Men who have trained for decades in marathons and endurance sports are more likely to have calcium deposits in their heart arteries than men who don't exercise much—even if they're otherwise healthy and have no heart disease risk factors.
Scientific Claim
Lifelong male endurance athletes with a low atherosclerotic risk profile have a higher prevalence of coronary artery plaques (44.3% vs. 22.2%) and more severe calcified plaques (CAC ≥300 Agatston units in 11.3% vs. 0%) compared to sedentary men of similar age and risk profile, suggesting endurance exercise may be associated with increased subclinical coronary atherosclerosis in this population.
Original Statement
“Male athletes had a higher prevalence of atherosclerotic plaques of any luminal irregularity (44.3% versus 22.2%; P=0.009) compared with sedentary males, and only male athletes showed a CAC ≥300 Agatston units (11.3%) and a luminal stenosis ≥50% (7.5%).”
Evidence Quality Assessment
Claim Status
appropriately stated
Study Design Support
Design supports claim
Appropriate Language Strength
association
Can only show association/correlation
Assessment Explanation
The observational cohort design cannot prove causation, and the authors correctly use associative language ('more likely to have') rather than causal claims. The verb strength is appropriate for the study type.
Gold Standard Evidence Needed
According to GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this specific claim, ordered from strongest to weakest evidence.
Systematic Review & Meta-AnalysisLevel 1aWhether the association between lifelong endurance exercise and coronary calcification is consistent across diverse populations and whether it predicts future cardiac events.
Whether the association between lifelong endurance exercise and coronary calcification is consistent across diverse populations and whether it predicts future cardiac events.
What This Would Prove
Whether the association between lifelong endurance exercise and coronary calcification is consistent across diverse populations and whether it predicts future cardiac events.
Ideal Study Design
A meta-analysis of 15+ prospective cohort studies including 50,000+ male and female endurance athletes (≥30 years of training, ≥10 marathons) and matched sedentary controls, with standardized CAC scoring, plaque morphology analysis, and 10-year follow-up for major adverse cardiac events.
Limitation: Cannot establish causation or rule out residual confounding from unmeasured lifestyle factors.
Prospective Cohort StudyLevel 2bIn EvidenceWhether higher cumulative endurance exercise dose predicts progression of coronary calcification over time in low-risk individuals.
Whether higher cumulative endurance exercise dose predicts progression of coronary calcification over time in low-risk individuals.
What This Would Prove
Whether higher cumulative endurance exercise dose predicts progression of coronary calcification over time in low-risk individuals.
Ideal Study Design
A 20-year prospective cohort of 2,000 healthy men aged 30–40, tracked with annual CAC scans, exercise logs, and biomarkers, comparing those who maintain >10 hrs/week endurance training vs. those who reduce to <5 hrs/week.
Limitation: Cannot isolate exercise effects from diet, genetics, or environmental exposures over decades.
Nested Case-Control StudyLevel 3bWhether calcified plaques in athletes are less likely to rupture than mixed plaques in sedentary individuals.
Whether calcified plaques in athletes are less likely to rupture than mixed plaques in sedentary individuals.
What This Would Prove
Whether calcified plaques in athletes are less likely to rupture than mixed plaques in sedentary individuals.
Ideal Study Design
A nested case-control study within a cohort of 10,000 athletes and controls, comparing 200 athletes with acute coronary events to 400 matched controls without events, analyzing plaque morphology via CT and histology from autopsies or interventions.
Limitation: Relies on rare clinical events and cannot capture subclinical progression.
Randomized Controlled TrialLevel 1bWhether increasing endurance exercise volume directly causes increased coronary calcification in healthy adults.
Whether increasing endurance exercise volume directly causes increased coronary calcification in healthy adults.
What This Would Prove
Whether increasing endurance exercise volume directly causes increased coronary calcification in healthy adults.
Ideal Study Design
A 10-year double-blind RCT of 500 healthy men aged 40–50 randomized to either 15 hrs/week endurance training (marathon-level) or 3 hrs/week moderate activity, with annual CAC scoring as primary outcome, controlling for diet and medication.
Limitation: Ethically and practically unfeasible due to long duration and difficulty blinding exercise exposure.
Evidence from Studies
Supporting (1)
This study found that older men who have trained for marathons for decades are more likely to have calcium deposits in their heart arteries than non-athletes, even if they’re otherwise healthy — which matches the claim that long-term endurance exercise may lead to more heart plaques.