Marathon run: cardiovascular adaptation and cardiovascular risk

Abstract

The first marathon run as an athletic event took place in the context of the Olympic Games in 1896 in Athens, Greece. Today, participation in a 'marathon run' has become a global phenomenon attracting young professional athletes as well as millions of mainly middle-aged amateur athletes worldwide each year. One of the main motives for these amateur marathon runners is the expectation that endurance exercise (EE) delivers profound beneficial health effects. However, with respect to the cardiovascular system, a controversial debate has emerged whether the marathon run itself is healthy or potentially harmful to the cardiovascular system, especially in middle-aged non-elite male amateur runners. In this cohort, exercise-induced increases in cardiac biomarkers-troponin and brain natriuretic peptide-and acute functional cardiac alterations have been observed and interpreted as potential cardiac damage. Furthermore, in the cohort of 40- to 65-year-old males engaged in intensive EE, a significant risk for the development of atrial fibrillation has been identified. Fortunately, recent studies demonstrated a normalization of the cardiac biomarkers and the functional alterations within a short time frame. Therefore, these alterations may be perceived as physiological myocardial reactions to the strenuous exercise and the term 'cardiac fatigue' has been coined. This interpretation is supported by a recent analysis of 10.9 million marathon runners demonstrating that there was no significantly increased overall risk of cardiac arrest during long-distance running races. In conclusion, intensive and long-lasting EE, e.g. running a full-distance Marathon, results in high cardiovascular strain whose clinical relevance especially for middle-aged and older athletes is unclear and remains a matter of controversy. Furthermore, there is a need for evidence-based recommendations with respect to medical screening and training strategies especially in male amateur runners over the age of 35 years engaged in regular and intensive EE.

Myocardial Adaptation in Response to Marathon Training

“…This is supported by echocardiographic studies shortly before and after a marathon showing usually small and transient right or biventricular systolic and diastolic functional impairment, 8,9 but no sustained short-or medium-term myocardial dysfunction. 10,11 Furthermore, a 9-year follow-up of 114 young (age, 22±4 years) Olympic athletes with evidence of physiological cardiac remodeling (athlete's heart) at baseline demonstrated no evidence of abnormalities in global or regional left ventricular structure and function and cardiovascular symptoms or events. 12 In this issue of Circulation: Cardiovascular Imaging, Zilinski et al 13 addressed the potential cardiovascular health benefits of marathon training in 45 middle-aged apparently healthy male recreational (nonelite) athletes.…”

The Prevalence of High Blood Pressure among Marathon Runners during Beirut-Marathon 2014

“…Endurance events such as marathon running may also have health benefits; however, the incidences of sudden cardiac deaths that have occurred during marathons imply an element of risk as well [6] [7] [8]. During aerobic exercise, Systolic BP increases as the exercise intensity increases.…”

Exercise dose in clinical practice: Should safety limits be set?

“…Atrial fibrillation (AF) is the most frequent arrhythmia in athletes. In the cohort of 40-to 65-year-old males who trained intensively, a significant risk for the development of AF has been identified [3]. Although yet, there has been no consensus as yet to whether a link between left atrial size and the occurence of supraventricular arrhythmias in athletes exists, the accumulated lifetime activity and the size of left atrium were reported as risk factors for lone AF [4].…”