Despite the increasingly sedentary nature of society, one participation sport that is thriving is long-distance running with approximately 2 million people participating in marathon or half-marathons in the United States annually. Tragically, this increase in participants has led to an increase in reports of race-related cardiac arrests and in this study by Kim et al the incidence and outcomes of cardiac arrests associated with long-distance running were explored.   The authors studied all marathon and half-marathon races in the USA between 2000 and 2010 in which a total of 10.9 million runners participated, and 59 (51 men) individuals suffered a cardiac arrest (incidence rate, 0.54 per 100,000 participants; 95% CI, 0.41 to 0.70). Using data from post-mortems and interviewing survivors, the vast majority of cases were found to have underlying cardiac disease with nearly half having HCM or probable HCM and nearly 20% having coronary disease. Risk of cardiac arrest was significantly higher in men (0.90 per 100,000; 95% CI, 0.67 to 1.18) than women (0.16; 95% CI, 0.07 to 0.31) and also significantly higher during marathons (1.01 per 100,000; 95% CI, 0.72 to 1.38) than half-marathons (0.27; 95% CI, 0.17 to 0.43) with the majority of arrests occurring during the final third of the race. HCM was associated with a particularly poor outcome and failed to respond to bystander CPR in the majority of cases. Interestingly, deaths from coronary disease did not appear to be from acute thrombosis secondary to plaque rupture but instead was due to demand ischemia in the presence of fixed coronary stenosis

Conclusions:

Marathons and half-marathons are associated with a low overall risk of cardiac arrest and sudden death. Cardiac arrest is most commonly attributable to hypertrophic cardiomyopathy or atherosclerotic coronary disease and occurs primarily among male marathon participants.

• Kim JH, Malhotra R, Chiampas G, d’Hemecourt P, Troyanos C, Cianca J, Smith RN, Wang TJ, Roberts WO, Thompson PD, Baggish AL; Race Associated Cardiac Arrest Event Registry (RACER) Study Group. Cardiac arrest during long-distance running races. N Engl J Med. 2012 Jan 12;366(2):130-40.