Transient myocardial tissue and function changes during a marathon in less fit marathon runners

Area of Science:

• Cardiology
• Sports Medicine
• Exercise Physiology

Background:

• Regular physical activity benefits health.
• Strenuous exercise may transiently elevate cardiac risk.
• Training and fitness may offer cardioprotection.

Purpose of the Study:

• To investigate myocardial changes in recreational marathon runners.
• To assess the impact of marathon running on cardiac function, edema, perfusion, and fibrosis.
• To determine the reversibility of exercise-induced cardiac alterations.

Main Methods:

• Prospective study of 20 recreational marathon runners.
• Cardiac assessment before, immediately after, and 3 months post-marathon.
• Measurement of global/segmental myocardial function, edema, perfusion, and fibrosis.

Main Results:

• Marathon completion led to decreased ejection fraction in 50% of runners, associated with lower training volume and fitness.
• Significant myocardial edema (36%), decreased function (53%), and perfusion (59%) were observed.
• These myocardial changes were reversible by 3 months post-marathon.

Conclusions:

• Marathon running induces reversible myocardial edema, reduced perfusion, and impaired function.
• Less trained and fit runners experienced more extensive cardiac changes.
• These transient changes may explain the increased cardiac risk associated with sustained strenuous exercise.