Cardiac Function and Remodeling in Endurance Athletes

Endurance training induces a characteristic pattern of cardiac adaptation known as the athlete’s heart, encompassing balanced enlargement of left and right ventricles, mild concentric or eccentric left ventricular hypertrophy and enhanced diastolic filling. These morphological changes translate into an augmented stroke volume and lower resting heart rate, optimising oxygen delivery during prolonged exercise. At the cellular level, hypertrophy predominantly reflects an increase in myocyte mass rather than extracellular expansion, while advanced imaging has revealed focal and diffuse alterations in myocardial tissue composition. Late gadolinium enhancement and T1 mapping by cardiac magnetic resonance have detected non-ischaemic fibrosis, often at ventricular insertion points, raising questions about its clinical significance and its differentiation from cardiomyopathic processes. Atrial structure and function also remodel, with increased chamber volumes and modified strain patterns that may relate to arrhythmia susceptibility. Emerging evidence highlights sex- and age-related differences in cardiac response, emphasising the need for tailored diagnostic thresholds. Understanding these adaptations is critical for accurate pre-participation screening, longitudinal athlete care and informing safe exercise recommendations on a global scale.

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Cardiac Function and Remodeling in Endurance Athletes publication trend

The graph below shows the total number of articles in cardiac function and remodeling in endurance athletes across all publications each year (not limited to Nature Index journals).

Technical terms

Athlete’s heart: The constellation of structural, functional and electrical cardiac adaptations resulting from sustained intensive endurance training.

Cardiac magnetic resonance (CMR): A non-invasive imaging technique that provides high-resolution assessment of cardiac morphology, function and tissue composition.

Late gadolinium enhancement (LGE): A CMR method that highlights focal myocardial fibrosis by showing regions of delayed contrast washout.

Extracellular volume (ECV): A quantitative CMR parameter estimating the proportion of myocardium occupied by extracellular space, used to detect diffuse fibrosis.

Ejection fraction (EF): The percentage of blood volume expelled from a ventricle with each heartbeat, reflecting systolic performance.

Myocardial fibrosis: The accumulation of collagen in the myocardial interstitium or replacement of cardiomyocytes, which can alter mechanical properties and electrical conduction.

References

1. Prognostic Relevance of Ischemic Late Gadolinium Enhancement in Apparently Healthy Endurance Athletes: A Follow-up Study Over 5 years. Sports Medicine - Open (2024).
2. Athletic Cardiac Adaptation in Males Is a Consequence of Elevated Myocyte Mass. Circulation Cardiovascular Imaging (2016).
3. Sex Matters: A Comprehensive Comparison of Female and Male Hearts. Frontiers in Physiology (2022).
4. Prevalence and pattern of cardiovascular magnetic resonance late gadolinium enhancement in highly trained endurance athletes. Journal of Cardiovascular Magnetic Resonance (2020).
5. Myocardial fibrosis in athletes—Current perspective. Clinical Cardiology (2020).
6. Relation between cardiac dimensions and peak oxygen uptake. Journal of Cardiovascular Magnetic Resonance (2010).
7. Left atrial function in elite athletes: A meta‐analysis of two‐dimensional speckle tracking echocardiographic studies. Clinical Cardiology (2019).