Shaun sent this study:
Increased Coronary Artery Plaque Volume Among Male Marathon Runners, Missouri Medicine, March/April 2014
Background: This hypothesis, that long-term marathon running is protective against coronary atherosclerosis, was tested by quantitatively assessing coronary artery plaque using high resolution coronary computed tomographic angiography (CCTA) in veteran marathon runners compared to sedentary control subjects.
Methods: Men in the study completed at least one marathon yearly for 25 consecutive years. All study subjects underwent CCTA, 12-lead electrocardiogram, measurement of blood pressure, heart rate, and lipid panel. A sedentary matched group was derived from a contemporaneous CCTA database of asymptomatic healthy individuals.
Results: Male marathon runners (n = 50) as compared with sedentary male controls (n = 23) had increased total plaque volume (200 vs. 126 mm3, p < 0.01), calcified plaque volume (84 vs. 44 mm3, p < 0.0001), and non-calcified plaque volume (116 vs. 82 mm3, p = 0.04).
Conclusion: Long-term male marathon runners may have paradoxically increased coronary artery plaque volume.
How could this be?
“… an emerging body of scientific data suggests that chronic, excessive, high-intensity exercise may induce oxidative stress and myocardial fibrosis, accelerate atherosclerosis, increase vascular wall thickness, and increase cardiac chamber stiffness.”
So, what constitutes excessive? They cited the Copenhagen City Heart Study which followed 1,878 runners and 10,158 non-runners for up to 35 years. It uncovered a U-shaped curve … those who exercised too little and also too much had increased risk for mortality compared to moderate exercisers.
“… the benefits of running were most significant for those who jogged between 1 to 2.5 hours per week, at a slow to moderate pace, with a frequency of about three times per week. In those runners who were performing higher volume, higher intensity running, the long-term mortality rates were not significantly different from non-runners. In other words, excessive running may have abolished the remarkable improvements in longevity conferred by lower doses of running.”
One hour a week is less than 10 minutes a day. At a slow to moderate pace. That was the best for health and longevity. Wow.
It looks like running itself may damage blood vessels. But what about diet? You’ll note that both the marathoners and sedentary men had elevated LDL cholesterol (sedentary: 108 mg/dl, marathoners: 112), and, some would say, elevated total cholesterol (sedentary: 183 mg/dl, marathoners 186). All that running may have been whittling away their weight, but it wasn’t whittling away their cholesterol.
As Dr. Esselstyn famously showed,1 cholesterol is strongly impacted by diet:
“After 5 years on Dr. Esselstyn’s plant-based diet, the average total cholesterol levels of his research group dropped from 246 milligrams per deciliter to 137 mg/dL This is the most profound drop in cholesterol ever documented in the medical literature in a study of this type.”
The Wall Street Journal covered this study and similar ones in Why Runners Can’t Eat Whatever They Want, Studies Show There Are Heart Risks to Devil-May-Care Diets—No Matter How Much You Run, and included this quote from the editor of Runner’s World:
“Ambrose Burfoot, winner of the 1968 Boston Marathon and editor-at-large of Runner’s World magazine, is 67 years old, 6 feet tall and only 147 pounds. A lifelong vegetarian, he subsists mostly on fruits, vegetables and nuts, though he also eats “cookies and all dairy products—cheeses, ice creams etc.,” he wrote in an email.
“Last March I learned that I have a very high coronary calcium,” he said.”
I know several vegetarians with high cholesterol, over 200 mg/dl. A good chunk of their calories come from animal foods – eggs, butter, cheese, yogurt, and other dairy products. “I have to get my protein,” they tell me. Dr. Esselstyn found that when his patients dropped the dairy, their cholesterol dropped along with it.
It may very well be, as Shaun says, that you can’t run from your diet.
By the way, the technology used to measure plaque, coronary computed tomographic angiography (CCTA), was referred to as “noninvasive.” Not true. All radiation is invasive. This report by the National Academies Press says that all ionizing radiation damages cells. There is no level of exposure below which damage to a cell does not occur.
1Prevent and Reverse Heart Disease, January 2008