For athletes: Preventing, slowing the progression and reversing arterial calcification in athletes (CAC score).

The New Neander's Medical
A young health man is undergoing coronary artery calcium scan (CAC).

Last review and update: January 29, 2020.

  • Life-long exercise has a lot of benefits, but we need to figure out how to do it without accelerating atherosclerosis.
    Life-long exercise has a lot of benefits, but we need to figure out how to do it without accelerating atherosclerosis.
  • When he is 85, his biological age is 33. The "Optimal Phenotype" explained.
    Linear regression analysis comparing actual (chronological) and predicted (biological) age. Plots for women (A) and men (B) are derived from analysis of the data from Framingham study (n=4,509 males and n=4,839). “When he is 85, his biological age is 33. The “Optimal Phenotype” explained.”

To keep our definition of the “Optimal Phenotype” up to date and as a part of our consulting and educational work, we needed to take another look at the recent literature on atherosclerosis and arterial calcification in athletes.

Our findings are below. Some of the text was a part of our correspondence with our consulting clients.

Life-long endurance exercise, as well as other forms of exercise, do not protect against atherosclerosis and arterial calcification.

The majority of the available data show that life-long endurance exercisers maintain optimal levels of HDL-c and TG throughout their lives. Other substantial benefits include high VO2max, preserved metabolic fitness of skeletal muscles that last well into the eighth decade of life (Gries, 2018 (1)).

A majority of the published articles on the subject found that “masters” endurance athletes have relatively high levels of atherosclerosis and arterial calcification.

Even in relatively healthy life-long runners (33 years of endurance exercise), atherosclerosis and arterial calcification are higher than in matching relatively healthy controls (Merghani, 2017).

Also, life-long masters athletes who have more hours of weekly exercise tend to have more atherosclerotic plaques and more calcification (Aengevaeren, 2017).

A case study from a paper published by Mohlenkamp in 2007 is a good illustration of how a life-long marathon runner can have an overall good metabolic profile (low TG and high HDL) and advanced atherosclerosis and arterial calcification at the same time.

A life-long marathon runner can have a very good metabolic profile and advance atherosclerosis and arterial calcification at the same time. From Mohlenkamp, 2007.
A life-long marathon runner can have a very good metabolic profile and advance atherosclerosis and arterial calcification at the same time. From Mohlenkamp, 2007.

Endurance athletes may want to pay attention to an elevated level of hsCRP and relatively high fasting glucose (see the table above). Elevated levels of hsCRP and fasting glucose are quite common in mature endurance athletes.

Below, there are coronary angiogram and ultrasound histology images of the atherosclerotic lesions in the life-long marathon runner from the same 2007 study by Mohlenkamp.

Coronary angiogram demonstrating marked lumen reduction in the mid LAD and mid LCX (arrows). The right coronary artery showed no stenosis (not shown). Abbreviations: LAD, left anterior descending artery; LCX, left circumflex artery. From Mohlenkamp, 2007.
Coronary angiogram demonstrating marked lumen reduction in the mid LAD and mid LCX (arrows). The right coronary artery showed no stenosis (not shown). Abbreviations: LAD, left anterior descending artery; LCX, left circumflex artery. From Mohlenkamp, 2007.
Intravascular ultrasound virtual histology image of a single plaque in the left anterior descending artery, demonstrating a relatively high amount of necrotic core plaque component (14%), as marked in red. Fibrous tissue is marked in dark green (61%), fibro–fatty tissue (21%) in light green and calcified plaque in white (4%). The total plaque area at this nonculprit lesion site is 62%. Abbreviation: EEL, external elastic lamina. Mohlenkamp, 2007.
Intravascular ultrasound virtual histology image of a single plaque in the left anterior descending artery, demonstrating a relatively high amount of necrotic core plaque component (14%), as marked in red. Fibrous tissue is marked in dark green (61%), fibro–fatty tissue (21%) in light green and calcified plaque in white (4%). The total plaque area at this nonculprit lesion site is 62%. Abbreviation: EEL, external elastic lamina. Mohlenkamp, 2007.

The fact that life-long endurance training does not protect against arterial calcification is unexpected. According to Sanjay Sharma, MD, one of the authors of the study already mentioned above (Marghani, 2017), being a masters athlete in other sports does not protect against atherosclerosis either.

Surprisingly little effort is put into trying to identify the possible causes of increased atherosclerosis and calcification in masters endurance athletes and in athletes in general. This applies to the authors of recently published articles on the subject and to a majority of medical practitioners.

The recommendations to exercise (“lifestyle change”) and to take statins that a majority of medical doctors give to their patients with high cardiovascular risk can both accelerate arterial calcification.

A low carb diet may also accelerate arterial calcification.

Another common recommendation, a low carb diet, may also accelerate arterial calcification. If a person is in ketosis on a low carb diet, urinary loss of calcium will increase. Hypercalciuria, or an excessive loss of urinary calcium, while the dietary intake of calcium is insufficient to cover the loss, will result in a negative calcium balance. Parathyroid gland will become more active to compensate for increase calcium loss. Increased activity of parathyroid gland is another possible cause of soft tissue calcification. There are also several other potential causes of increased arterial calcification on a low carb diet.

Regarding statins, there is a 2018 study by Gries, Trappe (the senior author) and colleagues, that investigated the health of life-long exercisers with mean aged 74. The life-long exercisers in the “elite” group had good health markers, but as much as 57% of them were on cholesterol-lowering medication, that is on statins. The study authors did not prescribe medication to their subjects. The subjects, elite life-long exercisers, got their prescription for statins from their doctors. In this group, already prone to increased arterial calcification, statins most likely further accelerated calcification.

Exercise and physiological data in life-long exercisers in their eight decade of life. From Gries, 2018.
Exercise and physiological data in life-long exercisers in their eighth decade of life. From Gries, 2018.

In order to prevent or to slow the progression and even reverse atherosclerosis and arterial calcification, we need to identify the biomarkers that are most likely to be causative in accelerated progression of atherosclerosis. We need then to make sure that those biomarkers are maintained in the “safe” optimal ranges.

Exercise, an activity that provides multiple health benefits but is associated with a faster progression of atherosclerosis, needs to be practiced smartly.

Selected references:

1. Gries et al., J Appl Physiol125: 1636–1645, 2018.