Cardiovascular Adaptations in Triathlon

  • Sanjay SharmaEmail author
  • Maximiliano Moreira Accame


Regular physical activity has a positive impact on general health and well-being. The volume and the intensity of training undertaken by competitive athletes, particularly those engaging in endurance sports, including the triathlon, is between 10- to 20-fold higher than the current recommendations for the general population. Such athletes develop a constellation structural and functional adaptations within the heart (“athlete’s heart”) that permit the generation of a large and sustained increase in cardiac output for prolonged periods and also impact on the surface 12-lead ECG.

Sinus bradycardia, first-degree atrioventricular (AV) block, voltage criteria for ventricular hypertrophy and incomplete right bundle branch block are common electrical manifestations in endurance athletes. Up to 50% of endurance athletes have a ventricular cavity dimensions that exceed the upper limit of normal, and a proportion of large males may reveal a left ventricular end diastolic diameter >60 mm. Occasionally structural adaptations may overlap with those observed in individuals with cardiomyopathy.

Sudden death is a very rare event in triathlons but usually affects males and most commonly occurs in the swim section. Deaths may be due to an inherited or genetic cardiac abnormality in young (<35-year-old) athletes and atherosclerotic coronary artery disease in older athletes.

The impact of life-long participation in endurance exercise on an otherwise normal heart is unclear, but there is emerging evidence that male endurance athletes who have been competing for several years have a higher prevalence of atrial fibrillation. A small proportion of studies have also shown a higher prevalence of myocardial scar.


Athletes Athlete’s heart Endurance sports Cardiovascular adaptation Sudden cardiac death 


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© Springer Nature Switzerland AG 2020

Authors and Affiliations

  1. 1.Cardiology Clinical and Academic GroupSt. George’s, University of LondonLondonUK
  2. 2.Emergency MedicineUniversity of Costa RicaSan JoséCosta Rica

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