Medial arterial calcification (MAC) is an under-recognized vascular condition that remains poorly characterized from an epidemiological perspective. In the general population, its estimated prevalence is approximately 2.5%, mainly based on ankle-brachial index measurements. In contrast, prevalence exceeds 10% in high-risk populations such as patients with diabetes, chronic kidney disease, or established cardiovascular disease, with wide variability depending on the diagnostic method used.

In these populations, MAC is associated with adverse clinical outcomes, including critical limb ischemia, major amputation, and increased cardiovascular mortality, sometimes exceeding the prognostic impact of atherosclerosis. However, data on MAC in healthy individuals are currently lacking, and its clinical significance in this population remains unknown.

Endurance athletes represent a unique population exposed to prolonged and intense hemodynamic stress. Previous studies have reported increased coronary artery calcification in athletes with very high levels of physical activity, and differences according to sporting discipline. Incidental findings of MAC have also been observed in endurance athletes, raising the question of a potential association with training volume and vascular adaptations to long-term exercise.

The objective of this study is to assess the prevalence of medial arterial calcification in endurance athletes using ultrasound imaging, and to explore its relationship with training characteristics and cardiovascular risk markers.

Inclusion Criteria:

• Healthy volunteer attending a sports medicine consultation for the performance of an exercise stress test*.
• Male or female subject.
• Age between 18 and 70 years, inclusive.
• High-level endurance athlete, with regular practice of endurance sports (trail running, road running, cycling, swimming, cross-country skiing, biathlon), with a MET-min/week > 2000, corresponding to more than 5 hours of vigorous physical activity per week, for more than 10 years.
• Affiliated with a social security system.
• No objection to participation in the study. * Undergoing a lower limb arterial ultrasound examination as part of routine clinical care.

Exclusion Criteria:

• Participants with type 1 or type 2 diabetes mellitus.
• Participants with chronic kidney disease, defined as an estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m².
• Resting arterial hypertension.
• Established cardiovascular disease (coronary artery disease, stroke, or peripheral arterial disease).
• Protected or vulnerable populations as defined by French Public Health Code articles L1121-5 to L1121-8, including:

pregnant or breastfeeding women, women in labor, individuals deprived of liberty by judicial or administrative decision, individuals receiving psychiatric care under articles L.3212-1 and L.3213-1, individuals admitted to healthcare or social institutions for purposes other than research, minors, individuals under legal protection, or individuals unable to provide informed consent.

Healthy endurance athletes volunteering for the study, engaging in more than 5 hours of high-intensity endurance exercise per week for at least the past 10 years.