow in focus. As a result, it did not measure the health benefits endurance runners might gain that might offset the slight buildup in plaque... lower BMI, reduced prevalence of diabetes, reduced hypertension
In my opinion, there is a greater risk of diseases in older runners that are exacerbated by a stressed immune system. In my circle of 55+ Boston Qualifiers, there seems to be a greater prevalence of diseases impacted by an impaired immune system. My 55+ recreational marathoner friends don't seem to have an increased frequency of these diseases.